Weather

NHC Atlantic Tropical Weather Discussion

NWS Weather - 4 hours 42 min ago

000
AXNT20 KNHC 222345
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
744 PM EDT Sun Oct 22 2017

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2315 UTC.

...SPECIAL FEATURES...
A cold front is currently analyzed across the NW Gulf waters from
the SW coast of Louisiana near 30N93W to the Texas coast near
Corpus Christi. The front is forecast to sweep across the Gulf
through Monday night with near gale to gale force N to NW winds
expected to materialize S of 21N W of 95W by 23/1800 UTC and
persist for 12 hours as the pressure gradient remains strong.
Please see the latest NWS High Seas Forecast under AWIPS/WMO
headers MIAHSFAT2/FZNT02 KNHC for more details.

...TROPICAL WAVES...
A tropical wave extend from 06N51W to 17N48W moving W at 5-10 kt.
The wave coincides with 700 mb troughing between 42W-52W and a
maximum in 850 mb relative vorticity to the east of the axis near
11N47W. Scattered moderate convection is from 07N-17N between
38W-50W and continues to be enhanced by a middle to upper level
trough with axis extending from 25N40W SW to a broad base over
northern Guyana.

A tropical wave extend from 10N89W to 20N89W moving W at 10-15
kt. The wave coincides with 700 mb troughing between 84W-94W and a
maximum in 850 mb relative vorticity along the wave axis near 18N.
Scattered moderate convection is from 12N-23N between 85W-92W.

...ITCZ/MONSOON TROUGH...
The monsoon trough extends from the African coast near 10N14W to
08N20W. The Intertropical Convergence Zone axis extends from 08N20W
to 04N40W to 06N50W. Isolated moderate convection is from 03N-06N
between 13W-18W.

...DISCUSSION...

GULF OF MEXICO...
A vigorous middle to upper level trough is progressing eastward
over the lower Mississippi River valley this evening and supports
a cold front extending from the Arklatex region to the SW
Louisiana coast near 30N93W to the Texas coast near Corpus Christi
then inland across northern Mexico. A leading outflow boundary
extends east of the cold front from 30N90W to 28N92W to 27N97W.
Low-level moisture convergence and middle to upper level
divergence is generating scattered showers and tstms primarily
across the eastern Gulf waters N of 25N between 82W-90W.
Additional isolated showers are occurring N of 25N W of 90W.
Farther south...the northern extent of a tropical wave along 90W
is providing focus for scattered showers and tstms S of 24N
between 83W-96W. Most of this convection is also enhanced due to
upper level divergence on the northern periphery of an upper level
ridge centered over the NW Caribbean Sea near 20N85W. Otherwise...
the cold front is expected to sweep across the basin through
Tuesday. As the front passes across the western Gulf...the Special
Features near gale to gale force winds are anticipated within a
broader fresh to strong northerly wind field that will spread
eastward in wake of the front. Strong high pressure will settle
in across the southern Plains and move out across the western Gulf
by Wednesday night into Thursday.

CARIBBEAN SEA...
The combination of a tropical wave along 90W...a surface trough
extending from the Gulf of Honduras SW to the offshore waters of
Nicaragua near 12N83W...and a favorable upper level divergent
environment over much of the western Caribbean anchored near
19N84W are supportive of scattered showers and strong tstms
occurring W of a line from western Cuba through 17N80W to northern
Colombia coast near 11N74W...including much of Central America.
Most of the western Caribbean falls within moderate to fresh
trades while farther east...fresh to strong trades prevail as a
strong pressure gradient remains in place due to strong high
pressure anchored across the western North Atlc.

...HISPANIOLA...
Dry air aloft within NW flow will support fair weather across the
island through Monday. Fresh to strong trades are expected through
Monday night and will diminish into moderate to occasional fresh
levels on Tuesday.

ATLANTIC OCEAN...
Much of the SW North Atlc is under the influence of a surface
ridge anchored by 1034 mb high centered over the Canadian
Maritimes near 47N64W. The southern periphery of this ridge is
providing moderate to fresh E-SE winds W of 65W. Farther east...an
upper level low is centered near 26N64W. In addition...a longwave
trough over the central North Atlc is supporting a cold front from
32N45W SW to 30N50W then becomes a stationary front to near the
upper level low around 28N63W. Scattered showers and isolated
tstms are occurring within 150 nm either side of the front...and
from 22N-30N between 60W-66W in association with the upper level
low. The remainder of the eastern Atlc is under the influence of
another surface ridge anchored by a 1030 mb high centered W of the
Iberian peninsula near 40N14W.

For additional information please visit
http://www.hurricanes.gov/marine

$$
HUFFMAN

Categories: Weather

SPC Day 2 Fire Weather Outlook

Weather - Fire Weather - 8 hours 29 min ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Sun Oct 22 2017 Valid 231200Z - 241200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN CALIFORNIA... ...Portions of southeastern Montana to northwest Kansas and vicinity... The Day 2/Monday Elevated fire weather area has been expanded farther southeast into portions of western Nebraska, far northeast Colorado, and northwest Kansas. The extension was made to account for the latest fuel guidance, which indicates increasingly receptive fuels across these areas (mainly fine fuels). This is especially true across northwest Kansas and far southwest Nebraska, where AHPS data suggests little meaningful precipitation over the last 14 days. Otherwise, similar meteorological conditions are expected across the entire Elevated area. See previous discussion below for information on the expected meteorological conditions. ...Southern California... Forecast of Elevated/Critical conditions is on track across this area. Thus, no changes to the ongoing forecast are needed. See previous discussion below for more information on tomorrow's fire weather threat over southern California. ..Elliott.. 10/22/2017 .PREV DISCUSSION... /ISSUED 0226 AM CDT Sun Oct 22 2017/ ...Synopsis... Expansive high pressure will persist across the Intermountain West, with a 1041mb high centered over Idaho late in the forecast period. To the east of this anticyclone, a strong surface low near the Great Lakes will set up a favorable surface pressure gradient for gusty winds in portions of the northern and central Plains. Southwest of the high, a persistent "offshore" pressure gradient will foster gusty winds and heightened fire weather concerns in portions of southern California. ...Coastal Ranges of southern California... The overall fire weather scenario will change very little compared to previous days. The aforementioned surface pressure gradient across the area will support widespread 15-25 mph surface winds, with gusts exceeding 40 mph especially near terrain-favored areas. Hot surface temperatures will occur during peak-heating hours, with 90s to near 100F expected amidst 7-12% surface RH values. Widespread elevated to critical fire weather conditions are likely, with at least elevated conditions persisting well into the overnight hours due to continued gusty winds and poor recovery. ...Portions of the High Plains from southeastern Montana to western Nebraska... Although surface temperatures will be relatively cool during peak-heating hours (50s F), 25-35 mph northwesterly flow (with higher gusts) will develop during the afternoon in response to the aforementioned surface pressure gradient across the region. RH values will remain mostly above critical thresholds and range from 22-28%. These conditions are consistent with elevated fire weather criteria and an attendant delineation has been made. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
Categories: Weather

SPC Day 2 Fire Weather Outlook

Weather - Fire Weather - 8 hours 29 min ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Sun Oct 22 2017 Valid 231200Z - 241200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN CALIFORNIA... ...Portions of southeastern Montana to northwest Kansas and vicinity... The Day 2/Monday Elevated fire weather area has been expanded farther southeast into portions of western Nebraska, far northeast Colorado, and northwest Kansas. The extension was made to account for the latest fuel guidance, which indicates increasingly receptive fuels across these areas (mainly fine fuels). This is especially true across northwest Kansas and far southwest Nebraska, where AHPS data suggests little meaningful precipitation over the last 14 days. Otherwise, similar meteorological conditions are expected across the entire Elevated area. See previous discussion below for information on the expected meteorological conditions. ...Southern California... Forecast of Elevated/Critical conditions is on track across this area. Thus, no changes to the ongoing forecast are needed. See previous discussion below for more information on tomorrow's fire weather threat over southern California. ..Elliott.. 10/22/2017 .PREV DISCUSSION... /ISSUED 0226 AM CDT Sun Oct 22 2017/ ...Synopsis... Expansive high pressure will persist across the Intermountain West, with a 1041mb high centered over Idaho late in the forecast period. To the east of this anticyclone, a strong surface low near the Great Lakes will set up a favorable surface pressure gradient for gusty winds in portions of the northern and central Plains. Southwest of the high, a persistent "offshore" pressure gradient will foster gusty winds and heightened fire weather concerns in portions of southern California. ...Coastal Ranges of southern California... The overall fire weather scenario will change very little compared to previous days. The aforementioned surface pressure gradient across the area will support widespread 15-25 mph surface winds, with gusts exceeding 40 mph especially near terrain-favored areas. Hot surface temperatures will occur during peak-heating hours, with 90s to near 100F expected amidst 7-12% surface RH values. Widespread elevated to critical fire weather conditions are likely, with at least elevated conditions persisting well into the overnight hours due to continued gusty winds and poor recovery. ...Portions of the High Plains from southeastern Montana to western Nebraska... Although surface temperatures will be relatively cool during peak-heating hours (50s F), 25-35 mph northwesterly flow (with higher gusts) will develop during the afternoon in response to the aforementioned surface pressure gradient across the region. RH values will remain mostly above critical thresholds and range from 22-28%. These conditions are consistent with elevated fire weather criteria and an attendant delineation has been made. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
Categories: Weather

NHC Atlantic Tropical Weather Discussion

NWS Weather - 11 hours 15 min ago

000
AXNT20 KNHC 221711
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
111 PM EDT Sun Oct 22 2017

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1200 UTC surface analysis and satellite imagery through
1600 UTC.

...SPECIAL FEATURES...

High pressure building behind a cold front moving off the Texas
coast tonight will tighten the pressure gradient along the
Veracruz coast of southern Mexico, and induce gale force winds
south of 21N west of 95W Monday afternoon through Tuesday
morning.

...TROPICAL WAVES...

A tropical wave has an axis extending from around 21N48W to
09N49W, moving westward at around 10 kt. The wave is embedded in a
700 mb trough between 44W and 51W, and coincides with a poleward
surge in low to mid level moisture. Widely scattered moderate
convection is from 08N to 16N within 500 nm east of the wave axis.

A tropical wave has moved inland from the Caribbean and now
extends from the Yucatan Peninsula to El Salvador to the Eastern
Pacific. The wave is separating from a surface trough being left
behind over the Gulf of Honduras. This wave is clearly defined in
700 mb wind fields. Scattered moderate convection is from 16N to
22N between 85W and 90W.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends across the African coast near 10N14W
to 07N20W, where it transitions to the ITCZ that extends to 04N40W
to 08N60W. Isolated moderate convection is from 03N to 07N
between 10W and 16W, and from 07N to 13N between 50W and 63W.

...DISCUSSION...

GULF OF MEXICO...

Atlantic high pressure supports moderate to fresh southeast winds
over the eastern Gulf. The flow becomes more southerly and gentle
to moderate over most of the western Gulf under a weaker pressure
pattern. An outflow boundary that as of 1500 UTC emerged off the
the eastern Texas and Louisiana coasts is producing numerous
thunderstorms, with fresh to locally strong northerly winds behind
the boundary. A diffluent upper level pattern over the eastern
Gulf supports numerous showers and scattered thunderstorms south
of 29N, east of 90W. Over the next 24 hours showers and
thunderstorms will fill in over the northern gulf ahead of an
approaching cold front. The cold front will emerge off the Texas
coast tonight, and reach from the Florida Panhandle to the SW Gulf
by Monday afternoon. Gale force winds are expected off the coast
of Veracruz, Mexico by tomorrow afternoon behind this cold front.
Please see the special features section for more details regarding
this gale.

CARIBBEAN SEA...

A tropical wave has moved inland over the Yucatan Peninsula and
central America. As of 1500 UTC, a new trough has been analyzed
over the Gulf of Honduras. The combination of the departing wave
and the trough supports convection over the northwestern
Caribbean. The eastern extent of the E Pacific monsoon trough over
Costa Rica is producing scattered moderate and isolated strong
convection S of 16N over the southwestern Caribbean. Strong
subsidence and dry air is inhibiting convection over the north
central and eastern Caribbean today. High pressure over the
western Atlantic supports fresh to strong easterly winds over much
of the central Caribbean. Over the next 24 hours convection will
continue over the western Caribbean. Winds will decrease slightly
over the basin as the high to the north weakens.

...HISPANIOLA...

Dry air will support fair weather over the island through at
least Monday. Strong trades across the western half of the island
will weaken to under 20 kt by late Monday.

ATLANTIC OCEAN...

A cold front enters the area of discussion near 31N47W and extends
to 30N51W, where it transitions to a weakening stationary front to
near 27N63W. The combination of the frontal boundary and an upper
low centered near 26N64W supports scattered moderate convection
from 23N to 31N between 59W and 65W, and within 120 nm north of
the stationary front east of 59W. High pressure centered offshore
New England and another high centered east of the Azores dominate
the remainder of the Atlantic discussion waters. Aside from the
stationary portion of the front dissipating, little change is
expected over the next 24 hours.

For additional information please visit
http://www.hurricanes.gov/marine

$$
Latto
Categories: Weather

SPC Day 1 Fire Weather Outlook

Weather - Fire Weather - 11 hours 25 min ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1200 PM CDT Sun Oct 22 2017 Valid 221700Z - 231200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN CALIFORNIA... ...Portions of eastern Wyoming, northwest Nebraska, and the Dakotas... An Elevated fire weather area has been introduced across the Northern Plains and vicinity. This is supported by 16Z surface observations, which are already indicating several pockets of RH values around 20-25% in conjunction with sustained surface winds around 15-20 mph. Additionally, latest hi-resolution guidance suggests continuation/expansion of these conditions across the Elevated area through late afternoon in areas where fuels (especially fine fuels) are at least marginally receptive. ...Southern California... No changes to the ongoing forecast are needed. See previous discussion below for more information on today's fire weather threat over Southern California. ..Elliott.. 10/22/2017 .PREV DISCUSSION... /ISSUED 0224 AM CDT Sun Oct 22 2017/ ...Synopsis... The primary synoptic features of interest are 1) an expansive area of high pressure in the Great Basin an Intermountain West and 2) a weak surface trough along the California coast. A synoptically evident fire weather scenario will evolve throughout the forecast period as the surface pressure gradient between these two systems fosters strong, dry offshore flow across parts of southern California. ...Coastal Ranges of Southern California... An extended period of gusty north to northeasterly low-level flow will persist throughout the day across the delineated fire weather threat areas. 15-25 mph surface winds (with gusts to 50 mph in terrain-favored areas) will persist throughout the day. Daytime heating will aid in increasingly warm surface temperatures (perhaps rising into the low 90s) along with RH values falling to around 10-15%. At least elevated fire weather conditions will persist into the overnight hours due to persistently gusty winds and poor overnight recovery. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
Categories: Weather

SPC Day 1 Fire Weather Outlook

Weather - Fire Weather - 11 hours 25 min ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1200 PM CDT Sun Oct 22 2017 Valid 221700Z - 231200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN CALIFORNIA... ...Portions of eastern Wyoming, northwest Nebraska, and the Dakotas... An Elevated fire weather area has been introduced across the Northern Plains and vicinity. This is supported by 16Z surface observations, which are already indicating several pockets of RH values around 20-25% in conjunction with sustained surface winds around 15-20 mph. Additionally, latest hi-resolution guidance suggests continuation/expansion of these conditions across the Elevated area through late afternoon in areas where fuels (especially fine fuels) are at least marginally receptive. ...Southern California... No changes to the ongoing forecast are needed. See previous discussion below for more information on today's fire weather threat over Southern California. ..Elliott.. 10/22/2017 .PREV DISCUSSION... /ISSUED 0224 AM CDT Sun Oct 22 2017/ ...Synopsis... The primary synoptic features of interest are 1) an expansive area of high pressure in the Great Basin an Intermountain West and 2) a weak surface trough along the California coast. A synoptically evident fire weather scenario will evolve throughout the forecast period as the surface pressure gradient between these two systems fosters strong, dry offshore flow across parts of southern California. ...Coastal Ranges of Southern California... An extended period of gusty north to northeasterly low-level flow will persist throughout the day across the delineated fire weather threat areas. 15-25 mph surface winds (with gusts to 50 mph in terrain-favored areas) will persist throughout the day. Daytime heating will aid in increasingly warm surface temperatures (perhaps rising into the low 90s) along with RH values falling to around 10-15%. At least elevated fire weather conditions will persist into the overnight hours due to persistently gusty winds and poor overnight recovery. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
Categories: Weather

NHC Atlantic Tropical Weather Discussion

NWS Weather - 17 hours 45 min ago

000
AXNT20 KNHC 221041
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 AM EDT Sun Oct 22 2017

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0600 UTC surface analysis and satellite imagery through
1015 UTC.

...SPECIAL FEATURES...

High pressure building behind a cold front moving off the Texas
coast tonight will tighten the pressure gradient along the
Veracruz coast of southern Mexico, and induce gale force winds
south of 20N west of 95W Monday through Tuesday.

...TROPICAL WAVES...

A tropical wave along 47W from 10N-21N is moving west at 10 kt.
It is embedded in an area of moderate moisture as seen on SSMI
TPW imagery, and troughing at 700 mb. Scattered showers are from
09N-19N between 33W-49W.

A tropical wave moving into Central America extends from 21N87W
to 10N86W, and moving W at 15 kt. The wave is embedded in deep
moisture with a well defined surface trough, and broad troughing
at 700 mb. Scattered moderate to strong convection is from 14N-
22N between 83W-88W.

...ITCZ/MONSOON TROUGH...

A monsoon trough is near the African coast from 09N13W to
07N18W. The ITCZ extends from 07N18W to 07N54W. Scattered
moderate convection is from 05N-10N between 21W-33W.

...DISCUSSION...

GULF OF MEXICO...

A high pressure ridge prevails across the NE Gulf. Widespread
showers in the SE Gulf are being enhanced by divergent upper
level winds between an upper level anticyclone in the NW
Caribbean and a trough moving into the western Gulf. A cold
front will enter the NW Gulf tonight, and a tropical wave will
move across the Yucatan peninsula through Monday. Strong
northerly winds are expected behind the cold front Monday and
Tuesday.

CARIBBEAN SEA...

A tropical wave over the Gulf of Honduras will move across
Central America later today. The eastern extent of the E Pacific
monsoon trough over Costa Rica and Panama is producing scattered
moderate convection S of 11N. A large upper level anticyclone is
centered near 19N83W with extensive moisture. Strong subsidence
is over the E Caribbean E of 75W. Saharan Airmass Layer Imagery
also shows a plume of dry air and dust over the E Caribbean E of
67W. Expect continued fair weather over most of the basin during
the next 24 hours.

...HISPANIOLA...

Fair weather prevails over Hispaniola except for a few high
level clouds. Expect little change during the next 24 hours as
relatively dry subsident air remains in place over the island.

ATLANTIC OCEAN...

A dissipating cold front is over the W Atlantic from 32N48W to
27N62W. Diffluence east of an upper low centered near 27N65W is
enhancing scattered showers associated with the front. High
pressure is north of 30N on both sides of the front, in the
eastern Atlantic and over the eastern U.S. An upper level low
centered near 22N45W is producing scattered showers east of the
low due to upper level diffluence.

For additional information please visit
http://www.hurricanes.gov/marine

$$
Mundell
Categories: Weather

NHC Atlantic Tropical Weather Discussion

NWS Weather - 18 hours 21 min ago

000
AXNT20 KNHC 221005
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 AM EDT Sun Oct 22 2017

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0600 UTC surface analysis and satellite imagery through
1015 UTC.

...SPECIAL FEATURES...

High pressure building behind a cold front moving off the Texas
coast tonight will tighten the pressure gradient along the
Veracruz coast of southern Mexico, and induce gale force winds
south of 20N west of 95W Monday through Tuesday.

...TROPICAL WAVES...

A tropical wave along 47W from 10N-21N is moving west at 10 kt.
It is embedded in an area of moderate moisture as seen on SSMI
TPW imagery, and troughing at 700 mb. Scattered showers are from
09N-19N between 33W-49W.

A tropical wave moving into Central America extends from 21N87W
to 10N86W, and moving W at 15 kt. The wave is embedded in deep
moisture with a well defined surface trough, and broad troughing
at 700 mb. Scattered moderate to strong convection is from 14N-
22N between 83W-88W.

...ITCZ/MONSOON TROUGH...

A monsoon trough is near the African coast from 09N13W to
07N18W. The ITCZ extends from 07N18W to 07N54W. Scattered
moderate convection is from 05N-10N between 21W-33W.

...DISCUSSION...

GULF OF MEXICO...

A high pressure ridge prevails across the NE Gulf. Widespread
showers in the SE Gulf are being enhanced by divergent upper
level winds between an upper level anticyclone in the NW
Caribbean and a trough moving into the western Gulf. A cold
front will enter the NW Gulf tonight, and a tropical wave will
move across the Yucatan peninsula through Monday. Strong
northerly winds are expected behind the cold front Monday and
Tuesday.

CARIBBEAN SEA...

A tropical wave over the Gulf of Honduras will move across
Central America later today. The eastern extent of the E Pacific
monsoon trough over Costa Rica and Panama is producing scattered
moderate convection S of 11N. A large upper level anticyclone is
centered near 19N83W with extensive moisture. Strong subsidence
is over the E Caribbean E of 75W. Saharan Airmass Layer Imagery
also shows a plume of dry air and dust over the E Caribbean E of
67W. Expect continued fair weather over most of the basin during
the next 24 hours.

...HISPANIOLA...

Fair weather prevails over Hispaniola except for a few high
level clouds. Expect little change during the next 24 hours as
relatively dry subsident air remains in place over the island.

ATLANTIC OCEAN...

A dissipating cold front is over the W Atlantic from 32N48W to
27N62W. Diffluence east of an upper low centered near 27N65W is
enhancing scattered showers associated with the front. High
pressure is north of 30N on both sides of the front, in the
eastern Atlantic and over the eastern U.S. An upper level low
centered near 22N45W is producing scattered showers east of the
low due to upper level diffluence.

For additional information please visit
http://www.hurricanes.gov/marine

$$
Mundell
Categories: Weather

SPC Day 2 Fire Weather Outlook

Weather - Fire Weather - 20 hours 59 min ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0226 AM CDT Sun Oct 22 2017 Valid 231200Z - 241200Z ...CRITICAL FIRE WEATHER AREA FOR COASTAL RANGES OF SOUTHERN CALIFORNIA... ...Synopsis... Expansive high pressure will persist across the Intermountain West, with a 1041mb high centered over Idaho late in the forecast period. To the east of this anticyclone, a strong surface low near the Great Lakes will set up a favorable surface pressure gradient for gusty winds in portions of the northern and central Plains. Southwest of the high, a persistent "offshore" pressure gradient will foster gusty winds and heightened fire weather concerns in portions of southern California. ...Coastal Ranges of southern California... The overall fire weather scenario will change very little compared to previous days. The aforementioned surface pressure gradient across the area will support widespread 15-25 mph surface winds, with gusts exceeding 40 mph especially near terrain-favored areas. Hot surface temperatures will occur during peak-heating hours, with 90s to near 100F expected amidst 7-12% surface RH values. Widespread elevated to critical fire weather conditions are likely, with at least elevated conditions persisting well into the overnight hours due to continued gusty winds and poor recovery. ...Portions of the High Plains from southeastern Montana to western Nebraska... Although surface temperatures will be relatively cool during peak-heating hours (50s F), 25-35 mph northwesterly flow (with higher gusts) will develop during the afternoon in response to the aforementioned surface pressure gradient across the region. RH values will remain mostly above critical thresholds and range from 22-28%. These conditions are consistent with elevated fire weather criteria and an attendant delineation has been made. ..Cook.. 10/22/2017 ...Please see www.spc.noaa.gov/fire for graphic product... Read more
Categories: Weather

SPC Day 2 Fire Weather Outlook

Weather - Fire Weather - 20 hours 59 min ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0226 AM CDT Sun Oct 22 2017 Valid 231200Z - 241200Z ...CRITICAL FIRE WEATHER AREA FOR COASTAL RANGES OF SOUTHERN CALIFORNIA... ...Synopsis... Expansive high pressure will persist across the Intermountain West, with a 1041mb high centered over Idaho late in the forecast period. To the east of this anticyclone, a strong surface low near the Great Lakes will set up a favorable surface pressure gradient for gusty winds in portions of the northern and central Plains. Southwest of the high, a persistent "offshore" pressure gradient will foster gusty winds and heightened fire weather concerns in portions of southern California. ...Coastal Ranges of southern California... The overall fire weather scenario will change very little compared to previous days. The aforementioned surface pressure gradient across the area will support widespread 15-25 mph surface winds, with gusts exceeding 40 mph especially near terrain-favored areas. Hot surface temperatures will occur during peak-heating hours, with 90s to near 100F expected amidst 7-12% surface RH values. Widespread elevated to critical fire weather conditions are likely, with at least elevated conditions persisting well into the overnight hours due to continued gusty winds and poor recovery. ...Portions of the High Plains from southeastern Montana to western Nebraska... Although surface temperatures will be relatively cool during peak-heating hours (50s F), 25-35 mph northwesterly flow (with higher gusts) will develop during the afternoon in response to the aforementioned surface pressure gradient across the region. RH values will remain mostly above critical thresholds and range from 22-28%. These conditions are consistent with elevated fire weather criteria and an attendant delineation has been made. ..Cook.. 10/22/2017 ...Please see www.spc.noaa.gov/fire for graphic product... Read more
Categories: Weather

SPC Day 1 Fire Weather Outlook

Weather - Fire Weather - 21 hours 1 min ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0224 AM CDT Sun Oct 22 2017 Valid 221200Z - 231200Z ...CRITICAL FIRE WEATHER AREA FOR COASTAL RANGES OF SOUTHERN CALIFORNIA... ...Synopsis... The primary synoptic features of interest are 1) an expansive area of high pressure in the Great Basin an Intermountain West and 2) a weak surface trough along the California coast. A synoptically evident fire weather scenario will evolve throughout the forecast period as the surface pressure gradient between these two systems fosters strong, dry offshore flow across parts of southern California. ...Coastal Ranges of Southern California... An extended period of gusty north to northeasterly low-level flow will persist throughout the day across the delineated fire weather threat areas. 15-25 mph surface winds (with gusts to 50 mph in terrain-favored areas) will persist throughout the day. Daytime heating will aid in increasingly warm surface temperatures (perhaps rising into the low 90s) along with RH values falling to around 10-15%. At least elevated fire weather conditions will persist into the overnight hours due to persistently gusty winds and poor overnight recovery. ..Cook.. 10/22/2017 ...Please see www.spc.noaa.gov/fire for graphic product... Read more
Categories: Weather

NHC Atlantic Tropical Weather Discussion

NWS Weather - 22 hours 24 min ago

000
AXNT20 KNHC 220602
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 AM EDT Sun Oct 22 2017

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0000 UTC surface analysis and satellite imagery through
0545 UTC.

...SPECIAL FEATURES...

High pressure building behind a cold front moving off the Texas
coast Sunday night will tighten the pressure gradient along the
Veracruz coast of Mexico, and induce gale force winds south of
20N west of 95W from Monday through Tuesday.

...TROPICAL WAVES...

A tropical wave in the western Atlantic is analyzed along 51W,
but based on long term satellite animation, will be relocated
further east along 47W at 0600 UTC. The wave is moving west at
10 kt, embedded in an area moderate moisture as seen on SSMI TPW
imagery, and troughing at 700 mb. Scattered showers are from 10N-
16N between 45W-50W.

A tropical wave in the western Caribbean extending from 21N85W
to 10N83W is moving W at 15 kt. The wave is embedded in deep
moisture with a well defined surface trough, and broad troughing
at 700 mb. Scattered moderate isolated strong convection is from
15N-20N between 81W-88W.

...ITCZ/MONSOON TROUGH...

A monsoon trough is near the African coast from 10N14W to
08N18W. The ITCZ extends from 08N18W to 07N34W to 08N58W.
Scattered moderate convection is from 08N-13N between 32W-44W.

...DISCUSSION...

GULF OF MEXICO...

High pressure prevails across the NE Gulf. Widespread showers
across the eastern Gulf are being enhanced by divergent upper
level winds. A cold front will enter the NW Gulf tonight, and a
tropical wave will move across the Yucatan peninsula through
Monday. Strong northerly winds are expected behind the cold
front Monday and Tuesday.

CARIBBEAN SEA...

A tropical wave over the Gulf of Honduras will move across
Central America Monday. The eastern extent of the E Pacific
monsoon trough over Costa Rica and Panama is producing scattered
moderate convection S of 11N. A large upper level anticyclone is
centered near 17N80W with extensive moisture. Strong subsidence
is over the E Caribbean E of 75W. Saharan Airmass Layer Imagery
also shows a plume of dry air and dust over the E Caribbean E of
67W. Expect continued fair weather over most of the basin during
the next 24 hours.

...HISPANIOLA...

Fair weather prevails over Hispaniola except for high level
clouds. Expect little change during the next 24 hours as
relatively dry subsident air remains in place over the island.

ATLANTIC OCEAN...

A dissipating cold front is over the W Atlantic from 31N52W to
25N63W. Diffluence east of an upper low centered near 29N66W is
enhancing scattered showers associated with the front. High
pressure is north of 30N on either side of the front, in the
eastern Atlantic and over the eastern U.S. An upper level low
centered near 23N43W is producing scattered showers east of the
low due to upper level diffluence.

For additional information please visit
http://www.hurricanes.gov/marine

$$
Mundell
Categories: Weather

NHC Atlantic Tropical Weather Discussion

NWS Weather - Sat, 10/21/2017 - 20:02

000
AXNT20 KNHC 220102
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
902 PM EDT Sat Oct 21 2017

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2315 UTC.

...SPECIAL FEATURES...

A cold front will be over the W Gulf of Mexico Monday evening
from 30N86W to 25N88W to 22N91W. Gale force winds will be S of
20N W of 95W with NW winds 30-35 kt, and seas 8-12 ft.

...TROPICAL WAVES...

A tropical wave is in the central Atlantic with axis extending
from 21N48W to 10N50W, moving W at 20 kt. The wave is embedded in
moderate moisture as seen on SSMI Imagery. There are distinct
surface and 700 mb troughs. Scattered showers are within 120 nm of
the wave axis S of 15N.

A tropical wave is in the western Caribbean with axis extending
from 21N81W to 09N81W, moving W at 15 kt. The wave is embedded in
abundant moisture as seen on SSMI Imagery. There is a well
defined surface trough, and a broad 700 mb trough. Clusters of
scattered moderate to isolated strong convection is from 13N-21N
between 77W-88W.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the African coast near 08N13W to
07N20W. The Intertropical Convergence Zone axis extends from
07N20W to 07N40W to 09N61W. Scattered moderate convection is from
07N-11N between 34W-41W.

...DISCUSSION...

GULF OF MEXICO...

A 1028 mb high is centered off the coast of New Jersey near
39N74W producing surface ridging over the N Gulf of Mexico.
Widely scattered moderate convection is over the Yucatan
Peninsula, the Yucatan Channel, W Cuba, and the Straits of
Florida, all moving N from the Caribbean Sea. In addition, radar
imagery shows scattered showers are over the E Gulf and Florida.
In the upper levels, an upper level trough is over Texas and the
W Gulf with axis along 100W. Upper level diffluence E of the axis
is enhancing the showers over the E Gulf of Mexico. An upper
level ridge is over the E Gulf with axis along 79W. Abundant upper
level moisture is over the E Gulf. Expect a cold front to enter
the NW Gulf Sunday night, and a tropical wave to move across the
SE Gulf waters Sunday night. Gale force winds are forecast to
develop behind the cold front Monday.

CARIBBEAN SEA...

A tropical wave is over the W Caribbean. See above. In addition,
the eastern extent of the E Pacific monsoon trough is over Costa
Rica and Panama producing scattered moderate to isolated strong
convection S of 11N. In the upper levels, a large upper level
high is centered over the NW Caribbean near 17N80W with abundant
upper level moisture. Scattered moderate convection is over most
of Cuba. Further E, very strong subsidence is over the E Caribbean
E of 72W, to include Puerto Rico and the Virgin Islands. The
Saharan Airmass Layer Imagery also shows a plume of dry air and
dust over the E Caribbean E of 67W decreasing air quality and
reducing visibility. Expect the tropical wave to move W with
convection. Also expect continued fair weather over Puerto Rico
and the Leeward Islands for the next 24 hours.

...HISPANIOLA...

Presently fair weather is over Hispaniola. Expect within the next
24 hours for the plume of dry air and dust to advect over the
island.

ATLANTIC OCEAN...

A dissipating stationary front is over the W Atlantic from 31N54W
to 24N67W. Scattered showers are within 120 nm of the front. A
1032 mb high is centered over the E Atlantic near 40N18W
producing surface ridging to the E Atlantic. Of note in the upper
levels, an upper level low is over the W Atlantic near 29N66W.
Upper level diffluence E of the low enhancing the showers over
the W Atlantic front. Another upper level low is centered over
the central Atlantic near 23N43W producing scattered showers
within 600 nm E of the center due to upper level diffluence.

For additional information please visit
http://www.hurricanes.gov/marine

$$
Formosa

Categories: Weather

NHC Atlantic Tropical Weather Discussion

NWS Weather - Sat, 10/21/2017 - 18:35

000
AXNT20 KNHC 212335
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
734 PM EDT Sat Oct 21 2017

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2315 UTC.

...TROPICAL WAVES...

A tropical wave is in the central Atlantic with axis extending
from 21N48W to 10N50W, moving W at 20 kt. The wave is embedded in
moderate moisture as seen on SSMI Imagery. There are distinct
surface and 700 mb troughs. Scattered showers are within 120 nm of
the wave axis S of 15N.

A tropical wave is in the western Caribbean with axis extending
from 21N81W to 09N81W, moving W at 15 kt. The wave is embedded in
abundant moisture as seen on SSMI Imagery. There is a well
defined surface trough, and a broad 700 mb trough. Clusters of
scattered moderate to isolated strong convection is from 13N-21N
between 77W-88W.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the African coast near 08N13W to
07N20W. The Intertropical Convergence Zone axis extends from
07N20W to 07N40W to 09N61W. Scattered moderate convection is from
07N-11N between 34W-41W.

...DISCUSSION...

GULF OF MEXICO...

A 1028 mb high is centered off the coast of New Jersey near
39N74W producing surface ridging over the N Gulf of Mexico.
Widely scattered moderate convection is over the Yucatan
Peninsula, the Yucatan Channel, W Cuba, and the Straits of
Florida, all moving N from the Caribbean Sea. In addition, radar
imagery shows scattered showers are over the E Gulf and Florida.
In the upper levels, an upper level trough is over Texas and the
W Gulf with axis along 100W. Upper level diffluence E of the axis
is enhancing the showers over the E Gulf of Mexico. An upper
level ridge is over the E Gulf with axis along 79W. Abundant upper
level moisture is over the E Gulf. Expect a cold front to enter
the NW Gulf Sunday night, and a tropical wave to move across the
SE Gulf waters Sunday night. Gale force winds are forecast to
develop behind the cold front Monday.

CARIBBEAN SEA...

A tropical wave is over the W Caribbean. See above. In addition,
the eastern extent of the E Pacific monsoon trough is over Costa
Rica and Panama producing scattered moderate to isolated strong
convection S of 11N. In the upper levels, a large upper level
high is centered over the NW Caribbean near 17N80W with abundant
upper level moisture. Scattered moderate convection is over most
of Cuba. Further E, very strong subsidence is over the E Caribbean
E of 72W, to include Puerto Rico and the Virgin Islands. The
Saharan Airmass Layer Imagery also shows a plume of dry air and
dust over the E Caribbean E of 67W decreasing air quality and
reducing visibility. Expect the tropical wave to move W with
convection. Also expect continued fair weather over Puerto Rico
and the Leeward Islands for the next 24 hours.

...HISPANIOLA...

Presently fair weather is over Hispaniola. Expect within the next
24 hours for the plume of dry air and dust to advect over the
island.

ATLANTIC OCEAN...

A dissipating stationary front is over the W Atlantic from 31N54W
to 24N67W. Scattered showers are within 120 nm of the front. A
1032 mb high is centered over the E Atlantic near 40N18W
producing surface ridging to the E Atlantic. Of note in the upper
levels, an upper level low is over the W Atlantic near 29N66W.
Upper level diffluence E of the low enhancing the showers over
the W Atlantic front. Another upper level low is centered over
the central Atlantic near 23N43W producing scattered showers
within 600 nm E of the center due to upper level diffluence.

For additional information please visit
http://www.hurricanes.gov/marine

$$
Formosa

Categories: Weather

SPC Day 2 Fire Weather Outlook

Weather - Fire Weather - Sat, 10/21/2017 - 13:43
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0141 PM CDT Sat Oct 21 2017 Valid 221200Z - 231200Z ...CRITICAL FIRE WEATHER AREA FOR COASTAL RANGES OF SOUTHERN CALIFORNIA... No changes are needed to the ongoing forecast for critical fire weather conditions across the coastal ranges of southern California on Sunday (see previous discussion below for more details). ..Jirak.. 10/21/2017 .PREV DISCUSSION... /ISSUED 0133 AM CDT Sat Oct 21 2017/ ...Synopsis... The primary synoptic-scale features of interest for the D2/Sun forecast period are 1) a large area of high pressure over the Great Basin/northern Rockies and 2) a weak surface trough along the California Coast. The pressure gradient between these two systems will foster gusty winds in portions of southwestern California along with widespread areas of elevated to critical fire weather conditions. ...Coastal Ranges of Southern California... The aforementioned surface pressure gradient across the region will foster an extended period of gusty northeasterly low-level flow across the elevated and critical areas, with gusts from 35-50 mph occurring especially near terrain-favored canyons and valleys. During peak heating hours, surface temperatures will rise into the low 90s as RH values fall to around 10-12% - consistent with critical fire weather thresholds. At least elevated fire weather conditions will persist overnight and into early Monday in response to continued gusty winds and poor relative humidity recovery. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
Categories: Weather

SPC Day 2 Fire Weather Outlook

Weather - Fire Weather - Sat, 10/21/2017 - 13:43
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0141 PM CDT Sat Oct 21 2017 Valid 221200Z - 231200Z ...CRITICAL FIRE WEATHER AREA FOR COASTAL RANGES OF SOUTHERN CALIFORNIA... No changes are needed to the ongoing forecast for critical fire weather conditions across the coastal ranges of southern California on Sunday (see previous discussion below for more details). ..Jirak.. 10/21/2017 .PREV DISCUSSION... /ISSUED 0133 AM CDT Sat Oct 21 2017/ ...Synopsis... The primary synoptic-scale features of interest for the D2/Sun forecast period are 1) a large area of high pressure over the Great Basin/northern Rockies and 2) a weak surface trough along the California Coast. The pressure gradient between these two systems will foster gusty winds in portions of southwestern California along with widespread areas of elevated to critical fire weather conditions. ...Coastal Ranges of Southern California... The aforementioned surface pressure gradient across the region will foster an extended period of gusty northeasterly low-level flow across the elevated and critical areas, with gusts from 35-50 mph occurring especially near terrain-favored canyons and valleys. During peak heating hours, surface temperatures will rise into the low 90s as RH values fall to around 10-12% - consistent with critical fire weather thresholds. At least elevated fire weather conditions will persist overnight and into early Monday in response to continued gusty winds and poor relative humidity recovery. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
Categories: Weather

NHC Atlantic Tropical Weather Discussion

NWS Weather - Sat, 10/21/2017 - 13:06

000
AXNT20 KNHC 211806
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
206 PM EDT Sat Oct 21 2017

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1200 UTC surface analysis and satellite imagery through
1745 UTC.

...TROPICAL WAVES...

A tropical wave is in the central Atlc with axis extending from
20N46W to 10N48W, moving W at 20 kt. Satellite derived data
indicate the wave is in a strong vertical wind shear environment.
CIRA LPW imagery show abundant dry air in the majority of the
wave environment at the lower levels. Enhanced IR imagery show
Saharan dry air and dust in the wave environment as well. The
aforementioned environment hinders convection at this time.

A tropical wave is in the western Caribbean with axis extending
from 20N80W to 09N79W, moving W at 20 kt. The wave is in a region
of low to moderate vertical wind shear. However, deep layer
moisture along with upper level divergence support scattered
heavy showers and tstms from 13N-20N between 75W-86W.

A tropical wave is across Central America with axis extending
from 21N86W across western Honduras to EPAC waters near 08N88W,
moving W at 20-25 kt. The wave is in a region of moderate to
strong vertical wind shear and shallow moisture. Middle level
diffluence support scattered showers from 16N-20N between 86W-89W.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the African coast near 08N13W to
07N20W. The Intertropical Convergence Zone axis extends from
07N20W to 06N34W to 06N48W. Scattered moderate convection is from
04N-10N between 32W-42W.

...DISCUSSION...

GULF OF MEXICO...

Middle to upper level ridging prevails across the eastern half of
the Gulf while a trough aloft covers the western half of it.
Diffluent flow between these two features along with shallow
moisture support scattered showers and isolated tstms E of 90W.
Strong dry air subsidence from aloft support clear skies W of 90W. The
SW periphery of a broad surface ridge anchored over the NE CONUS
covers the NE Gulf and provides the Gulf with moderate to fresh
return flow E of 90W. Gentle to moderate return flow is elsewhere. Return
flow is expected to continue through Sunday afternoon. The wind
flow will then change as a cold front enters the NW basin Sunday
night and a tropical wave moves across the southern Gulf waters.
Gale force winds are forecast to develop behind the cold front
Monday.

CARIBBEAN SEA...

Two tropical waves underneath an upper ancticylcone are the
drivers of the weather in the western Caribbean W of 75W along
with the eastern extension of the monsoon trough. Strong dry air
subsidence covers the remainder basin supporting fair weather.
However, a plume of Saharan dry air and dust is spread across
Puerto Rico, Hispaniola and the Leeward Islands, thus decreasing
the air quality and reducing visibility. Otherwise, strong high
pressure N of the area continue to support fresh to strong trades
in the central and E Caribbean. A tropical wave will enter the E
Caribbean Sunday morning and mover across Puerto Rico Tuesday.

...HISPANIOLA...

Cloudiness and possible isolated showers are mainly across the
western half of the Island while a plume of Saharan dry air and
dust is spread across the remainder Hispaniola, thus decreasing
the air quality and reducing visibility. Similar conditions
expected tomorrow Sunday.

ATLANTIC OCEAN...

A weakening stationary front extends from 30N56W to 25N67W to
26N77W. Isolated showers are within 200 nm either side of the
front. Strong high pressure centered NE of the Azores covers the
remainder basin.

For additional information please visit
http://www.hurricanes.gov/marine

$$
Ramos
Categories: Weather

SPC Day 1 Fire Weather Outlook

Weather - Fire Weather - Sat, 10/21/2017 - 11:54
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1153 AM CDT Sat Oct 21 2017 Valid 211700Z - 221200Z ...CRITICAL FIRE WEATHER AREA FOR COASTAL RANGES OF SOUTHERN CALIFORNIA... ...Coastal Ranges of Southern California... Ongoing forecast of critical fire weather conditions for the mountains of Santa Barbara, Ventura, and Los Angeles Counties in southern California remains on track with no changes needed (see previous discussion below for more details). ...Portions of the High Plains... Despite relatively cool surface temperatures across this region, windy and dry conditions will lead to elevated fire weather concerns (see previous discussion for more details). The only change was extend the elevated area westward in Colorado where strong northwesterly surface winds will contribute to warming and drying through downslope effects. ...Lower Colorado River Valley... An elevated area was added across the Lower Colorado River Valley, where a favorably oriented surface pressure gradient will lead to strong sustained northerly surface winds of 15-20 mph, especially through the early afternoon. As boundary layer deepening/mixing occurs, RH values will fall below 15% resulting in elevated fire weather conditions. ..Jirak.. 10/21/2017 .PREV DISCUSSION... /ISSUED 0131 AM CDT Sat Oct 21 2017/ ...Synopsis... A powerful mid-level trough will progress steadily eastward across the center of the country today. Upstream of this trough, mid/upper ridging will develop across California and adjacent areas of the Desert Southwest, while strong, zonally oriented mid-level flow develops across the Pacific Northwest and northern Rockies. At the surface, a lee trough and cold front will merge and make eastward progress across the Plains, extending from the eastern Dakotas southward to the Texas Panhandle by mid-afternoon. Upstream, an expansive anticyclone will build into the Great Basin, with 1030mb centered over western Colorado. Each of these surface features will foster fire weather concerns Saturday in the High Plains and in southern California. ...Coastal Ranges of Southern California... A synoptically evident fire weather scenario will unfold today as high pressure in the Great Basin fosters a favorable surface pressure gradient for gusty offshore winds. Northeasterly surface flow (with gusts as high as 50 mph) will develop especially in terrain-favored areas and persist throughout the day. By mid-afternoon, very warm surface temperatures (approaching 90F) will combine with RH values falling to around 10-15% to foster widespread areas of elevated to critical fire weather conditions. Critical thresholds are most likely in portions of Santa Barbara, Ventura, and Los Angeles Counties in southern California during the afternoon and evening hours. Overnight recoveries will be poor, and gusty northeasterly winds will likely persist into Sunday. ...A large part of the High Plains from eastern Colorado northward to southeastern Montana... Although surface temperatures will be substantially cooler than in previous days, continued westerly/downslope flow west of the lee trough/cold front will maintain a very dry airmass across the region. RH will fall to around 10-15% in portions of eastern Colorado, and near 20% across portions of southeastern Montana, southwestern South Dakota, and vicinity. Wind speeds will generally fall below critical thresholds in most areas (around 15 mph with a few higher gusts), although fuels appear to be capable of supporting fire spread. An elevated fire delineation remains in place across this region to address the threat. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
Categories: Weather

SPC Day 1 Fire Weather Outlook

Weather - Fire Weather - Sat, 10/21/2017 - 11:54
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1153 AM CDT Sat Oct 21 2017 Valid 211700Z - 221200Z ...CRITICAL FIRE WEATHER AREA FOR COASTAL RANGES OF SOUTHERN CALIFORNIA... ...Coastal Ranges of Southern California... Ongoing forecast of critical fire weather conditions for the mountains of Santa Barbara, Ventura, and Los Angeles Counties in southern California remains on track with no changes needed (see previous discussion below for more details). ...Portions of the High Plains... Despite relatively cool surface temperatures across this region, windy and dry conditions will lead to elevated fire weather concerns (see previous discussion for more details). The only change was extend the elevated area westward in Colorado where strong northwesterly surface winds will contribute to warming and drying through downslope effects. ...Lower Colorado River Valley... An elevated area was added across the Lower Colorado River Valley, where a favorably oriented surface pressure gradient will lead to strong sustained northerly surface winds of 15-20 mph, especially through the early afternoon. As boundary layer deepening/mixing occurs, RH values will fall below 15% resulting in elevated fire weather conditions. ..Jirak.. 10/21/2017 .PREV DISCUSSION... /ISSUED 0131 AM CDT Sat Oct 21 2017/ ...Synopsis... A powerful mid-level trough will progress steadily eastward across the center of the country today. Upstream of this trough, mid/upper ridging will develop across California and adjacent areas of the Desert Southwest, while strong, zonally oriented mid-level flow develops across the Pacific Northwest and northern Rockies. At the surface, a lee trough and cold front will merge and make eastward progress across the Plains, extending from the eastern Dakotas southward to the Texas Panhandle by mid-afternoon. Upstream, an expansive anticyclone will build into the Great Basin, with 1030mb centered over western Colorado. Each of these surface features will foster fire weather concerns Saturday in the High Plains and in southern California. ...Coastal Ranges of Southern California... A synoptically evident fire weather scenario will unfold today as high pressure in the Great Basin fosters a favorable surface pressure gradient for gusty offshore winds. Northeasterly surface flow (with gusts as high as 50 mph) will develop especially in terrain-favored areas and persist throughout the day. By mid-afternoon, very warm surface temperatures (approaching 90F) will combine with RH values falling to around 10-15% to foster widespread areas of elevated to critical fire weather conditions. Critical thresholds are most likely in portions of Santa Barbara, Ventura, and Los Angeles Counties in southern California during the afternoon and evening hours. Overnight recoveries will be poor, and gusty northeasterly winds will likely persist into Sunday. ...A large part of the High Plains from eastern Colorado northward to southeastern Montana... Although surface temperatures will be substantially cooler than in previous days, continued westerly/downslope flow west of the lee trough/cold front will maintain a very dry airmass across the region. RH will fall to around 10-15% in portions of eastern Colorado, and near 20% across portions of southeastern Montana, southwestern South Dakota, and vicinity. Wind speeds will generally fall below critical thresholds in most areas (around 15 mph with a few higher gusts), although fuels appear to be capable of supporting fire spread. An elevated fire delineation remains in place across this region to address the threat. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
Categories: Weather

NHC Atlantic Tropical Weather Discussion

NWS Weather - Sat, 10/21/2017 - 05:38

000
AXNT20 KNHC 211038
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 AM EDT Sat Oct 21 2017

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0600 UTC surface analysis and satellite imagery through
1030 UTC.

...TROPICAL WAVES...

A tropical wave is in the central Atlantic with axis extending
from 19N45W to 09N47W, moving W at 15 kt. The wave is embedded
in abundant moisture as seen on SSMI Imagery. There are distinct
surface and 700 mb troughs. Isolated convection is within 240 nm
of the wave axis.

A tropical wave is in the central Caribbean along 78W, moving W
at 10 kt. The wave is embedded in abundant moisture as seen on
SSMI Imagery. There is a well defined surface trough, and a
broad 700 mb trough. Scattered moderate to strong convection is
from 14N-20N between 75W-83W.

A tropical wave is in the Gulf of Honduras along 86W, moving W
at 10 kt. The wave is embedded in abundant moisture as seen on
SSMI Imagery. There are distinct surface and 700 mb troughs.
Scattered moderate convection is from 16N-19N between 86W-89W.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the African coast near 09N13W to
08N20W. The Intertropical Convergence Zone axis extends from
08N20W to 07N45W. Scattered moderate convection is from 06N-09N
between 32W-39W.

...DISCUSSION...

GULF OF MEXICO...

High pressure over the eastern U.S. extends a surface ridge into
the NE Gulf of Mexico. Diffluence E of an upper level trough
over Texas is enhancing scattered showers across the central
Gulf between 86W-93W. An upper level ridge is over the E Gulf
with axis along 82W. Strong subsidence is over north and central
Florida. Expect moderate to occasional fresh E-SE winds over the
Gulf today as the surface ridge remains in place.

CARIBBEAN SEA...

In addition to the two tropical waves mentioned above, the
eastern extent of the E Pacific monsoon trough is over Costa
Rica and Panama producing isolated convection. A large upper
level high is centered over the NW Caribbean near 19N81W with
abundant moisture. Strong subsidence is over the E Caribbean E
of 72W, including Puerto Rico and Virgin Islands. Expect fair
weather to persist in Puerto Rico and Leeward Islands today.

...HISPANIOLA...

With a tropical wave west of the area, fair weather is expected
over Hispaniola today. Fresh to strong trades are expected this
weekend as high pressure builds in N of the region. Scattered
showers are possible in the afternoon and evening hours.

ATLANTIC OCEAN...

A weakening cold front extends over the west-central Atlantic
from 32N55W to 27N65W, then stationary to 26N75W. Scattered
showers are within 200 nm NW of the front. Strong high pressure
is centered over the Azores, and high pressure extends into the
Atlc to around 68W off the the U.S. coast west of the front. An
upper level low centered in the central Atlc near 22N42W is
producing scattered showers within 600 nm E of the center due to
upper level diffluence.

For additional information please visit
http://www.hurricanes.gov/marine

$$
Mundell
Categories: Weather

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