[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120539
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST MON DEC 12 2011

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 0500 UTC.

...THE ITCZ/THE MONSOON TROUGH...

THE ITCZ BEGINS OVER WRN AFRICAN REACHING THE COAST OF GUINEA
NEAR 10N14W CONTINUING OVER ATLC WATERS ALONG 7N24W 5N40W.
ISOLATED MODERATE CONVECTION IS ALONG THE ITCZ AXIS.

...DISCUSSION...

GULF OF MEXICO...
SURFACE RIDGING DOMINATES THE ERN CONUS AROUND A PAIR OF 1038 MB
HIGHS OVER NEW ENGLAND WITH RIDGE AXIS EXTENDING SW TO ERN
TEXAS. THIS PATTERN IS PROVIDING MAINLY ELY FLOW ACROSS THE GULF
OF MEXICO TONIGHT WITH WINDS UP TO 15 KTS. ALOFT...A BROAD UPPER
TROUGH COVERS THE SE CONUS WITH AXIS EXTENDING ACROSS THE
FLORIDA PANHANDLE AND INTO THE ERN GULF. THIS UPPER TROUGH IS
HELPING SUPPORT AN AREA OF WIDESPREAD STRONG SHOWERS/SCATTERED
THUNDERSTORMS OVER THE FLORIDA PANHANDLE AND PORTIONS OF GEORGIA
FROM 29N-31N BETWEEN 83W-87W. SCATTERED SHOWERS ARE ALSO OVER NE
FLORIDA FROM 28N-31N E OF 83W. THE WRN HALF OF THE BASIN HAS
PARTLY CLOUDY SKIES WITH POSSIBLE ISOLATED SHOWERS WITH MOSTLY
CLOUDY SKIES AND ISOLATED SHOWERS ALONG THE TEXAS AND MEXICO
COASTLINE LIKELY DUE TO WIND CONVERGENCE. EXPECT LITTLE CHANGE
OVER THE NEXT 24 HOURS.

CARIBBEAN SEA...
DRY AIR ALOFT AROUND A BROAD UPPER RIDGE OVER THE CARIBBEAN IS
KEEPING MUCH OF THE NRN HALF OF THE BASIN UNDER CLEAR SKIES AND
FAIR CONDITIONS. HOWEVER...DUE TO A SHORTWAVE UPPER LEVEL TROUGH
EXTENDING FROM SRN MEXICO INTO THE E PACIFIC...UPPER LEVEL
DIFFLUENCE IS PRESENT OVER THE AREA JUST E OF CENTRAL AMERICA.
THIS IS HELPING PRODUCE ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS
N OF HONDURAS FROM 16N-20N BETWEEN 84W-88W...AND SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS E OF NICARAGUA S OF 15N BETWEEN
76W-84W. SOME OF THIS ACTIVITY IS ALSO INFLUENCED BY LOW LEVEL
CYCLONIC FLOW AROUND THE MONSOON TROUGH EXTENDING ACROSS COSTA
RICA TO NRN COLOMBIA. A FEW ISOLATED SHOWERS ARE ALSO IN THE NE
CARIBBEAN N OF 16N E OF 71W. EXPECT SHOWERS/THUNDERSTORMS TO
REMAIN ACROSS THE FAR WRN CARIBBEAN FOR THE NEXT COUPLE OF DAYS.

ATLANTIC OCEAN...
STRONG SHOWERS/POSSIBLE THUNDERSTORMS ARE OFF THE ERN COAST OF N
FLORIDA N OF 29N BETWEEN 77W-81W DUE TO DIFFLUENCE ALOFT AROUND
AN UPPER LEVEL TROUGH WITH AXIS DOWN THE W COAST OF FLORIDA.
SURFACE WIND CONVERGENCE MAY ALSO BE ATTRIBUTING TO THE STRONG
ACTIVITY. UPPER LEVEL RIDGING IS TO THE E PROVIDING FAIR WEATHER
ACROSS THE BAHAMAS. AN UPPER LEVEL LOW NEAR 23N56W IS SUPPORTING
A SURFACE TROUGH ALONG 31N62W 26N64W 20N62W. MOST OF THE SHOWER
ACTIVITY IS WELL E OF THE TROUGH NEAR THE AREA OF STRONGEST
DIFFLUENCE ALOFT. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE
FROM 17N-26N BETWEEN 48W-57W. THE REMAINDER OF THE BASIN IS
DOMINATED BY SURFACE RIDGING AROUND A 1032 MB HIGH NEAR 35N36W
PROVIDING MOSTLY FAIR WEATHER. THE RIDGE IS SUPPORTED BY AN
UPPER LEVEL RIDGE CENTERED NEAR 31N42W. A NARROW UPPER LEVEL
TROUGH IS TO THE E EXTENDING FROM THE CANARY ISLANDS ALONG
21N28W 24N44W. UPPER LEVEL MOISTURE IS BEING DRAWN AROUND THE
ERN SIDE OF THIS UPPER TROUGH SUPPORTING AREAS OF UPPER LEVEL
CLOUDS. EXPECT THE SURFACE TROUGH IN THE CENTRAL ATLC TO REMAIN
SOMEWHAT STATIONARY FOR THE NEXT COUPLE OF DAYS BEFORE MERGING
WITH A FRONTAL BOUNDARY.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
WALTON





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