[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121115
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1100 UTC.

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

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF
GUINEA-BISSAU NEAR 11N16W CONTINUING SW TO 9N20W. THE ITCZ
CONTINUES FROM 9N20W ALONG 5N28W 6N41W. SCATTERED MODERATE
CONVECTION IS WITHIN 75 NM OF THE AXIS BETWEEN 19W-42W.

...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 WITH A FEW SURFACE
STATIONS REPORTING 20 KTS. ALOFT...A BROAD UPPER TROUGH COVERS
THE SE CONUS WITH AXIS EXTENDING DOWN THE FLORIDA PENINSULA.
THIS UPPER TROUGH IS HELPING SUPPORT AN AREA OF WIDESPREAD
STRONG SHOWERS/POSSIBLE THUNDERSTORMS OVER NRN FLORIDA AND
PORTIONS OF ALABAMA...GEORGIA...AND SOUTH CAROLINA N OF 28N E OF
85W. 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 85W-88W...AND SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS S OF 15N BETWEEN 74W-86W. SOME OF
THIS ACTIVITY IS ALSO INFLUENCED BY LOW LEVEL CYCLONIC FLOW
AROUND THE MONSOON TROUGH EXTENDING ACROSS THE COSTA
RICA/PANAMA BORDER TO NRN COLOMBIA. A FEW ISOLATED SHOWERS ARE
ALSO IN THE NE CARIBBEAN FROM 15N-17N BETWEEN 64W-74W. 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 28N W OF 77W DUE TO DIFFLUENCE ALOFT AROUND AN
UPPER LEVEL TROUGH WITH AXIS DOWN THE FLORIDA PENINSULA ALONG
WITH SURFACE WIND CONVERGENCE DUE TO GALE FORCE WINDS NOTED OFF
THE COAST OF NRN FLORIDA. UPPER LEVEL RIDGING IS TO THE SE
PROVIDING FAIR WEATHER ACROSS THE NRN CARIBBEAN AND BAHAMAS. A
NOW ELONGATED UPPER LEVEL LOW NEAR 23N57W IS SUPPORTING A
SURFACE TROUGH ALONG 30N65W 26N66W 22N66W. MOST OF THE SHOWER
ACTIVITY IS WELL E OF THE TROUGH NEAR THE AREA OF STRONGEST
DIFFLUENCE ALOFT. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE
FROM 16N-25N BETWEEN 49W-61W. THE REMAINDER OF THE BASIN IS
DOMINATED BY SURFACE RIDGING AROUND A 1032 MB HIGH NEAR 34N34W
PROVIDING MOSTLY FAIR WEATHER. THE RIDGE IS SUPPORTED BY AN
UPPER LEVEL RIDGE CENTERED NEAR 31N40W. 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
SERN 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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