[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 032325
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT DEC 03 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2230 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH REMAINS INLAND ACROSS AFRICA. THE ITCZ BEGINS
NEAR THE COAST OF SIERRA LEONE NEAR 8N13W CONTINUING ALONG 9N16W
5N30W 6N45W. ONLY WEAK ISOLATED CONVECTION IS WITHIN 60 NM
EITHER SIDE OF THE AXIS BETWEEN 21W-30W.

...DISCUSSION...

GULF OF MEXICO...
SURFACE RIDGING CONTINUES TO DOMINATE THE GULF OF MEXICO AROUND
A 1038 MB HIGH OVER VIRGINIA. THIS IS PROVIDING MAINLY 15-20 KT
NE-E SURFACE FLOW ACROSS THE BASIN AROUND THE RIDGE WITH
STRONGER WINDS UP TO 25 KTS ALONG THE TEXAS COASTLINE. CLUSTERS
OF SCATTERED SHOWERS ARE EMBEDDED WITHIN THE ANTI-CYCLONIC FLOW
MAINLY FROM 22N-25N BETWEEN 84W-88W...AND FROM 24N-30N BETWEEN
89W-94W. ALOFT...MOSTLY DRY AIR COVERS THE AREA AROUND AN UPPER
LEVEL RIDGE WITH AXIS EXTENDING FROM THE ERN BAY OF CAMPECHE TO
THE FLORIDA PANHANDLE AND UP THE FAR ERN CONUS. A NARROW SWATH
OF UPPER LEVEL MOISTURE LIES ON THE WRN SIDE OF THE UPPER RIDGE
BETWEEN THE RIDGE AND AN APPROACHING TROUGH OVER THE WRN CONUS.
THIS MOISTURE IS SUPPORTING A FEW UPPER LEVEL CLOUDS OVER THE NW
GULF. EXPECT THE SURFACE RIDGE TO REMAIN MOSTLY STATIONARY UNTIL
THE NEXT COLD FRONT REACHES THE NW GULF ON MONDAY PUSHING THE
RIDGE EWD.

CARIBBEAN SEA...
MAINLY NELY FLOW COVERS THE WRN HALF OF THE CARIBBEAN AROUND THE
SURFACE RIDGE THAT COVERS THE ERN CONUS AND WRN ATLC. ISOLATED
SHOWERS ARE EMBEDDED WITHIN THIS FLOW S OF 18W W OF 75W WITH A
FEW ISOLATED THUNDERSTORMS NEAR THE MONSOON TROUGH EXTENDING
FROM SRN COSTA RICA TO NRN COLOMBIA. DRY AIR ALOFT AROUND A
BROAD UPPER LEVEL TROUGH WITH AXIS FROM HISPANIOLA TO THE SW
CARIBBEAN NEAR 11N79W IS SUPPRESSING ANY DEEP CONVECTION W OF
70W. E OF 70W...SCATTERED SHOWERS/THUNDERSTORMS COVER THE AREA
SE OF A LINE FROM THE LEEWARD ISLANDS NEAR 18N64W TO THE NW
COAST OF VENEZUELA NEAR 12N71W. MUCH OF THIS ACTIVITY IS
INFLUENCED BY A SURFACE TROUGH EXTENDING FROM 11N66W TO N OF
GUADELOUPE NEAR 17N62W CONTINUING INTO THE CENTRAL ATLC. SURFACE
CONVERGENCE ALONG WITH UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER
TROUGH OVER THE WRN AND CENTRAL CARIBBEAN AND AN UPPER LEVEL
RIDGE E OF THE LESSER ANTILLES IS HELPING SUPPORT THE CONVECTIVE
ACTIVITY. HEAVY RAINFALL HAS ALREADY FALLEN OVER MUCH OF THIS
AREA OVER THE PAST SEVERAL DAYS. CONTINUED RAIN OVER ALREADY
SATURATED GROUND INCREASES THE CHANCE FOR FLOODING ESPECIALLY IN
HIGHER TERRAIN. EXPECT THE SURFACE TROUGH AND ASSOCIATED
MOISTURE TO REMAIN SOMEWHAT STATIONARY FOR THE NEXT COUPLE OF
DAYS.

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE IS MOVING OVER THE FAR WRN ATLC WITH AXIS
UP THE ERN UNITED STATES SEABOARD SUPPORTING SURFACE RIDGING
AROUND A PAIR OF 1038 MB HIGHS OVER VIRGINIA AND MAINE. DRY AIR
ALOFT ACCOMPANIES THE UPPER RIDGE AND THE WRN SIDE OF AN UPPER
LEVEL TROUGH TO THE E WITH AXIS ALONG 65W WHICH IS PROVIDING
MOSTLY FAIR WEATHER. 20-25 KT NE WINDS ARE AROUND THE RIDGE IN
THE DISCUSSION AREA. TO THE E...UPPER LEVEL DIFFLUENCE AROUND
THE E SIDE OF THE UPPER TROUGH IS HELPING SUPPORT CONVECTION
NEAR A SURFACE TROUGH EXTENDING FROM THE NRN LEEWARD ISLANDS AT
17N62W ALONG 24N60W 30N58W. SCATTERED SHOWERS/THUNDERSTORMS ARE
WITHIN 175 NM E OF THE AXIS...AND WITHIN 75 NM W OF THE AXIS.
ANOTHER UPPER LEVEL RIDGE IS TO THE E SANDWICHED BETWEEN THE
AFOREMENTIONED UPPER TROUGH AND AN UPPER LEVEL LOW NEAR 28N38W.
THE UPPER LOW IS SUPPORTING A SECOND SURFACE TROUGH FROM 31N41W
TO 21N41W. SCATTERED SHOWERS ARE WITHIN 380 NM E OF THE AXIS
FROM 24N-32N. DIFFLUENCE SE OF THE LOW CENTER IS ALSO SUPPORTING
CLOUDY SKIES AND POSSIBLE ISOLATED SHOWERS FROM 11N-20N BETWEEN
20W-34W. EXPECT THE SURFACE TROUGH IN THE CENTRAL ATLC TO REMAIN
SOMEWHAT STATIONARY AND CONTINUE TO PRODUCE A LARGE AREA OF
SHOWERS/THUNDERSTORMS.

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

$$
WALTON





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