[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 052346
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST MON DEC 05 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
2335 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH REMAINS INLAND ACROSS AFRICA. THE ITCZ BEGINS
NEAR THE COAST OF SIERRA LEONE NEAR 8N13W CONTINUING WESTWARD
ALONG 6N20W 5N30W 6N40W 7N50W 6N55W. WIDELY SCATTERED MODERATE
CONVECTION IS FROM 2N-9N BETWEEN 30W-50W.

...DISCUSSION...

GULF OF MEXICO...
SW FLOW ALOFT COVERS THE GULF THIS EVENING...AHEAD OF THE UPPER
LEVEL TROUGH CURRENTLY MOVING ACROSS THE CENTRAL/EASTERN CONUS.
A STRONG JET-STREAK IS ASSOCIATED TO THIS SYSTEM MOVING ACROSS
SE TEXAS SUPPORTING A COLD FRONT EXTENDING INTO THE GULF ACROSS
THE LOUISIANA COAST ALONG 29N91W TO THE MEXICO COAST ALONG THE
CITY OF TAMPICO. STRONG NORTHERLY WINDS IN THE RANGE OF 20 TO 25
KT ARE OBSERVED WEST OF THE FRONT WITH SCATTERED SHOWERS AND
ISOLATED TSTMS OCCURRING WITHIN 60 NM EITHER SIDE OF THE FRONT.
SOUTHERLY WINDS UP TO 20 KT ARE AHEAD OF THE FRONT WITH A FEW
SCATTERED SHOWERS MOVING WITH THE FLOW INLAND OVER MISSISSIPPI
...ALABAMA...GEORGIA...AND THE WRN FLORIDA PANHANDLE N OF 27N
BETWEEN 86W-90W. THE FRONT IS FORECAST TO SLOWLY MOVE EASTWARD
THROUGH THE WEEK AND CLEAR EAST OF THE GULF REGION LATE THURSDAY
INTO EARLY FRIDAY AS HIGH PRESSURE BUILDS ACROSS THE SOUTHERN
PLAINS AND NW GULF OVER THE WEEKEND.

CARIBBEAN SEA...
A NARROW UPPER LEVEL TROUGH EXTENDS SOUTHWARD FROM THE ATLC
BASIN INTO THE CENTRAL CARIBBEAN. WATER VAPOR IMAGERY INDICATES
A VERY DRY AND STABLE AIRMASS ALOFT AROUND AND WEST OF THE UPPER
TROUGH PROVIDING MUCH OF THE CARIBBEAN W OF 66W WITH FAIR
WEATHER CONDITIONS WITH A FEW CLUSTERS OF LOW TOP SCATTERED
SHOWERS ACROSS THE AREA. THE UPPER LEVEL TROUGHING IS PROVIDING
DIFFLUENCE ALOFT ACROSS THE FAR ERN CARIBBEAN...GENERATING AN
AREA OF SCATTERED HEAVY SHOWERS AND THUNDERSTORMS E OF 66W S OF
18N INCLUDING THE LESSER ANTILLES. HEAVY RAINFALL HAS ALREADY
FALLEN OVER MUCH OF THIS GROUP OF ISLANDS OVER THE PAST SEVERAL
DAYS. CONTINUED RAIN OVER ALREADY SATURATED TERRAIN INCREASES
THE CHANCE FOR FLASH FLOODING...ESPECIALLY OVER THE HIGHER
TERRAIN.  OVER THE NEXT FEW DAYS...THE UPPER LEVEL TROUGH WILL
BE SLOW TO MAKE ANY SIGNIFICANT PROGRESS EASTWARD SO FAIR
WEATHER IS EXPECTED TO CONTINUE OVER WESTERN PORTIONS OF THE
BASIN...WHILE CONTINUED INCREASED CHANCES FOR PRECIPITATION WILL
LINGER OVER EASTERN PORTIONS OF THE BASIN THROUGH THURSDAY.

ATLANTIC OCEAN...
A NARROW UPPER LEVEL TROUGH AXIS EXTENDS SOUTHWARD FROM THE
CENTRAL ATLC INTO THE CENTRAL CARIBBEAN SEA. AN UPPER LEVEL LOW
IS EMBEDDED IN THIS TROUGHING CENTERED NEAR 26N62W. THIS UPPER
LEVEL SYSTEM SUPPORTS A SERIES OF SURFACE TROUGHS EXTENDING
ACROSS THE SOUTH CENTRAL ATLC...ONE EXTENDING FROM 27N62W TO
20N64W...THE SECOND ONE EXTENDING FROM 20N56W TO 14N62W...AND
THE THIRD ONE FROM 19N48W TO 13N50W. LOW-LEVEL CONVERGENCE
AROUND THESE SURFACE FEATURES IN COMBINATION WITH DIFFLUENCE
FLOW ALOFT ASSOCIATED TO THE UPPER TROUGH IS GENERATING A BROAD
AREA OF SCATTERED HEAVY SHOWERS AND THUNDERSTORMS WITHIN 200 NM
ON EITHER SIDE OF A LINE EXTENDING FROM 30N47W INTO THE ERN
CARIBBEAN ALONG 15N61W. FARTHER EAST...AN UPPER LEVEL LOW IS
CENTERED NEAR 27N28W BUT HAS MINIMAL IMPACT AT THE SURFACE AS A
STRONG RIDGE...ANCHORED BY A 1033 MB HIGH CENTERED OVER THE
AZORES NEAR 40N30W...CONTINUES TO INFLUENCE MUCH OF THE EASTERN
ATLC E OF 40W.

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

$$

GARCIA



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