[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 202356
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SUN NOV 20 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
2315 UTC.

...SPECIAL FEATURES...

A LARGE-SCALE TROUGH IS LOCATED OVER THE CENTRAL ATLC WITH AXIS
ALONG 59W AND A BASE NEAR 21N. EMBEDDED WITHIN THIS TROUGHING...
WATER VAPOR IMAGERY INDICATES A SHORTWAVE WITH AXIS FROM 28N56W
TO 21N47W. THIS UPPER LEVEL FEATURE SUPPORTS A 1009 MB LOW
CENTERED NEAR 23N53W AND A SURFACE TROUGH ANALYZED FROM 19N53W
THROUGH THE LOW TO 29N52W. THIS LOW REMAINS THE FOCUS FOR
POTENTIAL TROPICAL OR SUB-TROPICAL CYCLONE GENESIS WITHIN THE
NEXT 48 HOURS. WHILE UPPER LEVEL DIFFLUENCE CONTINUES TO BE
MAXIMIZED NORTH AND EAST OF THE TROUGHING...SCATTERED MODERATE
CONVECTION IS OCCURRING FROM 23N-32N BETWEEN 42W-54W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N15W TO
09N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
09N18W TO 08N40W TO 06N55W. SCATTERED MODERATE TO STRONG
CONVECTION IS FROM 05N-10N BETWEEN 16W-24W. SCATTERED MODERATE
CONVECTION IS ELSEWHERE FROM 05N-12N BETWEEN 08W-32W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL RIDGE AXIS EXTENDS
FROM SOUTHERN MEXICO OVER THE WESTERN GULF AND INTO THE SE
CONUS. DRY AIR AND SUBSIDENT CONDITIONS PREVAIL ALOFT ACROSS THE
GULF WHICH IS SUPPORTIVE OF A SURFACE RIDGE WITH AXIS EXTENDING
SW FROM A 1027 MB HIGH CENTERED OVER EASTERN SOUTH CAROLINA NEAR
33N80W. FAIR WEATHER AND OVERALL STABLE CONDITIONS ARE NOTED ON
SATELLITE IMAGERY ACROSS THE BASIN WITH ONLY A SMALL AREA OF
ISOLATED SHOWERS OCCURRING WITHIN 60 NM EITHER SIDE OF A LINE
FROM THE FLORIDA PANHANDLE NEAR 31N86W TO 27N89W...AND ACROSS
THE SOUTHERN FLORIDA PENINSULA INTO THE SE GULF S OF 27N E OF
85W. ELSEWHERE...E TO SE WINDS ARE IN THE RANGE OF 10-20 KT THIS
EVENING. THE RIDGE IS FORECAST TO REMAIN NEARLY STATIONARY
ACROSS THE GULF WITH LITTLE CHANGE IN CONDITIONS THROUGH TUESDAY
WITH THE NEXT COLD FRONT EXPECTED TO EMERGE OFF THE TEXAS GULF
COAST LATE TUESDAY INTO EARLY WEDNESDAY.

CARIBBEAN SEA...
WEAK UPPER LEVEL TROUGHING IS EVIDENT ACROSS THE SW CARIBBEAN
AND ALONG WITH CONVERGENT LOW-LEVEL NORTHEASTERLY WINDS...THE
RESULT IS ISOLATED SHOWERS AND TSTMS OCCURRING ACROSS INLAND
PORTIONS OF THE YUCATAN PENINSULA...HONDURAS...NICARAGUA...AND
PANAMA THIS EVENING. A FEW OF THESE SHOWERS EXTEND EASTWARD OVER
ADJACENT CARIBBEAN WATERS FROM 10N-14N W OF 75W. THE REMAINDER
OF THE CARIBBEAN BASIN IS UNDER THE INFLUENCE OF SUBSIDENT DRY
AIR ALOFT AND THE NE WINDS ORIGINATING FROM THE WESTERN
PERIPHERY OF THE SPECIAL FEATURES LOW MENTIONED ABOVE. A FEW
LOW-TOPPED ISOLATED SHOWERS ARE OCCURRING OVER THE NE CARIBBEAN
N OF 16N BETWEEN 62W-70W...AND S OF 14N BETWEEN 60W-72W...
INCLUDING THE WINDWARD AND ABC ISLANDS THIS EVENING. AS THE NE
WINDS CONTINUE OVER THE SW NORTH ATLC ACROSS THE GREATER
ANTILLES AND INTO NORTHERN PORTIONS OF THE BASIN...STRONGER
WINDS ARE ANTICIPATED THROUGH LATE MONDAY IN THE VICINITY OF THE
MONA AND WINDWARD PASSAGES.

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE AXIS EXTENDS FROM THE WESTERN GULF OF
MEXICO NORTHEASTWARD ACROSS THE SE CONUS TO THE MID-ATLC
SEABOARD AND SUPPORTS A 1027 MB HIGH CENTERED OVER EASTERN SOUTH
CAROLINA NEAR 33N80W. MOSTLY NE WINDS DOMINATE ACROSS THE W ATLC
WEST OF 60W WITH ISOLATED SHOWERS POSSIBLE S OF 28N BETWEEN
60W-70W AND FROM 23N-29N W OF 72W...INCLUDING THE INTERIOR
SOUTHERN FLORIDA PENINSULA S OF 28N. FARTHER EAST...AN UPPER
LEVEL TROUGH IS OVER THE CENTRAL ATLC ALONG 59W THAT SUPPORTS
THE 1009 MB SPECIAL FEATURES LOW AND AREA OF CONVECTION LOCATED
MAINLY EAST OF THE UPPER LEVEL TROUGHING FROM 23N-32N BETWEEN
42W-54W. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE
INFLUENCE OF A SURFACE RIDGE PROVIDING NE TO E WINDS IN THE 15
TO 20 KT RANGE S OF 32N E OF 35W.

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

$$
HUFFMAN



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