[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 252345
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE NOV 25 2008

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...THE ITCZ...
THE ITCZ AXIS IS ANALYZED ALONG 8N12W 6N40W 4N53W. SCATTERED
SHOWERS ARE ALONG THE ITCZ AXIS. SCATTERED MODERATE CONVECTION
IS NEAR 5N33W.

...DISCUSSION...

GULF OF MEXICO...
A COLD FRONT IS MOVING ACROSS THE GULF AND AT 2100 UTC EXTENDS
FROM FORT PIERCE FLORIDA TO CHARLOTTE HARBOR SW TO NEAR 25N90W
TO 25N94W. SUPPORTING THIS FRONT IS A DEEP-LAYERED TROUGH THAT
REMAINS OVER THE ERN CONUS EXTENDING A TROUGH AXIS INTO THE GULF
REGION FROM NRN FLORIDA TO THE ERN BAY OF CAMPECHE. IN THE WAKE
OF THE COLD FRONT...A COOLER AND DRIER REINFORCING AIRMASS
RESIDES...SUPPORTED BY A 1029 MB SURFACE HIGH OVER ERN TEXAS
NEAR 30N95W. MAINLY LOW/MID LEVEL CLOUDS ARE ASSOCIATED WITH THE
FRONTAL BOUNDARY WITH POSSIBLE ISOLATED SHOWERS WITHIN 70 NM OF
THE FRONT. ADDITIONALLY...A 1026 MB SURFACE HIGH IS OVER ERN
MEXICO NEAR CIUDAD VALLES. BROKEN TO OVERCAST LOW CLOUDS ARE
OBSERVED BANKING ALONG THE ERN COAST OF MEXICO AND ADJACENT
COASTAL WATERS FROM 18N-26N W OF 95W WITH ISOLATED SHOWERS
POSSIBLE ACROSS THAT AREA.

CARIBBEAN SEA...
MAIN WEATHER FEATURE CONTINUES TO BE THE BROAD AREA OF LOW
PRESSURE OVER THE SW CARIBBEAN. A 1008 MB SURFACE LOW IS NEAR
11N83W. LOW LEVEL CONVERGENCE NEAR THIS SURFACE LOW ALONG WITH
AN UPPER RIDGE PROVIDING UPPER LEVEL DIFFLUENCE IS SUPPORTING
NUMEROUS SHOWERS AND TSTMS S OF 17N AND W OF 72W. MOST OF THE
CONVECTION HOWEVER REMAINS POORLY ORGANIZED. AS THIS SYSTEM
DRIFTS WWD...IT WILL CONTINUE TO PRODUCE HEAVY RAINS AND
LOCALIZED FLOODING OVER A LARGE PORTION OF CENTRAL AMERICA
DURING THE NEXT COUPLE OF DAYS. THE PRESSURE GRADIENT BETWEEN
THIS SURFACE LOW AND A RIDGE N OF AREA IS GENERATING N TO NE
SURFACE WINDS OF 15 TO 20 KT FOR LOCATIONS IN THE WRN CARIBBEAN.
MODERATE TRADE WINDS ARE NOTED OVER THE REMAINDER OF THE BASIN.
AN UPPER-LEVEL RIDGE DOMINATES THE REGION WITH AXIS FROM
TRINIDAD TO PUERTO RICO AND WEAKER RIDGING ACROSS HISPANIOLA AND
ERN CUBA. THIS IS INDUCING SCATTERED SHOWERS OVER PUERTO RICO
AND HISPANIOLA WHICH ARE UNDER E-NE SURFACE FLOW.

ATLANTIC OCEAN...
A DEEP LAYERED TROUGH IS OVER THE ERN CONUS WITH STRONG WESTERLY
FLOW ALOFT OVER THE W ATLC. THIS UPPER TROUGH SUPPORTS A COLD
FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N75W AND EXTENDS SW
TO FORT PIERCE FLORIDA. A COOLER AND DRIER REINFORCING AIRMASS
FOLLOWS BEHIND THE FRONT. ISOLATED SHOWERS ARE WITHIN 60 NM ON
EITHER SIDE OF THE FRONT. FARTHER EAST...A SHARP UPPER TROUGH IS
OVER THE CENTRAL ATLC WITH AN UPPER LOW CENTERED NEAR 30N49W.
THIS UPPER LOW AND TROUGH SUPPORT A 998 MB SURFACE LOW LOCATED
NEAR 31N50W. A COLD FRONT EXTENDS FROM THIS LOW ALONG 28N47W TO
24N47W TO 20N50W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS FROM 24N-32N BETWEEN 38W-45W. A DIFFLUENT PATTERN ALOFT
LOCATED EAST OF THE AFOREMENTIONED UPPER-LEVEL TROUGH IS AIDING
IN THE ENHANCEMENT OF THIS CONVECTIVE ACTIVITY. FARTHER TO THE
SOUTH...A SURFACE TROUGH IS FROM 19N48W TO 11N51W WITH SCATTERED
SHOWERS FROM 15N-21N BETWEEN 39W-47W. A WEAKENING 1011 MB LOW IS
NEAR 27N31W WITH A SURFACE TROUGH EXTENDING FROM 28N34W THROUGH
THE LOW TO 26N26W. IT IS GENERATING ISOLATED SHOWERS EAST OF THE
LOW CENTER FROM 24N-30N BETWEEN 24W-27W. THE REMAINDER OF THE E
ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED N OF THE
AZORES AND EXTENDS A RIDGE THROUGH THE CANARY ISLANDS S-SW TO
OVER THE CAPE VERDE ISLANDS.

$$
HUFFMAN





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