[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 292347
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT NOV 29 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
2300 UTC.

...THE ITCZ...
THE ITCZ AXIS IS ANALYZED ALONG 6N9W 5N20W 3N30W 4N40W 7N50W AND
INTO SOUTH AMERICA NEAR 6N58W. A CLUSTER OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION IS WITHIN 100NM NORTH OF THE AXIS
BETWEEN THE COAST OF AFRICA AND 16W. SCATTERED MODERATE
CONVECTION FROM 1N-6N BETWEEN 20W-38W.

...DISCUSSION...

GULF OF MEXICO...
A STRONG COLD FRONT CONTINUES TO DOMINATE THE WEATHER PATTERN
IN THE GULF THIS EVENING. AS OF 2100 UTC...THE FRONT STRETCHED
ACROSS SE LOUISIANA ENTERING THE GULF WATERS NEAR 29N91W AND
CONTINUING ALONG 27N95W TO THE MEXICO/TEXAS BORDER AND THEN
INLAND OVER MEXICO. DOPPLER RADAR MOSAIC AND VISIBLE SATELLITE
IMAGERY DEPICT NUMEROUS SHOWERS AND EMBEDDED THUNDERSTORMS
BEHIND THE FRONT TO THE GULF COAST IN ADDITION TO WIDESPREAD
RAIN ACROSS THE SE CONUS AND OVER THE GULF WATERS NORTH OF 28N.
THE FRONTAL BOUNDARY WILL CONTINUE MOVING SE ACROSS THE GULF
OVER THE WEEKEND BEFORE EXITING THE REGION MONDAY MORNING. WINDS
ARE EXPECTED TO APPROACH GALE FORCE ON EITHER SIDE OF THE FRONT
AS IT TRAVERSES THE GULF. THE REMAINDER OF THE GULF IS COVERED
BY THE WESTERN PERIPHERY OF A SFC RIDGE CENTERED ON A 1018 MB
SFC HIGH IN THE W ATLC. AS SOUTHERLY RETURN FLOW AROUND THIS
HIGH DRAWS INCREASED MOISTURE AND INSTABILITY OVER THE GULF
REGION...THE THREAT FOR STRONG THUNDERSTORMS WILL EXIST ALONG
AND AHEAD OF THE COLD FRONT. LOOKING AHEAD...SFC HIGH PRESSURE
WILL BUILD IN THE WAKE OF THE FRONT AND QUICKLY MOVE W-E AHEAD
OF THE NEXT COLD FRONT WHICH IS FORECAST TO MOVE OFF THE TEXAS
COAST ON WED.

CARIBBEAN SEA...
A 1010 MB SFC LOW REMAINS SITUATED JUST NORTH OF COSTA RICA NEAR
10N81W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ASSOCIATED
WITH THIS FEATURE COVER THE SW CARIBBEAN S OF 11N. UPPER LEVEL
DIVERGENCE IS SUPPORTING MODERATE CONVECTION FROM 16N-18N WEST
OF 74W.  PATCHES OF LOW LEVEL MOISTURE EMBEDDED IN THE TRADE
WIND FLOW ARE NOTED ACROSS THE REMAINDER OF THE BASIN. A SFC
RIDGE CENTERED ON A 1018 MB HIGH IN THE WEST ATLC COVERS THE
CARIBBEAN NORTH OF 14N. THIS RIDGE IS EXPECTED TO SHIFT
EAST...INCREASING TRADE WIND FLOW THROUGHOUT THE REGION.
SOUTHERLY FLOW WILL INCREASE IN THE NW CARIBBEAN IN ADVANCE OF A
GULF OF MEXICO COLD FRONT...WHICH IS FORECAST TO REACH THE
YUCATAN CHANNEL SUNDAY NIGHT.

ATLANTIC OCEAN...
A 1018 MB SFC HIGH CENTERED NEAR 28N64W EXTENDS A RIDGE ACROSS
THE WEST ATLC MAINTAINING TRANQUIL CONDITIONS. A STATIONARY
FRONT NORTH OF THE AREA IS EXPECTED TO GRADUALLY MOVE
SOUTH...IMPACTING THE DISCUSSION AREA SUNDAY EVENING. FURTHER
EAST...A DEEP-LAYER TROUGH COVERS THE CENTRAL ATLC. AN
ASSOCIATED SFC TROUGH EXTENDS FROM 28N45W TO 19N49W. A WEAK SFC
LOW HAS DEVELOPED ALONG THE SFC TROUGH NEAR 23N46W. CONVECTION
ALONG THE SFC TROUGH HAS BEEN SHEARED TO THE NE WITH SCATTERED
SHOWERS NORTH OF 27N BETWEEN 25W-46W. A PERSISTENT SFC
TROUGH...REMNANTS OF A COLD FRONT...STRETCHES FROM 20N39W ALONG
14N49W TO 8N60W. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM
OF THE TROUGH NE OF 14N53W. A SFC RIDGE AXIS EXTENDS FROM THE
AZORES TO THE CANARY ISLANDS AND CONTINUES TO DOMINATE THE E
ATLC. ALOFT...A DIFFLUENT PATTERN AROUND AN UPPER RIDGE IS
ENHANCING CONVECTION ALONG THE ITCZ.

$$
RJW







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