[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 022329
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST MON JAN 02 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN 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
2300 UTC.

...SPECIAL FEATURE...

TROPICAL STORM ZETA IS NEAR 23.5N 41.1W OR ABOUT 1465
MILES...2360 KM...EAST-NORTHEAST OF THE NORTHERN LEEWARD ISLANDS
AT 02/1500 UTC. ZETA IS MOVING WEST-SOUTHWEST AT 7 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1000 MB.  THE MAXIMUM SUSTAINED WIND
SPEED IS 45 KT WITH GUSTS TO 55 KT. PLEASE REFER TO THE LATEST
FORECAST/ ADVISORY LISTED UNDER THE AWIPS/WMO HEADERS MIATCMAT5/
WTNT25 KNHC FOR MORE DETAILS. ZETA CONTINUES TO REFUSE TO WEAKEN
DESPITE WESTERLY VERTICAL WIND SHEAR IMPACTING THE CIRCULATION.
THE SHEAR IS RESTRICTING THE CONVECTION TO THE NORTHERN
SEMI-CIRCLE...DOWN-SHEAR LEFT AREA OF THE CYCLONE. SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION IS FROM 23.5N-26N BETWEEN
39W-42W. AN APPROACHING TROUGH WILL INCREASE THE SHEAR VALUES
OVER ZETA WITHIN THE NEXT DAY OR TWO WHICH SHOULD WEAKEN ZETA TO
A REMNANT LOW IN THE NEXT COUPLE OF DAYS.

...ITCZ...

THE ITCZ IS MUCH LESS CONVECTIVE THAN IT WAS YESTERDAY. ITS AXIS
IS CENTERED ALONG 7N13W 4N26W 3N35W 2N40W 2.5N50W. WIDELY
SCATTERED MODERATE CONVECTION IS WITHIN 150 NM ON EITHER SIDE OF
THE AXIS BETWEEN 20W-36W. THE MOST CONVECTIVE CELLS ARE 100-150
NM SOUTH OF THE AXIS BETWEEN 17W-21W.

...DISCUSSION...

THE GULF OF MEXICO...
A RIDGE OF HIGH PRESSURE OVER THE WESTERN ATLANTIC THAT WAS
SUPPORTING FAIR AND MILD WEATHER ACROSS THE GULF OF MEXICO OVER
THE PAST FEW DAYS IS RETREATING TO THE EAST...AS A COLD
FRONT...DRAPED FROM A 996 MB LOW OVER ILLINOIS EXTENDS INTO THE
CENTRAL GULF FROM SOUTHERN ALABAMA TO 27N93W. BROKEN CLOUDS AND
SCATTERED SHOWERS EXTEND A FEW HUNDRED NM AHEAD OF THE FRONT.
EAST OF THE COLD FRONT A SQUALL LINE STRETCHES FROM SOUTHERN
GEORGIA TO THE FLORIDA PANHANDLE TO NEAR 28N86W. STRONG
THUNDERSTORMS...SOME OF THEM SEVERE...ARE RACING TO THE
NORTHEAST. BREEZY 20-25 KT SOUTHERLY WINDS EAST OF THE COLD
FRONT DOMINATES THE FLOW IN THE CENTRAL AND EASTERN GULF.
WESTERLY WINDS NEAR 10-15 KTS...DRIER AND SLIGHTLY COOLER
CONDITIONS ARE BEHIND THE FRONT. AS THE FRONT CONTINUES TO PULL
EASTWARD...GLOBAL MODELS FORECAST A SURFACE HIGH PRESSURE SYSTEM
TO DEVELOP NEAR THE TEXAS COASTLINE TOMORROW. FAIR WEATHER IS
LIKELY ACROSS THE GULF FOR THE NEXT DAY OR TWO. IN THE UPPER
LEVELS...A DEEP LAYER TROUGH OVER THE MIDWEST U.S. EXTENDS
SOUTHWARD INTO THE NORTHERN CENTRAL GULF. WESTERLY FLOW
DOMINATES THE REST OF THE AREA. DRY UPPER LEVEL AIR AND STRONG
SUBSIDENCE EVIDENT ON WATER VAPOR IMAGERY IS NORTH OF 25N WEST
OF 88W.

THE CARIBBEAN SEA...
MODERATE TO STRONG EASTERLY TRADEWINDS NEAR 20KT ARE OVER THE
CARIBBEAN SEA EAST OF 80W. LIGHTER EAST-SOUTHEASTERLY WINDS
NEAR 10-15 KT ARE BLOWING OVER THE NORTHWESTERN CARIBBEAN.
PATCHY AREAS OF LOW LEVEL CLOUDS WITH EMBEDDED LIGHT SHOWERS ARE
QUICKLY MOVING WESTWARD ACROSS THE EASTERN AND CENTRAL CARIBBEAN
E OF 82W.  SHOWERS ARE MOST PREVALENT JUST NORTH OF
VENEZUELA...INCLUDING THE ABC ISLANDS. IN THE UPPER LEVELS...AN
UPPER HIGH IS CENTERED NEAR 14N63W. SSW WINDS ASSOCIATED WITH
THE PERIPHERY OF THIS UPPER HIGH IS PRODUCING BROKEN MID-HIGH
LEVEL CLOUDS ACROSS THE CENTRAL CARIBBEAN...JAMAICA...HISPANIOLA
AND EASTERN CUBA. THIS UPPER HIGH IS FORECAST TO REMAIN NEARLY
STATIONARY. CONTINUED MAINLY FAIR WEATHER IS LIKELY OVER MUCH OF
THE CARIBBEAN SEA DURING THE NEXT 24 HOURS.

THE ATLANTIC OCEAN WEST OF 50W...
A 1022 MB SURFACE HIGH IS OVER THE WESTERN ATLANTIC NEAR 28N66W.
THIS HIGH IS PRODUCING FAIR WEATHER ACROSS THE AREA. A FAIRLY
TIGHT PRESSURE GRADIENT SOUTH OF THE HIGH IS PRODUCING
MODERATE TO STRONG TRADES OF AROUND 20 KT IN THE TROPICS
FROM 10N-23N WEST OF 50W. IN THE UPPER LEVELS...WESTERLY WINDS
ON THE NORTH SIDE OF THE UPPER HIGH IN THE CARIBBEAN DOMINATE
THE UPPER LEVEL FLOW IN THE REGION. THE COLD FRONT CURRENTLY
OVER THE SOUTHEAST U.S. AND THE GULF OF MEXICO WILL MOVE INTO
THE WESTERN ATLANTIC TOMORROW WHILE THE SURFACE HIGH WILL
RETREAT TO THE NORTHEAST.  GALE CONDITIONS ARE POSSIBLE AHEAD OF
THE FRONT OVER THE WESTERN ATLANTIC...NORTH OF 30N TOMORROW
MORNING.

THE ATLANTIC OCEAN EAST OF 50W...
TROPICAL STORM ZETA...THE 27TH NAMED STORM OF THE 2005...AND THE
THIRD TROPICAL OR SUBTROPICAL CYCLONE IN JANUARY REMAINS THE
MAIN FEATURE OF INTEREST IN THE EASTERN ATLANTIC. IN THE UPPER
LEVELS...A WELL-DEFINED UPPER-LEVEL TROUGH EXTENDS FROM 32N41W
TO 23N48W. THIS IS THE UPPER LEVEL TROUGH LIKELY TO WEAKEN ZETA.
UPPER LEVEL WINDS OVER THE TROPICS ARE MAINLY WESTERLIES FROM
10N-25N...EAST OF 50W.

$$
CANGIALOSI


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