[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 032358
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE JAN 03 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
2315 UTC.

...SPECIAL FEATURE...

THE CENTER OF TROPICAL STORM ZETA AT 03/2100 UTC IS NEAR
23.2N 42.4W...OR ABOUT 1200 NM/2220 KM EAST-NORTHEAST OF THE
NORTHERN LEEWARD ISLANDS. IT IS MOVING WEST 4 KT. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 994 MB. THE MAXIMUM SUSTAINED WIND
SPEEDS ARE 55 KT WITH GUSTS TO 65 KT. PLEASE REFER TO THE LATEST
FORECAST/ADVISORY LISTED UNDER THE AWIPS/WMO HEADERS MIATCMAT5/
WTNT25 KNHC FOR MORE DETAILS. SCATTERED MODERATE TO STRONG
SHOWERS AND THUNDERSTORMS ARE OCCURRING FROM 23N TO 26N BETWEEN
40W AND 42W TO THE NORTHEAST OF THE CENTER. ISOLATED MODERATE TO
LOCALLY STRONG SHOWERS AND THUNDERSTORMS ARE FOUND ELSEWHERE
FROM 21N TO 23N BETWEEN 38W AND 43W. AN UPPER LEVEL TROUGH IS
PRACTICALLY SUPERIMPOSED ON ZETA AT THIS TIME.  THIS TROUGH
SHOULD CONTINUE TO MOVE EASTWARD...AND IT IS LIKELY THAT STRONG
NORTHWESTERLY FLOW IN ITS WAKE SHOULD BEGIN TO DISRUPT THE
SYSTEM IN 12 TO 24 HOURS. THE FORECAST SHOWS A WEAKENING TREND
TO BEGIN TOMORROW.

...ITCZ...
ITCZ 7N11W 6N16W 4N20W 3N28W 4N34W 3N43W TO THE EQUATOR AT 47W.
ISOLATED MODERATE TO LOCALLY STRONG SHOWERS AND THUNDERSTORMS
ARE WITHIN 250 NM ON EITHER SIDE OF AXIS. THE COMPARATIVELY
STRONGEST SHOWERS WITH THE COLDEST CLOUD TOP TEMPERATURES...
-69C TO -74C...ARE WITHIN 15 TO 30 NM ON EITHER SIDE OF 6N36W
5N41W 4N44W 3N47W.

...DISCUSSION...

THE GULF OF MEXICO...
A COLD FRONT PASSES THROUGH 32N74W IN THE WESTERN ATLANTIC OCEAN
TO THE FLORIDA EAST COAST NEAR 28N...ACROSS FLORIDA AND INTO THE
CENTRAL GULF OF MEXICO NEAR 24N91W. A 1019 MB HIGH PRESSURE
CENTER IS LOCATED ALONG THE NORTHERN COAST OF CUBA ALONG 80W.
A 1021 MB HIGH PRESSURE CENTER IS ALONG THE EAST TEXAS/
SOUTHWESTERN LOUISIANA BORDER RIGHT THROUGH 30N. A MIDDLE TO
UPPER LEVEL TROUGH IN CURRENT WATER VAPOR IMAGERY AND IN
03/2100 UTC CIMSS SATELLITE DERIVED WIND DATA PASSES THROUGH
33N75W TO THE NORTHERN BAHAMAS...INTO THE NORTHWESTERN CARIBBEAN
SEA NEAR 20N84W. THE TROUGH IS MUCH MORE WELL DEFINED...WITH A
SHARPER ANGLE TO THE FLOW...IN THE ATLANTIC WATERS. THE FLOW IS
MUCH MORE GRADUAL AND GENTLE AND BROAD IN THE GULF OF MEXICO AND
NORTHWESTERN CARIBBEAN SEA. MIDDLE TO UPPER LEVEL DRY AIR IS
NORTH AND NORTHEAST OF 24N98W 21N90W. MOISTURE IS MOVING
NORTHWARD TO THE SOUTH OF THE 24N98W 21N90W LINE...WITH THE
UPPER LEVEL SOUTHERLY WIND FLOW MOVING ACROSS MEXICO.

THE CARIBBEAN SEA...
EASTERLY TRADEWINDS OF 15 TO 20 KT ARE FOUND SOUTH OF 16N EAST
OF 80.5W. NORTHEASTERLY WIND FLOW OF 10 TO 15 KT IS FOUND
ELSEWHERE SOUTH OF 16N. LOW CLOUDS AND POSSIBLE PRECIPITATION
ARE SOUTHWEST OF 20N84W 18N80W 15N74W 15N70W 15N60W. ISOLATED
MODERATE SHOWERS ARE FOUND...FOR EXAMPLE...FROM 14N TO 18N
BETWEEN 81W AND 85W. AN UPPER LEVEL RIDGE IS POSITIONED ALONG
10N...PUSHING SCATTERED TO BROKEN HIGH CLOUDS UNDER THE
SOUTHWESTERLY TO WESTERLY WIND FLOW.

THE ATLANTIC OCEAN...
THE COLD FRONT PASSES THROUGH 32N74W IN THE WESTERN ATLANTIC
OCEAN TO THE FLORIDA EAST COAST NEAR 28N. SCATTERED MODERATE
SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE WITHIN 90 TO 120 NM
ON EITHER SIDE OF 28N74W 30N71W BEYOND 32N69W. A SURFACE
RIDGE PASSES THROUGH 32N54W TO 26N60W TO 23N71W TO 21N74W.
T.S. ZETA HAS BEEN MOVING WESTWARD SLOWLY BUT SURELY SINCE ITS
BIRTH ON 30 DEC AROUND 1700 UTC. A SURFACE RIDGE IS ALONG 28N34W
BEYOND 32N28W. UPPER LEVEL SOUTHERLY FLOW BECOMES SOUTHWESTERLY
AS IT CROSSES 10N BETWEEN 50W AND 60W...ASSOCIATED WITH THE SAME
UPPER LEVEL RIDGE WHICH IS INFLUENCING THE CARIBBEAN SEA WEATHER.
THIS FLOW IS MEETING UPPER LEVEL WESTERLY FLOW...ALSO FROM THE
CARIBBEAN SEA...AND CONTINUING EAST OF 40W FROM 10N TO 20N.
A RIDGE/TROUGH COUPLET FOLLOWS T.S. ZETA EASTWARD TO AFRICA.
THE FLOW BECOMES ANTICYCLONIC JUST EAST OF ZETA...FOLLOWED BY
A MIDDLE TO UPPER LEVEL TROUGH FROM 36N17W TO 30N19W TO 27N22W.
SOME OF THE UPPER LEVEL FLOW FROM 10N TO 20N BETWEEN 40W AND 50W
EVENTUALLY MOVES TOWARD 30W AND DIVES SOUTHEASTWARD AS PART OF
THE UPPER LEVEL RIDGE IN THAT AREA. THE REST OF THE FLOW
CONTINUES
EASTWARD TO AFRICA AS UPPER LEVEL SOUTHWESTERLY FLOW.

$$
MT

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