[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 041047
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE OCT 04 2005

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...

TROPICAL STORM STAN WAS UPGRADED TO HURRICANE AT 04/0600 UTC.
HURRICANE STAN IS CENTERED NEAR 18.8N 94.4W OR ABOUT 105 NM ESE
OF VERACRUZ MEXICO AT 04/0900 UTC MOVING SW AT 10 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 982 MB. MAXIMUM SUSTAINED WIND SPEED
IS 65 KT WITH GUSTS TO 80 KT. SEE LATEST FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC AND THE PUBLIC ADVISORY
UNDER AWIPS/WMO HEADERS MIATCPAT5/WTNT35 FOR MORE DETAILS.
HURRICANE STAN WENT THROUGH A RAPID INTENSIFICATION DURING THE
EARLY MORNING HOURS TODAY ACCORDING TO THE HURRICANE HUNTER
AIRCRAFT. ALONG THIS TRACK AND SPEED HURRICANE STAN WILL MAKE
LANDFALL LATER TODAY. HURRICANE STAN HAS COLD CLOUD TOPS IN THE
-80 TO -85 DEG C RANGE OVER A LARGE AREA OF THE BAY OF CAMPECHE
WITH NUMEROUS STRONG CONVECTION COVERING THE AREA S OF 20N TO
JUST INLAND OVER S MEXICO BETWEEN 93W-96.5W INCLUDING VERACRUZ.
SCATTERED MODERATE/STRONG CONVECTION COVERS THE REMAINDER OF THE
AREA S OF 22N W OF 91W TO INLAND OVER MEXICO. THIS WILL GIVE THE
AREA OF MEXICO FROM S OF TAMPICO TO CIUDAD DEL CARMEN HEAVY
RAINS OF 5 TO 10 INCHES WITH ISOLATED AMOUNTS UP TO 15 INCHES.

AREA OF CONCERN IN THE BAHAMAS CONSISTS OF A BROAD AREA OF LOW
PRESSURE WITH A SURFACE TROUGH EXTENDING FROM A 1006 MB LOW
CENTERED JUST S OF ANDROS ISLAND NEAR 23N77W ACROSS THE N BAHAMA
ISLANDS TO NEAR 31N79W. THIS SYSTEM HAS THE POTENTIAL FOR
TROPICAL DEVELOPMENT IN 36 HOURS. THIS SYSTEM HAS NOT BECOME
BETTER ORGANIZED OVER THE PAST 6 HOURS BUT THE SHOWER/
THUNDERSTORM ACTIVITY HAS INCREASED E OF THE TROUGH/LOW.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE E
OF THE TROUGH TO 70W FROM 22N-30N.

...TROPICAL WAVES...

E ATLC TROPICAL WAVE IS W OF THE CAPE VERDE ISLANDS ALONG 28W S
OF 16N MOVING W 5-10 KT. BROAD MID LEVEL CYCLONIC ROTATION IS
OBSERVED JUST S OF 10N. SCATTERED CLUSTERS OF SCATTERED MODERATE
CONVECTION ARE FROM 3N-10N BETWEEN 25W-30W.

A 1010 MB LOW IS CENTERED NEAR 22N41.5W DRIFTING W. LOW LEVEL
CENTER IS CLEARLY DEFINED BUT THE ASSOCIATED CONVECTION IS WELL
TO THE NE DUE TO SOUTHWESTERLY SHEAR.

CARIBBEAN TROPICAL WAVE IS ALONG 88W S OF 17N MOVING W 5-10 KT.
WAVE IS EMBEDDED UNDER THE UPPER HIGH FLOW ASSOCIATED WITH
HURRICANE STAN FULLY MASKING ANY SIGNATURE CURVATURE IN THE
CARIBBEAN...BUT IS FAIRLY WELL DEFINED IN THE E PACIFIC.
ASSOCIATED CONVECTION IS RELATED TO UPPER RIDGE AND NOT TO THE
TROPICAL WAVE ITSELF.

...ITCZ...

ITCZ IS CENTERED ALONG 13N16W 10N20W 9N30W 7N36W 10N44W 14N53W
15N61W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS MOVING
OFF AFRICA WITHIN 120 NM ALONG THE COAST OF LIBERIA/SIERRA LEONE
AND WITHIN 60 NM OF LINE FROM 13N49W-11N56W. CLUSTERS OF
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 1N-9N BETWEEN
30W-37W.

...DISCUSSION...

GULF OF MEXICO...
MAIN WEATHER MAKER TONIGHT IN THE GULF IS HURRICANE STAN AND ITS
ASSOCIATED CONVECTION IN THE SPECIAL FEATURES. BROAD UPPER
RIDGING DOMINATES THE GULF EXCEPT IN THE NE GULF WHERE A
MID/UPPER LEVEL TROUGH EXTENDS FROM AN UPPER LOW DEVELOPING OVER
SE GEORGIA INTO THE GULF ALONG 30N83W TO 27N92W. AN UPPER HIGH
IS SITUATED NEAR STAN EXTENDS A RIDGE E INTO THE CARIBBEAN AND
TO THE W ATLC...AND A SECOND UPPER HIGH OVER N MEXICO EXTENDS A
RIDGE N OVER TEXAS WITH NE FLOW IN THE NW GULF DRAWING DRY
CONTINENTAL AIR OVER THE N GULF N OF 26N. BROAD SURFACE RIDGE
FROM THE ATLC COVERS THE SE UNITED STATES AND THE FAR N GULF
GIVING MAJORITY OF THE GULF EASTERLY FLOW EXCEPT IN THE REGION
OF HURRICANE STAN.

CARIBBEAN SEA...
UPPER HIGH ASSOCIATED WITH HURRICANE STAN IS GIVING THE W
CARIBBEAN N TO NE FLOW WITH SCATTERED SHOWERS/THUNDERSTORMS OVER
THE AREA S OF 17N W OF 80W TO INLAND OVER CENTRAL AMERICA. AN
UPPER HIGH JUST N OF PUERTO RICO IS EXTENDING A RIDGE SW OVER
THE E CARIBBEAN TO NEAR 15N66W AND IS GIVING THE NE CARIBBEAN
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION N OF A
LINE FROM THE WINDWARD ISLANDS NEAR SAINT LUCIA NW ALONG 15N67W
TO THE S COAST OF HAITI INCLUDING PUERTO RICO TO OVER LEEWARD
ISLANDS. AN INDUCED UPPER TROUGH IS BETWEEN THE ABOVE RIDGES
OVER THE CENTRAL CARIBBEAN ACROSS E CUBA TO COLOMBIA REDUCING
THE SHOWER AND THUNDERSTORM ACTIVITY IN THAT AREA.

ATLANTIC OCEAN...
BROAD UPPER HIGH ASSOCIATED WITH HURRICANE STAN EXTENDS TO THE W
ATLC W OF 79W. THE UPPER TROUGH FROM OVER THE BAHAMAS IS IN THE
SPECIAL FEATURES. TO THE E OF THIS UPPER TROUGH IS AN UPPER
RIDGE THAT EXTENDS FROM AN UPPER HIGH N OF PUERTO RICO NEAR
19N66W NW TO BEYOND 32N69W. THIS IS ENHANCING THE SHOWERS/
CONVECTION ASSOCIATED WITH THE LOW/TROUGH OVER THE BAHAMAS.
BROAD UPPER TROUGH COVERS THE AREA FROM CENTRAL ATLC TO THE E
ATLC N OF 16N FROM 40W-60W WITH AN EMBEDDED UPPER LOW NEAR
24N52W. SCATTERED SHOWERS ARE W OF THE UPPER LOW FROM 23N-27N
BETWEEN 45W-53W. A SURFACE TROUGH EXTENDS FROM 19N43W THROUGH
THE 1010 MB LOW NEAR 22N41.5W NE OUT OF THE REGION NEAR 32N36W.
BROAD UPPER RIDGE COVERS THE REMAINDER OF THE E ATLC WITH A
RIDGE EXTENDING FROM AN UPPER HIGH W OF THE CAPE VERDE ISLANDS
NEAR 16N28W N TO BEYOND 32N25W. DIFFLUENCE BETWEEN THE RIDGE OF
THE E ATLC AND THE TROUGH OVER THE CENTRAL ATLC IS PRODUCING AN
AREA OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 20N
BETWEEN 26W-45W.

$$
WALLACE



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