00
AXNT20 KNHC 201045
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU OCT 20 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 FEATURE...

HURRICANE WILMA REMAINS A DANGEROUS CATEGORY 4 HURRICANE
CENTERED NEAR 18.3N 85.0W...OR 170 NM SE OF COZUMEL MEXICO...AT
20/0900 UTC MOVING WNW AT 7 KT. MAXIMUM SUSTAINED WIND SPEED IS
130 KT WITH GUSTS TO 160 KT. ESTIMATED MINIMUM CENTRAL PRESSURE
IS 900 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT4/WTNT24 KNHC AND THE PUBLIC ADVISORY UNDER
AWIPS/WMO HEADERS MIATCPAT4/WTNT34 KNHC FOR MORE DETAILS. THE
SATELLITE REPRESENTATION LOOP OF WILMA REMAINS IMPRESSIVE WITH
DEEP CONVECTION WRAPPING AROUND THE CORE. WILMA REMAINS SERIOUS
THREAT TO THE NW CARIBBEAN. SCATTERED/NUMEROUS STRONG CONVECTION
EXTENDS WITHIN 90 NM OF THE CENTER IN THE N SEMICIRCLE AND 120
NM IN S SEMICIRCLE. SCATTERED MODERATE/STRONG CONVECTION IS
LOCATED ELSEWHERE IN SPIRAL BAND WITHIN 90 NM OF LINE 16N81W-
20N82W-22N85W AND FROM 12N75W TO 19N78W INCLUDING ALL OF
JAMAICA. HEAVY SHOWERS/THUNDERSTORMS COVER ALL OF CUBA AND MOST
OF HONDURAS WITH SCATTERED SHOWERS/THUNDERSTORMS OVER THE
REMAINDER OF CENTRAL AMERICA AND THE E COAST OF THE YUCATAN
PENINSULA.

...TROPICAL WAVES...

E ATLC TROPICAL WAVE IS ALONG 28W/29W S OF 12N MOVING W 10-15
KT. WAVE HAS A LOW AMPLITUDE SIGNATURE WITH THE AXIS FOLLOWING A
CLUSTER OF CONVECTION WITHIN THE ITCZ. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE FROM 8N-11N BETWEEN
25W-33W.

CENTRAL ATLC TROPICAL WAVE IS ALONG 55W S OF 16N MOVING W 10-15
KT. LOW AMPLITUDE WAVE EMBEDDED WITHIN A LARGE AREA OF
CONVECTION WHERE STRONG E LOW-LEVEL FLOW CONVERGES WITH WEAKER
WINDS OFF THE SOUTH AMERICAN COAST. SCATTERED MODERATE/STRONG
CONVECTION IS FROM 10N-16N BETWEEN 52W-57W WITH A SMALL AREA OF
NUMEROUS STRONG CONVECTION WITHIN A 45/60 NM RADIUS OF 11.5N55W.

E CARIBBEAN TROPICAL WAVE IS ALONG 63W S OF 22N MOVING W 10-15
KT. WAVE IS LOCATED ON THE W SIDE OF A SHARP UPPER LEVEL TROUGH
WHICH IS DISPLACING THE DEEP CONVECTION TO THE E OVER THE LESSER
ANTILLES. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM 11N-20N BETWEEN 56W TO OVER THE LESSER
ANTILLES.

CENTRAL CARIBBEAN TROPICAL WAVE IS ALONG 75W/76W S OF 16N MOVING
W 10 KT. WAVE SIGNATURE REMAINS MASKED BY UPPER OUTFLOW FROM
HURRICANE WILMA WITH SCATTERED MODERATE/ISOLATED STRONG
CONVECTION INLAND OVER COLOMBIA MOVING TOWARD E PANAMA.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 13N17W 9N24W 6N41W 9N52W 12N62W.
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 90 NM S OF THE
AXIS FROM 37W-41W AND WITHIN 200 NM N OF THE AXIS FROM 41W-52W.

...DISCUSSION...

GULF OF MEXICO...
TRANQUIL WEATHER THIS MORNING OVER THE GULF WHICH IS DECEIVINGLY
COVERING UP THE APPROACHING HURRICANE THAT LOOMS IN THE NW
CARIBBEAN. THE UPPER RIDGE IS GIVING WAY TO HURRICANE WILMA IN
THE SE AND THE DEEP LAYERED TROUGH OVER THE CENTRAL UNITED
STATES. RIDGE AXIS EXTENDS INTO THE W GULF NEAR THE TEXAS/MEXICO
BORDER TO NEAR 25N91W IN THE CENTRAL GULF AND CONTINUES
PRODUCING STRONG SUBSIDENCE OVER THE ENTIRE AREA...EXCEPT OVER
THE SE GULF WHERE CIRRUS CLOUDS FROM WILMA ARE SPREADING S OF
27N E OF 90W. AS SUCH...THE WEATHER REMAINS MOSTLY DRY EXCEPT
FOR SCATTERED SHOWERS/ISOLATED THUNDERSTORMS JUST N OF CUBA AND
THE YUCATAN CHANNEL ASSOCIATED WITH THE OUTER MOST RAINBANDS OF
WILMA. CONDITIONS WILL CONTINUE TO DETERIORATE FROM CUBA TO THE
YUCATAN PENINSULA N THROUGH THE FLORIDA STRAITS SPREADING NE AS
WILMA CONTINUES ITS TREK TOWARDS THE GULF. THE WORST CONDITIONS
ARE EXPECTED FROM THE YUCATAN NE TO FLORIDA THROUGH THE WEEKEND
DUE TO WILMA WHILE THE REMAINDER OF THE GULF SHOULD HAVE A NICE
DRY WEEKEND.

CARIBBEAN...
SEE SPECIAL FEATURES FOR DISCUSSION ON WILMA. THE BROAD OUTFLOW
CANOPY OF WILMA SPREADS AWAY FROM THE STORM NE INTO THE W
ATLC...SE ACROSS THE ENTIRE W CARIBBEAN...AND SW ACROSS CENTRAL
AMERICA. FARTHER E...DRIER AIR CONTINUES TO INFILTRATE INTO THE
CENTRAL CARIBBEAN TO ABOUT 75W PRODUCING FAIR SKIES EXCEPT OVER
THE LESSER ANTILLES WHERE SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE MOVING INTO THE E CARIBBEAN ASSOCIATED WITH
THE TROPICAL WAVE OVER THE E CARIBBEAN. HISPANIOLA AND PUERTO
RICO ARE GETTING A BRIEF BREAK AS WILMA MOVES AWAY BEFORE THE
TROPICAL WAVE MOVES IN.

WEST ATLANTIC...
UPPER TROUGH IN THE W ATLC EXTENDS ALONG 32N72W TO 27N77W WITH
THE SUBTROPICAL JET WITH WINDS TO 50 KT EXTENDING FROM S FLORIDA
NEAR 25N84W E TO 27N71W THEN WITH WINDS INCREASING TO 90 KT NE
TO BEYOND 32N63W. A SURFACE TROUGH EXTENDS BENEATH THE JET FROM
A COLD FRONT NEAR 32N62W TO 26N72W WITH SCATTERED SHOWERS/
THUNDERSTORMS WITHIN 350/400 NM S OF THIS BOUNDARY.

EAST/CENTRAL ATLANTIC...
A SHARP NARROW UPPER TROUGH LIES JUST E OF THE LESSER ANTILLES
ALONG 59W FROM 10N-20N AND DOWNSTREAM UPPER DIFFLUENCE IS
TRIGGERING SCATTERED THUNDERSTORMS E OF THE TROPICAL WAVE THAT
IS IN THE E CARIBBEAN. LARGE UPPER HIGH IS CENTERED OVER THE
SUBTROPICS NEAR 28N40W AND IS SUPPORTING BROAD HIGH PRESSURE AT
THE SURFACE WITH A 1023 MB CENTERED NEAR 32N35W. THE WEAK LOW
THAT WAS IN THE CENTRAL ATLC IS NOW A SURFACE TROUGH EXTENDING
FROM 31N43W TO 25N45W AND STILL LACKS ANY SHOWERS. UPPER TROUGH
EXTENDS FROM INLAND OVER MOROCCO/WESTERN SAHARA INTO THE E ATLC
NEAR 21N16W TO OVER THE CAPE VERDE ISLANDS NEAR 16N25W AND SHEAR
AXIS CONTINUES NW TO 23N48W. WIDESPREAD SAHARAN DUST EXTENDS
ACROSS A GOOD PORTION OF THE ATLC WITHIN 250/300 NM OF LINE FROM
THE COAST OF AFRICA NEAR 17N16W 11N38W TO 23N54W.

$$
WALLACE