[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 210541
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI OCT 21 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURE...

DANGEROUS CATEGORY FOUR HURRICANE WILMA IS CENTERED NEAR 19.5N
86.1W...OR ABOUT 80 NM SE OF COZUMEL MEXICO...AT 21/0600 UTC
MOVING NW 5 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 930 MB.
MAXIMUM SUSTAINED WIND SPEED IS 130 KT WITH GUSTS TO 160 KT. 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. WILMA COMPLETED AN
EYEWALL REPLACEMENT CYCLE EARLIER TODAY AND THE NEW LARGER EYE
HAS A DIAMETER OF 30 NM OR SO. STRONG CONVECTION WITH CLOUD TOPS
TO -80C HAS BEEN MAINTAINED OVER THE PAST FEW HOURS ESPECIALLY
OVER THE ERN SEMICIRCLE AND WATER VAPOR IMAGERY INDICATES
EXCELLENT OUTFLOW TO THE N/NE OF THE SYSTEM...BUT SOMEWHAT MORE
MODEST TO THE S AND NON-EXISTENT TO THE W. NUMEROUS MODERATE/
STRONG CONVECTION IS WITHIN 200 NM SE SEMICIRCLE AND 150 NM NW
SEMICIRCLE (EXCEPT THE RAINBANDS ARE NOT PENETRATING THAT FAR
INLAND OVER THE YUCATAN PENINSULA). WIDELY SCATTERED MODERATE/
STRONG CONVECTION IN RAINBANDS ALSO EXTENDS MAINLY NE OF WILMA
FROM 21N-26N BETWEEN 80W-86W...EXTENDING ACROSS CUBA...THE
FLORIDA STRAITS...AND THE SE GULF. RADAR IMAGERY FROM CANCUN
SHOWS AN IMPRESSIVE CIRCULAR EYE WITH HEAVY RAINBANDS SPREADING
ACROSS THE YUCATAN CHANNEL AND THE NE PART OF THE MEXICAN STATE
OF QUINTANA ROO...INCLUDING AREAS SUCH AS CANCUN...COZUMEL...AND
TULUM. CONDITIONS WILL ONLY WORSEN IN THESE AREAS AS THE CORE OF
WILMA APPROACHES THE COAST THROUGHOUT THE DAY.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE ALONG 32W S OF 16N MOVING W 10-15
KT. THE WAVE IS LOW IN AMPLITUDE BUT HAS A WEAK INVERTED-V
SIGNATURE EMBEDDED WITHIN THE ITCZ. SCATTERED MODERATE
CONVECTION FROM 8N-12N BETWEEN 28W-34W.

STRONG TROPICAL WAVE APPROACHING THE LESSER ANTILLES ALONG
58W/59W S OF 17N MOVING W 10-15 KT. THE WAVE IS PRODUCING AN
AREA OF SCATTERED MODERATE CONVECTION FROM 11N-17N BETWEEN
57W-62W WHICH HAS ALREADY SPREAD ACROSS BARBADOS AND PARTS OF
THE WINDWARD ISLANDS BETWEEN ST. VINCENT AND MARTINIQUE. RADAR
IMAGERY FROM MARTINIQUE SHOWS A SEMI-ENCLOSED CIRCULATION
EMBEDDED IN THE PRECIPITATION ECHOES...MOVING WWD S OF BARBADOS
TOWARDS ST. VINCENT AND THE GRENADINES. IN ADDITION...THE WINDS
AT BARBADOS AND ST. LUCIA HAVE BEEN SUSTAINED AT 29 KT AND 23 KT
(WITH A GUST TO 37 KT AT ST. LUCIA) RESPECTIVELY OVER THE PAST
FEW HOURS. MOISTURE ASSOCIATED WITH THE WAVE IS EXPECTED TO
SPREAD NW ACROSS THE REMAINDER OF THE LESSER ANTILLES TOWARDS
HISPANIOLA OVER THE NEXT 48 HRS...AND SHOULD LINGER OVER THE
AREA SUPPORTING A THREAT FOR WIDELY SCATTERED SHOWERS/TSTMS AT
ANY TIME OVER THE WEEKEND.

CENTRAL CARIBBEAN TROPICAL WAVE ALONG 67W S OF 22N MOVING W 15
KT. THE MOST PRONOUNCED PART OF THE WAVE IS ASSOCIATED WITH A
SURFACE TROUGH N OF PUERTO RICO WHICH HAS SPLIT OFF FROM THE
MAIN AXIS AND IS MOVING NW. THE SECTION OF THE WAVE OVER THE
CARIBBEAN IS WEAK AND NOT ASSOCIATED WITH ANY DEEP CONVECTION.

WEST CARIBBEAN TROPICAL WAVE ALONG 79W S OF 15N MOVING W 10-15
KT. THE WAVE IS EMBEDDED IN BROAD SOUTHERLY FLOW FEEDING INTO
HURRICANE WILMA...SO IT DOES NOT HAVE A DISTINGUISHABLE
SIGNATURE AND IS NOT ASSOCIATED WITH ANY DEEP CONVECTION.

...ITCZ...

ITCZ IS CENTERED ALONG 12N16W 8N40W 12N58W. SCATTERED MODERATE
CONVECTION WITHIN 160 NM OF THE AXIS BETWEEN 23W-34W...PARTLY
ASSOCIATED WITH THE TROPICAL WAVE NEAR 34W. SCATTERED MODERATE
WITHIN 150 NM OF THE AXIS BETWEEN 34W-40W. WIDELY SCATTERED
MODERATE WITHIN 160 NM OF THE AXIS BETWEEN 44W-54W.

...DISCUSSION...

GULF OF MEXICO...
THE OUTERMOST RAIN BANDS OF HURRICANE WILMA HAVE BEGUN TO SPREAD
THROUGH THE YUCATAN CHANNEL INTO THE SE GULF AND WESTERN FLORIDA
STRAITS...AS OBSERVED IN SATELLITE IMAGERY AND CUBAN RADAR. IN
ADDITION...CIRRUS OUTFLOW FROM THE STORM IS TRAPPED E OF A LINE
FROM THE N COAST OF THE YUCATAN PENINSULA NEWD TO THE BIG BEND
OF FLORIDA...BOUNDED TO THE W BY A LARGE AREA OF DRY AIR AND
MODERATE/STRONG SUBSIDENCE. THIS DRY AIR IS BEING BROUGHT ACROSS
THE W GULF BY NORTHERLY FLOW ON THE E SIDE OF A MID/UPPER LEVEL
HIGH CENTERED OVER CNTRL MEXICO. ALSO...A BROAD UPPER LEVEL
TROUGH IS SWINGING EWD ALONG THE N GULF COAST AND MAY BE THE
CULPRIT FOR WILMA'S SHORT-TERM JOG TO THE NORTH...BUT IT IS A
LITTLE UNCERTAIN AT THIS TIME IF THIS IS ONLY TEMPORARY.
SHOWER/TSTMS ARE EXPECTED TO BECOME MORE SCATTERED OVER THE SE
GULF AS WILMA CONTINUES TO SLOWLY LIFT N...AND THEN THE
STRONGEST WINDS AND HEAVIEST RAINS WILL MOVE INTO THE AREA
WITHIN THE NEXT 24-36 HRS AS PER THE LATEST NHC FORECAST TRACK.
ELSEWHERE...A COASTAL TROUGH HAS SET UP JUST OFFSHORE TEXAS BUT
IS CAUSING NO PRECIPITATION. A COLD FRONT OVER S/E TEXAS IS
EXPECTED TO MOVE OFF THE COAST LATER TODAY.

CARIBBEAN...
SEE SPECIAL FEATURES FOR DISCUSSION ON WILMA. SATELLITE-DERIVED
UPPER LEVEL WINDS INDICATE THAT AN UPPER LEVEL ANTICYCLONE HAS
DEVELOPED SE OF WILMA NEAR 16N75W...OR JUST SE OF JAMAICA. A
SMALL AREA OF SUBSIDENCE IS LOCATED NEAR THE CENTER OF THE
ANTICYCLONE BUT UPPER LEVEL CIRRUS MOSTLY FROM WILMA COMPLETELY
ENSHROUDS THIS AREA FROM THE N AND W. AN UPPER LOW IS MOVING W
ACROSS NRN VENEZUELA NEAR 9N66W WITH AN INVERTED TROUGH
EXTENDING N TO THE NRN LEEWARD ISLANDS. UPPER DIFFLUENCE E OF
THE TROUGH IS INTERACTING WITH THE TROPICAL WAVE APPROACHING THE
LESSER ANTILLES TO PRODUCE AN AREA OF TSTMS SPREADING ACROSS
BARBADOS TO PARTS OF THE WINDWARD ISLANDS. CONVERSELY...
SUBSIDENCE AHEAD OF THE UPPER LOW IS SUPPORTING A NICE
CONVECTION-FREE NIGHT OVER MUCH OF VENEZUELA AND NRN COLOMBIA.

ATLANTIC...
THE UPPER LEVEL ANTICYCLONE OVER THE CNTRL CARIBBEAN STRETCHES
NWD ACROSS THE GREATER ANTILLES TO OVER FLORIDA AND THE BAHAMAS
WITH OUTFLOW FROM WILMA EXTENDING EWD INTO THE ATLC S OF 28N. AN
UPPER LEVEL SHORTWAVE TROUGH IS ALONG 69W N OF 26N AND
DIFFLUENCE ALOFT IS SUPPORTING SCATTERED MODERATE CONVECTION
FROM 25N-30N BETWEEN 54W-65W...POSSIBLY ALSO FOCUSED ALONG A
WEAK SURFACE TROUGH IN THE AREA. HOWEVER...A LARGE SUBTROPICAL
HIGH OVERWHELMINGLY COVERS MOST OF THE ATLC WITH A MEAN CENTER
NEAR 31N42W AND PRES OF 1023 MB. A SECOND LARGE UPPER LEVEL HIGH
IS CENTERED OVER THE CENTRAL ATLC NEAR 27N40W AND HAS PUSHED THE
SUBTROPICAL JET N OF THE AREA TOWARDS THE AZORES. A NARROW
MID-OCEANIC TROUGH LIES S OF THE HIGH FROM THE COAST OF
MAURITANIA WWD ACROSS THE CAPE VERDE ISLANDS TO 16N40W 20N50W
WITH THE SOUTHERN STREAM OF THE SUBTROPICAL JET DIPPING DOWN TO
ABOUT 13N/14N. THERE IS JUST ENOUGH DIFFLUENCE ASSOCIATED WITH
THE TROUGH TO ENHANCE CONVECTION ALONG THE TROPICAL WAVE NEAR
34W. FARTHER E...AN UPPER TROUGH IS DIGGING SWD FROM S/CNTRL
SPAIN TO THE CANARY ISLANDS...MOVING INTO MOROCCO...BUT THE
ASSOCIATED COLD FRONT REMAINS N OF THE AREA.

$$
BERG


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