[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 231205
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN OCT 23 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
1115 UTC.

...SPECIAL FEATURES...

HURRICANE WILMA IS CENTERED NEAR 22.4N 86.1W OR 78 NM/145 KM
NNE OF CANCUN MEXICO AND 274 NM/505 KM WSW OF KEY WEST
FLORIDA...AT 23/1200 UTC...MOVING NE 7 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 961 MB. MAXIMUM SUSTAINED WIND SPEED IS
85 KT WITH GUSTS TO 105 KT...MAKING WILMA A CATEGORY 2
HURRICANE. SEE THE 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.
DESPITE THE FACT THAT WILMA'S INNER CORE WAS OBLITERATED AFTER
MOVING ACROSS THE YUCATAN PENINSULA...INFRARED SATELLITE IMAGERY
INDICATES THAT A NEW EYEWALL HAS FORMED OVER THE PAST FEW HOURS
WITHIN 30 NM OF THE CENTER. THERE IS A GENERALLY CLEARER MOAT
REGION 40-50 NM OUT FROM THE CENTER...AND THEN ANOTHER RING OF
DEEP CONVECTION BEYOND 50 NM...VERIFIED BY CANCUN RADAR. THE
OUTER RING OF STRONG CONVECTION IS STILL POUNDING CANCUN WITH
HEAVY RAIN AND STRONG WINDS ALTHOUGH IT DOES APPEAR IT MAY
SETTLE DOWN WITHIN THE NEXT FEW HOURS. THE SATELLITE
REPRESENTATION OF WILMA...AND PROBABLY THE CIRCULATION TOO...HAS
BECOME ELONGATED NNE/SSW DUE TO INTERACTION WITH THE COLD FRONT
OVER THE GULF OF MEXICO. NUMEROUS MODERATE/STRONG CONVECTION
EXTENDS FROM 19N-26N BETWEEN 84W-89W...STRONGEST OVER THE NRN
SEMICIRCLE. WILMA'S LANDFALL IS EXPECTED ALONG THE SW FLORIDA
COAST MON MORNING LIKELY AS A CATEGORY 2...BUT POSSIBLY AS A
CATEGORY 3 HURRICANE.

TROPICAL STORM ALPHA IS CENTERED NEAR 18.4N 71.4W OR 22 NM/35 KM
WNW OF BARAHONA IN THE DOMINICAN REPUBLIC...AT 23/1200 UTC
MOVING NW 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB.
MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SEE
THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT5/WTNT25 KNHC AND THE PUBLIC ADVISORY UNDER HEADERS
MIATCPAT5/WTNT35 KNHC FOR MORE DETAILS. IT IS EXTREMELY
DIFFICULT TO DETERMINE FROM INFRARED SATELLITE IMAGERY...BUT IT
IS POSSIBLE THAT ALPHA HAS OR IS CLOSE TO MAKING LANDFALL OVER
SW DOMINICAN REPUBLIC. DEEP CONVECTION HAS INCREASED IN COVERAGE
AND INTENSITY OVER THE PAST SEVERAL HOURS...WHICH HEIGHTENS THE
CONCERN OF FLASH FLOODING AND MUDSLIDES OVER THE MOUNTAINOUS
TERRAIN OF HISPANIOLA. NUMEROUS MODERATE/STRONG CONVECTION IS
FROM 15.5N-20N BETWEEN 68W-74W AND CONTINUES TO SPREAD N AND W
OVER THE DOMINICAN REPUBLIC AND HAITI. THE STRONGEST CONVECTION
IS LOCATED ON THE S SHORE OF THE ISLAND...POSSIBLY DUE TO STRONG
OROGRAPHIC LIFTING OF THE SLY FLOW. FOUR TO EIGHT INCHES OF RAIN
ARE EXPECTED OVER HISPANIOLA WITH ISOLATED AMOUNTS UP TO 15" IN
THE MOUNTAINS.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE ADDED ALONG 32W/33W S OF 15N MOVING
W 10-15 KT. THE WAVE IS ADDED BASED ON A CLUSTER OF CONVECTION
WHICH HAS FORMED NEAR THE AXIS...A SATELLITE HOVMOELLER DIAGRAM
WHICH SHOWS A CONTINUOUS CLUSTER OF CLOUDS/CONVECTION HAVING
MOVED OFF THE AFRICAN COAST OCT 19...AND 700 MB RELATIVE
VORTICITY GUIDANCE FROM THE GFS. NUMEROUS MODERATE/STRONG
CONVECTION FROM 7N-10N BETWEEN 28W-34W.

CENTRAL ATLANTIC TROPICAL WAVE ALONG 46W S OF 17N MOVING
W 15 KT. THE WAVE HAS A LOW AMPLITUDE AND IS UNDER THE INFLUENCE
OF STRONG WESTERLY SHEAR...WHICH IS PUSHING ALL DEEP CONVECTION
E OF THE UPPER TROUGH AXIS (ALONG 44W) IN THE AREA OF BROADEST
UPPER DIFFLUENCE. SCATTERED SHOWERS/TSTMS FROM 7N-15N BETWEEN
40W-45W.

WEST CARIBBEAN TROPICAL WAVE ALONG 79W/80W S OF 15N MOVING
W 15 KT. THE WAVE'S SIGNATURE IS BECOMING INCREASINGLY DIFFICULT
TO FIND NOW THAT IT IS EMBEDDED IN BROAD SOUTHERLY FLOW FEEDING
INTO HURRICANE WILMA. ISOLATED SHOWERS/TSTMS LIE S OF 13N OVER
THE SW CARIBBEAN WATERS.

...ITCZ...

ITCZ IS CENTERED ALONG 15N10W 6N20W 12N44W 10N50W 11N64W.
NUMEROUS MODERATE/STRONG CONVECTION FROM 3N-10N BETWEEN
11W-23W...POSSIBLY ASSOCIATED WITH A NEW TROPICAL WAVE MOVING
OFF THE AFRICAN COAST. WIDELY SCATTERED MODERATE FROM 1N-6N
BETWEEN 25W-34W. SCATTERED MODERATE FROM 10N-13N BETWEEN 55W-61W
SLIDING SWD FROM BARBADOS AND TOBAGO. SEE ABOVE FOR ADDITIONAL
CONVECTION ASSOCIATED WITH TROPICAL WAVES.

...DISCUSSION...

GULF OF MEXICO...
HURRICANE WILMA IS JUST N OF THE NE TIP OF THE YUCATAN PENINSULA
AND IS BEGINNING TO SLOWLY LIFT NE AHEAD OF AN APPROACHING COLD
FRONT. SEE SPECIAL FEATURES FOR DISCUSSION ON WILMA. THE COLD
FRONT NOW STRETCHES FROM DAYTONA BEACH FLORIDA SW JUST N OF
TAMPA TO 24N90W...AND THEN SW TO NEAR MINATITLAN MEXICO. A WIND
SHIFT IS NOTED ACROSS THE FRONT OVER N FLORIDA...BUT THE
BOUNDARY OVER THE GULF WATERS IS LESS DISTINCT AND IS PRIMARILY
ALIGNED ALONG THE LEADING EDGE OF A DROP IN DEWPOINTS. THE DRIER
AIR HAS MADE IT ALL THE WAY INTO THE BAY OF CAMPECHE...WITH
VERACRUZ RECENTLY REPORTING THE DEWPOINT DROPPING BELOW 70F. THE
BROAD UPPER LEVEL TROUGH WHICH IS HELPING TO LIFT WILMA SLOWLY
NWD IS ALONG 90W N OF 27N...BUT A MORE SIGNIFICANT SHORTWAVE
TROUGH IS STILL LOCATED OVER THE CENTRAL PLAINS OF THE U.S. AND
IS EXPECTED TO DIG S TO THE N GULF COAST BY MON MORNING...
INITIATING WILMA'S ACCELERATION TO THE NE. FOR NOW...EXTREMELY
DRY AIR AND STRONG SUBSIDENCE LIE W OF 90W DUE TO A MID/UPPER
RIDGE OVER CNTRL MEXICO WHILE EXTENSIVE CIRRUS OUTFLOW FROM
WILMA EXTENDS NE OF THE STORM ACROSS THE E GULF AND FLORIDA.

CARIBBEAN...
DEEP CONVECTION ON THE SE SIDE OF HURRICANE WILMA CONTINUES TO
AFFECT PARTS OF THE FAR NW CARIBBEAN AND THE YUCATAN
CHANNEL...BUT THE WORST CONDITIONS ARE NOW BEGINNING TO LIFT N
OF THE AREA. THE UPPER LEVEL FLOW OVER THE CARIBBEAN IS RATHER
COMPLEX ALTHOUGH GENERALLY SPEAKING IT IS DOMINATED BY
SUBSTANTIAL EASTERLY FLOW FROM THE 67W TO 80W...AND THEN SPLITS
N ACROSS THE CAYMAN ISLANDS AND SW TOWARDS CNTRL AMERICA INTO
THE OUTFLOW JETS OF HURRICANE WILMA. TROPICAL STORM ALPHA IS
CLOSE TO MAKING LANDFALL ON THE S COAST OF THE DOMINICAN
REPUBLIC. SEE SPECIAL FEATURES FOR FURTHER DISCUSSION. NORTHERLY
UPPER FLOW LIES ACROSS THE LESSER ANTILLES ON THE W SIDE OF A
LARGE UPPER TROUGH OVER THE CNTRL ATLC. ABUNDANT MOISTURE IS
POOLED OVER THE E CARIBBEAN...RESULTING IN WIDESPREAD CLOUDINESS
AND SCATTERED SHOWERS...BUT A PUNCH OF DRIER AIR IS EXPECTED TO
MOVE IN FROM THE ATLC SUN NIGHT AND MON AND WILL PUSH THE
WETTEST WEATHER WWD TO THE W CARIBBEAN BY MID-WEEK.

WEST ATLANTIC...
THE COLD FRONT WHICH HAS SPREAD ACROSS THE GULF OF MEXICO IS
OVER THE FAR W ATLC WATERS FROM 32N76W SW TO JUST N OF TAMPA
FLORIDA. THE SUBTROPICAL JET LIES ON THE NRN PERIPHERY OF
HURRICANE WILMA AND EXTENDS ACROSS SRN GEORGIA AND SOUTH
CAROLINA...MERGING WITH THE VIGOROUS POLAR JET OFF THE MID-ATLC
STATES. WIDESPREAD TROPICAL MOISTURE AND HIGH CIRRUS EXTEND UP
TO 600 NM SE OF THE JET TO ABOUT 25N WITH SCATTERED
SHOWERS/TSTMS EXTENDING N OF 28N BETWEEN 73W-81W. SCATTERED
MODERATE CONVECTION ALSO EXTENDS WITHIN 180 NM SE OF A SURFACE
TROUGH WHICH LIES ALONG 32N67W 28N72W. ALL THIS ACTIVITY LIES N
OF AN UPPER HIGH CENTERED JUST E OF THE TURKS AND CAICOS ISLANDS
NEAR 24N71W.

EAST/CENTRAL ATLANTIC...
A SHARP UPPER RIDGE EXTENDS FROM THE UPPER HIGH NEAR THE TURKS
AND CAICOS ISLANDS NEWD TO 27N50W. A STATIONARY UPPER TROUGH
CONTINUES TO LIE S OF THE RIDGE ALONG 16N WITH A WEAK UPPER LOW
NEAR 16N43W. THE LOW IS MAKING A SWD INDENTATION IN A 50 KT
WESTERLY JET TO ITS S...WHICH IS CONSEQUENTLY INCREASING
DIFFLUENCE OVER THE ITCZ BETWEEN 30W-45W. ANOTHER UPPER LEVEL
TROUGH LIES FARTHER N ALONG 37W AND IS TRIGGERING SCATTERED
MODERATE CONVECTION E OF A SURFACE TROUGH N OF 28N BETWEEN
37W-49W. FARTHER E...A THIRD UPPER TROUGH IS DROPPING SWD ALONG
THE MOROCCAN COAST SW PAST THE CANARY ISLANDS BUT THE LACK OF
MOISTURE IS PREVENTING THE DEVELOPMENT OF ANY ASSOCIATED SHOWER
ACTIVITY.

$$
BERG



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