[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 180003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON OCT 17 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURE...

TROPICAL STORM WILMA IS CENTERED NEAR 15.7N 79.9W AT 18/0000
UTC...OR 265 MILES SSE OF GRAND CAYMAN...MOVING S 2 KT. MAXIMUM
SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 989 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.  A SMALL CENTRAL DENSE OVERCAST (CDO) HAS
FORMED WITH A STRONG BAND IN THE SOUTHERN SEMICIRCLE WITHIN 60
NM OF A CURVED LINE FROM 15N79W 14N81W TO THE E TIP OF
HONDURAS.  CIRRUS CLOUDS ON THE WEST SIDE OF THE CIRCULATION ARE
ALSO MOVING OUTWARD FROM THE STORM... A SIGN THAT THE NW SHEAR
IS ABATING.  ALL INDICATIONS ARE THAT AS THIS SYSTEM MOVES
SLOWLY IN A GENERAL W TO NW DIRECTION OVER THE NEXT COUPLE OF
DAYS.. IT WILL TURN INTO A POWERFUL HURRICANE.

...TROPICAL WAVES...

CENTRAL ATLANTIC TROPICAL WAVE ALONG 45W S OF 20N MOVING W 10 KT
WITH A WEAKENING 1010 MB LOW ALONG THE AXIS NEAR 15.5N. NOAA
BUOY 41041 RECENTLY SHIFTED TO SLY WINDS... PROBABLY INDICATING
THE WAVE HAS PASSED THE AREA.  SATELLITE PICTURES GIVE THE
APPEARANCE OF THE WAVE BEING TILTED FROM NE TO SW.  THE WAVE
SHOULD CONTINUE TO BE VERY CONVECTIVELY ACTIVE WITH WLY SHEAR
ENHANCING TSTM DEVELOPMENT.  WIDELY SCATTERED MODERATE
CONVECTION FROM 12N-16N BETWEEN 42W-48W.

A TROPICAL WAVE IS ADDED JUST W OF THE LESSER ANTILLES ALONG 62W
S OF 16N MOVING W 10-15 KT. ISOLATED TO WIDELY SCATTERED SHOWERS
ACCOMPANY THE WAVE.. MOSTLY ON THE E SIDE FROM ABOUT DOMINICA TO
GRENADA BETWEEN BARBADOS AND 64W.  THE GFS FORECASTS MOST OF THE
MOISTURE TO PASS N OF THE ABC ISLANDS BUT IT COULD ENHANCE THE
RAIN CHANCE THERE LATE TOMORROW.

CENTRAL CARIBBEAN TROPICAL WAVE EXTENDS FROM HAITI SWD ALONG 74W
MOVING W 10 KT.  THE WAVE SEEMS TO BE GETTING ABSORBED INTO THE
LARGE CIRCULATION OF WILMA BUT IS POSSIBLY ENHANCING TSTMS ON
THE E SIDE.  SCATTERED MODERATE CONVECTION IS FROM 15N-20N
BETWEEN 70W-76W.  THIS MOISTURE SHOULD CAUSE HEAVY RAINS FROM
JAMAICA TO HISPANIOLA AND SE CUBA AS IT SLOWLY ROTATING NW
AROUND THE CYCLONE.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N12W 8N35W 12N44W 10N61W.
SCATTERED MODERATE CONVECTION IS FROM 3N-10N BETWEEN 29W-44W IN
A LARGE AREA OF UPPER DIFFLUENCE.

...DISCUSSION...

GULF OF MEXICO...
STRONG HIGH PRES IN THE MID/UPPER LEVELS IS CENTERED OVER THE
BAY OF CAMPECHE NEAR 22N93W AND HAS CLEARED THE AREA OF
SIGNIFICANT MOISTURE ALOFT.  DRY CONTINENTAL AIR CONTINUES TO
RIDE THE NLY SURFACE WINDS OVER THE GULF LEAVING MOSTLY CLEAR
SKIES N OF 26N WITH ISOLATED SHOWERS ARE MOVING S NEAR THE W
COAST OF THE YUCATAN AND IN THE BAY OF CAMPECHE. THE COLD FRONT
OVER FLORIDA HAS DISSIPATED.  THE ATMOSPHERE WILL REMAIN MOSTLY
DRY OVER THE AREA FOR THE NEXT FEW DAYS BUT MOISTURE WILL
GRADUALLY INCREASE FROM THE SE LATER IN THE WEEK AS T.S. WILMA
APPROACHES FROM THE CARIBBEAN... FIRST UPPING RAIN CHANCES IN
THE FLORIDA STRAITS BY TOMORROW AND OVER S FLORIDA BY WED.

CARIBBEAN...
THE CIRCULATION OF T.S. WILMA ENCOMPASSES THE ENTIRE W HALF OF
THE CARIBBEAN...AND BROAD E/SE FLOW FEEDING INTO THE CIRCULATION
COVERS THE REST OF THE AREA. THE UPPER LEVEL ANTICYCLONE OVER
WILMA IS TAKING SHAPE NEAR JAMAICA WITH EXCELLENT OUTFLOW OVER
CONVECTION LOCATED FROM JAMAICA TO HISPANIOLA. DRY AIR AND
STRONG SUBSIDENCE EXTENDS NW OF AN UPPER LEVEL TROUGH/SHEAR AXIS
WHICH STRETCHES FROM CNTRL CUBA SSW NEAR THE E TIP OF HONDURAS.
THIS FEATURE HAS BEEN WEAKENING WITH TIME CAUSING LESS SHEAR
THAN EARLIER.  A LARGE RAIN AREA IS IN THE DIFFLUENT REGION OF
THE HIGH OVER JAMAICA...SE CUBA AND HISPANIOLA AND THIS HEAVY
RAIN SHOULD SLOWLY SHIFT NW DURING THE NEXT COUPLE OF DAYS.
FARTHER E...THE WEATHER IS CONSIDERABLY QUIETER NOW THAT TSTMS
FROM A TROPICAL WAVE HAVE LESSENED.  A LITTLE DRIER AIR SHOULD
MOVE INTO E CARIBBEAN TOMORROW THOUGH DEEP-LAYER RELATIVE
HUMIDITY REMAINS HIGH... LEADING TO A DECENT CHANCE OF TRADEWIND
SHOWERS.  THE NEXT WAVE COULD ENTER THE CARIBBEAN LATE THU/EARLY
FRI AND ENHANCE RAIN CHANCES IN THE LESSER ANTILLES.

ATLANTIC...
A WEAK COLD FRONT EXTENDS FROM JUST S OF 28N78W E OF FLORIDA
MARKED BY A WEAKENING ROPE CLOUD AND LOWER DEWPOINTS.  THE
REMNANTS OF COLD FRONT ARE A SURFACE TROUGH FROM CENTRAL CUBA
NEAR 22N79W ACROSS THE CENTRAL BAHAMAS TO 27N73W PRODUCING
WIDELY SCATTERED SHOWERS WITHIN 90 NM OF THE TROUGH.  STATIONARY
TROUGH LIES FROM 26N59W 14N58W ASSISTING ISOLATED TSTMS WITHIN
60 NM OF THE TROUGH AXIS.  A MUCH LARGER W ATLC TROUGH IS N OF
27N W OF 60W WITH VERY DRY AIR ALOFT.  SMALL ANTICYCLONE IS NEAR
13N50W WITH A LITTLE UPPER DIFFLUENCE CAUSING SOME TSTMS BETWEEN
11N-15N FROM 45W-48W.  A SECOND SMALL UPPER TROUGH/LOW IS
CENTERED OVER THE TROPICAL ATLC NEAR 20N42W AND IS NEAR A WEAK
1016 MB LOW NEAR 23N39W. WEAK SURFACE TROUGH EXTENDS SW OF THE
LOW TO THE TROPICAL WAVE ALONG 45W AND IS PRODUCING ISOLATED
SHOWERS/TSTMS FROM 17N-23N BETWEEN 37W-43W. THESE FEATURES OVER
THE CENTRAL ATLC ARE STUCK BENEATH A BUILDING UPPER HIGH NEAR
31N44W CAUSING LITTLE OVERALL MOTION.  AN UPPER RIDGE LIES ALONG
8N E OF 40W AND THE ASSOCIATED DIFFLUENCE ALOFT HAS INITIATED A
LARGE AREA OF ITCZ CONVECTION BETWEEN 30W-40W. FARTHER E...A
SHARP UPPER TROUGH IS INTO NW AFRICA WITH A FRESH INFUSION OF
COOLER AIR FOR THE REGION.  A LARGE AREA OF AFRICAN DUST IS S OF
20N E OF 40W AND IS BEING PUSHED SOUTHWARD BY THE DRIER AIR IN
THE NE ATLC.

$$
BLAKE

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