[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 171200
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURE...

TROPICAL DEPRESSION TWENTY-FOUR WAS UPGRADED TO TROPICAL STORM
WILMA AT 17/0900 UTC. TROPICAL STORM WILMA IS CENTERED NEAR
16.8N 79.6W AT 17/1200 UTC...OR 180 NM SE OF GRAND
CAYMAN...MOVING S AT 4 KT. MAXIMUM SUSTAINED WIND SPEED IS 35 KT
WITH GUSTS TO 45 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000
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. THIS IS THE 21ST
NAMED STORM OF THE 2005 SEASON AND TIES THE RECORD SET IN 1933.
DEEP CONVECTION CONTINUES TO THE S OF THE CENTER. NUMEROUS
STRONG CONVECTION IS WITHIN A 60 NM RADIUS OF 15.5N80W.
SCATTERED STRONG CONVECTION COVERS THE REMAINDER OF THE AREA
WITHIN 75/90 NM OF LINE 16N78.5W-15N82.5W. CLUSTERS OF SCATTERED
MODERATE/STRONG CONVECTION IN THE FORM OF RAINBANDS MOSTLY TO
THE E OF THE CENTER ARE FROM 11N-21N BETWEEN 72W-78W WITH
SCATTERED CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION FROM 11N-19N BETWEEN 78W-87W. AT THE UPPER
LEVELS...UPPER HIGH WITH GOOD OUTFLOW IS TO THE E OF THE CENTER.
DRY UPPER AIR IS ENCROACHING INTO T.S. WILMA FROM THE NW...THUS
LIMITING CONVECTION AND OUTFLOW.

...TROPICAL WAVES...

CENTRAL ATLC WAVE IS TILTED NE/SW FROM 18N40W THROUGH A 1009 MB
LOW NEAR 14.5N43.5W TO 10N48W MOVING W NEAR 10 KT. SCATTERED
SHOWERS/THUNDERSTORMS ARE WITHIN 120/150 NM OF THE WAVE AXIS
BETWEEN 12N-18N.

CENTRAL CARIBBEAN WAVE IS ALONG 72W S OF 17N MOVING W 5-10 KT.
THIS WAVE CONTINUES TO BE DIFFICULT TO TRACK AND MAY ULTIMATELY
DISSIPATE AS IT APPROACHES T.S. WILMA. WAVE IS BENEATH UPPER
LEVEL S FLOW OF THE UPPER HIGH NEAR T.S. WILMA.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N9W 4N12W 6N23W 6N29W 8N34W 10N45W
11N49W 12N62W. SCATTERED STRONG CONVECTION IS FROM 3N-9N BETWEEN
28W-35W. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 125 NM
OF THE ITCZ AXIS FROM 47W-51W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS FROM 3N-10N BETWEEN 35W-42W AND WITHIN
120/150 NM ON OF THE ITCZ AXIS FROM 55W-61W. SCATTERED CLUSTERS
OF SIMILAR CONVECTION ARE WITHIN 200 NM OF THE AXIS FROM 9W-27W.

...DISCUSSION...

GULF OF MEXICO...
CLEAR SKIES REIGN ALONG THE N GULF COAST DESPITE THE PRESENCE OF
A WEAK COLD FRONT THAT EXTENDS FROM THE W ATLC ACROSS N FLORIDA
NEAR 29N82W CONTINUING W TO JUST INLAND OVER SE LOUISIANA. THE
FRONT IS DELINEATED BY A STEADY DROP IN DEW POINTS. SCATTERED
LOW/MID CLOUDS DOT THE GULF S OF 26N. AT THE UPPER LEVELS...
UPPER HIGH ANCHORED N OF THE BAY OF CAMPECHE NEAR 22N93W
DOMINATING THE GULF WITH MODERATE/STRONG SUBSIDENCE. MOSTLY DRY
CONDITIONS ARE LIKELY THROUGH MID WEEK WITH A VERY SLIGHT CHANCE
OF SHOWERS IN THE BAY OF CAMPECHE AND AN INCREASE IN RAIN CHANCE
FOR S FLORIDA AND THE STRAITS OF FLORIDA AS T.S. WILMA MOVES
ACROSS THE NW CARIBBEAN.

CARIBBEAN SEA...
BIGGEST WEATHER MAKER FOR THE ATLC BASIN IS T.S. WILMA IN THE W
CARIBBEAN. UPPER HIGH IS JUST TO THE E OF THE STORM WITH RIDGING
EXTENDING E TO JUST S OF PUERTO RICO. HEAVY RAIN CONTINUES TO BE
A CONCERN AS RAINBANDS ON THE E SIDE OF THE SYSTEM. RAINBANDS
WILL SHIFT WESTWARD AS THE STORM DRIFTS SOUTHWESTWARD. SEE
SPECIAL FEATURES FOR MORE DETAILS. THE FAR NW CARIBBEAN IS UNDER
THE INFLUENCE OF THE BROAD UPPER HIGH AND STRONG SUBSIDENCE OF
THE GULF COVERING W CUBA SW TO OVER THE YUCATAN PENINSULA. THE E
CARIBBEAN IS UNDER S UPPER FLOW FROM AN UPPER LOW JUST E OF THE
LEEWARD ISLANDS. DIFFLUENCE IS GENERATING SCATTERED SHOWERS
THUNDERSTORMS E OF 70W OVER THE LEEWARD/VIRGIN ISLANDS. A SURGE
OF MOISTURE AND ACCOMPANYING SHOWERS/THUNDERSTORMS ARE MOVING
ACROSS THE WINDWARD ISLANDS AND THE SOUTH AMERICA COAST S OF 14N
FROM 57W-64W ASSOCIATED WITH THE ITCZ AXIS.

ATLANTIC OCEAN...
DEEP LAYERED TROUGH IS OVER THE W ATLC N OF 26N W OF 60W WITH AN
ASSOCIATED COLD FRONT EXTENDING THROUGH 32N70W TO INLAND OVER NE
FLORIDA NEAR 29N82W. A WEAK SURFACE TROUGH EXTENDS ACROSS THE
BAHAMA ISLANDS FROM 26N74W TO 23N79W. THE NW ATLC IS DOMINATED
BY STRONG SUBSIDENCE AND DRY UPPER AIR LEAVING THE AREA N OF 27N
MOSTLY CLEAR WITH NO SHOWER ACTIVITY. THE UPPER HIGH ASSOCIATED
WITH T.S. WILMA EXTENDS A RIDGE THROUGH THE WINDWARD PASSAGE NE
TO 24N64W WITH THE UPPER DIFFLUENCE GENERATING SCATTERED
SHOWERS/THUNDERSTORMS S OF 27N FROM 69W-78W INCLUDING MOST OF
THE BAHAMA ISLANDS. THIS IS ALSO GIVING E CUBA...HISPANIOLA...TO
PUERTO RICO MORE HEAVY RAIN WHICH HAS PLAGUED THE AREA FOR THE
PAST WEEK. BROAD UPPER HIGH OVER THE CENTRAL ATLC IS CENTERED
NEAR 29N48W COVERING THE AREA N OF 21N BETWEEN 40W-57W.
WEAKENING UPPER LOW IS JUST TO E THE LEEWARD ISLANDS NEAR 19N59W
WITH AN UPPER TROUGH EXTENDING S TO 13N60W. DIFFLUENCE TO THE E
OF THE UPPER LOW IS GENERATING A SMALL AREA OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION WITHIN A 60 NM RADIUS OF
19N58W. DEEP LAYERED TROUGH EXTENDS THROUGH THE MADEIRA ISLANDS
S TO JUST W OF THE CANARY ISLANDS ALONG 28N19W 22N31W TO A
SMALL...WEAK UPPER LOW NEAR 21N39W. A SURFACE TROUGH EXTENDS
THROUGH 32N12W ACROSS THE CANARY ISLANDS TO 25N22W WITH A SECOND
SURGE/COLD FRONT APPROACHING THE MADEIRA ISLANDS. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 60/75 NM OF LINE FROM
OVER THE CANARY ISLANDS NEAR 27N17W TO 32N13W. BROAD WESTERLY
FLOW DOMINATES THE REMAINDER OF THE E TROPICAL ATLC.

$$
WALLACE/BERG


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