[Tropical] Tropical Weather Discussion

Tue Oct 18 06:56:58 CDT 2005

AXNT20 KNHC 181156
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE OCT 18 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 STORM WILMA IS CENTERED NEAR 15.9N 80.2W...OR 215 NM
SSE OF GRAND CAYMAN...AT 18/1200 UTC DRIFTING NW. MAXIMUM
SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 980 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. WILMA IS BECOMING BETTER ORGANIZED AND
STRENGTHENING WITH THE DEEPEST CONVECTION CLOSER TO THE CENTER
AND CLOUD POSSIBLY BE A HURRICANE LATER TODAY. THE DEEPEST
CONVECTION ASSOCIATED WITH WILMA IS TO THE S OF THE CENTER.
SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN 90 NM OF LINE
16.5N79.5W- 11N82.5W AND WITHIN 45 NM OF LINE 14.5N81.5W TO THE
TIP OF NICARAGUA/HONDURAS NEAR 15N83.5W. SCATTERED MODERATE/
STRONG CONVECTION IS OFF THE COAST OF COLOMBIA WITHIN 60/75 NM
OF LINE 12N73W-15N74W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS NE OF THE CENTER WITHIN 90 NM OF LINE 16.5N79W
ACROSS JAMAICA TO E CUBA NEAR 20N75W. AN UPPER TROUGH/SHEAR AXIS
EXTENDS FROM W CUBA NEAR THE ISLE OF YOUTH W OF THE CAYMAN
ISLANDS TO THE W GULF OF HONDURAS AND IS PLACING SOME NW SHEAR
OVER WILMA...AS WELL AS PROVIDING DRIER AIR TO THE NW THE
CIRCULATION. OUTFLOW IS BEST TO THE S AND E DUE TO THE RIDGE
AXIS BEING ORIENTED FROM NICARAGUA TO HISPANIOLA. WITH THE
INCREASE ORGANIZATION SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
ARE N AND E OF THE MAIN CONVECTION FROM 15N TO OVER PUERTO RICO
AND HISPANIOLA BETWEEN 64W-74W.

...TROPICAL WAVES...

CENTRAL ATLANTIC TROPICAL WAVE IS TILTED NNE/SSW ALONG 46W/48W
S OF 19N MOVING W 10 KT. WAVE REMAINS WEDGED BETWEEN A SMALL
UPPER HIGH IN THE W TROPICAL ATLC AND A BROAD RIDGE EXTENDING
FROM OFF AFRICA ACROSS THE REMAINDER OF THE TROPICAL ATLC AND IS
MOVING INTO AN AREA OF DRIER AIR. THUS...NO ASSOCIATED
SHOWERS/CONVECTION.

E CARIBBEAN TROPICAL WAVE IS ALONG 65W/66W S OF 15N MOVING W
10-15 KT. WAVE IS BENEATH S OUTFLOW FROM T.S. WILMA AND E
SURFACE FLOW GENERATING ISOLATED SHOWERS S OF 15N E OF 66W TO
OVER THE WINDWARD ISLANDS.

W CARIBBEAN TROPICAL WAVE IS ALONG 76W/77W S OF 13N MOVING W
10-15 KT. LOW AMPLITUDE WAVE IS MOVING TOWARD THE E PACIFIC
REGION WITH SCATTERED MODERATE CONVECTION S OF 9N FROM OVER
COLOMBIA AND E PANAMA. WAVE IS VOID OF CONVECTION IN THE
CARIBBEAN.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N12W 6N17W 8N23W 9N38W 13N45W THEN
ALONG 14N50W 10N55W 9N62W. SCATTERED MODERATE/STRONG CONVECTION
IS WITHIN 90 NM OF THE AXIS FROM 31W-38W. SCATTERED MODERATE/
ISOLATED STRONG CONVECTION IS WITHIN 250/300 NM OF THE AXIS FROM
40W-47W. CLUSTERS OF SIMILAR CONVECTION DOT THE AREA FROM 1N-10N
BETWEEN 9W-43W.

...DISCUSSION...

GULF OF MEXICO...
SKIES REMAIN MOSTLY CLEAR ACROSS THE GULF THIS MORNING EXCEPT IN
THE BAY OF CAMPECHE AND THE FAR SE GULF. STRONG UPPER HIGH
REMAINS ANCHORED OVER THE SW GULF NEAR 23N96W DOMINATING THE
AREA AND CONTINUES TO PUMP DRY/STABLE AIR S OVER THE NE
GULF...THEN CURLING IT BACK TO THE W ACROSS THE YUCATAN INTO THE
BAY OF CAMPECHE. CLEAR SKIES ARE N OF 23N WITH PATCHY CLOUDS
WITH POSSIBLE ISOLATED SHOWERS MOVING FROM 23N S TO OVER THE
YUCATAN PENINSULA AND THE BAY OF CAMPECHE. OVERCAST LOW/MID
CLOUDS WITH SCATTERED SHOWERS ARE OVER THE STRAITS OF FLORIDA
AND THE FLORIDA KEYS S OF 25N E OF 83W PRECEDING A SURFACE
TROUGH OVER THE W ATLC. WEAK SURFACE HIGH PRESSURE EXTENDS INTO
THE NW GULF WITH A 1017 MB HIGH ALONG THE COAST OF SW LOUISIANA.
THE ATMOSPHERE WILL REMAIN MOSTLY DRY OVER THE AREA FOR THE NEXT
DAY OR TWO BUT WILL GRADUALLY INCREASE TODAY OVER THE SE AS A
SURFACE TROUGH MOVES IN FROM THE W ATLC...THEN WILMA WILL
APPROACH FROM THE NW CARIBBEAN.

CARIBBEAN...
THE CIRCULATION OF T.S. WILMA ENCOMPASSES THE ENTIRE W HALF OF
THE CARIBBEAN...AND BROAD E/SE FLOW FEEDING INTO THE CIRCULATION
COVERING THE REMAINDER OF THE AREA. THE UPPER LEVEL HIGH OVER
WILMA IS BECOMING BETTER DEFINED AND THE RIDGE AXIS EXTENDS FROM
14N78W NE PAST HISPANIOLA AND PUERTO RICO PRODUCING EXCELLENT
OUTFLOW OVER THE CONVECTION LOCATED FROM JAMAICA TO HAITI. A
SIGNIFICANT AREA OF DRY AIR AND STRONG SUBSIDENCE EXTENDS NW OF
AN UPPER LEVEL TROUGH/SHEAR AXIS WHICH STRETCHES FROM W CUBA SW
INTO THE GULF OF HONDURAS PROVIDING  NW SHEAR AFFECTING WILMA.
FARTHER E...THE WEATHER IS A LITTLE LESS CONVECTIVE E OF 72W
WITH THE EXCEPTION OF ISOLATED SHOWERS N OF 15N FROM 64W-74W.
DRIER AIR IS EXPECTED TO BEGIN MOVING INTO THE AREA FROM THE E
OVER THE NEXT 24 HRS...HANGING AROUND OVER THE E CARIBBEAN AS
WILMA BEGINS ITS TRACK NW THEN BY THU/FRI THE ARRIVAL OF THE
NEXT TROPICAL WAVE WILL MOVE ANOTHER ROUND OF MOISTURE ACROSS
THE LESSER ANTILLES.

ATLANTIC...
A DEEP LAYERED TROUGH REMAINS OVER THE NW ATLC N OF 27N W OF 56W
WITH A E/W SURFACE TROUGH EXTENDING FROM 28N62W 26N73W AND A
SECOND TROUGH EXTENDING FROM N OF T.S. WILMA OVER W/CENTRAL CUBA
NEAR 22N81W TO OVER THE N BAHAMAS NEAR 26N77W WITH MOISTURE S OF
THE TROUGH BOUNDARY PRODUCING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS S OF 27N BETWEEN 70W-80W. LARGE CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE ALONG THE E/W
SURFACE TROUGH FROM 25N29N BETWEEN 60W-70W. THE CUT-OFF
ELONGATED UPPER LOW E OF THE LESSER ANTILLES IS ALONG 59W FROM
JUST NE OF BARBADOS TO 25N. THE SECOND CUT-OFF UPPER LOW HAS
DISSIPATED WITH A TROUGH/SHEAR AXIS ALONG 20N FROM 36W-49W WITH
THE ONCE ASSOCIATED WEAK 1018 MB SURFACE LOW NEAR 24N43W. A
SURFACE TROUGH REMAINS EXTENDING FROM 26N38W TO 20N45W BEARING A
THIN LINE OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS. A BROAD
UPPER HIGH IS LOCATED NEAR 32N43W DIPPING DOWN INTO THE REGION N
OF THE TROUGH/SHEAR AXIS IN THE CENTRAL ATLC BETWEEN 27W-55W.
OVER THE NE ATLC...AN UPPER TROUGH IS N OF 20N E OF 25W WITH THE
UPPER LOW MOVING ACROSS MOROCCO. TO THE S...IS A BROAD RIDGE
EXTENDING OFF AFRICA ALONG 7N/8N E OF 48W AND THE ASSOCIATED
DIFFLUENCE ALOFT HAS INITIATED THE LARGE AREA OF ITCZ
CONVECTION. THE UPPER TROUGH IS ALSO PUSHING THIS AIR S OVER THE
E ATLC...FORCING A LARGE AREA OF AFRICAN DUST S OF 21N/22N AND E
OF 43W.

$$
WALLACE

WWWW
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