[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 261749
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN 26 SEP 2004

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS
OF SOUTH AMERICA...AND ATLC 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

HURRICANE JEANNE WEAKENED TO A TROPICAL STORM AT 1800 UTC...
IS CENTERED NEAR 28.3N 82.2W...ABOUT 20 MILES SE  OF BROOKSVILLE
FLORIDA AT 26/1800 UTC MOVING NW AT 9 KT. MAXIMUM SUSTAINED WIND
SPEED HAS DECREASED TO 60 KT WITH GUSTS TO 75 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 972 MB. SEE LATEST NHC PUBLIC
ADVISORY OR NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT1/WTNT31 KNHC OR MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.
JEANNE CONTINUES TO MOVE WNW ACROSS THE FLORIDA PENINSULA AS IT
CONTINUES TO WEAKEN. THE EYE OF JEANNE HAS BECOME VERY RAGGED
AND CLOUD FILLED AS IT ENCOUNTERS FRICTION WITH THE LAND. MOST
OF THE CONVECTION IS NOW N OF THE CENTER. SCATTERED
MODERATE/ISOLATED STRONG CONNECTION IS N OF LAKE OKEECHOBEE
JACKSONVILLE FLORIDA COVERING THE STATE OF FLORIDA AND EXTENDING
INTO THE GULF OF MEXICO TO 84W.

TROPICAL STORM LISA IS CENTERED NEAR 19.0N 46.1W...OR ABOUT 900
NM ENE OF GUADELOUPE IN THE LEEWARD ISLANDS AT 26/1200 UTC
MOVING NNW AT 8 KT. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH
GUSTS TO 60 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 997 MB.
SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADER
MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. THE LOW LEVEL CENTER
REMAINS PARTIALLY EXPOSED TO THE W OF THE STRONG CONVECTION. THE
SYSTEM IS LOCATED ON THE EASTERN PERIPHERY OF A MID/UPPER HIGH
WHICH IS EXERTING WESTERLY SHEAR OVER THE STORM. THIS COUPLED
WITH THE ASSOCIATED STRONG SUBSIDENCE/DRY AIR ARE DISPLACING THE
CONVECTION TO THE E. SCATTERED STRONG/ISOLATED STRONG CONVECTION
EXTENDS OUT 250 NM FROM THE CENTER MAINLY TO THE NE.

...TROPICAL WAVES...

TROPICAL WAVE LOCATED ABOUT 520 NM W OF THE CAPE VERDE ISLANDS
IS ALONG 34W S OF 19N MOVING W 10-15 KT. A WEAK 1012 MB LOW IS
ALONG THE WAVE NEAR 15N.  ANTICYCLONIC CIRCULATION REMAINS BROAD
AND ILL-DEFINED ON SATELLITE IMAGERY.  WIDELY SCATTERED MODERATE
CONVECTION IS NOTED FROM 14N-15N BETWEEN 27W-31W.

...ITCZ...

ITCZ AXIS EXTENDS ALONG 11N15W 10N30W 8N60W. WIDELY SCATTERED
MODERATED CONVECTION IS NOTED FROM 3N-12N BETWEEN 10W-21W AND
FROM 1N-6N BETWEEN 22W-24W.

...DISCUSSION...

GULF OF MEXICO INTO THE W ATLANTIC...
HURRICANE JEANNE REMAINS THE DOMINATE FEATURE IN THE E
GULF...LARGE DEEP LAYERED TROUGH EXTENDS OVER THE CENTRAL UNITED
STATES AND INTO THE W GULF N OF 22N W OF 89W. A WEAK UPPER LEVEL
TROUGH EXTEND INTO THE GULF FROM LOUISIANA AND REMAINS
COLLOCATED WITH A MID/UPPER LEVEL LOW CENTERED NEAR 27N91W. MOST
OF THE SHOWERS ARE LOCATED WITHIN THE UNSTABLE ATMOSPHERE  ALONG
THE MEXICO COAST.  RADAR IMAGERY SHOWS MODERATE/ISOLATED STRONG
CONVECTION  ASSOCIATED WITH JEANNE ARE BEGINNING TO MOVE OFF THE
COAST OF FLORIDA E OF 84W BETWEEN 27N-29N.  MODERATE/STRONG
SUBSIDENCE AND DRY AIR OVER THE CENTRAL GULF FROM THE YUCATAN
PENINSULA N TO THE GULF COAST BETWEEN 85W-94W.

CARIBBEAN SEA...
MID/UPPER LEVEL HIGH IS INLAND OVER NE GUATEMALA COVERING THE
FAR SE GULF INTO THE W CARIBBEAN S OF 20N W OF 80W. THIS HIGH
CONTINUES TO PRODUCE WIDELY SCATTERED MODERATE CONVECTION FROM
15N-19N W OF 78W TO INLAND OVER THE YUCATAN PENINSULA.  A
MID/UPPER LEVEL LOW IS CENTERED BETWEEN JAMAICA AND E CUBA NEAR
19N78W WITH A  WEAK TROUGH EXTENDING SW TO 17N81W.  STRONG
SUBSIDENCE/DRY AIR COVERS THE  THE MAJORITY OF THE CARIBBEAN
INCLUDING THE LEEWARD AND VIRGIN ISLANDS.

REMAINDER OF THE SUBTROPICAL ATLANTIC...
A LARGE DEEP LAYERED TROUGH EXTENDS FROM A LARGE UPPER LEVEL LOW
CENTERED OVER THE N CENTRAL ATLC NEAR 37N42W WITH THE BASE OF
THE TROF EXTENDING SW INTO THE AREA TO NEAR 24N57W AND CONTINUES
NW TO NEAR 29N71W. AT THE SURFACE...A TROUGH EXTENDS INTO THE
CENTRAL ATLC NEAR 29N40W SW ALONG 23N56W THEN NW TO 30N72W.
WIDELY SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 150
NM OF THE EAST SURFACE TROUGH. MODERATE SUBSIDENCE/DRY AIR ALOFT
IS FILTERING S INTO THE CENTRAL ATLC N OF 25N FROM 45W-76W THUS
SUPPRESSING SHOWER ACTIVITY TO DEVELOP...ONLY LOW LEVEL CLOUDS.
A MID/UPPER LEVEL RIDGE AXIS EXTENDS FROM NEAR T.S. LISA ALONG
23N41W NE TO BEYOND 32N24W.  BROAD MID/UPPER LEVEL HIGH
CONTAINED TO MOVE E AND IS NOW INLAND OVER AFRICA W OF 17W.

TROPICAL ATLANTIC...
MID/UPPER LEVEL HIGH IS CENTERED ABOUT 700 NM E OF GUADELOUPE IN
THE LESSER ANTILLES NEAR 15N54W WITH MODERATE SUBSIDENCE OVER
THE AREA W OF 48W. T.S. LISA IS ON E SIDE OF THE ANTICYCLONIC
FLOW.

$$
JP/MN




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