[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 261158
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1140 UTC.

...SPECIAL FEATURES...

HURRICANE JEANNE IS CENTERED NEAR 27.7N 81.5W...ABOUT 10 MILES
WNW OF BARTOW FLORIDA AT 26/1200 UTC MOVING SLIGHTLY NORTH
OF DUE WEST AT 11 KT. MAXIMUM SUSTAINED WIND SPEED HAS DECREASED
TO 95 KT WITH GUSTS TO 115 KT. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 955 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
ACROSS THE FLORIDA PANHANDLE AS A STRONG CATEGORY TWO HURRICANE.
THE EYE OF JEANNE HAS BECOME VERY RAGGED 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 TO JUST S OF JACKSONVILLE FLORIDA BETWEEN
79W-83W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS IN THE FORM OF
OUTER RAINBANDS COVER A LARGER AREA FROM THE STRAITS OF FLORIDA
INTO E GEORGIA BETWEEN 77W-85W INCLUDING THE N BAHAMA ISLANDS.

TROPICAL STORM LISA IS CENTERED NEAR 18.4N 46.0W...OR ABOUT 900
NM ENE OF GUADELOUPE IN THE LEEWARD ISLANDS AT 26/0900 UTC
MOVING N AT 7 KT. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH
GUSTS TO 55 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1001 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 CONVECTION
IS WITHIN A 45 NM RADIUS OF 19N44.5W. SCATTERED MODERATE/
ISOLATED STRONG CONVECTION COVERS THE REMAINDER OF THE AREA FROM
14N-22N BETWEEN 40W-46W.

...TROPICAL WAVES...

TROPICAL WAVE LOCATED ABOUT 475 NM W OF THE CAPE VERDE ISLANDS
IS ALONG 33W S OF 19N MOVING W 10-15 KT. A WEAK 1012 MB LOW IS
ALONG THE WAVE NEAR 14N. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS NE OF THE LOW WITHIN A 75 NM RADIUS OF 16N31W.

...ITCZ...

ITCZ AXIS EXTENDS ALONG 18N10W OFF THE COAST OF GUINEA-BISSAU
ALONG 10N20W 12N31W 7N39W 9N61W 10N70W. THE AXIS IS DISRUPTED IN
THE AREA OF THE TROPICAL WAVE AND T.S. LISA. CLUSTERS OF
SCATTERED MODERATE CONVECTION ARE OFF THE COAST OF AFRICA WITHIN
120/150 NM OF LINE FROM 4N8W 9N18W AND WITHIN 120 NM 3N FROM
21W-34W.

...DISCUSSION...

GULF OF MEXICO INTO THE W ATLANTIC...
OTHER THAN HURRICANE JEANNE...LARGE DEEP LAYERED TROUGH EXTENDS
OVER THE CENTRAL UNITED STATES AND THE W GULF N OF 21N W OF 89W.
A WEAK UPPER LEVEL SHORTWAVE TROUGH IS IN THE GULF FROM 29N92W-
23N89W. A SURFACE REFLECTION...IN THE FORM OF A SURFACE
TROUGH...EXTENDS FROM THE CENTRAL TEXAS COAST NEAR 30N97W TO
JUST OFF THE YUCATAN PENINSULA NEAR 20N91W. THE UPPER LEVEL HIGH
OVER JEANNE EXTENDS INTO THE E GULF AND NE OVER THE SE UNITED
STATES TO NEAR 40N. OUTFLOW REMAINS IN ALL QUADRANTS DESPITE THE
CENTER OF JEANNE IS OVER LAND. A WEAK UPPER RIDGE IS TO THE SE
OF JEANNE FROM 27N74W EXTENDING SE TO THE DOMINICAN REPUBLIC
NEAR 20N70W.

CARIBBEAN SEA...
MID/UPPER LEVEL HIGH IS INLAND OVER NE GUATEMALA COVERING THE
FAR SE GULF INTO THE W CARIBBEAN S OF 20N FROM 85W-93W. THIS IS
PRODUCING CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION FROM
15N-20N W OF 85W TO INLAND OVER THE YUCATAN PENINSULA. BROAD BUT
WEAK MID/UPPER LEVEL HIGH IS OVER NE COLOMBIA NEAR 10N74W WITH
ANTICYCLONIC FLOW S OF 15N FROM 67W-77W. AN INDUCED MID/UPPER
LEVEL LOW IS CENTERED BETWEEN JAMAICA AND E CUBA NEAR 19N77W
WITH A TROUGH EXTENDING SW 17N81W. AN UPPER LEVEL WEAKNESS/
TROUGH IS ACROSS THE LEEWARD ISLANDS EXTENDING FROM A DEEP
LAYERED TROUGH OVER THE CENTRAL ATLC NEAR 21N60W SW TO 15N65W.
STRONG SUBSIDENCE/DRY AIR COVERS THE LEEWARD AND VIRGIN ISLANDS.
LOW/MID LEVEL SHOWERS ARE ACROSS THE WINDWARD ISLANDS S OF 15N
FROM 60W-64W.

REMAINDER OF THE SUBTROPICAL ATLANTIC...
A LARGE DEEP LAYERED TROUGH EXTENDS FROM A LARGE UPPER LEVEL LOW
CENTERED OVER THE N CENTRAL ATLC NEAR 40N42W WITH THE BASE OF
THE TROF EXTENDING SW INTO THE AREA TO NEAR 22N58W. AT THE
SURFACE...A TROUGH EXTENDS INTO THE CENTRAL ATLC NEAR 32N39W SW
ALONG 24N57W THEN NW TO 28N69W. A SECOND SURGE IN THE FORM OF A
SURFACE TROUGH ENTERS THE REGION NEAR 32N46W EXTENDING SW TO
28N51W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN
120/150 NM OF THE EAST SURFACE TROUGH. MODERATE SUBSIDENCE AND
DRY UPPER LEVEL AIR IS FILTERING S INTO THE CENTRAL ATLC N OF
25N FROM 50W-65W THUS PREVENTING ANY SHOWER ACTIVITY TO
DEVELOP...ONLY LOW LEVEL CLOUDS. A MID/UPPER LEVEL RIDGE AXIS
EXTENDS FROM NEAR T.S. LISA ALONG 21N41W NE TO BEYOND 32N33W.
THIS RIDGE IS NARROWING THE MID/UPPER LEVEL TROUGH IN THE FAR NE
ATLC NEAR 30N AND HAS CUT OFF AN UPPER LEVEL LOW NEAR 21N27W.
THE BROAD MID/UPPER LEVEL HIGH THAT COVERED THE E ATLC 24 HOURS
AGO IS NOW CONFINED TO 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 16N49W WITH WEAK/MODERATE SUBSIDENCE
OVER THE AREA W OF 38W. T.S. LISA IS ON E SIDE OF THE
ANTICYCLONIC FLOW. RIDGE AXIS IN THE EASTERN/CENTRAL ATLC
EXTENDS FROM THE HIGH NEAR LISA.

$$
WALLACE



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