[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 241224
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI 24 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 1045 UTC.

...SPECIAL FEATURES...

T.S. IVAN IS INLAND OVER OF TEXAS NEAR 30.2N 94.4W JUST W OF
PORT AUTHOR AT 24/0900 UTC MOVING NW AT 7 KT. MAXIMUM SUSTAINED
WIND SPEED IS 25 KT WITH GUSTS TO 35 KT AND THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1009 MB. THIS THE LAST ADVISORY
ISSUED BY THE NATIONAL HURRICANE CENTER. SEE LATEST NHC PUBLIC
OR FORECAST/ADVISORY UNDER AWIPS/WMO HEADER NFDTCPAT4/WTNT34 OR
TCMAT4/WTNT24 FOR MORE DETAILS. ALL BUT A FEW SCATTERED SHOWERS
REMAIN OVER SW LOUISIANA AND E TEXAS.

AT 8 AM EDT...1200Z...THE CENTER OF HURRICANE JEANNE WAS LOCATED
NEAR LATITUDE 26.1 NORTH...LONGITUDE  72.0 WEST OR ABOUT  315
MILES...505 KM...EAST OF GREAT ABACO ISLAND IN THE NORTHWESTERN
BAHAMAS...MOVING WEST 8 KT. MAXIMUM SUSTAINED WIND SPEED IS
85 KT WITH GUSTS TO 105 KT AND THE ESTIMATED MINIMUM CENTRAL
PRESSURE IS 969 MB. SEE LATEST NHC PUBLIC ADVISORY OR NHC
FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC
OR MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. WELL DEFINED BUT
RATHER SMALL EYE REMAINS AND THE ASSOCIATED DEEP CONVECTION HAS
RETURNED OVER THE PAST SIX HOURS. STRONG UPPER LEVEL HIGH JUST
OFF THE NE UNITED STATES CONTINUES TO MOVE SE OVER THE NW ATLC
AND IS LIMITING JEANNE SOMEWHAT. AS THIS HIGH CONTINUES TO MOVE
SE IT WILL BE PUSHING JEANNE TO THE WEST TOWARDS THE BAHAMAS AND
FLORIDA. THE OUTFLOW STILL REMAINS GOOD IN ALL QUADRANTS.
MODERATE SUBSIDENCE/DRY AIR SURROUNDS JEANNE HOPEFULLY HAMPERING
FURTHER INTENSIFICATION ALTHOUGH A MORE FAVORABLE ENVIRONMENT
WILL BE ENCOUNTERED AS THE SYSTEM MOVES FURTHER WEST...AT THAT
TIME JEANNE COULD INTENSIFY. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 90 NM OF THE CENTER IN THE SE SEMICIRCLE.

HURRICANE KARL IS CENTERED NEAR 40.8N 41.0W OR ABOUT 550 NM WNW
OF THE AZORES AT 24/0900 UTC MOVING N AT 26 KT. MAXIMUM
SUSTAINED WIND SPEED IS 75 KT WITH GUSTS TO 90 KT AND THE
ESTIMATED MINIMUM CENTRAL PRESSURE IS 965 MB. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT2/WTNT22 KNHC
FOR MORE DETAILS. KARL IS FAST BECOMING UNORGANIZED WITH THE LOW
LEVEL CENTER COMPLETELY DEVOID DEEP CONVECTION. KARL SHOULD
BECOME EXTRATROPICAL OVER THE NEXT 6 TO 12 HOURS AND WILL
CONTINUE TO WEAKEN OVER THE NEXT SEVERAL DAYS.

TROPICAL DEPRESSION LISA IS CENTERED NEAR 14.6N 43.5W OR ABOUT
1020 NM EAST OF THE OUTER LESSER ANTILLES OR ABOUT 1140 NM WEST
OF THE CAPE VERDE ISLANDS AT 24/0900 UTC MOVING W AT 9 KT.
MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT AND
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1003 MB. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT3/WTNT23 KNHC
FOR MORE DETAILS. THE LOW LEVEL CENTER IS MOSTLY EXPOSED TO THE
N OF THE ASSOCIATED DEEP CONVECTION. LISA CONTINUES TO
EXPERIENCE NORTHEASTERLY SHEAR WHICH ACCOUNTS FOR THE
DISPLACEMENT OF THE DEEP CONVECTION. NUMEROUS STRONG CONVECTION
IS WITHIN 90 NM OF LINE FROM 11.5N41W-13.5N44.5W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION COVERS THE REMAINDER OF THE
AREA FROM 9N-14.5N BETWEEN 40.5W-46W.

...TROPICAL WAVES...
TROPICAL WAVE IS OVER THE CAPE VERDE ISLANDS ALONG 24W/25W S OF
17N MOVING W 10-15 KT. A BROAD LOW/MID LEVEL CENTER IS OBSERVED
NEAR THE WAVE ABOUT 13N. SATELLITE SIGNATURE IS OBSERVED ON THE
FIRST FEW IMAGES OF VISIBLE SATELLITE IMAGERY. ISOLATED SHOWERS
DOT THE AREA. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
WITHIN 75 NM OF LINE FROM 13N23W-17N18W.

...ITCZ...

ITCZ EXTENDS ALONG 16N10W 13N21W 10N27W 13N39W 9N48W 12N62W.
OTHER THAN THE TROPICAL WAVE AND T.D. LISA...SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS MOVING OFF THE COAST OF
AFRICA FROM 13N-16N. CLUSTERS OF SIMILAR CONVECTION ARE WITHIN
120 NM OF LINE FROM 4N13W-8N26W- 14N35W.

...DISCUSSION...

GULF OF MEXICO...
MID/UPPER HIGH IS OVER THE E PACIFIC WITH ANTICYCLONIC FLOW
COVERING MEXICO W OF 97W. MID/UPPER LEVEL HIGH IS CENTERED JUST
N OF THE YUCATAN CHANNEL NEAR 23N87W CONTINUING TO PUSH
NORTHWARD. A RIDGE AXIS EXTENDS N ACROSS TO THE E GULF OVER THE
SE UNITED STATES. THIS RIDGE HAS PRODUCED STRONG SOUTHERLY SHEAR
OVER IVAN THUS IT NEVER RE-INTENSIFIED BEFORE MAKING LANDFALL. A
NARROW TROUGH IS INDUCED BETWEEN THESE TWO UPPER HIGHS ALONG
95W. AT THE SURFACE...A N/S SURFACE TROUGH EXTENDS FROM NEAR
IVAN ALONG 26N92W TO THE NW YUCATAN PENINSULA NEAR 21N90W. THE
SOUTHERLY UPPER LEVEL FLOW COUPLED WITH TROPICAL MOISTURE AND
THE SURFACE TROUGH ARE CREATING SHOWERS/STRONG THUNDERSTORMS
OVER THE CENTRAL GULF FROM 88W-93W. A WEAKNESS/TROUGH OVER THE
FLORIDA PENINSULA IS A RESULT FROM THE UPPER HIGH N OF THE
YUCATAN CHANNEL AND THE HIGH OVER HURRICANE JEANNE. THIS IS
PRODUCING STRONG SUBSIDENCE AND DRY AIR AT ALL LEVELS OVER
FLORIDA GIVING WAY CLEAR SKIES THIS MORNING BUT WILL GRADUALLY
BECOME CLOUDIER AS JEANNE CONTINUES TO MOVE WEST.

THE CARIBBEAN SEA AND W TROPICAL ATLANTIC...
LARGE MID/UPPER LEVEL HIGH CENTERED N OF THE YUCATAN CHANNEL
COVERS THE CARIBBEAN WITH ANTICYCLONIC FLOW W OF 78W. A LARGE
MID/UPPER LEVEL HIGH IS OVER THE W TROPICAL ATLC ABOUT 350 NM W
OF THE LEEWARD ISLANDS NEAR 18N57W. ANTICYCLONIC FLOW COVERS THE
AREA FROM 41W-66W. A TROUGH IS INDUCED BETWEEN THESE TWO UPPER
HIGHS ALONG 73W THAT EXTENDS N TO JUST S OF JEANNE. STRONG
SUBSIDENCE/DRY AIR COVERS THE E CARIBBEAN AND TROPICAL ATLC FROM
51W-70W. SCATTERED MODERATE/STRONG CONVECTION IS S OF 10N E OF
79W TO INLAND OVER N COLOMBIA AND NW VENEZUELA INCLUDING ALL OF
LAKE MARACAIBO. CLUSTERS OF STRONG THUNDERSTORMS DOT THE COASTAL
WATERS OF HISPANIOLA TO JAMAICA...BELIZE...NICARAGUA...COSTA
RICA...AND PANAMA. ONLY ISOLATED LOW LEVEL SHOWERS ARE OVER THE
LESSER ANTILLES.

SUBTROPICAL ATLANTIC AND THE E TROPICAL
ATLANTIC...STRONG...LARGE MID/UPPER LEVEL HIGH IS SITUATED OFF
THE COAST OF VIRGINIA NEAR 37N74W WITH STRONG ANTICYCLONIC FLOW
W OF 65W THUS PREVENTING HURRICANE JEANNE FROM MOVING NORTHWARD.
THE HIGH IS ALSO PROVIDING STRONG SUBSIDENCE/DRY AIR TO THE W
ATLANTIC N OF 30N AND SURROUNDING JEANNE. THE LARGE DEEP LAYERED
TROUGH OVER THE CENTRAL ATLC IS NOW N OF 24N BETWEEN 38W-63W AND
CONTINUES TO LIFT NE. ELSEWHERE OVER THE CENTRAL ATLC...A LARGE
MID/UPPER LEVEL HIGH IS CENTERED NEAR 18N57W IN THE TROPICAL
ATLC WITH ANTICYCLONIC FLOW S OF 23N FROM 35W-65W. A RIDGE AXIS
EXTENDS FROM NEAR 23N41W NE TO WELL BEYOND 32N35W. THIS UPPER
LEVEL HIGH IS PRODUCING NORTHEASTERLY SHEAR OVER T.D. LISA.
MID/UPPER LEVEL LOW IS OVER THE E ATLANTIC NEAR 27N28W WITH A
TROUGH EXTENDING S TO 12N31W. LARGE MID/UPPER LEVEL HIGH IS
INLAND OVER W AFRICA WITH ANTICYCLONIC FLOW COVERING THE E ATLC
E OF 21W. AT THE SURFACE...A SURFACE TROUGH ENTERS THE CENTRAL
ATLC NEAR 32N38W EXTENDING SW TO 25N51W THEN NW TO 30N64W. THE
SUBTROPICAL RIDGE EXTENDS THROUGH THE AZORES S TO 22N35W.
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN
90 NM OF THE SURFACE TROUGH.

$$
WALLACE




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