[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 241807
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM 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 1200 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 1745 UTC.

...SPECIAL FEATURES...

AT 10 AM CDT...15Z...TROPICAL DEPRESSION IVAN WAS LOCATED NEAR
30.9 NORTH LATITUDE AND 95.0 WEST LONGITUDE...OR APPROXIMATELY
10 MILES NORTH OF LIVINGSTON TEXAS AND MOVING NORTH-NORTHWEST
10 MPH. WINDS ARE GENERALLY 10-15 MPH. THE CENTRAL PRESSURE IS
1013 MB OR 29.92 INCHES OF MERCURY. ADDITIONAL RAINFALL OF
2-3 INCHES WITH ISOLATED AMOUNTS UP TO 5 INCHES ARE POSSIBLE
OVER PORTIONS OF EAST TEXAS AND LOUISIANA. SEE LATEST NHC PUBLIC
OR FORECAST/ADVISORY UNDER AWIPS/WMO HEADER NFDTCPAT4/WTNT34 OR
TCMAT4/WTNT24 FOR MORE DETAILS. ISOLATED MODERATE TO LOCALLY
STRONG SHOWERS AND THUNDERSTORMS FROM SOUTH CENTRAL COASTAL
LOUISIANA TO EAST TEXAS.

CENTER OF HURRICANE JEANNE AT 24/1800 UTC...200 PM EDT...NEAR
26.3N 72.9W OR ABOUT 255 MILES/415 KM...EAST OF GREAT ABACO
ISLAND...MOVING WEST 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE
969 MB. MAXIMUM SUSTAINED WIND SPEED 85 KT GUSTS 105 KT. SEE
LATEST NHC PUBLIC ADVISORY OR NHC FORECAST/ ADVISORY UNDER
AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC OR MIATCMAT1/WTNT21 KNHC
FOR MORE DETAILS. THE COLDEST CLOUD TOP TEMPERATURES WITH THE
STRONGEST SHOWERS AND THUNDERSTORMS ARE WITHIN 60 TO 90 NM
RADIUS AWAY FROM THE CENTER. OVERCAST MULTILAYERED CLOUDS AND
SCATTERED MODERATE TO ISOLATED STRONG SHOWERS ELSEWHERE FROM
23N TO 29N BETWEEN 68W AND 77W. ISOLATED MODERATE SHOWERS AND
THUNDERSTORMS WITHIN 30 NM ON EITHER SIDE OF 27N64W 25N64W...
AND 24N65W 22N67W. JEANNE IS BEING GUIDED BY AN UPPER LEVEL
ANTICYCLONE...MOVING IT WESTWARD. MIDDLE TO UPPER LEVEL DRY
AIR NORTH OF AND ALL AROUND JEANNE...SOME IT EVEN WRAPPING
INTO THE CENTER A BIT DURING THE PAST FEW HOURS.

CENTER OF HURRICANE KARL AT 24/1500 UTC NEAR 44.4N 40.2W...
OR ABOUT 815 MILES/1310 KM NORTHWEST OF THE AZORES...MOVING
NORTH 35 KT. ESTIMATED MINIMUM CENTRAL PRESSURE 970 MB. MAXIMUM
SUSTAINED WIND SPEED 70 KT GUSTS 85 KT. HURRICANE FORCE WINDS
EXTEND OUTWARD UP TO 105 MILES/165 KM FROM THE CENTER...AND
TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 405 MILES/650 KM.
KARL IS NOT QUITE YET EXTRATROPICAL. SCATTERED MODERATE TO STRONG
SHOWERS AND THUNDERSTORMS FROM 45N TO 47N BETWEEN 40W AND 43W.

CENTER OF TROPICAL DEPRESSION LISA AT 24/1500 UTC NEAR 14.1N
43.3W...OR ABOUT 1295 MILES/2080 KM...WEST OF THE CAPE VERDE
ISLANDS...MOVING WEST-NORTHWEST 7 KT. ESTIMATED MINIMUM CENTRAL
PRESSURE 1002 MB. MAXIMUM SUSTAINED WIND SPEED 30 KT GUSTS
40 KT. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM 10N TO
13N BETWEEN 43W AND 46W. THE FORECAST IDEA FOR LISA IS THAT THE
RIDGE NORTH OF LISA WILL CONTINUE TO WEAKEN AS A LARGE MIDDLE
TO UPPER LEVEL TROUGH WILL MOVE SOUTHEAST INTO THE CENTRAL
ATLANTIC. THIS SHOULD TURN LISA NORTHWESTWARD AND NORTHWARD
DURING THE NEXT 48 TO 72 HOURS. LISA HAS BEEN MOVING AWAY FROM

UPPER LEVEL NORTHERLY FLOW WHICH ACCOMPANIES A MIDDLE TO UPPER
LEVEL TROUGH IN THE EASTERN ATLANTIC OCEAN.

...TROPICAL WAVES...
TROPICAL WAVE JUST MOVING THROUGH THE WESTERN PART OF THE CAPE
VERDE ISLANDS ALONG 25W/26W SOUTH OF 17N MOVING WEST 10 TO
15 KT. THIS WAVE IS TO THE EAST OF THE EASTERN ATLANTIC MIDDLE
TO UPPER LEVEL TROUGH...CAUSING SOUTHWESTERLY WINDS TO SHEAR
THE WAVE TO SOME DEGREE. THE CLOUD TOPS OF THE SHOWERS AND
THUNDERSTORMS ARE BEING PUSHED NORTHWARD. SCATTERED MODERATE
TO ISOLATED STRONG SHOWERS AND THUNDERSTORMS FROM 15N TO 18N
BETWEEN 23W AND 26W. LOW TO MIDDLE LEVEL CLOUDS HAVE A CYCLONIC
CURVATURE TO THEM IN VISIBLE AND INFRARED IMAGERY FROM FROM
11N TO 16N BETWEEN 21W AND 30W.

...ITCZ...

ITCZ 15N17W 13N24W...13N27W 14N39W...10N46W 12N61W...AND IN
THE SOUTHWESTERN CARIBBEAN SEA FROM 12N71W OVER THE GUAJIRA
PENINSULA OF COLOMBIA TO 9N83W IN SOUTHERN COSTA RICA.
WIDELY SCATTERED TO SCATTERED MODERATE/ISOLATED STRONG SHOWERS
AND THUNDERSTORMS FROM 2N TO 10N BETWEEN 20W AND 33W. SOME
STRONG SHOWERS AND THUNDERSTORMS IN COASTAL EXTREME NORTHEASTERN
VENEZUELA NEAR 8N61W. WARMING CLOUD TOP TEMPERATURES AND SOME
LINGERING SHOWERS/THUNDERSTORMS FROM 8N TO 11N BETWEEN 75W AND
79W...AND SOUTH OF 11N TO THE PANAMA/COSTA RICA COASTS BETWEEN
79W AND 83W.

...DISCUSSION...

THE GULF OF MEXICO...
UPPER LEVEL CYCLONIC CIRCULATION CENTER NEAR 23.5N94W...CYCLONIC
FLOW FROM THE MEXICO COAST NEAR 18N TO 27N BETWEEN 91W AND 98W.
ISOLATED SHOWERS IN THE SOUTHWESTERN CORNER OF THE GULF. SURFACE
TROUGH FROM THE T.D. IVAN REMNANT LOW IN THE UPPER TEXAS COASTAL
REGION TO 26N95W 21N92W. SCATTERED STRONG SHOWERS AND
THUNDERSTORMS FROM 23.5N TO 27N BETWEEN 87W AND 90W. MIDDLE TO
UPPER LEVEL DRY AIR WHICH SURROUNDS THE AREA TO THE WEST OF
HURRICANE JEANNE COVERS THE GULF EAST OF 86W. A BROAD TROUGH
MOVES INTO THE WESTERN UNITED STATES...WITH ITS BASE REACHING
NORTHERN MEXICO AND THE SOUTHWESTERN UNITED STATES. A RIDGE HAS
BUILT OVER CENTRAL MEXICO...RIGHT UP AGAINST THE SOUTHWESTERN
GULF CYCLONIC CIRCULATION CENTER. AN ELONGATED RIDGE RUNS FROM
SOUTHEASTERN LOUISIANA TO THE CENTRAL GULF WATERS...OVER THE
NORTHEASTERN CORNER OF THE YUCATAN PENINSULA...THROUGH THE
YUCATAN CHANNEL...INTO THE NORTHWESTERN CARIBBEAN SEA.

THE CARIBBEAN SEA AND WESTERN TROPICAL ATLANTIC...
WATER VAPOR SATELLITE IMAGERY AND CIMSS SATELLITE DERIVED WIND
DATA FROM 24/1500 UTC SHOW THE UPPER LEVEL ANTICYCLONIC
CIRCULATION ON TOP OF HURRICANE JEANNE IN THE ATLANTIC
WATERS...AN UPPER LEVEL TROUGH WITH A BASE NEAR JAMAICA...AND
THE UPPER LEVEL EAST-TO-NORTHEASTERLY WIND FLOW WITH THE UPPER
LEVEL ANTICYCLONE WHICH IS STEERING HURRICANE JEANNE. SOME OF
THE CYCLONIC FLOW WITH THE TROUGH GOES FROM THE EASTERN GULF OF
MEXICO...OVER WESTERN CUBA...AND BECOMES NORTHEASTERLY FLOW INTO
THE NORTHWESTERN CARIBBEAN SEA. THE CYCLONIC FLOW FROM THE UPPER
LEVEL TROUGH GOES FROM THE EASTERN GULF OF MEXICO...TOWARD THE
BROAD BASE NEAR JAMAICA...AND EXITS INTO THE ATLANTIC OCEAN
THROUGH THE MONA PASSAGE. UPPER LEVEL ANTICYCLONIC FLOW AND
MOISTURE FROM SOME NORTHERN SOUTH AMERICA COASTAL SHOWERS AND
THUNDERSTORMS SOUTH OF 17N BETWEEN 65W AND 84W.

THE SUBTROPICAL ATLANTIC AND THE TROPICAL ATLANTIC...
DEEP LAYER TROUGH THROUGH 32N48W TO 24N47W WAY AWAY FROM
HURRICANE JEANNE. SURFACE COLD FRONT STILL NORTH OF THE
AREA...IS MAKING ITS WAY TOWARD THE EAST-SOUTHEAST. SURFACE
TROUGH THROUGH 32N38W TO 25N48W 25N56W. ISOLATED TO WIDELY
SCATTERED MODERATE/LOCALLY STRONG SHOWERS AND THUNDERSTORMS
WITHIN 30 TO 60 NM ON EITHER SIDE OF 32N37W 26N44W 22N51W.
ISOLATED MODERATE SHOWERS/THUNDERSTORMS...WHOSE CLOUD TOPS ARE
BEING SHEARED BY THE UPPER LEVEL WIND FLOW...FROM 24N TO 28N
BETWEEN 52W AND 60W. SURFACE RIDGE FROM 24N42W TO 27N30W BEYOND
32N24W. MIDDLE TO UPPER LEVEL TROUGH FROM ITS BASE NEAR 14N33W
TO 23N28W TO 29N28W TO 34N27W. BROAD UPPER LEVEL ANTICYCLONIC
FLOW IN THE TROPICS EAST OF 23N FROM 10N TO 32N.

$$
MT


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