[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 221811
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED 22 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 CENTER NEAR 26.3N 68.5W OR ABOUT 530 MILES...
855 KM EAST OF GREAT ABACO ISLAND IN THE BAHAMAS AT 22/1500
UTC...MOVING SOUTH 4 KT. MAXIMUM SUSTAINED WIND SPEED 80 KT
GUSTS 100 KT. ESTIMATED MINIMUM CENTRAL PRESSURE 968 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 STRENGTHEN...VERTICAL
SHEAR IS FORECAST TO WEAKEN OVER THE NEXT 24 HOURS SO SOME
STRENGTHENING IS POSSIBLE.  SCATTERED MODERATE/ISOLATED STRONG
CONVECTION EXTENDS OUT 80 NM FROM THE CENTER.

HURRICANE KARL CENTER NEAR 26.9N 49.0W OR ABOUT 1490 MILES...
2395 KM WEST-SOUTHWEST OF WESTERN AZORES AT 22/1500 UTC...MOVING
NORTH 14 KT. MAXIMUM SUSTAINED WIND SPEED 90 KT GUSTS 110 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE 970 MB. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT2/WTNT22 KNHC
FOR MORE DETAILS. KARL IS STARTING TO MAKE MORE OF A TURN TO THE
NORTH AS THE SYSTEM IS EXPECTED TO BEGIN INTERACTING WITH A MID
ATLANTIC LONG WAVE THROUGH. SOME WEAKENING IS EXPECTED OVER THE
NEXT 24 HOURS. SCATTERED MODERATE/ ISOLATED STRONG CONVECTION
EXTENDS OUT 110 NM FROM THE CENTER.


TROPICAL STORM LISA CENTER NEAR 13.9N 41.3W OR ABOUT 1165
MILES...1875 KM WEST OF THE CAPE VERDE ISLANDS AT 22/1500
UTC...MOVING WEST-NORTHWEST 6 KT. MAXIMUM SUSTAINED WIND SPEED
45 KT GUSTS 55 KT. ESTIMATED MINIMUM CENTRAL PRESSURE 1000 MB.
SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADER
MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. SATELLITE IMAGERY
INDICATES A PARTLY EXPOSED CIRCULATION WITH THE BULK OF
CONVECTION FORCED OVER THE SW SEMICIRCLE.  LISA IS BEGINNING TO
BE AFFECTED BY A LARGE AREA OF DISTURBED WEATHER TO THE SE. SOME
WEAKENING IS EXPECTED OVER THE NEXT 24 HOURS. SCATTERED
MODERATE/ ISOLATED STRONG CONVECTION EXTENDS OUT 40 NM FROM THE
CENTER.


TROPICAL WAVE LOCATED APPROXIMATELY 800 NM WEST OF THE CAPE
VERDE ISLAND ALONG 36W/37W SOUTH OF 17N MOVING WEST 15 KT IS NOW
BEING TRACKED AS A LOW. AN 1010 MB LOW.  SCATTERED MODERATE/
ISOLATED STRONG CONVECTION ALTHOUGH EXTENDS OUT 100 NM FROM THE
CENTER ALTHOUGH IN CLOSE PROXIMITY TO T.S. LISA. CONDITIONS
REMAIN FAVORABLE FOR DEVELOPMENT AND A TROPICAL CYCLONE WITHIN
THE NEXT 24 HOURS.

...TROPICAL WAVES...

SEE SPECIAL FEATURES FOR TROPICAL WAVE ALONG 36W.

...ITCZ...

ITCZ EXTENDS ALONG 10N12W 10N40W 10N58W... DISRUPTED BY T.S LISA
AND THE LOW JUST TO THE SE OF LISA. ASIDE FROM THE CONVECTION
ASSOCIATED WITH THE THE TROPICAL SYSTEM... AREA OF SCATTERED
MODERATE CONVECTION EXTENDS FROM 4N-18N BETWEEN 13N-23N.

...DISCUSSION...

GULF OF MEXICO...
MIDDLE TO UPPER LEVEL LOW CENTERED NEAR 24N94W CONTINUES TO
DOMINATE THE WESTERN TWO-THIRDS OF THE GULF...A UPPER LEVEL HIGH
LOCATED NEAR 22N109W WITH A RIDGE EXTENDING N IN THE MIDWEST OF
THE US. A SECOND UPPER LEVEL HIGH IN THE CARIBBEAN IS HELPING TO
ELONGATE THE LOW IN THE GULF.  A 1011 MB SURFACE LOW ASSOCIATED
WITH THE REMNANTS OF IVAN CONTINUES TO PUSH WEST ACROSS THE
GULF. SCATTERED MODERATE CONVECTION IS NOTED FROM 26N-29N
BETWEEN 84W-90W THE UPPER LEVEL WEATHER PATTERN IS EXPECTED TO
REMAIN UNCHANGED THROUGH THE NEXT 24-36 HOURS KEEPING CLOUDINESS
AND SHOWERS AND THUNDERSTORMS ACROSS THE NORTHERN GULF OF
MEXICO. THE BULK OF THIS ACTIVITY SHOULD BE FOCUSED ALONG THE
NORTHERN GULF COAST FROM MOBILE BAY WESTWARD TO EAST TEXAS.

THE CARIBBEAN SEA...
LARGE MID/UPPER LEVEL HIGH IS CENTERED JUST E OF THE YUCATAN
PENINSULA NEAR 18N83W.  ASSOCIATED ANTICYCLONIC FLOW COVERS THE
WESTERN PORTION OF THE GULF. WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS W OF 89W.   DRY AIR IN THE MID/UPPER LEVELS
CONTINUES DOMINATE THE E PORTION OF THE GULF E OF 69W.
SCATTERED MODERATE CONVECTION ALONG A CONVERGENCE ZONE WITH AN
AXIS THAT RUNS FROM THE CENTRAL CARIBBEAN NEAR 15N74W EXTENDING
NORTH OVER EASTERN HISPANIOLA INTO THE WESTERN ATLANTIC...  THIS
CONVECTION IS A RESULT OF THE INTERACTION OF HURRICANE JEANNE
AND WITH LIGHT SE TO S WINDS OVER PORTIONS OF THE TROPICAL
ATLANTIC.


SUBTROPICAL ATLANTIC...
TROUGH FROM YESTERDAY HAS BEGUN TO LIFT NORTH OF THE AREA.
ASSOCIATED SURFACE STATIONARY FRONT MAKES IT'S WAY INTO THE AREA
NEAR 30N55W AND EXTENDS W TO JUST NORTH OF HURRICANE JEANNE AS
A DYEING STATIONARY FRONT.  THE INTERACTION WITH JEANNE HAS
BECOME LESS AS THE BOUNDARY CONTINUES TO DISSIPATE.  THIS
BOUNDARY IS EXPECTED TO REACH TOWARD KARL IN THE 48-72 HOURS
TIME FRAME AND BEGIN IT'S TRANSITION TO X-TROP.  A STRONG
SURFACE HIGH PRESSURE CONTINUES TO PUSH EASTWARD INTO THE W
ATLANTIC.  OVER THE CENTRAL ATLANTIC... MODERATE SUBSIDENCE
EXISTS BETWEEN HURRICANE KARL AND TROPICAL STORM JEANNE...
PRODUCING DRY AIR AND TRANQUIL WEATHER.  MID/UPPER LEVEL TROUGH
OVER THE E ATLANTIC EXTENDS FROM THE CANARY SWD TO THE CAPE
VERDE ISLANDS.

TROPICAL ATLANTIC...
WEAK MID/UPPER LEVEL RIDGING EXTENDS E/T ACROSS THE AREA ALONG
20N BUT REMAINS DISRUPTED IN THE VICINITY OF HURRICANE KARL AND
TROPICAL STORM LISA. DEEP LAYERED EASTERLY FLOW SOUTH OF THE
RIDGE EXTENDS ACROSS THE TROPICAL ATLC WEST OF 35W.

$$
JP/EH





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