[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111142
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST THU 11 NOV 2004

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND ATLANTIC 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
1115 UTC.

...SPECIAL FEATURE...
WIDESPREAD CLOUDINESS AND SHOWERS/THUNDERSTORMS CONTINUE ACROSS
THE SOUTH-CENTRAL AND E CARIBBEAN EXTENDING FROM COLOMBIA
NORTHEASTWARD TO THE VIRGIN/LEEWARD ISLANDS. THIS ACTIVITY IS
ASSOCIATED WITH AN ELONGATED AREA OF LOW PRESSURE ORIGINATING
FROM A REMNANT FRONTAL TROUGH EXTENDING S FROM THE CENTRAL ATLC.
SATELLITE IMAGERY INDICATES THAT THE SYSTEM REMAINS ELONGATED
AND POORLY ORGANIZED WITH MULTIPLE LOW LEVEL CYCLONIC CENTERS.
HOWEVER...UPPER LEVEL WINDS ARE MARGINALLY FAVORABLE AND THERE
STILL EXISTS SOME POTENTIAL FOR A TROPICAL OR SUBTROPICAL
CYCLONE TO DEVELOP. REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY
RAINFALL AND FLOODING WITH POSSIBLE MUDSLIDES ARE LIKELY OVER
THE VIRGIN AND LEEWARD ISLANDS DURING TODAY AND TONIGHT AS THE
AREA OF DISTURBED WEATHER LIFTS NE.

...TROPICAL WAVES...

WEAK TROPICAL WAVE OVER THE CENTRAL CARIBBEAN IS ALONG 77W S OF
18N MOVING W 10 KT. THE WAVE IS POORLY DEFINED IN SATELLITE
IMAGERY AND THE LATEST POSITION IS PRIMARILY BASED ON
EXTRAPOLATION. STRONG UPPER LEVEL SW SHEAR EXISTS JUST TO THE E
OF THE WAVE AND THE WAVE IS NOW IN AN AREA OF VERY DRY/STABLE
MID/UPPER LEVEL AIR OVER THE W CARIBBEAN WHICH WILL LIKELY LIMIT
ANY DEVELOPMENT OR SIGNIFICANT DEEP CONVECTION.

...ITCZ...

ITCZ AXIS IS ALONG 10N10W 13N24W 3N31W TO INLAND OVER SOUTH
AMERICA NEAR 3N51W. THE AXIS REMAINS UNUSUALLY FAR SOUTH FOR
THIS TIME OF YEAR. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE
OVER THE FAR E ATLC FROM 2N-15N BETWEEN 16W-37W INCLUDING THE
CAPE VERDE ISLANDS.

...DISCUSSION...

GULF OF MEXICO...
MID/UPPER LEVEL RIDGE CONTINUES TO MOVE E ACROSS THE GULF AS THE
DEEP LAYERED LOW PREVIOUSLY OVER THE CENTRAL UNITED STATES IS
NOW MOVING NE. RIDGE AXIS CURRENTLY EXTENDS FROM THE SE UNITED
STATES/W ATLC TO THE BAY OF CAMPECHE. AT THE SURFACE...BACKDOOR
COLD FRONT HAS CLEARED THE BAHAMAS ACROSS E CUBA TO THE YUCATAN
CHANNEL WITH REMNANT SHOWERS REMAIN OVER THE CENTRAL GULF AS
RESULT OF THE RETURN FLOW GENERATED BY THE FRONT AS IT CONTINUES
TO MOVE E. HIGH PRESSURE OFF THE NE UNITED STATES IS CONTINUES
TO PRODUCE EASTERLY WINDS OVER FLORIDA ALTHOUGH NOT AS STRONG AS
YESTERDAY. RIP CURRANTS ARE EXPECTED ALONG THE E COAST OF
FLORIDA TODAY. DRY/TRANQUIL CONDITIONS PREVAIL OVER THE
REMAINDER OF THE GULF. LOOKING UPSTREAM...THE NEXT WEATHER
SYSTEM TO AFFECT THE AREA WILL BE A COLD FRONT WHICH WILL EMERGE
OFF THE SE TEXAS COAST THIS AFTERNOON.

CARIBBEAN SEA...
COMPLEX PATTERN REMAINS OVER THE E CARIBBEAN AS MID-LATITUDE
DYNAMICS INTERACT WITH DEEP TROPICAL MOISTURE. AT THE MID/UPPER
LEVELS...TROUGH EXTENDS FROM THE W ATLC S ACROSS HISPANIOLA AND
E CUBA TO OFF THE COAST OF NICARAGUA. THE TROUGH IS FLANKED ON
THE EAST SIDE BY AN 80-100 KT SUBTROPICAL JET EXTENDING FROM THE
NE CARIBBEAN NE INTO THE CENTRAL ATLC. WEST OF THE UPPER
TROUGH...STRONG SUBSIDENCE AND VERY DRY/STABLE MID/UPPER LEVEL
AIR BLANKETS THE W CARIBBEAN AND CENTRAL AMERICA N OF COSTA
RICA. AT THE SURFACE...AN ELONGATED AREA OF LOW PRESSURE
ASSOCIATED WITH A REMNANT FRONTAL TROUGH EXTENDS ACROSS THE E
CARIBBEAN FROM COLOMBIA NE TO THE LEEWARD ISLANDS WITH A 1008 MB
LOW S OF THE MONA PASSAGE NEAR 14N67W. WIDESPREAD CLOUDINESS AND
STRONG SHOWERS/THUNDERSTORMS CONTINUE OVER THE REGION WITHIN
APPROXIMATELY 150/200 NM EITHER SIDE OF THE ELONGATED TROUGH.
THIS AREA OF DISTURBED WEATHER REMAINS POORLY ORGANIZED BUT IS
PRODUCING LOCALLY HEAVY RAINS FROM PUERTO RICO E OVER THE VIRGIN
AND LEEWARD ISLANDS. LATEST WATER VAPOR IMAGERY INDICATES THAT
THE UPPER TROUGH AXIS IS ALLOWING THE AXIS OF DRY AIR TO CLEAR
OUT MOST OF HISPANIOLA ALTHOUGH SHOWERS GENERATED BY THE COLD
FRONT IN THE CENTRAL ATLC REMAIN. THIS DRY AIR IS ALSO
APPROACHING THE PUERTO RICO AND SHOULD LIMIT THE STRONGEST
ACTIVITY WELL TO THE EAST OVER THE VIRGIN AND LEEWARD ISLANDS
WHERE FLOODING AND MUD SLIDES ARE POSSIBLE.

ATLANTIC...
SHARP MID/UPPER LEVEL TROUGH OVER THE W ATLC IS THE PRIMARY
WEATHER MAKER EXTENDING FROM E OF BERMUDA SW TO AN UPPER
LEVEL...INSIGNIFICANT LOW NEAR 30N66W S INTO THE CARIBBEAN NEAR
HISPANIOLA AND E CUBA. STRONG SUBTROPICAL JET ALONG E SIDE OF
THE TROUGH IS ADVECTING DEEP TROPICAL MOISTURE N FROM THE E
CARIBBEAN ACROSS THE CENTRAL/WESTERN ATLC. AS A RESULT...
CLOUDINESS AND WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS
CONTINUE OVER THE CENTRAL ATLC WITHIN APPROXIMATELY 150/200 NM
EITHER SIDE OF AN ILL-DEFINED SURFACE TROUGH EXTENDING FROM THE
N LEEWARD ISLANDS NE TO 28N53W. THE N EXTENT OF THIS BOUNDARY IS
QUICKLY BEING OVERTAKEN BY A COLD FRONT PUSHING E OVER THE W
ATLC FROM 32N52W SW JUST S OF THE TURKS/CAICOS TO ACROSS E CUBA.
THE FRONT IS USHERING IN A REINFORCING SHOT OF COOL/DRY AIR OVER
THE W ATLC WHICH IS ALREADY DOMINATED BY STRONG MID/UPPER LEVEL
SUBSIDENCE W OF THE FRONT. AS A RESULT...A LARGE FIELD OF
BROKEN/OVERCAST STRATOCUMULUS CLOUDS COVERS THE AREA N OF THE
COLD FRONT INDICATING VERY STABLE CONDITIONS. OVER THE CENTRAL
ATLC...HIGH AMPLITUDE MID/UPPER LEVEL RIDGE EXTENDS FROM
VENEZUELA NE ACROSS THE FAR E CARIBBEAN TO BEYOND 32N46W. THE
RIDGE IS PRODUCING A SHARP DELINEATION IN AVAILABLE MOISTURE AS
THE UPSTREAM SUBTROPICAL JET AND ASSOCIATED MOISTURE RIDE UP
LEAVING STRONG SUBSIDENCE AND DRY AIR TO THE EAST. THE DRY AIR
IS BEING ENHANCED BY CONFLUENT FLOW AROUND THE BACKSIDE OF A
LARGE DEEP LAYERED LOW OVER THE E ATLC NEAR 29N32W. THE LARGE
LOW EXTENDS A TROUGH WELL S INTO THE TROPICAL ATLC ALONG 20N37W
TO THE COAST OF S AMERICA OVER N BRAZIL JUST E OF FRENCH GUIANA.
ASSOCIATED SUBSIDENCE IS PENETRATING S TO NEAR THE EQUATOR
RESTRICTING ITCZ CONVECTION TO E OF 40W. CONVERSELY...DIFFLUENT
UPPER LEVEL FLOW E OF THE TROUGH IS ENHANCING ITCZ ACTIVITY
BETWEEN 20W-40W WHILE STRONG SOUTHERLY FLOW ALLOWS ASSOCIATED
MOISTURE TO SURGE N ACROSS THE CAPE VERDE ISLANDS PRODUCING
CLOUDINESS AND WIDESPREAD SHOWERS/ISOLATED THUNDERSTORMS.
SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO OBSERVED N AND E OF THE
COLD CORE 1006 MB LOW NEAR 29N34W FROM 27N-32N BETWEEN 28W-37W.
A SURFACE TROUGH EXTENDS FROM THE 1006 MB LOW SW ALONG 23N28W TO
21N47W BUT IS NOT PRODUCING ANY SHOWER ACTIVITY.

$$
WALLACE


This weather bulletin was brought to you by:
www.nashvilleweather.net