[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 102331
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED 10 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2245 UTC.

...SPECIAL FEATURE...
WIDESPREAD CLOUDINESS AND SHOWERS/THUNDERSTORMS CONTINUE ACROSS
THE CENTRAL AND E CARIBBEAN EXTENDING FROM COSTA RICA AND PANAMA
NORTHEASTWARD TO THE VIRGIN/N LEEWARD ISLANDS. THIS ACTIVITY IS
ASSOCIATED WITH AN ELONGATED AREA OF LOW PRESSURE ORIGINATING
FROM A REMNANT FRONTAL TROUGH EXTENDING SWD FROM THE 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 IS LIKELY OVER THE VIRGIN ISLANDS AND THE
LEEWARD ISLANDS DURING THE NEXT DAY OR TWO AS THE AREA OF
DISTURBED WEATHER LIFTS NE.

...TROPICAL WAVES...

WEAK TROPICAL WAVE OVER THE CENTRAL CARIBBEAN ALONG 75W SOUTH OF
18N MOVING WEST 10 TO 15 KT. THE WAVE IS POORLY DEFINED IN
SATELLITE IMAGERY AND THE LATEST POSITION IS BASED PRIMARILY ON
EXTRAPOLATION.  STRONG UPPER LEVEL SHEAR EXIST OVER THE WAVE
WHICH WILL LIKELY LIMIT ANY DEVELOPMENT.  ADDITIONALLY...THE
WAVE IS MOVING INTO AN AREA OF VERY DRY/STABLE MIDDLE TO UPPER
LEVEL AIR OVER THE W CARIBBEAN WHICH SHOULD LIMIT SIGNIFICANT
DEEP CONVECTION DURING THE NEXT FEW DAYS.

...ITCZ...

ITCZ AXIS IS ALONG 9N10W 5N30W 3N40W 9N50W 12N70W 11N80W.
SCATTERED MODERATE CONVECTION OVER THE FAR E ATLC FROM 4N TO THE
CAPE VERDE ISLANDS BETWEEN 20W-27W. SIMILAR ACTIVITY FROM 1N-6N
BETWEEN 33W-40W.

...DISCUSSION...

GULF OF MEXICO...
MIDDLE TO UPPER LEVEL RIDGE IS MARCHING EWD OVER THE GLFMEX
AHEAD OF A PROGRESSIVE DEEP LAYERED LOW OVER THE CENTRAL UNITED
STATES. RIDGE AXIS CURRENTLY EXTENDS FROM THE SE UNITED STATES
TO THE BAY OF CAMPECHE.  AT THE SURFACE...BACKDOOR COLD FRONT
HAS CLEARED S FLORIDA NOW EXTENDING OVER W CUBA AND THE FLORIDA
STRAITS.  HIGH PRESSURE MIGRATING EWD OFF THE E UNITED STATES IS
PRODUCING STRONG NE TO E WINDS OVER FLORIDA AND THE E GLFMEX
BEHIND THE FRONT WITH MODERATE RETURN FLOW DEVELOPING OVER THE W
GLFMEX INTO TEXAS.  LOW LEVEL MOISTURE ASSOCIATED WITH THE
BACKDOOR COLD FRONT MOVED ACROSS FLORIDA LAST NIGHT AND INTO THE
E GLFMEX TODAY PRODUCING SCATTERED SHALLOW TOPPED
SHOWERS/ISOLATED THUNDERSTORMS. THE BULK OF THIS ACTIVITY
CURRENTLY LIES WITHIN 50 NM EITHER SIDE OF A LINE FROM W CUBA
NEAR HAVANA TO SE LOUISIANA AND WILL LIFT SLOWLY NWD TONIGHT.
ELSEWHERE...DRY/TRANQUIL CONDITIONS PREVAIL.  LOOKING
UPSTREAM...THE NEXT WEATHER SYSTEM TO AFFECT THE AREA WILL BE A
COLD FRONT WHICH WILL EMERGE OFF THE SE TEXAS COAST THU
AFTERNOON.

CARIBBEAN SEA...
COMPLEX PATTERN REMAINS OVER THE CARIBBEAN AS MID-LATITUDE
DYNAMICS INTERACT WITH DEEP TROPICAL MOISTURE. AT THE MIDDLE TO
UPPER LEVELS...SHARP TROUGH EXTENDS FROM THE W ATLC SWD OVER
HISPANIOLA INTO CENTRAL AMERICA NEAR NICARAGUA.  THE TROUGH IS
FLANKED ON THE EAST SIDE BY A 100 KT SUBTROPICAL JET EXTENDING
FROM THE CENTRAL CARIBBEAN NEWD INTO THE CENTRAL ATLC. WEST OF
THE UPPER TROUGH...STRONG SUBSIDENCE AND VERY DRY/STABLE MIDDLE
TO UPPER LEVEL AIR BLANKETS THE NW 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 CENTRAL AND E CARIBBEAN FROM PANAMA NEWD TO THE LEEWARD
ISLANDS WITH A 1008 MB LOW S OF HISPANIOLA NEAR 15N69W.
WIDESPREAD CLOUDINESS AND STRONG SHOWERS/THUNDERSTORMS CONTINUE
OVER THE REGION WITHIN APPROXIMATELY 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
EWD OVER THE VIRGIN ISLANDS AND LESSER ANTILLES.  LATEST WATER
VAPOR IMAGERY INDICATES THAT THE UPPER TROUGH AXIS HAS MIGRATED
SLOWLY EWD DURING THE LAST 24 HOURS ALLOWING THE AXIS OF DRY TO
THE WEST TO CLEAR OUT HISPANIOLA.  THIS DRY IS ALSO APPROACHING
PUERTO RICO AND SHOULD LIMIT THE STRONGEST ACTIVITY TO THE EAST
OVER THE VIRGIN ISLANDS AND N LEEWARD ISLANDS WHERE FLOODING AND
MUD SLIDES ARE POSSIBLE.

ATLANTIC...
SHARP MIDDLE TO UPPER LEVEL TROUGH OVER THE W ATLC IS THE
PRIMARY WEATHER MAKER EXTENDING FROM JUST E OF BERMUDA SWD INTO
THE CARIBBEAN NEAR HISPANIOLA.  STRONG SUBTROPICAL JET ALONG E
SIDE OF THE TROUGH IS TAPPING INTO DEEP TROPICAL MOISTURE
SURGING NWD FROM THE CARIBBEAN.  AS A RESULT...CLOUDINESS AND
WIDESPREAD SHOWERS/THUNDERSTORMS CONTINUE OVER THE CENTRAL ATLC
WITHIN APPROXIMATELY 200 NM EITHER SIDE OF AN ILL-DEFINED
SURFACE TROUGH EXTENDING FROM THE N LEEWARD ISLANDS NEWD TO
BEYOND 30N55W. THE N EXTENT OF THIS BOUNDARY IS QUICKLY BEING
OVERTAKEN BY A COLD FRONT PUSHING SWD OVER THE W ATLC FROM
32N53W SWD OVER THE TURKS/CAICOS TO W CUBA. THE FRONT IS
USHERING IN A REINFORCING SHOT OF COOL/DRY AIR OVER THE W ATLC
WHICH IS ALREADY DOMINATED BY STRONG MIDDLE TO UPPER LEVEL
SUBSIDENCE WEST OF THE UPPER TROUGH AXIS.  AS A RESULT...A LARGE
FIELD OF BROKEN TO OVERCAST STRATOCUMULUS CLOUDS COVERS THE AREA
N OF THE COLD FRONT INDICATING VERY STABLE CONDITIONS.  OVER THE
CENTRAL ATLC...HIGH AMPLITUDE MIDDLE TO UPPER LEVEL RIDGE
EXTENDS FROM THE E CARIBBEAN NEWD TO BEYOND 32N48W. THE RIDGE IS
PRODUCING A SHARP DELINEATION IN AVAILABLE MOISTURE AS THE
UPSTREAM SUBTROPICAL JET AND ASSOCIATED MOISTURE RIDE UP AND
OVER THE RIDE 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
30N30N.  THE LARGE LOW EXTENDS A TROUGH WELL SWD INTO THE
TROPICAL ATLC WATERS ALONG 20N40W TO THE COAST OF S AMERICA NEAR
FRENCH GUIANA.   ASSOCIATED SUBSIDENCE IS PENETRATING S OF 10N
RESTRICTING ITCZ CONVECTION BETWEEN 40W-60W.
CONVERSELY...DIFFLUENT UPPER LEVEL FLOW E OF THE TROUGH IS
ENHANCING ITCZ ACTIVITY BETWEEN 20W-40W WHILE STRONG SLY FLOW
ALLOWS ASSOCIATED MOISTURE TO SURGE NWD OVER THE CAPE VERDE
ISLANDS PRODUCING CLOUDINESS AND WIDESPREAD
SHOWERS/THUNDERSTORMS.  SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO
OBSERVED N OF THE COLD CORE LOW NEAR 30N30W FROM 29N-32N BETWEEN
25W-35W.

$$
RHOME



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