[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 061744
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT 06 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS ALONG 4N10W 8N27W 4N38W 8N50W 5N62W 7N80W. WIDELY
SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN 75 NM OF
THE AXIS OFF THE COAST OF LIBERIA BETWEEN 9W-11W. SCATTERED
MODERATE WITHIN 220 NM OF THE AXIS BETWEEN 18W-30W. WIDELY
SCATTERED MODERATE WITHIN 300 NM N AND 75 NM S OF THE AXIS
BETWEEN 30W-51W.

...DISCUSSION...

GULF OF MEXICO AND WEST ATLANTIC...
A STATIONARY FRONT EXTENDS OVER THE SW ATLC AND NW CARIBBEAN
ALONG A LINE FROM 30N67W TO NASSAU BAHAMAS...TO 20N84W...TO
SOUTHERN BELIZE AND E GUATEMALA WITH A LOW BANK OF STRATUS AND
EMBEDDED SHOWERS EXTENDING UP TO 120 NM NW OF THE BOUNDARY.
STRONG HIGH PRES HAS BUILT IN BEHIND THE FRONT ANCHORED BY A
1027 MB HIGH OVER NE MEXICO AND THIS IS PRODUCING BRISK
NORTHERLY WINDS OVER THE GULF. SKIES ARE CLEAR UP TO 150 NM S OF
THE U.S. GULF COAST BUT THEN PATCHY STRATOCUMULUS FORMS FARTHER
S AS THE AIR MASS PICKS UP MOISTURE AND BECOMES SLIGHTLY MORE
UNSTABLE IN THE LOW LEVELS. AN UPPER LEVEL SHORTWAVE TROF IS
DROPPING SE OVER THE E GULF AT THE MOMENT WITH THE SUBTROPICAL
JET EXTENDING FROM TEXAS TO SOUTH FLORIDA THEN NEWD JUST N OF
BERMUDA. STRONG CONFLUENCE INTO THE BASE OF THE TROF IS
PRODUCING MODERATE/STRONG SUBSIDENCE OVER THE ENTIRE GULF AND
ATLC COASTAL WATERS.

CARIBBEAN...
A LARGE UPPER LEVEL CYCLONIC CIRCULATION IS CENTERED JUST N OF
PUERTO RICO WITH BROAD TROUGHING LOCATED OVER MOST OF THE
CARIBBEAN E OF ABOUT JAMAICA AND THE CAYMAN ISLANDS. THE TROF IS
ASSOCIATED WITH GENERALLY DRY MID/UPPER LEVEL AIR AND SO HAS
SUPPRESSED DEEP CONVECTION OVER A GOOD PART OF THE E/CNTRL
CARIBBEAN. HOWEVER...UPPER DIFFLUENCE IS INCREASING TO THE E OF
THE TROF OVER THE LESSER ANTILLES AS RIDGING BUILDS OVER THE
ATLC AND SO WIDELY SCATTERED SHOWERS/TSTMS HAVE BEGUN TO DEVELOP
FROM TRINIDAD NWD TO ANTIGUA BETWEEN 58W-64W. FARTHER
W...LOW-LEVEL SPEED CONVERGENCE CONTINUES JUST OFF THE CENTRAL
AMERICAN COAST WITH AN UPPER LEVEL RIDGE EXTENDING FROM PANAMA
TO THE GULF OF HONDURAS. THIS HAS SUBSEQUENTLY CAUSED SCATTERED
MODERATE CONVECTION TO PERSIST FROM 9N-16N BETWEEN 76W-84W. LOW
CLOUDS AND POSSIBLE SHOWERS ALSO EXTEND FROM W CUBA TO THE MAYAN
COAST ALONG A STATIONARY FRONT OVER THE NW CARIBBEAN WATERS.

SUBTROPICAL ATLANTIC...
SURFACE RIDGING CONTINUES TO BUILD OVER THE W/CNTRL ATLC AS A
LOW AND COLD FRONT MOVE E INTO THE E ATLC. A 1022 MB HIGH IS
CENTERED NEAR 33N46W WITH A RIDGE EXTENDING SW TOWARDS THE
BAHAMAS...AND AN UPPER HIGH CENTERED NEAR 26N57W. THE UPPER
LEVELS OVER THE E ATLC ARE DOMINATED BY A LARGE CYCLONIC VORTEX
WITH SEVERAL EMBEDDED CIRCULATIONS SPIRALING N OF THE AREA N OF
MADEIRA ISLAND AND SW OF THE AZORES. THE TROF IS SUPPORTING A
COLD FRONT WHICH EXTENDS FROM A 1010 MB LOW NEAR 34N31W TO
30N32W 25N44W THEN AS A DISSIPATING STATIONARY FRONT TO 27N56W.
A TROF IS LOCATED AHEAD OF THE FRONT ALONG 32N28W 25N30W 22N36W.
THERE IS LITTLE ACTIVE WEATHER ALONG THE COLD FRONT HOWEVER
SCATTERED MODERATE CONVECTION IS LOCATED UP TO 120 NM E OF THE
TROF N OF 24N.

TROPICAL ATLANTIC...
A SURFACE TROF IS LOCATED ABOUT 550 NM E OF THE LESSER ANTILLES
TILTED ALONG 11N56W 18N47W AND MOVING W 10-15 KT WITH THE TRADE
WINDS. ISOLATED SHOWERS/TSTMS HAVE BEEN DEVELOPING WITHIN 120 NM
OF THE AXIS ALTHOUGH THE COVERAGE IS NOWHERE NEAR AS IMPRESSIVE
AS THAT OF THE ITCZ. UPPER LEVEL WINDS OVER THE TROPICS IS
GENERALLY IN A UNIFORM WESTERLY DIRECTION BUT SOME OF THE FLOW
TURNS S OF 8N TOWARDS THE EQUATOR AND SUPPORTS A ZONE OF UPPER
DIFFLUENCE OVER THE ITCZ...MAKING IT CONVECTIVELY ACTIVE TODAY
OVER MOST OF THE ATLC.

$$
BERG




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