[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 051734
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI 05 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.

...TROPICAL WAVES...

TROPICAL WAVE LOCATED OVER GUATEMALA AND THE YUCATAN PENINSULA
ALONG 90W S OF 18N MOVING W 5-10 KT. STRONG LOW-LEVEL ROTATION
IS NOTED OVER THE E PACIFIC SOUTH OF EL SALVADOR...BUT THE
NORTHERN EXTENT OF THE WAVE IS BEGINNING TO MERGE WITH A COLD
FRONT MOVING ACROSS THE YUCATAN PENINSULA. SCATTERED MODERATE
CONVECTION IS LOCATED OFF THE CARIBBEAN COAST OF CENTRAL AMERICA
BUT IS NOT DIRECTLY ASSOCIATED WITH THE WAVE.

...ITCZ...

ITCZ AXIS IS ALONG 10N10W 7N16W 6N24W 4N33W 6N45W 5N58W 10N71W
11N84W. SCATTERED MODERATE WITHIN 225 NM N AND 150 NM S OF THE
AXIS BETWEEN 18W-29W. WIDELY SCATTERED MODERATE WITHIN 100 NM OF
THE AXIS BETWEEN 34W-45W.

...DISCUSSION...

GULF OF MEXICO AND SW ATLANTIC...
A STRONG COLD FRONT HAS ALMOST PUSHED COMPLETELY ACROSS FLORIDA
AND THE GULF OF MEXICO...EXTENDING FROM 32N72W TO WEST PALM
BEACH FLORIDA TO CANCUN MEXICO TO 16N93W ON THE LATEST SURFACE
ANALYSIS. THE FRONT IS MOVING RATHER SLOWLY TO THE SE...AT LEAST
OVER THE GULF AND FLORIDA...PROBABLY DUE TO THE UPPER LEVEL TROF
OVER THE AREA HAVING A MOSTLY FLAT CHARACTER. WATER VAPOR
IMAGERY DOES INDICATE A SECOND SHORTWAVE DROPPING S OVER THE
MISSISSIPPI VALLEY WHICH SHOULD DEEPEN THE TROF OVER THE NEXT 24
HOURS AND PUSH THE FRONT TOWARDS CUBA AND THE W ATLC. THE UPPER
TROF IS ADVECTING DRIER MID/UPPER LEVEL AIR ACROSS THE ENTIRE
AREA...BUT LOW-LEVEL COLD ADVECTION OVER THE WARMER WATERS OF
THE GULF AND SW ATLC HAS FORMED A NEARLY SOLID DECK OF STRATUS
AND STRATOCUMULUS. STRATUS WITH ISOLATED SHOWERS ALSO EXTENDS UP
TO 100 NM BEHIND THE SURFACE FRONT WITH SOME THICKER CLOUDS AND
SOME TSTMS POSSIBLE ALONG THE ISTHMUS OF TEHAUNTEPEC.

CARIBBEAN...
MOSTLY FAIR WEATHER COVERS A GOOD CHUNK OF THE CARIBBEAN WITH
THE MOST INCLEMENT WEATHER FOCUSED ON THE EDGES NEAR THE
WINDWARD ISLANDS AND NEAR CENTRAL AMERICA. SHIP OBSERVATIONS AND
QSCAT IMAGERY SHOW STRONG 20 KT EASTERLY FLOW ACROSS THE ENTIRE
BASIN WHICH CONVERGES WITH MUCH WEAKER FLOW ALONG THE CENTRAL
AMERICAN COAST. IN ADDITION...AN UPPER RIDGE EXTENDS FROM COSTA
RICA NWD TO THE YUCATAN CHANNEL AND SCATTERED MODERATE/STRONG
CONVECTION HAS DEVELOPED WITHIN 200 NM OF THE COAST OF NICARAGUA
AND HONDURAS. SCATTERED MODERATE CONVECTION IS ALSO OVER N
BELIZE AND NEAR CHETUMAL MEXICO. FARTHER E...A DEEP UPPER TROF
HAS CARVES INTO THE CARIBBEAN FROM CUBA SWD TO N VENEZUELA THEN
INTO THE CNTRL ATLC WITH DRY MID/UPPER LEVEL AIR E OF 79W. AN
AXIS OF LOW-LEVEL CONVERGENCE IS LOCATED E OF THE LESSER
ANTILLES WITH WIDELY SCATTERED SHOWERS/TSTMS SPREADING SLOWLY W
FROM TRINIDAD NWD TO DOMINICA.

SUBTROPICAL ATLANTIC...
A PROGRESSIVE UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE W
ATLC NEAR 27N63W AND AN ASSOCIATED SFC RIDGE IS BUILDING BETWEEN
35W AND THE BAHAMAS. A COLD FRONT IS EMBEDDED WITHIN THE RIDGE
EXTENDING ALONG 32N38W 26N52W THEN AS A STATIONARY FRONT TO
25N66W. A BROKEN BAND OF CLOUDINESS EXTENDS WITHIN 50 NM OF THE
FRONT BUT THERE IS NO DEEP CONVECTION. A SFC TROF IS LOCATED E
OF THE FRONT ALONG 32N32W 27N33W 22N40W 19N50W AND SCATTERED
MODERATE CONVECTION HAS BEEN ALONG THIS BOUNDARY FROM 24N-31N
BETWEEN 26W-33W. THESE TSTMS ARE BEING FORCED BY WEAK DIVERGENCE
AHEAD OF A NARROW UPPER TROF ALONG 40W N OF 26N. WEAK RIDGING IS
LOCATED ALONG 30W BUT IS BEING OVERSHADOWED BY A LARGE CYCLONIC
VORTEX CENTERED JUST SW OF PORTUGAL AND EXTENDING S PAST THE
CANARY ISLANDS.

TROPICAL ATLANTIC...
AN ELONGATED SUBTROPICAL JET ORIGINATES JUST E OF THE LESSER
ANTILLES NEAR 15N60W AND EXTENDS E ACROSS THE ATLC ALONG 19N45W
19N15W WITH SPEEDS AS HIGH AS 50 KT NEAR THE CAPE VERDE ISLANDS.
A SUBTROPICAL MOISTURE PLUME EXTENDS UP TO 400 NM S OF THE
JET...MAKING THE ATMOSPHERE ACROSS THE TROPICAL ATLC
SUFFICIENTLY MOIST FOR DEEP CONVECTION. LOW-LEVEL CONVERGENCE IS
ALIGNED ALONG A LINE NE OF TRINIDAD WITH SCATTERED MODERATE
CONVECTION FORMING FROM 10N-16N BETWEEN 48W-61W. ALSO...A WEAK
TROF IS LOCATED ALONG 45W/46W MOVING W 10-15 KT AND IS
RE-INFORCING CONVECTIVE DEVELOPMENT. UPPER LEVEL DIVERGENCE IS
ALSO SIGNIFICANT OVER THE ITCZ...WHICH IS SUPPORTING WIDESPREAD
CONVECTION ALONG THE AXIS ESPECIALLY S OF THE CAPE VERDE ISLANDS.

$$
BERG




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