[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 301834
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON MAR 30 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1645 UTC.

...ITCZ...
FROM 05N09W TO 00N30W TO 01S37W TO COAST OF BRAZIL AT 01S46W.
NUMEROUS MODERATE ISOLATED STRONG CONVECTION WITHIN 90 NM OF
AXIS E OF 17W THEN SCATTERED MODERATE FROM 17W-26W.  ISOLATED
MODERATE WITHIN 90 NM OF AXIS W OF 40W.

...DISCUSSION...
UPPER LEVELS...
FLOW ALOFT BECOMING QUASI-ZONAL AS LONGWAVE TROUGH SUPPORTING
SURFACE COLD FRONT OVER SW N ATLC WEAKENS AND SHIFTS NE.  WEAK
UPSTREAM RIDGE CREST FLATTENS UNDER INFLUENCE OF NEW CYCLONIC
VORTEX ACROSS CENTRAL PLAINS.  EXCEPT THE MOISTURE ASSOCIATED
WITH COLD FRONT ALONG SW N ATLC...REMAINDER OF FORECAST AREA
REMAINS UNDER MODERATE TO STRONG SUBSIDING AIR MASS WHICH
INHIBITS CLOUD DEVELOPMENT.  LARGE AMPLITUDE LONG WAVE UPPER
LEVEL TROUGH ACROSS CENTRAL ATLC FROM 31N35W TO 17N52W TO 13N61W
SUPPORTS ILL DEFINED STATIONARY FRONT FROM 31N31W TO 19N42W.
RIDGE OVER AFRICAN CONTINENT BRINGS ONLY SIGNIFICANT AMOUNT OF
TROPICAL MOISTURE INTO E ATLC MAINLY S OF 15N W OF 40W.

ELSEWHERE AT THE SURFACE...
GULF OF MEXICO...
HIGH PRESSURE RIDGE COVER EASTERN HALF OF GULF WITH LOW LEVEL
STRATIFIED CLOUDS OF LITTLE OR NO VERTICAL DEVELOPMENT.
MOISTURE FROM TAIL END OF STATIONARY FRONT OVER STRAITS OF
FLORIDA PROMPTING BROKEN TO OVERCAST LOW LEVEL CLOUDS WITH
ISOLATED SHOWERS S OF 27N E OF 87W.  REMAINDER GULF CARRIES
MOSTLY SCATTERED LOW CLOUDS AND BRIEF ISOLATED ALONG COASTAL
SECTIONS.  ANOTHER COLD FRONT FORECAST TO APPROACH BASIN BY TUE.

CARIBBEAN SEA...
VERY WEAK ANTICYCLONIC FLOW COVERS ENTIRE AREA WITH DRY AIR MASS
DUE TO MODERATE TO STRONG SUBSIDENCE.  ONLY MOISTURE MOVING N
FROM OVER SOUTH AMERICA CONTINENT IS IMMEDIATELY DRIED OVER THE
CARIBBEAN BASIN ALLOWING ONLY ISOLATED SHOWERS OF SHORT
DURATION.  EVEN MOISTURE FROM STATIONARY FRONT FROM WESTERN TIP
OF CUBA TO BELIZE QUICKLY DISAPPEAR WHEN MIXED WITH CARIBBEAN
SUBSIDING AIR MASS.

ATLANTIC OCEAN...
STATIONARY FRONT FROM 31N31W TO 19N42W PROMPTING SCATTERED DEEP
CONVECTION MOSTLY N OF 28N FROM 26W-32W.  MOISTURE INCOMING OVER
CANARY ISLANDS ADVECTED BY RIDGE OVER AFRICAN CONTINENT
PROMPTING SCATTERED SHOWERS.  HIGH PRESSURE RIDGE AXIS FROM
31N20W TO 16N29W.

$$
WALLY BARNES


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