[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 302357
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT 30 APR 2005

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
2315 UTC.

...ITCZ...

ITCZ AXIS IS ALONG 7N12W 3N25W 2N52W.  ISOLATED MODERATE WITHIN
60 NM OF 2N34W...3.5N25W AND 3N8W.  WIDELY SCATTERED MODERATE
CONVECTION IS BETWEEN 1N-4N FROM 39W-47W...PERHAPS ASSOCIATED
WITH A WEAK LOW-LATITUDE TROPICAL WAVE.

...DISCUSSION...

GULF OF MEXICO...
MOST OF THE SIGNIFICANT WEATHER IS FOCUSING NEAR OR AHEAD OF A
COLD FRONT EXTENDING FROM EXTREME NW FLORIDA INTO THE GULF OF
MEXICO TO E MEXICO NEAR 23N98W.  A BRIEF GALE IS ONGOING BEHIND
THE FRONT OVER THE NW GULF.  UPPER SHORTWAVE MOVING ACROSS N
LOUISIANA CONTINUES TO TRIGGER A LARGE AREA OF TSTMS N OF 27N E
OF THE FRONT.  ELSEWHERE BROKEN LOW/MID CLOUDINESS LIES BEHIND
THE FRONT WITH A FEW SHOWERS WITHIN 60 NM OF THE FRONTAL ZONE.
FRONT SHOULD CONTINUE TO SLIP SE AND CAUSE LARGE TSTMS TO MOVE
INTO CENTRAL FLORIDA BY TOMORROW BEFORE SLOWLY MOVING THRU SE
FLORIDA DURING THE DAY ON MON.  OUTSIDE OF THE UPPER
SHORTWAVE... THE UPPER FLOW IS RATHER ZONAL WITH MID/UPPER DRY
AIR NOTED IN PRETTY MUCH ALL AREAS EXCEPT NEAR THE TSTMS.
A LARGE AREA OF SMOKE/HAZE CONTINUES TO MOVE NORTHWARD FROM
SOUTHERN MEXICO AND CENTRAL AMERICA...COVERING THE AREA BETWEEN
88W-94W S OF THE FRONTAL BOUNDARY.

CARIBBEAN SEA...
DEEP TROUGH FROM THE W ATLC EXTENDS INTO THE AREA FROM THE NE
CARIBBEAN TO 14N80W...BRINGING DRIER AIR ALOFT THRU THE REGION.
SOME UPPER RIDGING IS BUILDING OVER THE SW CARIBBEAN AND IS
RESPONSIBLE FOR MOVING HIGH CLOUDS INTO THE W CARIBBEAN. FAIRLY
TYPICAL TRADEWIND SHOWERS SPOT THE LEEWARD ISLANDS INTO PUERTO
RICO.  DECENT LOW/MID LEVEL MOISTURE SHOULD KEEP THE E CARIBBEAN
NEAR CLIMATOLOGICAL CHANCES OF PRECIPITATION WITH MAYBE SOME
DRYING FOR PUERTO RICO AND BEST CHANCES OF RAIN ALONG ABOUT THE
LATITUDE OF GUADELOUPE.  OTHERWISE A COLD FRONT FORECAST TO BE
OVER THE EXTREME SE GULF LATE TOMORROW SHOULD ENHANCE THE
SEA-BREEZE CONVECTION OVER THE YUCATAN AND W CUBA WITH SOME
STRONG TSTMS POSSIBLE.

ATLANTIC OCEAN...
N OF 18N...THE UPPER PATTERN HAS RIDGING OVER THE ATLC W OF
70W...A DEEP TROUGH OVER THE AREA BETWEEN 45W-70W... AND GENERAL
ZONAL FLOW E OF 45W.  THE DEEP TROUGH IS THE MAIN STORY... WITH
A MID/UPPER LOW NEAR 32N55W TROUGHING SSW TO THE LEEWARD
ISLANDS.  STRONG SUBSIDENCE ON THE WESTERN SIDE OF THE TROUGH IS
LEADING TO GENERALLY PARTLY CLOUDY SKIES... WHILE INDUCING A
SURFACE 1014 MB LOW NEAR 27N54W ON A TROUGH AXIS FROM 17N56W TO
31N53W.  WIDELY SCATTERED TSTMS ARE BETWEEN 21N-29N FROM
45W-52W.  A TREND TOWARD INCREASING RAIN COVERAGE IS FORECAST E
OF THE TROUGH AXIS AS THE SURFACE LOW INTENSIFIES ON INITIALLY
WEAK BAROCLINICITY BUT STRONG UPPER DYNAMICS.  THE LOW SHOULD
MOVE NE AND BE NEAR 26N42W BY EARLY MON.  THE DEEP TROPICS E OF
50W ARE CONTROLLED BY A MID/UPPER HIGH NEAR 5N31W RIDGING
WESTWARD INTO S AMERICA.  SLIGHTLY DIFFLUENT ELY FLOW NEAR THE
ITCZ IS SPARKING SOME TSTMS WITH DRY CONDITIONS/ MODERATE
SUBSIDENCE IN THE E ATLC.... ENHANCED BY A RECENT DUST OUTBREAK
OVER THE AREA E OF 40W BETWEEN THE ITCZ AND 21N.

$$
BLAKE

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