[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 291046
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI 29 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...ITCZ...

ITCZ IS CENTERED ALONG 7N1W 3N30W 2N50W. WIDELY SCATTERED
MODERATE/ISOLATED STRONG CONVECTION S OF 5N BETWEEN 45W-50W.

...DISCUSSION...
GULF OF MEXICO...
BROAD MIDDLE TO UPPER LEVEL RIDGE CONTINUES TO BUILD EWD FROM
MEXICO AND NOW COVERS THE ENTIRE AREA CREATING TRANQUIL
WEATHER.  AT THE SURFACE...1020 MB HIGH OVER THE W ATLC NEAR
30N75W IS CREATING E TO SE FLOW ACROSS FLORIDA AND THE GULF
WATERS.  EXPECT THIS OVERALL PATTERN TO REMAIN THROUGH TONIGHT
WITH THE NEXT COLD FRONT MOVING OFF THE SE TEXAS COAST EARLY
SAT.  THE FRONT WILL INITIALLY BE MOISTURE STARVED WITH LIMITED
SHOWER/THUNDERSTORM ACTIVITY AS IT MOVES OFF THE COAST.  A LINE
OF SHOWERS/ THUNDERSTORMS SHOULD DEVELOP N OF 26N DURING THE DAY
SAT AS THE FRONT MOVES ACROSS THE N CENTRAL AND E GULF.  UNLIKE
THE PREVIOUS TWO FRONTS...THIS FRONT IS NOT FORECAST TO MAKE AS
MUCH SWD PROGRESS STALLING OUT AROUND CENTRAL FLORIDA SUN.

CARIBBEAN SEA...
A WELL DEFINED ANTICYCLONE HAS FORMED OVER CENTRAL AMERICA NEAR
HONDURAS WITH ASSOCIATED RIDGE BUILDING EWD ACROSS THE CARIBBEAN
TO 15N70W.  MIDDLE TO UPPER LEVEL TROUGH MOVING EWD OVER THE W
ATLC CLIPS THE NE CARIBBEAN WITH ASSOCIATED CONFLUENT FLOW AND
SUBSIDENCE ALOFT FINALLY BRINGING ABOUT RAPID DRYING OVER
HISPANIOLA.  AS A RESULT...THE AREA OF SHOWERS WHICH PERSISTED
OVER THE ISLAND FOR SEVERAL DAYS HAVE DISSIPATED.  ELSEWHERE
ACROSS THE AREA...SCATTERED SHOWERS MOVING ACROSS THE
LEEWARD/WINDWARD ISLANDS CONTINUE TO HAVE DIFFICULTY MAKING MUCH
WESTWARD PROGRESS BEYOND 65W AS THEY ENCOUNTER MAINLY DRY LOW
LEVEL AIR IN PLACE ACROSS THE BULK OF THE CARIBBEAN.  EXPECT
MAINLY DRY CONDITIONS TO CONTINUE INTO THE WEEKEND SAVE THE
EXTREME NE CARIBBEAN WHERE SHOWERS/THUNDERSTORMS WITH THE
PASSING UPPER TROUGH AND FRONT ARE POSSIBLE DURING THE NEXT 2
DAYS.

ATLANTIC OCEAN...
THE MIDDLE TO UPPER LEVEL TROUGH WHICH MOVED OFF THE E COAST OF
THE UNITED STATES YESTERDAY IS NOW E OF BERMUDA EXTENDING SWD TO
HISPANIOLA.  STRONG SUBSIDENCE ON THE BACK/WEST SIDE OF THE
TROUGH IS CREATING VERY DRY/STABLE CONDITIONS ALOFT AND
GENERALLY CLOUD FREE CONDITIONS.  E OF THE TROUGH...UPPER LEVEL
DIFFLUENCE IS PRODUCING WIDESPREAD CLOUDINESS AND WIDELY
SCATTERED SHOWERS/THUNDERSTORMS WITHIN 400 NM E OF A COLD FRONT
FROM 32N60W TO THE MONA PASSAGE.  THIS ACTIVITY WILL CONTINUE TO
MARCH EWD ACROSS THE CENTRAL ATLC DURING THE NEXT 24 HOUR EVEN
THOUGH THE FRONT WILL WEAKEN.  EXPECT BEST COVERAGE OF
SHOWERS/THUNDERSTORMS TO BE N OF 20N BETWEEN 50W-60W TONIGHT.
OVER THE CENTRAL ATLC...MIDDLE TO UPPER LEVEL RIDGING PREVAILS N
OF 20N BETWEEN 45W-60W. THE RIDGE IS UNDERCUT BY A BROAD/DIFFUSE
UPPER LEVEL TROUGH WHICH EXTENDS FROM THE E ATLC JUST W OF
CANARY ISLANDS NEAR 32N27W SWD ALONG 20N40W TO 10N60W. AT THE
SURFACE...A 996 MB LOW NEAR THE AZORES TRAILS A COLD FRONT SWD
ENTERING THE AREA NEAR 32N27W SW TO 26N33W.  THE BULK OF THE
UPPER LIFT/DYNAMICS WITH THIS SYSTEM IS WELL N OF THE AREA WITH
ONLY A NARROW BAND OF WIDELY SCATTERED SHOWERS WITHIN 60 NM E OF
FRONT.  FINALLY OVER THE TROPICAL ATLC....A WELL DEFINED MIDDLE
TO UPPER LEVEL ANTICYCLONE HAS DEVELOPED OFF THE W COAST OF
AFRICA NEAR 7N20W WITH ASSOCIATED RIDGE EXTENDING WESTWARD TO
8N35W.  THIS SETUP WOULD TYPICALLY FAVOR ITCZ CONVECTION OVER
THE E ATLC.  HOWEVER...VISIBLE SATELLITE IMAGERY INDICATES AN
AREA OF VERY DRY AIR AND DUST ORIGINATING FROM AFRICA PUSHING
WESTWARD WITH LEADING EDGE ALONG 32W/33W.

$$
RHOME





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