[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 280502
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU 28 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0430 UTC.

...ITCZ...

ITCZ AXIS IS ALONG 8N1W 3N40W 3N55W.  SCATTERED
MODERATE/ISOLATED STRONG CONVECTION FROM 2N-5N BETWEEN 12W-16W.
WIDELY SCATTERED MODERATE CONVECTION FROM 1N-7N BETWEEN
25W-36W.

...DISCUSSION...

GULF OF MEXICO...
DEEP LAYERED TROUGH OVER THE EASTERN UNITED STATES IS NOW
LIFTING NEWD AWAY FROM THE AREA WITH CONFLUENT FLOW ON ITS BACK
SIDE NOW PRODUCING STRONG SUBSIDENCE ACROSS THE NE GULF AND N
HALF OF FLORIDA.  AS A RESULT...SHOWER ACTIVITY ALONG THE
ATTENDANT COLD FRONT...CURRENTLY FROM THE S TIP OF FLORIDA TO
THE NE TIP OF THE YUCATAN PENINSULA...CONTINUE TO DISSIPATE.
ONLY WIDELY SCATTERED SHOWERS REMAIN WITHIN 90 NM AHEAD OF
FRONT.  BEHIND THE FRONT...UNUSUALLY DRY LOW LEVEL AIR FOR THIS
TIME OF YEAR IS FILTERING SWD PRODUCING MOSTLY CLEAR SKIES SAVE
SOME STREAKS OF HIGH CLOUDS OVER THE W GULF.  THIS SHOULD
PRODUCE A COOL NIGHT OVER THE E GULF AND FLORIDA PRIOR TO THE
POST-FRONTAL HIGH...CURRENTLY OVER THE TENNESSEE VALLEY...MOVING
EWD AND ESTABLISHING MOIST ELY FLOW OFF THE ATLC WATERS BY THE
END OF THE WEEK.  OVER THE W GULF...THE FLOW HAS ALREADY VEERED
TO THE SE AND SHOULD INCREASE THROUGH THE END OF THE WEEK AHEAD
OF THE NEXT COLD FRONT WHICH IS SCHEDULED TO ENTER THE GULF
EARLY SAT.  CURRENTLY...BEST LOW LEVEL MOISTURE CONVERGENCE AND
UPPER SUPPORT ARE FORECAST TO OCCUR OVER THE CENTRAL AND EASTERN
GULF N OF 25N.  FRONT WILL LIKELY HAVE LESS SWD PUSH THAN THE
PREVIOUS 2 SYSTEMS.

CARIBBEAN SEA...
DESPITE WHAT APPEARED TO BE A DRY/STABLE ENVIRONMENT ALOFT IN
WATER VAPOR IMAGERY...ISOLATED CELLS OF MODERATE
CONVECTION FORMED WED AFTERNOON ALONG THE SEA BREEZE FRONT OVER
THE E YUCATAN PENINSULA AND BELIZE.  CLOUD TOP TEMPERATURES
INDICATE THIS ACTIVITY IS NOW WEAKENING AND SHOULD CONTINUE TO
DO SO THROUGH THE NIGHT.  ELSEWHERE....PERSISTENT CLOUDINESS AND
SHOWERS CONTINUE OVER HISPANIOLA TONIGHT MAINTAINING THE WET
PATTERN DURING THE LAST SEVERAL DAYS.  EXPECT THIS ACTIVITY TO
REMAIN THROUGH EARLY FRI WHEN A FRONT MOVING OVER THE ATLC
WATERS PROVIDES SOME DRYING OVER THE WEEKEND.
ELSEWHERE...SHOWER ACTIVITY OVER THE CARIBBEAN HAS BEEN HAVING
TROUBLE MAKING MUCH WESTWARD PROGRESS APPARENTLY DUE TO VERY DRY
CONDITIONS IN PLACE.  FURTHER S...MIDDLE TO UPPER LEVEL RIDGE
OVER S AMERICA HAS BEEN SUPPRESSED A LITTLE S WITH MEAN AXIS NOW
ALONG 10N/11N.  ASSOCIATED DIFFLUENT FLOW ALOFT AROUND THE
EQUATORWARD PERIPHERY OF THE RIDGE CONTINUES TO SUPPORT DEEP
CONVECTION OVER COLOMBIA BUT THIS ACTIVITY IS UNABLE TO MAKE ANY
NWD PROGRESS.

ATLANTIC OCEAN...
MAIN WEATHER MAKER TONIGHT IS A DEEP LAYERED TROUGH MOVING OFF
THE E COAST OF THE UNITED STATES WITH ASSOCIATED COLD FRONT
ENTERING THE AREA ALONG 32N72W SW ACROSS THE EXTREME S TIP OF
FLORIDA.  THE STRONGEST UPPER LIFT/DYNAMICS IS NOW MAINLY N OF
THE BAHAMAS WITH SCATTERED MODERATE CONVECTION WITHIN 300 NM E
OF FRONT N OF 27N. ELSEWHERE ALONG THE FRONT...WIDELY SCATTERED
ARE WITHIN 300 NM AHEAD OF BOUNDARY.   BEHIND THE FRONT...DRY
AIR THROUGH ALL LEVELS OF THE ATMOSPHERE IS FILTERING SWD
PRODUCING RAPIDLY CLEARING.  ELSEWHERE OVER THE W ATLC...PATTERN
REMAINS TRANQUIL WITH A SURFACE RIDGE EXTENDING SW FROM A 1022
MB HIGH NEAR 32N60W TO THE CENTRAL BAHAMAS.  OVER THE CENTRAL
ATLC...A PAIR OF COLD FRONTS ASSOCIATED WITH A 1004 MB LOW N OF
THE AREA NEAR 37N40W CLIP THE AREA.  AS A RESULT...A NARROW LINE
OF SCATTERED MODERATE CONVECTION EXIST WITHIN 30 NM EITHER SIDE
OF A LINE FROM 35N30W 28N37W.  WIDELY SCATTERED SHOWERS ARE ALSO
NOTED WITHIN 30 NM EITHER SIDE OF A SURFACE TROF FROM 28N37W TO
23N47W.  OVER THE E ATLC...BROAD/FLAT TROUGH IS PRODUCING MAINLY
CONFLUENT AND DRY CONDITIONS W OF THE CAPE VERDE ISLANDS.
FINALLY OVER THE TROPICAL ATLC...E/W ORIENTED UPPER RIDGE IS
BUILDING WESTWARD FROM AFRICA ALONG 5N/6N WITH ASSOCIATED
DIFFLUENT FLOW SUPPORTING ITCZ CONVECTION E OF 30W. EXPECT THIS
RIDGE TO PREVAIL THROUGH THE NEXT SEVERAL DAYS WITH A WELL
DEFINED ANTICYCLONE JUST S OF THE CAPE VERDE ISLANDS BY THE
WEEKEND.  ITCZ CONVECTION SHOULD BE MOST NUMEROUS NEAR THE SW
PERIPHERY OF THE ANTICYCLONE.

$$
RHOME


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