[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 241730
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE APR 24 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE 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
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N10W 3N18W 5N47W 4N59W. ISOLATED
MODERATE/STRONG CONVECTION FROM 3N-7N BETWEEN 9W-15W. WIDELY
SCATTERED MODERATE S OF 6N BETWEEN 22W-43W. ISOLATED SHOWERS/
TSTMS FROM 5N-9N BETWEEN 48W-54W.

...DISCUSSION...

GULF OF MEXICO...
MAINLY FAIR CONDITIONS DOMINATE THE GULF WATERS TODAY BUT THE
LEADING EDGE OF CLOUDS ASSOCIATED WITH A FRONTAL BOUNDARY OVER
TEXAS IS JUST STARTING TO MOVE OFF THE COAST. THE COLD
FRONT/DRYLINE IS STILL LOCATED OVER W TEXAS WITH ISOLATED TO
WIDELY SCATTERED SHOWERS BREAKING OUT ACROSS E/CENTRAL TEXAS
WITH SOME POTENTIALLY BRUSHING THROUGH THE COASTAL WATERS. AN
UPPER RIDGE AXIS LIES FROM THE BAY OF CAMPECHE TO THE SE U.S.
WITH THE E HALF OF THE GULF AND FLORIDA DOMINATED BY
MODERATE/STRONG SUBSIDENCE...AND INCREASING UPPER LEVEL MOISTURE
OVER THE W PART STREAMING ACROSS NE MEXICO. THE COLD FRONT IS
EXPECTED TO EASE ITS WAY TO THE COAST BY WED NIGHT/EARLY THU BUT
THEN STALL DUE TO LACK OF UPPER SUPPORT. THIS SCENARIO WOULD
THEN ONLY SUPPORT SCATTERED SHOWERS/TSTMS OVER THE FAR NRN GULF
WED THROUGH FRI AS THE MAIN ENERGY ASSOCIATED WITH THE FRONT
SKIRTS BY TO THE N.

CARIBBEAN...
AN UPPER LEVEL TROUGH LOCATED OVER THE W/CENTRAL ATLC DRAPES SW
INTO THE W CARIBBEAN FROM THE WINDWARD PASSAGE SW TO NICARAGUA
AND HONDURAS. STRONG CONFLUENCE INTO THE TROUGH AXIS IS
PRODUCING MODERATE TO VERY STRONG SUBSIDENCE OVER THE W
CARIBBEAN...FOCUSED MOST STRONGLY FROM E CUBA TO THE CAYMAN
ISLANDS. TO THE E...BROAD SW FLOW ALOFT LIES AHEAD OF THE TROUGH
AND IS PULLING SLIGHTLY MORE MOIST AIR UP FROM SOUTH AMERICA.
THE PATTERN IS SOMEWHAT DECEIVING DUE TO A MOIST LOW-LEVEL
ENVIRONMENT AND A WEAKENING SURFACE TROUGH EXTENDING FROM NEAR
ANGUILLA AND THE BRITISH VIRGIN ISLANDS SW TO 15N74W. WIDELY
SCATTERED SHOWERS LIE TO THE N OF THE TROUGH...SOME OF WHICH ARE
MOVING E TO W ACROSS PUERTO RICO AND THE VIRGIN ISLANDS...
HISPANIOLA...AND JAMAICA. A FEW TSTMS ARE ALSO LOCATED OVER THE
WATERS NEAR THE COLOMBIA/PANAMA JUNCTURE WWD TO THE PANAMA
CANAL...PARTLY AIDED BY OUTFLOW ALOFT. SE OF THE TROUGH...DRIER
LOW-LEVEL AIR AND SUBSIDENCE IN THE MID/UPPER LEVELS IS
PRODUCING A MAINLY CLEAR DAY ACROSS THE SRN LEEWARD AND WINDWARD
ISLANDS AS WELL AS ACROSS THE VENEZUELA COAST.

ATLANTIC...
A 1028 MB HIGH IS CENTERED OVER THE W ATLC NEAR 31N74W WITH A
RIDGE ALIGNED FROM BERMUDA TO N FLORIDA. AN UPPER LEVEL TROUGH
IS LOCATED OVER THE SAME AREA WITH THE AXIS FROM 31N63W TO THE
WINDWARD PASSAGE...AND THIS IS PRODUCING MAINLY DRY CONDITIONS
AT ALL LEVELS OF THE ATMOSPHERE. ONLY A FEW VERY ISOLATED
SHOWERS ARE NOTED IN THE TRADES JUST TO THE E OF THE BAHAMAS.
FARTHER E...THE UPPER TROUGH AND AN ASSOCIATED UPPER LOW NEAR
33N54W HAVE SUPPORTED THE DEVELOPMENT OF A WEAK 1020 MB LOW NEAR
30N52W ALONG THE FRONTAL BOUNDARY WHICH HAS BEEN OVER THE
CENTRAL ATLC FOR A FEW DAYS. A STATIONARY FRONT STILL EXTENDS SW
OF THE LOW TO THE NRN LEEWARD ISLANDS WITH WIDELY SCATTERED
SHOWERS UP TO 180 NM OF THE BOUNDARY. TO THE E OF THE LOW...THE
FRONT HAS MOVED N AS A WARM FRONT TO 30N48W 28N43W THEN
CONNECTED TO A STATIONARY FRONT TO 31N27W. OVER THE E ATLC...A
STRONG MID-LEVEL HIGH IS CENTERED NEAR 20N40W WHICH IS KEEPING
MOST OF THE HIGH CLOUDINESS STREAMING N OF THE AREA TOWARDS THE
AZORES...AND MODERATE/STRONG SUBSIDENCE SWD TO 6N. THE
DEVELOPMENT OF THIS SUBSIDENCE IS BEING AIDED BY AN UPPER LOW IN
THE TROPICS NEAR 10N27W...WHICH SEPARATES DRY AIR TO THE NW WITH
A DEEP TROPICAL MOISTURE PLUME TO THE E AND SE. THE ITCZ HAS
COME CONVECTION NEAR ITS AXIS TODAY...BUT NONE OF IT IS REALLY
ALL THAT FOCUSED AS IT HAD BEEN IN PREVIOUS DAYS.

$$
BERG


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