[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 262357
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU APR 26 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N11W 2N25W 3N40W EQ50W. CLUSTERS OF
SCATTERED MODERATE CONVECTION ARE FROM 2N-6N BETWEEN 11W-16W...
AND WITHIN 80 NM N OF THE AXIS BETWEEN 24W-28W. CLUSTERS OF
MODERATE/ISOLATED STRONG CONVECTION ARE ALONG THE NE BRAZILIAN
COAST...AS WELL AS OVER SW AFRICA.

...DISCUSSION...

GULF OF MEXICO...
AS OF 21Z...A WEAK COLD FRONT EXTENDS FROM MOBILE ALABAMA TO
25N92W WHERE IT BEGINS TO DISSIPATE. A SQUALL LINE IS AHEAD OF
THE FRONT MOVING ACROSS THE FLORIDA PANHANDLE. MOSAIC DOPPLER
RADAR FROM THE SE IS SHOWING A NARROW LINE OF STRONG TSTMS ALONG
31N85W 29N87W. SOME CONVECTIVE ACTIVITY IS ALSO FIRING UP OVER
THE NE QUADRANT OF THE GULF. THE FRONT IS FORECAST TO STEADILY
WEAKEN AND DISSIPATE IN THE NEXT 24-48 HOURS. MODERATE SLY
RETURN FLOW IS AHEAD OF THE FRONT SHIFTING TO THE NE WITH THE
FRONTAL PASSAGE. ALOFT...A SHARP UPPER LEVEL TROUGH IS MOVING
EWD ACROSS THE EASTERN GULF EXTENDING SOUTH ACROSS THE YUCATAN
PENINSULA AND GUATEMALA INTO THE EPAC. STRONG SWLY WINDS AHEAD
OF THE TROUGH ARE TRANSPORTING UPPER LEVEL MOISTURE/HIGH CLOUDS
ACROSS CENTRAL AMERICA INTO THE WESTERN CARIBBEAN. STRONG
SUBSIDENCE AND DRY AIR DOMINATES THE WEST GULF.

CARIBBEAN...
A SHARP UPPER LEVEL TROUGH IS ENTERING THE NW CARIBBEAN WHILE AN
UPPER RIDGE...ANCHORED ON A HIGH OVER VENEZUELA DOMINATES THE
REMAINDER OF THE BASIN. SWLY WINDS BETWEEN THE TROUGH AND THE
RIDGE ARE SUPPORTING CONVECTIVE ACTIVITY ACROSS CENTRAL
AMERICA...FROM PANAMA TO BELIZE. THESE WINDS ARE ALSO ADVECTING
UPPER LEVEL MOISTURE/HIGH CLOUDS ACROSS CENTRAL AMERICA INTO THE
WESTERN CARIBBEAN/CUBA. THE BASE OF AN ATLC UPPER TROUGH CLIPS
PUERTO RICO AND THE VIRGIN/LEEWARD ISLANDS ENHANCING THE SHOWER
ACTIVITY OVER THE NE CARIBBEAN. A JET STREAM BRANCH WITH CORE
WINDS OF 70 TO 90 KT EXTENDS NE AND THEN E FROM THE BASE OF THIS
TROUGH ACROSS THE ATLC TO W AFRICA...CROSSING JUST NORTH OF THE
CANARY ISLANDS. THIN HIGH CLOUDS ARE ASSOCIATED WITH THE JET. A
SFC TROUGH...REMNANTS OF THE STATIONARY FRONT THAT PREVIOUSLY
AFFECTED PUERTO RICO AND THE VIRGIN ISLANDS IS ANALYZED ON THE
18Z MAP OVER THE SAME ISLANDS. CLUSTERS OF MODERATE TO STRONG
CONVECTION HAVE DEVELOPED OVER NORTHERN COLOMBIA EARLY THIS
EVENING AND ARE BEING AIDED BY THE TYPICAL HEAT LOW THAT USUALLY
RESIDES IN THIS AREA. HIGH PRES N OF THE AREA IS GENERATING
MODERATE TO STRONG EASTERLY TRADE WINDS ACROSS THE ENTIRE
CARIBBEAN.

ATLANTIC...
A BROAD DEEP LAYERED TROUGH COVERS THE CENTRAL ATLC WITH THE
ASSOCIATED STATIONARY FRONT EXTENDING SOUTHWESTWARD FROM 31N36W
TO 26N51W. FROM THERE...A SFC TROUGH EXTENDS TO THE VIRGIN
ISLANDS. BROKEN LOW/MID CLOUDS ARE RELATED TO THE FRONT/TROUGH.
AT THE SURFACE...A RIDGE IS BEHIND THE FRONT COVERING THE W ATLC
THE BAHAMAS...CUBA AND THE STATE OF FLORIDA ANCHORED BY A 1024 MB
HIGH LOCATED SE OF BERMUDAS NEAR 31N60W. ANOTHER 1024 MB HIGH
LOCATED WELL N OF THE AREA EXTENDS A RIDGE OVER THE E-CENTRAL
ATLC. PATCHES OF LOW LEVEL CLOUDS ARE SEEN ACROSS THE ATLC UNDER
THE INFLUENCE OF THIS RIDGE SOME OF WHICH ARE NOW MOVING INTO
THE EASTERN CARIBBEAN THROUGH THE LESSER ANTILLES. ALOFT... AN
UPPER LOW REMAINS IN THE E TROPICAL ATLC SW OF THE CAPE VERDE
ISLANDS NEAR 12N37W.

$$
GR





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