[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111804
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED APR 11 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
1745 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N11W 4N20W 3N30W 1N40W EQ45W 1S51W.
ISOLATED MODERATE CONVECTION IS WITHIN 150NM N AND 60NM S OF THE
AXIS BETWEEN 21W-29W. SCATTERED MODERATE/ISOLATED STRONG IS
WITHIN 240NM N OF THE AXIS BETWEEN 31W-40W...AND WITHIN 300NM N
AND 180NM S OF THE AXIS W OF 40W.

...DISCUSSION...

GULF OF MEXICO...
A COLD FRONT IS APPROACHING THE TEXAS COAST. INTERESTING CLOUD
SIGNATURE/GRAVITY WAVES ARE OUT AHEAD OF THE MAIN FRONT BETWEEN
BROWNSVILLE AND SE LOUISIANA...THAT LED TO THE RECENT SW TO NW
WIND SHIFT AT BUOY 42019. HAVE OPTED WITH A PREFRONTAL TROUGH
WITH THIS ON THE 1500 UTC MAP PER COORDINATION WITH HPC. A WARM
FRONT EXTENDS SE FROM THE FL/ALABAMA BORDER TO THE NE GULF NEAR
29N84W...WHICH APPEARS TO HAVE RECENTLY LIFTED N ALONG THE FL
PANHANDLE WITH ISOLATED SHOWERS/TSTMS DEVELOPING JUST S OF THIS
BOUNDARY NOTED FROM TALLAHASSEE RADAR IMAGERY. MORE NUMEROUS
SHOWERS/TSTMS NOTED AROUND THE STRAITS OF FLORIDA...ASSOCIATED
WITH DYNAMICS AHEAD OF A FLATTENING MID TO UPPER SHORTWAVE
TROUGH...ALONG WITH LINGERING LOW LEVEL BOUNDARIES FROM ALL THE
RECENT CONVECTION. THE COLD FRONT MOVING INTO THE NW PORTION
WILL BECOME DIFFUSE DURING THU AS IT HEADS SE. ANOTHER COLD
FRONT...THIS ONE EXPECTED TO BE MUCH STRONGER...IS FORECAST TO
MOVE INTO THE NW GULF EARLY SAT INCREASING THE CHANCE OF RAIN
AHEAD OF IT AND BRINGING ABOUT A MUCH COOLER AIRMASS THIS
WEEKEND. WINDS/SEAS WILL ALSO BE STRONGER BOTH IN ADVANCE AND
BEHIND THIS NEXT FRONT...SEE OFFSHORE WATERS FORECAST UNDER
AWIPS HEADER MIAOFFNT4 FOR MORE DETAILS.

THE CARIBBEAN SEA...
A BROAD MID TO UPPER LEVEL RIDGE COVERS THE REGION ANCHORED BY
AN UPPER HIGH CENTERED OVER THE S CENTRAL CARIB NEAR 12N76W.
DIFFLUENCE ON THE W SIDE OF THIS UPPER ANTICYCLONE IS ENHANCING
SCATTERED SHOWERS/ISOLD TSTMS NEAR THE EPAC COASTS OF PANAMA AND
COSTA RICA. SIMILAR ACTIVITY NOTED IN THE SW CARIBBEAN BETWEEN
THE COAST OF NICARAGUA AND COLOMBIA...WHICH SEEMS MOST
ASSOCIATED WITH LOW LEVEL SPEED CONFLUENCE AS NOTED IN THIS
MORNINGS QUIKSCAT PASS. ELSEWHERE AT THE SFC...HIGH PRES NE OF
THE AREA IS PRODUCING MODERATE TO FRESH ELY TRADES ACROSS THE E
AND CENTRAL CARIB VEERING TO THE SE IN THE NW CARIB AROUND THE
SW PORTION OF THE RIDGE. LOW-LEVEL MOISTURE PATCHES REMAIN VERY
THIN SO OUTSIDE OF THE AREAS OUTLINED FAIR SKIES ARE THE RULE.
NO SIGNIFICANT CHANGES ARE EXPECTED OVER THE NEXT COUPLE OF DAYS
AS MOST OF THE WX FEATURES REMAIN N OF THE REGION.

ATLANTIC OCEAN...
A 1009 MB SFC LOW IS OFF THE COAST OF NRN FLORIDA THAT HAS A
STATIONARY FRONT EXTENDING E ALONG 30N80W 29N75W 31N68W. AS OF
11/1500 UTC...A SFC TROUGH EXTENDS THROUGH THE SW N ATLC THROUGH
THE BAHAMAS AND INTO THE STRAITS OF FLORIDA ALONG 26N74W 24N80W.
IN ADDITION TO THESE SFC FEATURES...UPPER DIFFLUENCE BETWEEN THE
SHORTWAVE TROUGH EXTENDING S THROUGH FL/ERN GULF AND THE RIDGING
EXTENDING N FROM THE CARIBBEAN IS SUPPORTING THE CONVECTION OVER
THE WRN ATLC. ASIDE FROM THE ACTIVITY ALREADY MENTIONED IN THE
STRAITS OF FLORIDA...THE MOST CONCENTRATED AREA OF SHOWS/TSTMS
IS NOTED N OF 24N BETWEEN 68W-75W. MUCH OF THE REMAINDER OF THE
E AND CENTRAL ATLC SFC PATTERN IS DOMINATED BY A 1025MB HIGH S
OF THE AZORES NEAR 34N27W. THIS IS PRODUCING LIGHT TO MODERATE
TRADES AND FAIR WEATHER OVER MUCH OF THE AREA E OF 45W. UPPER
TROUGHING EXTENDING S ALONG 35W IS INTERACTING WITH RIDGING OVER
AFRICA TO PRODUCE A SWLY JET SE OF THE CAPE VERDE ISLANDS.
ASSOCIATED UPPER MOISTURE IS SPREADING NE INTO AFRICA...FROM
5N-18N E OF 28W.


$$
WILLIS




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