[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 080005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT APR 07 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
2345 UTC.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 9N11W 2N25W EQ47W AND INTO NE
BRAZIL NEAR 1S53W. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION
IS OVER AFRICA AND ADJACENT ATLC WATERS FROM 3N-12N BETWEEN
1W-9W. ISOLATED MODERATE IS WITHIN 220 NM EITHER SIDE OF THE
AXIS BETWEEN 20W-40W. STRONGER ACTIVITY HAS AGAIN FLARED UP OVER
NE SOUTH AMERICA S OF 6S W OF 40W.

...DISCUSSION...

THE GULF OF MEXICO...
A DEVELOPING SFC TROUGH IS OVER THE WRN GULF ALONG 27N95W
22N95W. THIS...ALONG WITH DYNAMICS AHEAD OF A MID TO UPPER
SHORTWAVE TROUGH CURRENTLY EXTENDING SSW THROUGH EL PASO TX AND
INTO NRN MEX...IS SUPPORTING THE OVERCAST MULTILAYERED
CLOUDINESS WITH NUMEROUS SHOWERS IN THE NW GULF N OF 24N W OF
90W. MESSY WEATHER TO PERSIST IN THE WRN GULF THROUGH SUN AS
LOWER PRESSURE MEANDERS OFF THE TX COAST. SFC WINDS ARE
CURRENTLY AND WILL REMAIN STRONGEST IN THE NRN GULF...ESPECIALLY
N OF 26N W OF 90W...AS THE TROUGHING INTERACTS WITH HIGH PRES
OVER THE SRN/SE U.S. THE ERN GULF IS CURRENTLY MUCH QUIETER
ASIDE FROM THE UNSEASONABLY COOL AIR MASS OVER THE AREA.
INCREASING MID TO HIGH CLOUD COVER IS APPROACHING FLORIDA FROM
THE WEST WITH WLY FLOW ALOFT WHICH WILL LIMIT RADIATIONAL
COOLING TONIGHT BUT CHILLY TEMPS STILL ANTICIPATED...SEE
STATEMENTS FROM LOCAL FORECAST OFFICES FOR MORE INFO.

THE CARIBBEAN SEA...
A DISSIPATING STATIONARY FRONT IS OVER THE NW CARIB ALONG 20N76W
TO THE GULF OF HONDURAS NEAR 16N87W. A PREFRONTAL TROUGH IS
BETWEEN HAITI AND 13N78W. THE LATTER BOUNDARY SEEMS TO BE
GENERATING MORE MOISTURE WITH POSSIBLE SHOWERS WITHIN 60 NM OF
THE TROUGH...WITH DEEPER MOISTURE/SHOWERS NOTED OVER HISPANIOLA
AND ADJACENT ATLC WATERS. THESE SFC FEATURES HAVE LED TO A
WEAKNESS IN THE PRESSURE GRADIENT AND LIGHTER THAN NORMAL WINDS
ACROSS MUCH OF THE BASIN...THOUGH HIGH PRES WILL REBUILD N OF
THE AREA THROUGH EARLY NEXT WEEK ALLOWING MORE TYPICAL MODERATE
TO FRESH TRADE FLOW TO RESUME. LINGERING LOW LEVEL CONFLUENCE
WILL SUPPORT SCATTERED SHOWER ACTIVITY BETWEEN COSTA RICA/PANAMA
AND HISPANIOLA OVER THE NEXT DAY OR SO THOUGH. UPSLOPE
FLOW...SPEED CONFLUENCE...AND THE EPAC ITCZ WILL SUPPORT DEEPER
CONVECTION AND SHOWER/TSTM ACTIVITY IN THE FAR SW CARIBBEAN AND
OVER COSTA RICA/PANAMA INTO EARLY NEXT WEEK AS WELL.
ALOFT...BROAD AREA OF SW/WSW FLOW DOMINATES NE OF A PRONOUNCED
ANTICYCLONE OVER NE SOUTH AMERICA. VERY DRY/STABLE UPPER AIR IS
OVER THE FAR NW CARIB WHILE SCATTERED HIGH CLOUDS ARE OVER THE
MIDDLE AND ERN PORTIONS OF THE BASIN...DOWNSTREAM FROM
CONVECTION OVER THE EPAC ITCZ AND S AMERICA.

THE ATLANTIC OCEAN...
LARGE DEEP LAYERED LOW CONTINUES TO SPIN OVER THE ERN U.S. A
RAPIDLY INTENSIFYING SFC LOW JUST E OF DELMARVA HAS A TRAILING
COLD FRONT THAT ENTERS THE AREA NEAR 32N70W AND CONTINUES SW TO
SRN FLORIDA. COLD AIR ADVECTION PATTERN BEHIND THE FRONT HAS
BROKEN STRATOCUMULUS CLOUDS OVER THE WRN ATLC...MAINLY N
OF 27N. ANOTHER COLD FRONT REMAINS AHEAD OF THIS BETWEEN 32N60W
TO THE TURKS AND CAICOS. A PREFRONTAL TROUGH IS ALONG 27N61W
22N67W TO THE COAST OF HISPANIOLA AT 20N71W. THIS SFC TROUGH HAS
SCATTERED SHOWERS/ISOLD TSTMS WITHIN 60 NM EITHER SIDE...AND IS
ALSO BEING SUPPORTED BY UPPER DIFFLUENCE BETWEEN THE LARGE
TROUGH OVER THE ERN U.S. AND RIDGING OVER THE CENTRAL ATLC. THE
WRN ATLC SFC BOUNDARIES EXPECTED TO GRADUALLY CONSOLIDATE INTO A
REMNANT FRONTAL FRONT BETWEEN THE WINDWARD PASSAGE AND 32N57W AS
WEAK HIGH PRES BUILDS INTO THE WRN ATLC THRU MON. MUCH OF THE E
AND CENTRAL ATLC IS DOMINATED BY THE SRN PERIPHERY OF A 1025 MB
HIGH NEAR 31N43W. A WEAK SFC TROUGH IS OVER THE FAR NE PORTION
OF THE DISCUSSION AREA ALONG 30N18W 24N27W...WHICH IS A
REFLECTION OF THE UPPER TROUGHING OVER THE AREA.

$$
WILLIS




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