[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 010011
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED FEB 28 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 7N11W 3N20W 2N30W CROSSING
THE EQUATOR AT 42W...INTO NORTHEASTERN BRAZIL NEAR 2S48W.
ISOLATED MODERATE CONVECTION IS WITHIN 90 NM OF THE AXIS BETWEEN
THE COAST OF AFRICA AND 17W....AND WITHIN 150 NM OF AXIS BETWEEN
37W AND COASTAL BRAZIL.

...DISCUSSION...

THE GULF OF MEXICO...
COMPLEX FRONTAL PATTERN CONTINUES TO DOMINATE THE ERN
GULF...THOUGH THINGS SEEM A LITTLE MORE SORTED OUT THAN
YESTERDAY. THE LAST FEW VISIBLE PICTURES THIS EVENING SHOW A
REGION OF LOW LEVEL CONFLUENCE WITH A CLUSTER OF MODERATE
CONVECTION FROM 24N-28N BETWEEN 83W-91W...WHERE ESE FLOW IN THE
NE GULF IS COLLIDING WITH MORE SLY FLOW SPREADING N THROUGH THE
YUCATAN CHANNEL. AS OF 2100 UTC...HAVE PLACED A FORMING WARM
FRONT THROUGH THIS ZONE FROM SW FLORIDA TO SRN LOUISIANA ALONG
26N82W 26N87W 29N91W. THIS IS A BIT OF A CHANGE FROM EARLIER
MAPS BUT THINK THE SATELLITE SIGNATURE AND SFC OBS...ESPECIALLY
THE DEWPOINTS...JUSTIFY SUCH A CHANGE. MUCH OF THE REMAINDER OF
THE GULF IS SEEING JUST PATCHES OF BENIGN LOW CLOUDS...IN
ADDITION TO HIGH CIRRUS SPREADING SE THROUGH THE AREA N OF 22N
WITH DOMINATING UPPER NW FLOW AROUND RIDGING. SLY SFC WINDS WILL
INCREASE TONIGHT INTO THU AHEAD OF THE NEXT FRONT TO PUSH OFF
THE TEXAS COAST INTO THU AFTERNOON.

THE CARIBBEAN SEA...
THE MAIN STORY IN THE CARIBBEAN CONTINUES TO BE THE BRISK ELY
TRADES OVER MUCH OF THE AREA E OF 82W. THE TRADE FLOW CONTINUES
TO BE STRONGEST NEAR THE COLOMBIAN COAST WHERE GALE CONDITIONS
ARE EXPECTED THROUGH EARLY SAT. THIS WILL ALSO CONTINUE TO
SEND MODERATE TO STRONG SURF TO THE CARIB COAST OF
NICARAGUA...COSTA RICA...AND PANAMA OVER THE NEXT FEW DAYS. A
BIT LIGHTER SE FLOW IS SEEN IN THE NW CARIBBEAN...AROUND THE SW
PORTION OF ATLC HI PRES AND IN ADVANCE OF THE SYSTEM DEVELOPING
OVER THE CENTRAL USA. THE TRADES ARE ADVECTING TYPICAL PATCHES
OF LOW LEVEL MOISTURE WWD. HOWEVER...VERY LITTLE CLOUD COVER IS
SEEN OVER THE CENTRAL CARIB WATERS WHERE THE TRADES ARE
STRONGEST WHICH HAS LED TO A WELL MIXED LOWER ATMOSPHERE. ON THE
CONTRARY...SPEED CONFLUENCE HAS LED TO A REGION OF BROKEN LOW
CLOUDS FROM THE COAST OF PANAMA TO 14N BETWEEN 78W-82W.
ALOFT...VERY DRY AND STABLE AIR DOMINATES YET AGAIN WHICH HAS
BEEN THE STORY FOR MUCH OF THE WINTER. THIS DRY AIR IS ROTATING
AROUND A MID TO UPPER TROUGH EXTENDING SW BETWEEN CUBA AND
CENTRAL AMERICA...AND RIDGING OVER THE ERN CARIB.

THE ATLANTIC OCEAN...
AS OF 28/2100 UTC A COLD FRONT ENTERS THE AREA NEAR 30N64W AND
CONTINUES WSW TO NEAR 27N76W WHERE IT BECOMES A DISSIPATING COLD
FRONT NEAR PALM BEACH. THE ERN PORTION OF THIS FRONT HAS BEEN
FAIRLY STRAIGHTFORWARD WITH A RESEMBLANCE OF A ROPE CLOUD SEEN E
OF ABOUT 70W. THINGS HAVE BEEN MORE CHALLENGING TO THE W THOUGH.
A SHARP UPPER SHORTWAVE TROUGH IS EXTENDING S THROUGH THE WRN
ATLC AND CENTRAL BAHAMAS. SCATTERED MODERATE CONVECTION IS IN
THE DIFFLUENT ZONE AHEAD OF THIS TROUGH FROM 23N-28N BETWEEN
69W-74W. THERE ALSO APPEARS TO BE SOME SFC TROUGHING AHEAD OF
THE MAIN FRONT THAT IS RESPONSIBLE FOR THE SCATTERED MODERATE
CONVECTION WITHIN 90 NM OF A LINE FROM 23N69W 32N50W. HOPING
THAT TONIGHTS QUIKSCAT PASS WILL SHED SOME LIGHT ON ANY LOWS
THAT MAY HAVE DEVELOPED ON THE COMPLEX FRONTAL PATTERN OVER THE
WRN ATLC.  THE REMAINDER OF THE E AND CENTRAL ATLC SFC PATTERN
IS DOMINATED BY THE 1030 MB HIGH NEAR 32N24W...WHICH IS
PRODUCING ABUNDANT FAIR WEATHER AND MODERATE TRADES. BROAD UPPER
RIDGING ALSO DOMINATES MUCH OF THE CENTRAL AND E ATLC AS
WELL...THOUGH AN UPPER TROUGH SURROUNDED BY VERY DRY AIR IS N OF
12N OFF THE COAST OF AFRICA.


$$
WILLIS


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