[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 261756
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU JUL 26 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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.

...TROPICAL WAVES...
TROPICAL WAVE IS TILTED ALONG 16N28W 8N31W MOVING W 10-15 KT.
THIS WAVE SHOWS UP WELL IN VISIBLE IMAGERY WITH LOW TO MID LEVEL
CYCLONIC TURNING NOTED FROM 9N-16N BETWEEN 26W-33W. ALTHOUGH
CONVECTION IS MINIMAL AND DISORGANIZED OVERALL...A RECENT FLARE
UP OF SCATTERED MODERATE/ISOLATED STRONG IS FROM 12N-15N BETWEEN
29W-33W.

TROPICAL WAVE IS TILTED ALONG 15N42W 11N44W 6N45W MOVING W 10-15
KT. THE WAVE IS CHARACTERIZED BY AN ELONGATED ZONE OF LOW LEVEL
CYCLONIC TURNING FROM 9N-15N BETWEEN 39W-46W. LIKE ITS
COUNTERPART FURTHER E...THE WAVE SHOWS UP WELL IN SATELLITE
DERIVED VORTICITY AND TPW PRODUCTS. THE NEARBY MODERATE
CONVECTION IS MOSTLY EMBEDDED IN THE ITCZ FROM 10N-12N BETWEEN
45W-51W. ANOTHER LESS IMPRESSIVE CLUSTER IS WITHIN 90 NM EITHER
SIDE OF THE AXIS FROM 6N-8N. ALL OF THIS CONVECTION IS BEING
STRETCHED TO THE W WITH UPPER ELY FLOW OVER THE AREA.

A CENTRAL CARIBBEAN SEA TROPICAL WAVE IS ALONG 72W S OF 17N
MOVING W NEAR 25 KT. THE WAVE PASSAGE WAS EVIDENT IN THE CURACAO
SOUNDING DATA BETWEEN 26/0000 UTC AND 26/1200 UTC. ASSOCIATED
SCATTERED MODERATE CONVECTION IS FROM 15N-17N BETWEEN 69W-73W.

TROPICAL WAVE ALONG 96/97W S OF 21N IS NOW BECOMING MORE OF AN
EPAC FEATURE. HOWEVER...SOME OF THE ASSOCIATED MID LEVEL ENERGY
MAY HAVE ROUNDED THE ATLC RIDGE AND ENHANCED THE CONVECTION IN
THE NW GULF. SEE GULF DISCUSSION BELOW AND THE PACIFIC TROPICAL
WEATHER DISCUSSION UNDER AWIPS HEADER MIATWDEP FOR MORE INFO.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N13W 9N22W 12N26W 11N33W 12N40W
10N50W 9N61W. ASIDE FROM THE CONVECTION ALREADY MENTIONED WITH
THE TROPICAL WAVES...SCATTERED MODERATE IS WITHIN 120NM S OF THE
AXIS E OF 23W. A FEW STRONGER CELLS ARE WITHIN 30NM EITHER SIDE
OF THE COAST OF AFRICA FROM 6N-13N.

...DISCUSSION...
GULF OF MEXICO...
ANOTHER ROUND OF STRONG CONVECTION IS AFFECTING THE NW GULF THIS
AFTERNOON. LIGHTNING DATA...RADAR...AND SATELLITE IMAGERY DEPICT
NUMEROUS SHOWERS AND TSTMS N OF 22N BETWEEN 86W-97W. THIS
ACTIVITY IS LARGELY BEING SUPPORTED BY A DIFFLUENT PATTERN ALOFT
BETWEEN THE UPPER LOW OVER S CENTRAL TX AND AN UPPER HIGH OVER
THE NRN YUCATAN PENINSULA. THIS MORNINGS QUIKSCAT PASS DID
REVEAL SOME WEAK SFC TROUGHING AS WELL. IN ADDITION...THE RECENT
SERIES OF TROPICAL WAVES HAVE INCREASED THE LOW LEVEL MOISTURE
IN THE VICINITY. REGARDLESS...SURFACE PRESSURES ARE NOT FALLING
AND UPPER-LEVEL WINDS ARE NOT FAVORABLE FOR SIGNIFICANT
DEVELOPMENT. ELSEWHERE...A WEAK SFC HIGH IS OVER NRN FLORIDA
WHICH IS EXPECTED TO DRIFT W OVER THE NEXT COUPLE OF DAYS. THIS
WILL ALLOW LIGHT WINDS OVER THE NE PORTION WITH SLIGHTLY
STRONGER 10-20 KT E TO SE FLOW ELSEWHERE.

CARIBBEAN SEA...
ASIDE FOR THE WEATHER ASSOCIATED WITH THE TROPICAL WAVE IN THE
CENTRAL CARIB THE ONLY OTHER DEEP CONVECTION NOTED IS IN THE SW
PORTION. THIS SCATTERED MODERATE IS S OF 12N ALONG THE COAST OF
CENTRAL AMERICA...AND IS LIKELY TIED TO THE ITCZ IN ADDITION TO
LOW LEVEL SPEED CONFLUENCE DOWNSTREAM FROM THE FRESH TRADES
OCCURRING N OF THE COLOMBIAN COAST. MODERATE TO FRESH TRADES TO
PERSIST INTO THE WEEKEND...REMAINING STRONGEST BETWEEN COLOMBIA
AND HISPANIOLA. UPPER RIDGING DOMINATES THE NW AND ERN PORTIONS
OF THE BASIN WHILE AN INVERTED UPPER TROUGH DOMINATES THE
CENTRAL PORTION. DIFFLUENCE E OF THE UPPER TROUGH IS ENHANCING
THE CONVECTION NEAR THE TROPICAL WAVE ALONG 72W.

ATLANTIC OCEAN...
A SFC TROUGH WAS ADDED TO THE 1500 UTC MAP IN THE WRN ATLC ALONG
30N72W 24N75W...SPARKED BY LOW LEVEL CONFLUENCE BETWEEN A NEWLY
FORMED 1021 MB SFC HIGH OVER N FLORIDA AND THE FLOW AROUND THE
1026 MB HIGH IN THE CENTRAL ATLC NEAR 34N41W. ASSOCIATED
SCATTERED MODERATE CONVECTION IS FROM 25N-30N BETWEEN 70W-74W.
ISOLATED TSTMS ARE ALSO OVER THE NW BAHAMAS AND ADJACENT WATERS
AGAIN THIS AFTN. A WELL DEFINED UPPER LOW NEAR 32N56W HAS
ISOLATED TSTMS N OF 25N BETWEEN 52W-62W. SOME OF THE NWP MODELS
CONTINUE TO DEVELOP A WEAK TROUGH OR LOW AT THE SFC IN THIS
VICINITY SW OF BERMUDA. MUCH OF THE E ATLC N OF 17N AND E OF 50W
IS DOMINATED BY LARGE SCALE UPPER RIDGING...MODERATE
TRADES...AND FAIR WEATHER.

$$
WILLIS




This weather bulletin was brought to you by:
www.nashvilleweather.net