[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231802
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON JUL 23 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...
A LARGE ATLC OCEAN TROPICAL WAVE IS ALONG 24N38W 7N36W MOVING
QUICKLY W NEAR 25 KT. THE WAVE EXHIBITS A VERY LARGE INVERTED V
SHAPE AND MAY EXTEND EVEN FURTHER N BASED ON THIS AFTERNOONS
VISIBLE IMAGERY. A DENSE LAYER OF SAHARAN DUST IS EVIDENT ON
BOTH SIDES OF THE AXIS. DEEP CONVECTION IS MINIMAL.

E CARIBBEAN TROPICAL WAVE IS ALONG 70W S OF 19N MOVING W 15-20
KT. WAVE PASSAGE WAS EVIDENT IN THE SAN JUAN SOUNDING DATA
YESTERDAY EVENING. ASSOCIATED SCATTERED SHOWERS/ISOLATED TSTMS
ARE FROM 14N-21N BETWEEN 64W-75W.

W CARIBBEAN TROPICAL WAVE IS ALONG 86W/87W S OF 20N MOVING W
NEAR 15 KT. SOME SLIGHT LOW TO MID LEVEL CYCLONIC TURNING NOTED
IN SATELLITE IMAGERY. SCATTERED SHOWERS/ISOLATED TSTMS ARE OVER
THE GULF OF HONDURAS...BELIZE..AND THE ERN YUCATAN PENINSULA
FROM 16N-22N BETWEEN 84W-89W. SIMILAR ACTIVITY IS OVER ERN
NICARAGUA.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 14N16W 13N25W 11N35W 8N50W 6N57W.
SCATTERED MODERATE CONVECTION IS S OF THE AXIS FROM 8N-11N
BETWEEN 16W-33W. ISOLATED MODERATE IS WITHIN 90NM EITHER SIDE OF
THE AXIS BETWEEN 46W-51W.

...DISCUSSION...
GULF OF MEXICO...
COMPLEX FRONTAL PATTERN CONTINUES TO PRODUCE MESSY WEATHER OVER
THE ERN GULF THIS AFTERNOON. THE MOST CONCENTRATED CLUSTER OF
MODERATE CONVECTION IS NEAR THE FLORIDA PANHANDLE N OF 28N E OF
89W. SCATTERED SHOWERS/ISOLATED TSTMS DOT THE REMAINDER OF THE
GULF E OF 89W. AS OF 23/1500 UTC A 1014 MB LOW WAS JUST OFF THE
COAST OF SE LOUISIANA NEAR 29N88W. THIS LOW HAS A DYING
STATIONARY FRONT EXTENDING ESE AND ENTERING CENTRAL FLORIDA NEAR
28N83W OR JUST N OF CLEARWATER FL. A COLD FRONT EXTENDS SW FROM
THE LOW TO 26N92W AND THEN NW TO THE TEXAS COAST NEAR FREEPORT
TEXAS. IT HAS REMAINED A CHALLENGE TO ANALYZE THE FRONTAL SYSTEM
THIS MORNING GIVEN THE MANY CONVECTIVE BOUNDARIES EVIDENT AND
THE FRONT LOSING MUCH OF ITS THERMAL CONTRAST.
HOWEVER...DEWPOINTS REMAIN IN THE LOW TO MID 70S S OF THE
BOUNDARY AND MOSTLY IN THE 60S TO THE N. THE UPPER SUPPORT
CONSISTS OF AN ELONGATED UPPER TROUGH EXTENDING SW FROM MOBILE
TO THE WRN BAY OF CAMPECHE NEAR 20N97W. THIS IS ALSO SUPPORTING
ISOLATED TSTMS JUST OFF THE MEXICAN COAST FROM 19N-23N W OF 93W.
RIDGING WILL GRADUALLY FILL BUILD OVER THE GULF FROM THE ATLC
THROUGH MIDWEEK AS THE FRONT CONTINUES TO SLOWLY WEAKEN AND LIFT
N.

CARIBBEAN SEA...
THE TROPICAL WAVES IN THE CARIBBEAN ARE RESPONSIBLE FOR MOST OF
THE WEATHER IN THE CARIBBEAN THIS AFTERNOON AS DESCRIBED ABOVE.
OTHERWISE LIGHT TO MODERATE TRADES DOMINATE SW OF THE ATLC HIGH.
THE EXCEPTION IS LIGHTER SE FLOW IN THE FAR NW PORTION. TRADES
INCREASE SLIGHTLY...MAINLY FOR THE CENTRAL CARIB...THROUGH
MIDWEEK. ALOFT...AN UPPER HIGH IN THE NW CARIBBEAN NEAR 18N81W
DOMINATES. THIS IS SPREADING DEBRIS MOISTURE ASSOCIATED WITH THE
CONVECTION FROM THE WAVE S OF HISPANIOLA TO THE SW.

ATLANTIC OCEAN...
THE SAME DYING STATIONARY FRONT DESCRIBED IN THE GULF SECTION
EXITS CENTRAL FLORIDA NEAR COCOA BEACH AND CONTINUES NE TO
31N75W. SCATTERED SHOWERS/ISOLATED TSTMS ARE IN THE UNSTABLE
ENVIRONMENT WITHIN 200 NM AHEAD OF THE FRONT. A SEPARATE AREA OF
SCATTERED MODERATE CONVECTION IS FURTHER E...N OF 27N BETWEEN
64W-71W. LOW CLOUD MOTIONS SHOW SOME LOW LEVEL CONFLUENCE IN
THIS VICINITY...THOUGH THE CONVECTION IS ALSO BEING SUPPORTED BY
DIFFLUENCE ALOFT BETWEEN THE LARGE UPPER LOW OVER THE ERN U.S.
AND RIDGING EXTENDING NE FROM THE CARIBBEAN. ANOTHER UPPER LOW
IS NEAR 24N52W BUT IS NOT GENERATING ANY SIGNIFICANT WEATHER.
THE REMAINDER OF DISCUSSION AREA N OF 15N E OF 60W IS WIDELY
DOMINATED BY FAIR WEATHER AND MODERATE TO FRESH TRADES S OF A
1031 MB HIGH NEAR 37N45W.

$$
WILLIS




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