[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 292314
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN JUN 29 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND 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
2245 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 33W/34W S OF 13N MOVING W 10-15 KT. THE
WAVE REMAINS EMBEDDED WITHIN THE ITCZ WITH NO ORGANIZED DEEP
CONVECTION OBSERVED.

A TROPICAL WAVE IS ALONG 43W S OF 14N MOVING W 10-15 KT. A
LOW-AMPLITUDE INVERTED-V CURVATURE IS NOTED ON SATELLITE IMAGERY
FROM 9N-12N. SCATTERED MODERATE CONVECTION IS IN THIS REGION
BETWEEN 39W-45W.

A TROPICAL WAVE IS ALONG 59W S OF 14N MOVING W NEAR 15 KT. NO
SIGNIFICANT CONVECTION IS ASSOCIATED WITH THIS WAVE. DUE TO A
LACK OF OBSERVATIONS IN THE VICINITY...THE POSITION OF THE AXIS
IS BASED ON CONTINUITY.

A WEAK TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN ALONG 74W FROM
WESTERN HAITI TO COLOMBIA MOVING W NEAR 15 KT. THE WAVE IS IN AN
AREA OF VERY DRY STABLE AIR ALOFT...THUS CONVECTION IS INHIBITED.

...ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 6N11W 8N20W 8N30W 7N40W AND INTO
FRENCH GUIANA NEAR 5N52W. IN ADDITION TO ACTIVITY ASSOCIATED
WITH TROPICAL WAVES...SCATTERED MODERATE CONVECTION IS MOVING
OFF THE W AFRICA COAST FROM 4N-7N E OF 18W. SIMILAR CONVECTION
IS WITHIN 60 NM OF THE AXIS BETWEEN 24W-31W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LOW SITUATED OFF THE LOUISIANA COAST EXTENDS A TROUGH
ACROSS THE NW GULF TO THE TEXAS/MEXICO BORDER. AN UPPER RIDGE
COVERS THE REMAINDER OF THE GULF. DIFFLUENT SWLY FLOW BETWEEN
THESE FEATURES IS ADVECTING A DEEP LAYER OF TROPICAL MOISTURE
INTO THE REGION AND IS SUPPORTING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ALONG THE MEXICAN COASTLINE FROM VERACRUZ TO THE
TEXAS BORDER W OF 95W. HEATING-INDUCED THUNDERSTORMS OVER CUBA
AND FLORIDA ARE AFFECTING THE GULF WATERS WITHIN 50 NM OF THEIR
RESPECTIVE COASTLINES. A BAND OF SCATTERED SHOWERS AND
THUNDERSTORMS IS MOVING AHEAD OF A COLD FRONT OVER THE SERN
CONUS AND IS BEGINNING TO ENTER THE FAR NE GULF WATERS BETWEEN
NEW ORLEANS AND PANAMA CITY FLORIDA. EXPECT THIS FRONTAL TROUGH
TO ENTER THE NE GULF MON BEFORE DISSIPATING TUE. A SFC RIDGE
EXTENDS FROM THE CENTRAL ATLC ACROSS FLORIDA AND INTO MEXICO
PRODUCING LIGHT SOUTHERLY RETURN FLOW THROUGHOUT THE REGION.

CARIBBEAN...
AN UPPER-LEVEL RIDGE/TROUGH/RIDGE PATTERN REMAINS IN PLACE OVER
THE CARIBBEAN. DIVERGENCE ALONG THE SRN EXTENT OF THE
WESTERNMOST RIDGE COUPLED WITH LOW-LEVEL WIND SPEED CONVERGENCE
IS GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
ACROSS THE SW CARIBBEAN S OF 12N. THIS DIVERGENCE IS ALSO
PROVIDING LIFT TO ENHANCE SCATTERED THUNDERSTORMS GENERATED FROM
ONSHORE FLOW ALONG THE COASTS OF NICARAGUA AND BELIZE. STRONG
SUBSIDENCE ALONG THE BASE OF THE UPPER TROUGH EXTENDING ACROSS
THE WINDWARD PASSAGE IS INHIBITING DEEP CONVECTION IN THE
CENTRAL CARIBBEAN BETWEEN 73W-83W. DIVERGENCE ALONG THE LEADING
EDGE OF THE TROUGH IS GENERATING NUMEROUS SHOWERS AND ISOLATED
THUNDERSTORMS OVER THE EASTERN CARIBBEAN N OF 14N AS WELL AS
OVER HISPANIOLA...PUERTO RICO...AND THE VIRGIN ISLANDS. A STRONG
SURFACE RIDGE OVER THE CENTRAL ATLC CONTINUES TO PROVIDE STRONG
EASTERLY TRADES THROUGHOUT THE CARIBBEAN.

ATLANTIC...
A PRE-FRONTAL TROUGH OVER THE EASTERN CONUS IS PUSHING A BAND OF
SHOWERS AND THUNDERSTORMS INTO THE W ATLC W OF 80W N OF 29N. A
SECOND AREA OF SCATTERED SHOWERS AND THUNDERSTORMS IS BETWEEN
73W-79W N OF 27W. THIS ACTIVITY IS INDUCED BY INSTABILITY ALONG
AN UPPER SHORTWAVE TROUGH. SWLY UPPER FLOW AROUND A HIGH EAST OF
THE WINDWARD ISLANDS IS ADVECTING MOISTURE INTO THE ATLC S OF
23N AND W OF 55W. THE REMAINDER OF THE DISCUSSION AREA IS
DOMINATED BY A VERY STABLE SURFACE RIDGE ANCHORED BY A 1028 MB
HIGH PRESSURE CENTERED NEAR 35N35W SW OF THE AZORES. THIS RIDGE
IS MAINTAINING MODERATE EASTERLY FLOW THROUGHOUT THE ERN AND
CENTRAL ATLC.

$$
WADDINGTON




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