[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 081749
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI AUG 08 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 30W S OF 16N MOVING W 10-15 KT. WAVE IS
LOW AMPLITUDE WITH A BROAD AREA OF MID LEVEL ROTATION. ANY
CONVECTION IS W OF THE WAVE AND ASSOCIATED WITH THE ITCZ.

TROPICAL WAVE IS ALONG 49W/50W FROM 13N-26N MOVING W 15-20 KT.
HIGH AMPLITUDE WAVE N OF THE ITCZ WITH WELL DEFINED INVERTED-V
CURVATURE OBSERVED ON SATELLITE IMAGERY. THE MIMIC TPW PRODUCT
SHOWS A WEAK AREA OF DEEP LAYERED MOISTURE FIELD WELL N OF THE
ITCZ. NO ASSOCIATED SHOWERS/CONVECTION.

TROPICAL WAVE IS TILTED FROM 21N60W INTO THE CARIBBEAN ALONG
14N62W TO 9N62W MOVING W 10-15 KT. THE MIMIC TPW PRODUCT SHOWS A
WEAK AREA OF DEEP LAYERED MOISTURE FIELD EXTENDING FROM THE
CENTRAL ATLC ACROSS THE LEEWARD ISLANDS INTO THE NE CARIBBEAN.
SHOWER ACTIVITY IS W OF THE WAVE AND ASSOCIATED WITH AN UPPER
LEVEL TROUGH.

TROPICAL WAVE IS ALONG 82W/83W S OF 21N MOVING W 10-15 KT. BROAD
AREA OF DEEP LAYERED MOISTURE FIELD IS OBSERVED ON MIMIC TPW
PRODUCT COVERING THE CARIBBEAN W OF 78W. WAVE REMAINS AT THE
LEADING EDGE OF A SURGE OF AFRICAN DUST THAT COVERS THE
CARIBBEAN TO 68W AND TO OVER THE GREATER ANTILLES. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 15N W OF THE WAVE TO
INLAND OVER CENTRAL AMERICA.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 13N16W 11N26W 8N36W 7N47W 8N62W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 45/60 NM
ALONG THE COAST OF W AFRICA FROM 7N-12N AND WITHIN 60/75 NM OF
THE ITCZ FROM 34W-41W. SCATTERED MODERATE CONVECTION IS FROM
7N-10N BETWEEN 14W-29W AND WITHIN 120 NM OF ITCZ FROM 29W-34W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH OVER THE E U.S. IS PUSHING S TO ALONG THE N GULF
COAST ALTHOUGH THE ASSOCIATED FRONTAL BOUNDARY REMAINS INLAND
ACROSS THE SE U.S. A PRE-FRONTAL SURFACE TROUGH EXTENDS FROM SW
GEORGIA INTO THE GULF NEAR PANAMA CITY FLORIDA THEN INLAND
ACROSS S LOUISIANA OVER LAKE PONTCHARTRAIN GENERATING SCATTERED/
NUMEROUS SHOWERS WITH SCATTERED THUNDERSTORMS OVER THE GULF
WATERS WITHIN 150 NM S OF THE SURFACE TROUGH. THE SW GULF IS
DOMINATED BY AN UPPER RIDGE ANCHORED OVER SW MEXICO. THE SE GULF
IS DOMINATED BY AN ELONGATED UPPER LOW CENTERED ALONG THE SW
COAST OF CUBA. CLUSTERS OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE FROM 23N-27N E OF 90W TO OVER THE FLORIDA
PENINSULA. OTHERWISE AT THE SURFACE A WEAK 1016 MB HIGH REMAINS
LOCATED NEAR 27N93W. A FRONTAL BOUNDARY IS EXPECTED TO MOVE E
INTO THE W ATLC WITH THE ASSOCIATED SHOWERS/THUNDERSTORM
ACTIVITY REMAINING WILL BE OVER THE N GULF THROUGH EARLY SUN.

CARIBBEAN SEA...
THE ELONGATED UPPER LOW COVERING THE SE GULF IS ANCHORED ALONG
THE SW COAST OF CUBA NEAR THE ISLE OF YOUTH COVERING THE NW
CARIBBEAN N OF THE CAYMAN ISLANDS BETWEEN E CUBA NEAR 78W AND
THE YUCATAN PENINSULA WITH AN UPPER HIGH COVERING THE S
CARIBBEAN S OF 18N W OF 80W ANCHORED ALONG THE W COAST OF
NICARAGUA. UPPER LEVEL DIFFLUENCE IS ENHANCING THE ACTIVITY
ASSOCIATED WITH THE TROPICAL WAVE ALONG 82W/83W. AN UPPER LOW IS
NE OF THE LEEWARD ISLAND EXTENDING AN UPPER TROUGH OVER THE E
CARIBBEAN E OF 67W. MODERATE/STRONG SUBSIDENCE AND DRY STABLE
AIR DOMINATES THE E CARIBBEAN E OF 73W LIMITING SHOWER ACTIVITY
OVER THAT AREA WITH THE EXCEPTION OF ISOLATED SHOWERS/
THUNDERSTORMS ALONG THE LEADING EDGE OF THE UPPER TROUGH N OF
17N TO OVER THE VIRGIN ISLANDS. THIS ACTIVITY WILL REACH PUERTO
RICO IN THE NEXT FEW HOURS. SURGE OF AFRICAN DUST IS BETWEEN THE
UPPER TROUGH AND TRAILING THE TROPICAL WAVE ALONG 82W/83W.
MODERATE/STRONG EASTERLY TRADE WINDS COVER THE ENTIRE CARIBBEAN
WITH THE STRONGEST WINDS ALONG THE COAST OF COLOMBIA.

ATLANTIC OCEAN...
THE UPPER TROUGH OVER THE E U.S. IS MOVING INTO THE NW ATLC WITH
THE ASSOCIATED FRONTAL BOUNDARY WELL N OF THE REGION AND INLAND
OVER THE SE U.S. GENERATING SCATTERED/NUMEROUS SHOWERS WITH
SCATTERED THUNDERSTORMS N OF 29N BETWEEN 75W-80W. THE WEAK 1013
MB LOW HAS DISSIPATED LEAVING THE SURFACE TROUGH EXTENDING FROM
30N77W OVER THE N BAHAMA ISLANDS TO 25N79W GENERATING SCATTERED
SHOWERS/THUNDERSTORMS WITHIN 60 NM OF THE TROUGH. A NARROWING
UPPER LOW IS TO THE E NEAR 27N73W GENERATING SCATTERED SHOWERS/
THUNDERSTORMS WITHIN 120 NM OF LINE FROM 31N71W TO 26N74W. A
NARROW UPPER RIDGE IS BETWEEN THIS UPPER LOW AND THE UPPER
TROUGH OVER THE CENTRAL ATLC. A SERIES OF UPPER LOWS EXTENDS
FROM THE E ATLC INTO THE S/CENTRAL ATLC WITH THE UPPER LOWS
CENTERED NEAR 31N24W 30N42W TO THE LARGE UPPER LOW IN THE
S/CENTRAL ATLC NEAR 22N59W WITH THE UPPER TROUGH EXTENDING
ACROSS THE LEEWARD ISLANDS INTO THE E CARIBBEAN. ISOLATED
SHOWERS/THUNDERSTORMS ARE WITHIN 120 NM OF THE W EDGE OF THE
UPPER TROUGH FROM 24N61W ACROSS THE VIRGIN ISLANDS INTO THE FAR
NE CARIBBEAN NEAR 17N66W. THIS ACTIVITY WILL REACH PUERTO RICO
IN THE NEXT FEW HOURS. BROAD UPPER RIDGE EXTENDS OFF THE COAST
OF AFRICA NEAR 19N16W TO OVER THE CAPE VERDE ISLANDS AND S OF
THE CANARY ISLANDS. OTHERWISE THE ATLC IS DOMINATED BY MODERATE/
STRONG SUBSIDENCE AND DRY STABLE AIR AND A SURFACE RIDGE
EXTENDING FROM A HIGH NE OF THE AZORES THROUGH A 1022 MB HIGH
NEAR 32N41W TO E OF THE BAHAMAS NEAR 26N70W...THUS GIVING THE
REMAINDER OF THE ATLC FAIR WEATHER THIS AFTERNOON. THE FRONTAL
BOUNDARY OVER THE E U.S. IS EXPECTED TO MOVE INTO THE W ATLC
LATE TONIGHT/SAT AND IS EXPECTED TO REMAIN N OF 30N.

$$
WALLACE




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