[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 091757
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT AUG 09 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 36W/37W S OF 16N MOVING W 15-20 KT. WAVE
IS LOW AMPLITUDE WITH A BROAD AREA OF MID LEVEL ROTATION
EMBEDDED WITHIN THE ITCZ. CLUSTERS OF SCATTERED MODERATE
CONVECTION ARE W OF THE WAVE FROM 9N-14N BETWEEN 37W-42W.

TROPICAL WAVE IS ALONG 56W S OF 24N MOVING W 15 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. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE
WITHIN 90 NM EITHER SIDE OF THE WAVE N OF 17N.

TROPICAL WAVE IS ALONG 66W-67W S OF 21N MOVING W 15 KT. THE
MIMIC TPW PRODUCT SHOWS A VERY WEAK AREA OF DEEP LAYERED
MOISTURE FIELD EXTENDING FROM THE CENTRAL ATLC INTO THE CENTRAL
CARIBBEAN. SHOWER ACTIVITY IS W OF THE WAVE AND ASSOCIATED WITH
AN UPPER LEVEL TROUGH.

TROPICAL WAVE THAT WAS ALONG 82W/83W WAS RELOCATED ALONG 94W S
OF 19N BASED ON LONGTERM SATELLITE IMAGERY AND UPPER AIR
SOUNDINGS. WAVE IS MOVING W NEAR 10 KT. WAVE IS MOSTLY IN THE E
PACIFIC REGION. NO SHOWER ACTIVITY OR CONVECTION IN THE ATLC
BASIN REGION.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N13W 9N18W 11N27W 9N41W 13N53W 11N
62W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION
ARE FROM 8N-12N BETWEEN 25W-32W. CLUSTERS OF SCATTERED MODERATE
CONVECTION ARE FROM 6N-12N E OF 24W TO THE W COAST OF AFRICA AND
FROM 6N-9N BETWEEN 33W-43W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER TROUGH COVERS THE E U.S. PUSHING S INTO THE N GULF N
OF 25N WITH THE ASSOCIATED COLD FRONT CLIPPING THE NE GULF
EXTENDING ACROSS FLORIDA NEAR JACKSONVILLE ALONG 29N86W TO ALONG
THE COAST OF LOUISIANA TO OVER E TEXAS. A PRE-FRONTAL SURFACE
TROUGH EXTENDS FROM THE W ATLC INTO THE GULF NEAR DAYTONA BEACH
TO N OF TAMPA TO 28N84W. SCATTERED/NUMEROUS SHOWERS AND
THUNDERSTORMS ARE FROM 25N-28N E OF 85W ACROSS THE FLORIDA
PENINSULA INTO THE W ATLC WITH SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 23N-28N E OF 93W INCLUDING PORTIONS OF THE
FLORIDA PENINSULA AND THE FLORIDA KEYS. DRY STABLE AIR AND
STRONG SUBSIDENCE DOMINATE THE AREA N OF THE FRONT AND OVER THE
SE U.S. THE S GULF IS DOMINATED BY AN UPPER RIDGE ANCHORED IN
THE E PACIFIC REGION S OF MEXICO. OTHERWISE AT THE SURFACE A
WEAK 1016 MB HIGH IS LOCATED ALONG THE COAST OF W CUBA NEAR
23N84W. THE FRONT IS EXPECTED TO LIFT N LATER TODAY AND BE N OF
THE GULF LATE TONIGHT/SUN MORNING LEAVING A WEAK RIDGE OVER THE
GULF THROUGH MID WEEK.

CARIBBEAN SEA...
THE ELONGATED UPPER LOW EXTENDS FROM HAITI TO THE YUCATAN
CHANNEL COVERING THE NW CARIBBEAN N OF 18N INCLUDING THE CAYMAN
ISLANDS AND JAMAICA. AN UPPER HIGH ANCHORED IN THE SW CARIBBEAN
NEAR 12N77W COVERING THE S CARIBBEAN W OF 68W. AN UPPER LOW IS N
OF THE LEEWARD/VIRGIN ISLANDS EXTENDING AN UPPER TROUGH OVER THE
FAR E CARIBBEAN E OF 67W. MODERATE/STRONG SUBSIDENCE AND DRY
SOMEWHAT STABLE AIR DOMINATES THE E CARIBBEAN E OF 73W LIMITING
SHOWER ACTIVITY OVER THAT AREA WITH THE EXCEPTION OF ISOLATED
SHOWERS/THUNDERSTORMS ALONG THE W EDGE OF THE UPPER TROUGH N OF
15N TO OVER PUERTO RICO AND THE DOMINICAN REPUBLIC. THIN LAYER
OF AFRICAN DUST COVERS MUCH OF THE CARIBBEAN AS WELL AS
MODERATE/STRONG EASTERLY TRADE WINDS WITH THE STRONGEST WINDS
ALONG THE COAST OF COLOMBIA.

ATLANTIC OCEAN...
THE UPPER TROUGH IS OVER THE E U.S. INTO FAR W ATLC WITH THE
ASSOCIATED COLD FRONT ENTERING THE REGION FROM A 1008 MB LOW OFF
THE SOUTH CAROLINA COAST NEAR 32N78W INTO THE GULF OF MEXICO
ACROSS NE FLORIDA NEAR JACKSONVILLE. A PRE-FRONTAL SURFACE
TROUGH EXTENDS FROM 31N78W IN THE W ATLC INTO THE GULF NEAR
DAYTONA BEACH. AN UPPER RIDGE IS TO THE SE AND COUPLED WITH THE
LARGE UPPER LOW N OF THE LEEWARD/VIRGIN ISLANDS ARE GENERATING
SCATTERED/NUMEROUS SHOWERS AND THUNDERSTORMS FROM 25N-31N W OF
70W TO THE SURFACE TROUGH AND OVER THE FLORIDA PENINSULA. AN
UPPER LOW IS N OF THE LEEWARD/VIRGIN ISLANDS NEAR 26N62W WITH AN
UPPER TROUGH EXTENDING S OVER THE E CARIBBEAN. ISOLATED SHOWERS/
THUNDERSTORMS ARE ALONG THE W EDGE OF THE UPPER TROUGH WITHIN
120 NM OF LINE FROM 26N62W INTO THE CARIBBEAN OVER PUERTO RICO
AND THE DOMINICAN REPUBLIC. A SECOND UPPER LOW IS IN THE CENTRAL
ATLC CENTERED NEAR 27N45W COVERING THE AREA N OF 20N FROM
37W-52W. AN UPPER TROUGH IS IN THE E ATLC EXTENDING ACROSS THE
MADEIRA ISLANDS THROUGH 32N22W SW ALONG 22N30W INTO THE TROPICAL
TO 14N45W. OTHERWISE THE ATLC IS DOMINATED BY MODERATE/STRONG
SUBSIDENCE AND DRY STABLE AIR MAINLY W OF 55W AND A SURFACE
RIDGE EXTENDING FROM A HIGH JUST SE OF THE AZORES THROUGH A 1027
MB HIGH NEAR 32N46W NARROWING TO OVER THE TURKS AND CAICOS NEAR
22N70W...THUS GIVING THE REMAINDER OF THE ATLC FAIR WEATHER THIS
AFTERNOON. THE SURFACE LOW OFF SOUTH CAROLINA IS EXPECTED TO
RACE NE WHILE THE FRONT IS EXPECTED TO SLOWLY LIFT N AS A SECOND
LOW FORMS JUST N OF THE REGION IN THE W ATLC DRAPING THE FRONT
TO OVER THE SE U.S. AND CLEARING THE REGION MON. HIGH PRESSURE
WILL REMAIN IN CONTROL OF THE REMAINDER OF THE ATLC AND
EXTENDING W OVER THE GULF OF MEXICO THROUGH MID WEEK.

$$
WALLACE




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