[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 021155
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED SEP 02 2009

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...

TROPICAL STORM ERIKA IS CENTERED NEAR 16.5N 59.5W OR ABOUT 140
NM ESE OF THE LEEWARD ISLANDS AT 02/1200 UTC MOVING W AT 6 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED
WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. SEE LATEST NHC PUBLIC
ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC AND THE
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC
FOR MORE DETAILS. ERIKA APPEARS TO BE LESS ORGANIZED BUT
CONTINUES TO MAINTAIN OUTFLOW IN ALL QUADRANTS.  NUMEROUS STRONG
CONVECTION IS WITHIN A 60 NM RADIUS OF 15.5N57W WITH SCATTERED
MODERATE/STRONG CONVECTION COVERING THE REMAINDER OF THE AREA
FROM 13N-19N BETWEEN 54W-60W.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 23W/24W S OF 20N MOVING W 10-15 KT. WAVE
IS EMBEDDED WITHIN A DEEP LAYER OF MOISTURE AS INDICATED BY THE
TOTAL PRECIPITABLE WATER IMAGERY. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE FROM 16N-20N BETWEEN
20W-27W WITH ISOLATED SHOWERS FROM 12N-15N BETWEEN 24W-28W.

TROPICAL WAVE EXTENDS FROM 16N40W TO 8N37W MOVING W 10-15 KT.
THIS WAVE REMAINS ILL-DEFINED AS IT HAS DRY AIR INTRODUCED AS
INDICATED BY TOTAL PRECIPITABLE WATER IMAGERY. WAVE IS ALSO
EMBEDDED WITHIN SAHARAN DUST THUS LIMITING ANY SHOWERS OR
CONVECTION.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N11W 9N14W 10N20W 8N28W 9N39W
6N48W 8N61W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM 8N-11N BETWEEN 21N-40W AND FROM 6N-10N
BETWEEN 40W-48W.

...DISCUSSION...

GULF OF MEXICO...
A STATIONARY FRONT CONTINUES TO MEANDER ALONG THE N GULF ACROSS
THE FLORIDA PENINSULA FROM THE W ATLC THROUGH ST. AUGUSTINE
ENTERING THE GULF WATERS NEAR CEDAR KEY CONTINUING ALONG 29N85W
27N90W TO THE TEXAS COAST BETWEEN CORPUS CHRISTI AND
BROWNSVILLE. A SURFACE TROUGH EXTENDS OVER THE SE GULF FROM THE
W ATLC ACROSS EXTREME S FLORIDA NEAR MIAMI CONTINUING SW TO
23N86W. AN UPPER RIDGE ANCHORED IN THE E PACIFIC EXTENDS ACROSS
MEXICO INTO THE GULF BETWEEN MATAMOROS AND TAMPICO TO NEAR
24N90W WITH A SHORTWAVE UPPER TROUGH OVER E GULF EXTENDING FROM
A BROAD UPPER TROUGH COVERING THE E HALF OF THE U.S. THROUGH W
FLORIDA PANHANDLE TO W CUBA. CLUSTERS OF SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS ARE ACROSS THE E GULF N OF 24N E OF 90W
AND OVER THE SW GULF/BAY OF CAMPECHE S OF 23N W OF 92W.
SCATTERED SHOWERS ARE OVER THE NW GULF FROM 24N-28N W OF 90W
WITH CLEARING SKIES ALONG THE GULF COAST FROM ALABAMA AND
MISSISSIPPI BORDER TO CORPUS CHRISTI TEXAS.

CARIBBEAN SEA...
AN UPPER TROUGH OVER THE W/CENTRAL ATLC COVERS MOST OF THE W
CARIBBEAN WITH AN UPPER LOW OFF THE COAST OF HAITI IN THE
WINDWARD PASSAGE AND A SMALLER UPPER LOW W OF THE CAYMAN ISLANDS
NEAR 20N84W. ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS ARE
WITHIN 75 NM ALONG THE S COAST OF CUBA. MODERATE/STRONG EASTERLY
TRADE WINDS CONTINUE ACROSS THE AREA. SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS ARE OVER THE E CARIBBEAN N OF
12N E OF 70W TO ACROSS THE LESSER ANTILLES COMPLIMENTS OF
TROPICAL STORM ERIKA. OTHERWISE...THE REMAINDER OF THE CARIBBEAN
REMAINS UNDER RELATIVELY CLEAR SKIES THIS MORNING.

ATLANTIC OCEAN...
THE MAIN FOCUS THIS MORNING IS TROPICAL STORM ERIKA LOCATED JUST
E OF THE LESSER ANTILLES. IN THE W ATLC...A STATIONARY FRONT
ENTERS THE REGION NEAR 32N77W EXTENDING SW ACROSS THE FLORIDA
PENINSULA NEAR ST. AUGUSTINE WITH SCATTERED SHOWERS/
THUNDERSTORMS N OF THE FRONT TO THE SE U.S. COAST. A SURFACE
TROUGH EXTENDS FROM 31N76W OVER GRAND BAHAMA ISLANDS ACROSS
EXTREME S FLORIDA PENINSULA NEAR MIAMI CONTINUING INTO THE GULF
OF MEXICO. NARROW UPPER RIDGE IS OVER THE FAR W ATLC EXTENDING
FROM W CUBA NEAR 23N81W TO 31N71W PROVIDING DIFFLUENCE ALOFT TO
GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 25N W OF
76W TO OVER THE FLORIDA PENINSULA. AN UPPER TROUGH IS OVER THE
W/CENTRAL ATLC EXTENDING OVER THE REMAINDER OF THE W ATLC NEAR
32N60W TO AN UPPER LOW OFF THE COAST OF HAITI IN THE WINDWARD
PASSAGE. A SURFACE TROUGH IS JUST TO THE W EXTENDING FROM 28N74W
ACROSS THE BAHAMAS TO E CUBA NEAR 22N77W. SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS ARE E OF THE SURFACE TROUGH FROM 21N-25N
BETWEEN 71W-75W INCLUDING THE TURKS AND CAICOS. A LONGER UPPER
TROUGH EXTENDS ACROSS THE E AND CENTRAL ATLC THROUGH A PAIR OF
UPPER LOWS CENTERED NEAR 30N19W AND 25N45W BUT IS NOT PRODUCING
ANY SIGNIFICANT WEATHER. OTHERWISE THE REMAINDER OF THE ATLC
BASIN REMAINS TRANQUIL AGAIN THIS MORNING AS A SURFACE RIDGE
CONTINUES TO DOMINATE THE BASIN BETWEEN 20W-70W ANCHORED BY A
1029 MB HIGH WELL N OF THE REGION WSW OF THE AZORES.

$$
WALLACE





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