[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 020558
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0345 UTC.

...SPECIAL FEATURES...

TROPICAL STORM ERIKA IS CENTERED NEAR 17.5N 57.6W OR ABOUT 320
NM E OF THE NORTHERN LEEWARD ISLANDS AT 0600 UTC MOVING WNW AT 7
KT. MINIMUM CENTRAL PRESSURE REPORTED BY AN AIR FORCE
RECONNAISSANCE AIRCRAFT WAS 1004 MB. MAXIMUM SUSTAINED WIND
SPEED IS 50 KT WITH GUSTS TO 60 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. THE CENTER OF ERIKA IS EXPECTED TO PASS TO THE
NE OF THE LEEWARD ISLANDS ON THURSDAY. NUMEROUS STRONG
CONVECTION IS WITHIN A 60 NM RADIUS OF 16N56.5W WITH SCATTERED
MODERATE/STRONG CONVECTION COVERING THE REMAINDER OF THE AREA
FROM 13N-20N BETWEEN 53W-59W.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 21W/22W S OF 19N MOVING W NEAR 10 KT.
WELL DEFINED MID LEVEL CURVATURE ASSOCIATED WITH THIS WAVE AS IT
IS EMBEDDED IN A DEEP LAYER OF MOISTURE AS INDICATED BY THE
TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS E OF THE WAVE FROM 18N-19N E OF 19W TO
INLAND OVER MAURITANIA AFRICA WITH ISOLATED SHOWERS WITHIN
120/150 NM OF LINE FROM 12N26W ACROSS THE CAPE VERDE ISLANDS TO
19N22W. THIS WAVE HAS A LOW CHANCE OF TROPICAL DEVELOPMENT.

TROPICAL WAVE EXTENDS FROM 16N39W TO 8N35W MOVING W 10-15 KT.
THIS WAVE IS LESS DEFINED AS IT HAS DRY AIR BEING INTRODUCED AS
INDICATED BY TOTAL PRECIPITABLE WATER IMAGERY. WAVE IS ALSO
EMBEDDED WITHIN SAHARAN DUST THUS LIMITING ANY SHOWERS OR
CONVECTION.

TROPICAL WAVE IS ALONG 87W/88W S OF 15N MOVING W NEAR 15 KT.
THIS WAVE IS INLAND OVER CENTRAL AMERICA AND IN THE E PACIFIC
REGION. SEE MIATWDEP FOR MORE DETAILS.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 13N15W 15N20W 10N28W 8N44W
12N53W 12N59W 10N64W. THE ITCZ IS BEING DISTORTED BY TROPICAL
STORM ERIKA. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE WITHIN 180/200 NM S OF THE ITCZ FROM 36W-52W.

...DISCUSSION...

GULF OF MEXICO...
A STATIONARY FRONT CONTINUES TO MEANDER ALONG THE N GULF ACROSS
NE FLORIDA EXTENDING INTO THE GULF WATERS NEAR PENSACOLA FLORIDA
ALONG 30N87W 27N90W TO THE TEXAS COAST NEAR CORPUS CHRISTI. A
SURFACE TROUGH EXTENDS OVER THE SE GULF FROM THE W ATLC ACROSS S
FLORIDA BETWEEN PALM BEACH AND NAPLES CONTINUING SW TO 22N89W. A
BROAD UPPER RIDGE ANCHORED IN THE E PACIFIC EXTENDS ACROSS
MEXICO INTO THE GULF BETWEEN MATAMOROS AND TAMPICO TO NEAR
24N88W WITH A SHORTWAVE UPPER TROUGH OVER E GULF EXTENDING FROM
A BROAD UPPER TROUGH COVERING THE E HALF OF THE U.S. THROUGH NW
FLORIDA PANHANDLE TO W CUBA. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE ACROSS THE E GULF N OF 24N E OF 86W WITH
CLUSTERS OF SIMILAR ACTIVITY OVER THE SW GULF AND THE BAY OF
CAMPECHE WITHIN 90 NM ALONG THE COAST FROM TAMPICO MEXICO TO THE
NW TIP OF THE YUCATAN. ISOLATED SHOWERS CAN DOT THE REMAINDER OF
THE GULF WATERS TONIGHT.

CARIBBEAN SEA...
AN UPPER TROUGH OVER THE W/CENTRAL ATLC COVERS MOST OF THE W
CARIBBEAN WITH AN UPPER LOW OVER HAITI AND A SMALLER UPPER LOW
JUST S OF THE YUCATAN CHANNEL. ISOLATED SHOWERS ARE INLAND AND
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 66W TO ACROSS THE LESSER ANTILLES COMPLIMENTS OF
TROPICAL STORM ERIKA. OTHERWISE...THE REMAINDER OF THE CARIBBEAN
REMAINS UNDER CLEAR SKIES TONIGHT.

ATLANTIC OCEAN...
THE MAIN FOCUS TONIGHT IS TROPICAL STORM ERIKA LOCATED E OF THE
LESSER ANTILLES. IN THE W ATLC...A SURFACE TROUGH EXTENDS FROM
31N77W ACROSS THE FLORIDA PENINSULA NEAR PALM BEACH CONTINUING
INTO THE GULF OF MEXICO. NARROW UPPER RIDGE IS OVER THE FAR W
ATLC EXTENDING FROM W CUBA NEAR 23N81W TO 31N72W PROVIDING
DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS N OF 25N W OF 77W TO OVER THE FLORIDA PENINSULA.
AN UPPER TROUGH IS OVER THE W/CENTRAL ATLC EXTENDING FROM AN
UPPER LOW NEAR 34N56W TO A SECOND UPPER LOW OVER HAITI. A
SURFACE TROUGH IS JUST TO THE W EXTENDING FROM 27N76W TO E CUBA
NEAR 22N77W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE E OF
THE SURFACE TROUGH WITHIN 75 NM OF 73W FROM 20N-25N 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
TONIGHT AS A SURFACE RIDGE CONTINUES TO DOMINATE THE BASIN
BETWEEN 20W-70W ANCHORED BY A 1030 MB HIGH WELL N OF THE REGION
WSW OF THE AZORES.

$$
WALLACE



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