[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 080555
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE SEP 08 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
0515 UTC.

...SPECIAL FEATURES...

TROPICAL STORM FRED IS CENTERED NEAR 11.8N 26.3W AT 08/0300 UTC
OR ABOUT 210 NM SSW OF THE SOUTHERNMOST CAPE VERDE ISLANDS
MOVING W AT 13 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004
MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT.
SCATTERED MODERATE TO STRONG CONVECTION IS FROM 9N-14N BETWEEN
24W-29W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 57W S OF 20N MOVING W NEAR 18 KT. CIMSS
WAVETRAK MODEL GUIDANCE INDICATES A MAXIMUM OF 850 MB VORTICITY
IN THE VICINITY OF THE WAVE AXIS N OF 15N BETWEEN 52W-58W. AS
THE WAVE MOVES BENEATH A MODERATELY SUBSIDENT ATMOSPHERE AS
NOTED ON WATER VAPOR IMAGERY...ONLY ISOLATED SHOWERS ARE WITHIN
120 NM OF A LINE FROM 20N53W TO 16N60W.

TROPICAL WAVE IS ALONG 76W S OF 20N MOVING W NEAR 15 KT. THIS
WAVE REMAINS ILL-DEFINED ACROSS THE WRN CARIBBEAN AND MODERATELY
DRY AIR IS NOTED ALOFT IN THE UPPER LEVELS. NO DEEP CONVECTION
ACCOMPANIES THIS WAVE.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 17N16W 14N23W 9N27W 6N31W 14N54W
13N58W 10N62W. BESIDES THE CONVECTION ASSOCIATED WITH TROPICAL
STORM FRED AND THE TROPICAL WAVE ALONG 57W...SCATTERED MODERATE
CONVECTION IS ALONG THE W AFRICA COAST FROM 8N-11N BETWEEN
13W-17W. SIMILAR CONVECTION IS FROM 5N-8N BETWEEN 30W-36W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED IN THE BAY
OF CAMPECHE NEAR 20N95W AND EXTENDS UPPER RIDGING ACROSS MUCH OF
THE GULF IN THE WAY OF WESTERLY ZONAL FLOW. THE LACK OF ANY
SIGNIFICANT SURFACE LEVEL FEATURES AND AN OVERALL WEAK PRESSURE
GRADIENT IS PROVIDING THE GULF WITH GENERALLY LIGHT WINDS
CIRCULATING AROUND THE SRN PERIPHERY OF A 1016 MB SURFACE HIGH
CENTERED OVER W/CENTRAL GEORGIA NEAR 33N85W. UPPER LEVEL
DIFFLUENCE IN ASSOCIATION WITH THE UPPER LEVEL RIDGE IS
GENERATING ENOUGH ATMOSPHERIC LIFT FOR SCATTERED SHOWERS AND A
FEW ISOLATED TSTMS ACROSS THE WRN GULF FROM 23N-28N W OF 90W AND
ALSO OVER THE ERN BAY OF CAMPECHE S OF 22N E OF 93W. MORE
NUMEROUS SHOWERS AND SCATTERED TSTMS ARE OVER SRN INTERIOR
MEXICO BETWEEN 90W-97W.

CARIBBEAN SEA...
A TROPICAL WAVE IS ALONG 76W WITH NO SIGNIFICANT CONVECTION
ASSOCIATED WITH THE WAVE OVER THE WRN CARIBBEAN. AN UPPER LEVEL
TROUGH DIPS SW FROM THE SW NORTH ATLC ACROSS HISPANIOLA TO NEAR
COASTAL NICARAGUA. NLY UPPER LEVEL WINDS ARE FOUND W OF 80W AND
ARE PROVIDING AN OVERALL SUBSIDENT ATMOSPHERE ACROSS THE NW
CARIBBEAN AND PORTIONS OF CENTRAL AMERICA. HOWEVER...SCATTERED
SHOWERS AND TSTMS THAT FORMED OVER CUBA DURING THE LATE
AFTERNOON HOURS HAVE MOVED SWD OVER THE NW CARIBBEAN AND ARE
LOCATED FROM 18N-22N BETWEEN 77W-83W. MOSTLY DRY AIR ALOFT ON
SWLY WINDS ARE ACROSS THE REMAINDER OF THE CARIBBEAN BASIN E OF
80W. AS MODERATE TO FRESH TRADES CONTINUE ACROSS THE BASIN IN
THE LOW LEVELS...PASSING ISOLATED SHOWERS ARE N OF 13N E OF 70W.

ATLANTIC OCEAN...
A SURFACE TROUGH ENTERS THE DISCUSSION AREA NEAR 32N78W AND
EXTENDS SSW TO NEAR MIAMI FLORIDA. SCATTERED SHOWERS ARE WITHIN
120 NM TO THE E OF THE SURFACE TROUGH. FARTHER TO THE E...AN
UPPER LEVEL LOW IS CENTERED NEAR 24N68W AND IS GENERATING AN
AREA OF SCATTERED SHOWERS FROM 22N-30N BETWEEN 64W-71W. INTO THE
CENTRAL ATLC...A COLD FRONT DIPS INTO THE DISCUSSION AREA NEAR
32N41W AND EXTENDS SW TO 29N49W. SCATTERED SHOWERS AND POSSIBLE
ISOLATED TSTMS ARE WITHIN 75 NM EITHER SIDE OF THE FRONT. TO THE
SE OF THE FRONT A SURFACE TROUGH IS ANALYZED ALONG 24N39W TO
17N36W. A 1012 MB LOW IS EMBEDDED ALONG THE TROUGH NEAR 20N38W.
SCATTERED SHOWERS ARE MAINLY N OF THE LOW CENTER FROM 20N-24N
BETWEEN 34W-38W. ACROSS THE TROPICAL ATLC...AN UPPER LEVEL
ANTICYCLONIC CIRCULATION IS CENTERED NW OF TROPICAL STORM FRED
NEAR 15N32W.

$$
HUFFMAN





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