[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081104
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...

TROPICAL STORM FRED IS CENTERED NEAR 11.8N 27.3W AT 08/0900 UTC
OR ABOUT 245 NM SW OF THE SOUTHERNMOST CAPE VERDE ISLANDS MOVING
W AT 13 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB.
MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT.
SCATTERED MODERATE TO STRONG CONVECTION IS FROM 9N-14N BETWEEN
25W-30W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 58W S OF 23N 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 53W-59W. AS
THE WAVE MOVES BENEATH A MODERATELY SUBSIDENT ATMOSPHERE AS
NOTED ON WATER VAPOR IMAGERY...ONLY ISOLATED SHOWERS AND TSTMS
ARE WITHIN 90 NM EITHER SIDE OF A LINE FROM 20N53W TO 16N62W.

TROPICAL WAVE IS ALONG 77W S OF 19N 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 15N17W 14N23W 8N29W 5N40W
10N57W. BESIDES THE CONVECTION ASSOCIATED WITH TROPICAL STORM
FRED AND THE TROPICAL WAVE ALONG 58W...SCATTERED MODERATE
CONVECTION IS ALONG THE W AFRICA COAST FROM 8N-19N BETWEEN
12W-18W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 4N-7N
BETWEEN 30W-38W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED IN THE BAY
OF CAMPECHE NEAR 19N95W 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 A SURFACE RIDGE THAT EXTENDS FROM THE SE
CONUS THROUGH 25N90W TO NEAR TUXPAN MEXICO. UPPER LEVEL
DIFFLUENCE IN ASSOCIATION WITH THE UPPER LEVEL RIDGE IS
GENERATING ENOUGH ATMOSPHERIC LIFT FOR ISOLATED SHOWERS ACROSS
THE WRN GULF FROM 23N-28N W OF 88W. SCATTERED SHOWERS ARE TSTMS
ARE ALSO OCCURRING OVER THE BAY OF CAMPECHE S OF 21N BETWEEN
91W-99W...INCLUDING PORTIONS OF INTERIOR SRN MEXICO.

CARIBBEAN SEA...
A TROPICAL WAVE IS ALONG 77W WITH NO SIGNIFICANT CONVECTION
ASSOCIATED WITH THE WAVE OVER THE WRN CARIBBEAN. AN UPPER LEVEL
TROUGH DIPS SW FROM A SW NORTH ATLC UPPER LOW CENTERED NEAR
25N68W ACROSS HISPANIOLA TO NEAR COASTAL COSTA RICA. 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 CONTINUE
S OF CUBA AND ARE LOCATED FROM 18N-22N BETWEEN 77W-82W. 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 14N E OF 70W. ALSO WITH THE APPROACH OF THE TROPICAL
WAVE ALONG 58W...EXPECT SHOWERS TO INCREASE IN COVERAGE ACROSS
THE LEEWARD ISLANDS OVER THE NEXT 12-24 HOURS.

ATLANTIC OCEAN...
A SURFACE TROUGH ENTERS THE DISCUSSION AREA NEAR 32N77W AND
EXTENDS SSW TO NEAR WEST PALM BEACH FLORIDA. ISOLATED SHOWERS
ARE WITHIN 150 NM TO THE E OF THE SURFACE TROUGH. FARTHER TO THE
E...AN UPPER LEVEL LOW IS CENTERED NEAR 25N68W AND IS GENERATING
AN AREA OF SCATTERED SHOWERS FROM 20N-30N BETWEEN 63W-74W. INTO
THE CENTRAL ATLC...A COLD FRONT DIPS INTO THE DISCUSSION AREA
NEAR 32N39W AND EXTENDS SW TO 29N51W. SCATTERED SHOWERS AND
POSSIBLE ISOLATED TSTMS ARE WITHIN 90 NM EITHER SIDE OF THE
FRONT. TO THE SE OF THE FRONT...A SURFACE TROUGH IS ANALYZED
ALONG 25N37W TO 18N38W. A 1012 MB LOW IS EMBEDDED ALONG THE
TROUGH NEAR 20N38W. SCATTERED SHOWERS ARE MAINLY N OF THE LOW
CENTER FROM 21N-26N BETWEEN 33W-39W. ACROSS THE TROPICAL ERN
ATLC...AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NW OF
TROPICAL STORM FRED NEAR 16N33W.

$$
HUFFMAN



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