[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 071750
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN SEP 07 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.

...SPECIAL FEATURES...

HURRICANE IKE IS CENTERED NEAR 20.9N 74.0W AT 07/1800 UTC OR
JUST W OF GREAT INAGUA ISLAND AND ABOUT 78 NM EAST-NORTHEAST OF
GUANTANAMO CUBA MOVING W AT 11 KT. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 949 MB. MAXIMUM SUSTAINED WIND SPEED IS 115 KT WITH
GUSTS TO 140 KT. PLEASE SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. IKE IS
AN EXTREMELY DANGEROUS CATEGORY FOUR HURRICANE ON THE
SAFFIR-SIMPSON SCALE. FLUCTUATIONS IN STRENGTH ARE POSSIBLE
TODAY AND TONIGHT BUT IKE IS EXPECTED TO REMAIN A MAJOR
HURRICANE AS IT APPROACHES E CUBA THEN WEAKEN AS IT MOVES OVER E
AND CENTRAL CUBA ON MON. THE INTENSITY FORECAST AS IT MOVES INTO
THE GULF OF MEXICO IS DEPENDANT ON THE LENGTH OF TIME IKE
REMAINS INLAND OVER CUBA. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 60 NM OF THE CENTER IN THE W SEMICIRCLE AND
WITHIN 90 NM OF THE CENTER IN THE E SEMICIRCLE. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS COVER THE REMAINDER OF THE AREA
FROM 18N-23N BETWEEN 72W-75W WITH CLUSTERS OF SIMILAR ACTIVITY
IN THE OUTER RAINS FROM 17N-24N BETWEEN 65W-76W INCLUDING THE
ISLANDS BETWEEN PUERTO RICO AND CUBA.

...TROPICAL WAVES...

TROPICAL WAVE IS W OF THE CAPE VERDE ISLANDS ALONG 36W S OF 13N
MOVING W NEAR 15 KT. WAVE IS AT THE LEADING EDGE OF A SURGE OF
AFRICAN DUST AND IS NOW LOW AMPLITUDE DUE TO THE REMNANTS OF
JOSEPHINE. ANY ACTIVITY IS ASSOCIATED WITH THE ITCZ.

TROPICAL WAVE WAS REPOSITIONED ALONG 65W S OF 15N MOVING W NEAR
15 KT BASED ON UPPER AIR DATA FROM THE WINDWARD ISLANDS OVER THE
PAST FEW DAYS AND IS EMBEDDED WITHIN AN AREA OF DEEP LAYERED
MOISTURE AS INDICATED BY MIMIC-TPW. MOST OF THIS WAVES ENERGY
WAS DISPLACED SEVERAL DAYS IN THE DEVELOPMENT OF WHAT IS NOW
HURRICANE IKE. SCATTERED SHOWERS/AND POSSIBLE ISOLATED
THUNDERSTORMS ARE S OF 14N E OF 66W AND IS COMBINED WITH
CONVECTION ASSOCIATED WITH THE ITCZ.

...THE ITCZ...

THE ITCZ AXIS IS ANALYZED ALONG 13N16W 6N29W 10N38W 10N46W
13N55W 11N62W. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION
ARE FROM 10N-14N BETWEEN 58W-64W INCLUDING THE WINDWARD ISLANDS.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM OF
A LINE FROM 8N27W TO 5N34W AND WITHIN 90 NM N OF THE ITCZ FROM
53W-56W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER LONGWAVE TROUGH IS OVER THE E US TO THE N GULF
COAST WITH THE ASSOCIATED FRONTAL BOUNDARY ENTERING THE GULF
NEAR PENSACOLA FLORIDA SW TO 27N91W THEN RETURNING N AS A WARM
TO NEAR CORPUS CHRISTI TEXAS. SCATTERED SHOWERS WITH POSSIBLE
ISOLATED THUNDERSTORMS ARE WITHIN 75 NM N OF THE WARM FRONT. AN
UPPER LEVEL RIDE IS DEVELOPING OVER THE SW GULF AND THE BAY OF
CAMPECHE EXTENDING E N OF THE YUCATAN PENINSULA TO N OF W CUBA
TO NEAR 24N83W. A SURFACE TROUGH EXTENDS FROM S MEXICO IN THE
BAY OF CAMPECHE NEAR 17N93W TO 23N94W. UPPER LEVEL DIFFLUENCE IS
GENERATING SCATTERED SHOWERS/THUNDERSTORMS S OF A LINE 25N83W TO
24N95W INCLUDING W CUBA AND THE YUCATAN CHANNEL TO THE COAST OF
THE YUCATAN PENINSULA WITH SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS S OF 24N W OF 92W TO INLAND OVER MEXICO. THE
REMAINDER OF THE GULF IS CLEAR THIS AFTERNOON.

CARIBBEAN SEA...
HURRICANE IKE CONTINUES TO GENERATE SHOWERS/THUNDERSTORMS OVER
THE N CENTRAL CARIBBEAN AS IT TRACKS ACROSS THE TURKS AND CAICOS
EXPECTING TO MAKE LANDFALL OVER CUBA LATE TONIGHT/MON
MORNING...SEE SPECIAL FEATURES ABOVE. NE TO E UPPER LEVEL FLOW
DOMINATES THE CARIBBEAN. THE UPPER RIDGE ASSOCIATED WITH
HURRICANE IKE IS DRAWING A SWATH OF DRY AIR E OF THE SYSTEM
ACROSS CENTRAL CUBA AND JAMAICA. UPPER DIFFLUENCE IS GENERATING
A NARROW BAND IF SCATTERED SHOWERS/THUNDERSTORMS WITHIN 30/45 NM
OF LINE FROM 21N80W ACROSS CUBA INTO THE FLORIDA STRAITS NEAR
25N79.5W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 10N
W OF 80W TO INLAND OVER PANAMA AND TO THE COAST OF COSTA RICA.
THE ACTIVITY OVER THE E CARIBBEAN IS ASSOCIATED WITH THE ITCZ
AND THE TROPICAL WAVE. STRONG SUBSIDENCE/DRY AIR ARE ACROSS THE
REMAINDER OF THE CARIBBEAN RESULTING IN TRANQUIL WEATHER THIS
AFTERNOON.

ATLANTIC OCEAN...
HURRICANE IKE CONTINUES TO BE THE MAIN CONCERN THIS AFTERNOON AS
WELL AS FOR THE NEXT FEW DAYS AS IT TRACKS TOWARD CUBA AND
EVENTUALLY INTO THE GULF OF MEXICO...SEE SPECIAL FEATURES ABOVE.
A BROAD UPPER RIDGE ASSOCIATED WITH HURRICANE IKE COVERS THE W
ATLC RESULTING IN OUTFLOW WITHIN 200 NM W OF THE CENTER AND 600
NM TO THE E. AN UPPER TROUGH THAT HAS BEEN CUTOFF FROM THE SHEAR
AXIS THAT DID EXTEND FROM THE E ATLC IS CONFINED TO THE CENTRAL
ATLC EXTENDING AN AXIS FROM 30N41W THROUGH A WEAK UPPER LOW NEAR
26N46W TO A LARGER UPPER LOW NEAR 21N54W CONTINUING W TO THE
LEEWARD ISLANDS NEAR 18N62W. THIS UPPER TROUGH IS ENHANCING THE
ACTIVITY ASSOCIATED WITH THE ITCZ THAT IS OVER THE WINDWARD
ISLANDS. THE REMNANT OF JOSEPHINE...A 1010 MB LOW IS CENTERED
NEAR 17N41W WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION
NW OF THE CENTER FROM 17N-21N BETWEEN 40W-44W. AN E/W UPPER
RIDGE EXTENDS FROM W AFRICA ALONG 21N/22N TO 40W AND S OF 28N.
ALSO AT THE SURFACE IS A BROAD RIDGE THAT COVERS THE AREA N OF
25N BETWEEN 30W-65W ANCHORED N OF THE REGION BY A 1025 MB HIGH.
SURGE OF AFRICAN DUST COVERS THE E TROPICAL ATLC S OF 24N E OF
THE TROPICAL WAVE.

$$
WALLACE




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