[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 161748
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI AUG 15 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...
TROPICAL STORM FAY IS CENTERED NEAR 19.2N 74.9W OR ABOUT 45 NM
SOUTH-SOUTHEAST OF GUANTANAMO CUBA AND ABOUT 150 NM
WEST-NORTHWEST OF PORT AU PRINCE HAITI...AT 16/1800 UTC MOVING W
AT 13 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. MAXIMUM
SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. PLEASE SEE
THE LATEST NHC THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT1/WTNT21 KNHC AND PUBLIC ADVISORY UNDER AWIPS/WMO
HEADERS MIATCPAT1/WTNT31 KNHC FOR MORE DETAILS. SCATTERED/HEAVY
SHOWERS WITH EMBEDDED THUNDERSTORMS COVERS THE AREA FROM 15N-23N
BETWEEN 69W-77W. BROAD UPPER HIGH IS LOCATED OVER FAY COVERING
THE CENTRAL CARIBBEAN FROM THE COAST OF SOUTH AMERICA ACROSS THE
BAHAMA ISLANDS TO 26N BETWEEN 64W-80W INCLUDING THE VIRGIN
ISLANDS. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS
ENROUTE TO INVESTIGATE FAY TO PROVIDE BETTER DATA ON THE
INTENSITY/STRUCTURE AND WILL BE ARRIVING SHORTLY. FAY IS
EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS OF 4 TO 8
INCHES OVER HISPANIOLA...EASTERN AND CENTRAL CUBA...JAMAICA...
AND THE NORTHERN CAYMAN ISLANDS...WITH ISOLATED MAXIMUM AMOUNTS
OF 15 INCHES. THESE RAINS COULD PRODUCE LIFE-THREATENING FLASH
FLOODS AND MUD SLIDES.

...TROPICAL WAVES...
TROPICAL WAVE IN THE E TROPICAL ATLC IS ALONG 27W/28W S OF 16N
MOVING W 10-15 KT. BROAD AREA OF DEEP LAYERED MOISTURE IS
INDICATED BY MIMIC-TPW ANIMATION WITH A SMALL AREA OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION 13N-16N BETWEEN 25W-28W.
STRONG EASTERLY UPPER FLOW IS LIMITING CONVECTION.

TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC IS TILTED FROM 25N51W
ALONG 17N53W TO 8N57W MOVING NW 10-15 KT. WAVE AXIS IS BEING
DISTORTED BY A STRONG UPPER LOW TO THE W OF THE WAVE AXIS AND
DISPLACING CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION FROM 20N-25N BETWEEN 48W-53W WITH SMALL CLUSTERS OF
SCATTERED MODERATE CONVECTION WITHIN 60 NM OF LINE FROM 19N51W
TO 12N60W.

...THE ITCZ...
THE ITCZ IS CENTERED ALONG 16N16W 13N22W 8N37W 12N53W 10N62W.
SCATTERED MODERATE/STRONG CONVECTION IS FROM 11N-14N E OF 19W TO
JUST INLAND OVER SOUTHERN SENEGAL.

...DISCUSSION...

GULF OF MEXICO...
THE BROAD UPPER TROUGH REMAINS OVER THE E U.S. TO THE N GULF
COAST INTO THE W ATLC WITH ASSOCIATED FRONTAL BOUNDARY JUST
INLAND EXTENDING FROM SW GEORGIA ACROSS PENSACOLA FLORIDA W TO
OVER NEW ORLEANS LOUISIANA TO OVER TEXAS. HOWEVER...MOST OF THE
ASSOCIATED ACTIVITY IS IN THE GULF WATERS. SCATTERED/HEAVY
SHOWERS WITH EMBEDDED THUNDERSTORMS ARE N OF 28N W OF 84W TO
JUST INLAND OVER TEXAS WITH SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS INLAND OVER THE N GULF COAST AND N OF 27N E OF 84W
TO INLAND OVER FLORIDA. THE UPPER LEVEL RIDGE REMAINS ACROSS THE
GULF BUT IS BEGINNING TO WEAKEN OVER THE E GULF IN RESPONSE TO
THE ENCROACHMENT OF THE UPPER LOW OVER W CUBA AHEAD OF TROPICAL
STORM FAY. THE UPPER RIDGE REMAINS ANCHORED OVER N/CENTRAL
MEXICO AND EXTENDS ALONG 25N TO 84W. WEAKENING SURFACE RIDGE
EXTENDS ACROSS S FLORIDA OVER THE E GULF WITH A 1017 MB HIGH
ALONG THE W COAST OF FLORIDA NEAR TAMPA. A SMALL AREA OF
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE IN THE W BAY OF
CAMPECHE FROM 19N-22N BETWEEN 95W-97W. THE REMAINDER OF THE GULF
REMAINS RATHER CLEAR THIS AFTERNOON WITH SOME ISOLATED
SHOWERS/THUNDERSTORMS POSSIBLE OVER S FLORIDA AND THE FLORIDA
STRAITS ASSOCIATED WITH THE UPPER LOW OVER W CUBA.

CARIBBEAN SEA...
THE PRIMARY CONCERN THIS AFTERNOON AND WILL CONTINUING TO BE
THROUGH MON IS TROPICAL STORM FAY. SEE SPECIAL FEATURES ABOVE.
ELONGATED UPPER LOW IS OVER W CUBA NEAR THE ISLE OF YOUTH
EXTENDING AN UPPER TROUGH SW TO THE N COAST OF HONDURAS NEAR
ROATAN ISLAND AND IS PUSHING W INTO THE FLORIDA STRAITS. BROAD
UPPER HIGH IS LOCATED OVER THE TROPICAL STORM FAY...SEE SPECIAL
FEATURES SECTION ABOVE. THE ITCZ AXIS EXTENDS FROM COLOMBIA
ACROSS PANAMA/COSTA RICA BORDER INTO THE E PACIFIC REGION
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE SW
CARIBBEAN S OF 12N W OF 74W. THE REMAINDER OF THE CARIBBEAN IS
REMARKABLY CLEAR THIS AFTERNOON. FAY IS FORECASTER TO REMAIN IN
THE CARIBBEAN IN THE SHORT-TERM AND CONDITIONS WILL DETERIORATE
AS IT MOVES ALONG THE FORECAST TRACK.

ATLANTIC OCEAN...
THE MAIN CONCERN FOR THE W ATLC THIS AFTERNOON IS TROPICAL STORM
FAY WITH OUTER RAINBANDS CURRENTLY OVER THE TURKS AND CAICOS.
SEE SPECIAL FEATURES ABOVE. THE UPPER TROUGH IS OVER THE E US.
INTO THE W ATLC WITH THE ASSOCIATED FRONTAL BOUNDARY N OF THE
REGION. HOWEVER...SCATTERED SHOWERS WITH EMBEDDED THUNDERSTORMS
ARE N OF WEST PALM BEACH FLORIDA W OF 78W TO INLAND ACROSS THE
FLORIDA PENINSULA. AN ELONGATED UPPER LOW IS OVER W CUBA
EXTENDING AN UPPER TROUGH NE TO OVER THE N BAHAMA ISLANDS. UPPER
HIGH IS OVER TROPICAL STORM FAY..SEE SPECIAL FEATURES ABOVE.
THIS UPPER RIDGE IS PROVIDING ENOUGH UPPER DIFFLUENCE TO
GENERATE A BAND OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
PRECEDING THE OUTER RAIN BANDS OF FAY WITHIN 60 NM OF LINE FROM
26N72W ACROSS THE BAHAMAS NEAR 24N76W TO OVER CUBA NEAR 21N78W.
LARGE UPPER LOW IS IN THE W/CENTRAL ATLC NEAR 24N56W AND IS
TILTING THE TROPICAL WAVE JUST TO THE E. A BENIGN UPPER LOW IS
IN THE E ATLC JUST W OF THE CANARY ISLANDS NEAR 28N20W WITH AN
UPPER HIGH TO THE SW NEAR 24N39W. MODERATE/STRONG SUBSIDENCE AND
SOMEWHAT DRY STABLE AIR COVERS MOST OF THE ATLC BASIN...THUS
FAIR WEATHER CONDITIONS ARE ACROSS THE REMAINDER OF THE ATLC. A
SURFACE RIDGE CONTINUES TO DOMINATE THE ATLC ANCHORED BY A 1016
MB HIGH SW OF THE AZORES AND A 1025 MB HIGH IN THE N/CENTRAL
ATLC EXTENDING A RIDGE AXIS SW THROUGH 32N58W ACROSS FLORIDA TO
OVER THE E GULF OF MEXICO. OUTER RAINBANDS WILL MOVE FROM THE
TURKS AND CAICOS TO OVER THE CENTRAL BAHAMAS AS FAY CONTINUES ON
THE FORECASTER TRACK.

$$
WALLACE


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