[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 240552
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN AUG 24 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...
FAY WAS DOWNGRADED TO A TROPICAL DEPRESSION AT 24/0300 UTC AND
THE LAST FORECAST/ADVISORY WAS ISSUED BY THE NATIONAL HURRICANE
CENTER ON THIS SYSTEM AT THAT TIME. HOWEVER...HEAVY RAINS AND
FLOODING ASSOCIATED WITH FAY COULD CONTINUE FOR SEVERAL DAYS.
T.D. FAY IS CENTERED NEAR 30.9N 87.1W AT 24/0300 UTC MOVING
WEST-NORTHWEST AT 7 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE
IS 999 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 30 KT WITH
GUSTS TO 40 KT. PLEASE READ THE LATEST NHC FORECAST/ ADVISORY
UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC AND THE PUBLIC
ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC FOR MORE
DETAILS. THIS SLOW-MOVING SYSTEM WILL CONTINUE TO POSE A
SIGNIFICANT RAINFALL AND FLOODING HAZARD FOR SEVERAL DAYS TO
COME...ALONG THE NORTHERN GULF COAST AND ADJACENT AREAS WELL
INLAND. FAY IS EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS
OF 6 TO 12 INCHES ACROSS THE EXTREME WESTERN PORTION OF THE
NORTHERN FLORIDA PENINSULA...THE FLORIDA PANHANDLE...
SOUTHWESTERN GEORGIA...THE SOUTHERN AND CENTRAL PORTIONS OF
MISSISSIPPI AND ALABAMA...AND EASTERN LOUISIANA...WITH ISOLATED
MAXIMUM AMOUNTS OF 20 INCHES POSSIBLE.  ADDITIONAL RAINFALL
ACCUMULATIONS OF 1 TO 2 INCHES ARE POSSIBLE OVER THE REMAINDER
OF THE FLORIDA PENINSULA AND SOUTHEASTERN GEORGIA. ISOLATED
TORNADOES ARE POSSIBLE TONIGHT AND SUNDAY IN PORTIONS OF THE
FLORIDA PANHANDLE...WESTERN GEORGIA...AND SOUTHERN AND CENTRAL
ALABAMA. PRESENTLY MOST HEAVY PRECIPITATION IS N OF THE CENTER
IN RAIN BANDS AFFECTING MAINLY SW GEORGIA AND CENTRAL ALABAMA.

...TROPICAL WAVES...
A TROPICAL WAVE IS JUST WEST OF THE CAPE VERDE ISLANDS ALONG
25W/26W MOVING WEST AT 10-15 KT. SATELLITE DERIVED WINDS
INDICATE THAT A BROAD AREA OF CYCLONIC TURNING IS ALONG THE WAVE
AXIS NEAR 12N WITH A CLUSTER OF MODERATE TO ISOLATED STRONG
CONVECTION.

A TROPICAL WAVE IS ALONG 50W S OF 24N. A 1012 MB LOW IS ON THE
WAVE AXIS NEAR 21N50W PRODUCING SEVERAL SMALL CLUSTERS OF
MODERATE CONVECTION FROM 20N-24N BETWEEN 46W-55W. UPPER-LEVEL
WINDS ARE FORECAST TO GRADUALLY BECOME LESS CONDUCIVE...BUT SOME
SLOW DEVELOPMENT OF THIS DISTURBANCE IS STILL POSSIBLE DURING
THE NEXT COUPLE OF DAYS AS IT MOVES W-NW OR NW AT 10-15 KT.

A TROPICAL WAVE OVER THE EASTERN CARIBBEAN ALONG 66W PAIRED WITH
A 1008 MB LOW PRESSURE LOCATED BETWEEN BARBADOS AND TRINIDAD IS
PRODUCING A LARGE BUT DISORGANIZED AREA OF SHOWERS AND TSTMS
OVER THE WINDWARD ISLANDS AND THE E CARIBBEAN SEA SOUTH OF 15N.
ATMOSPHERIC CONDITIONS APPEAR CONDUCIVE FOR SOME SLOW
DEVELOPMENT OF THIS SYSTEM DURING THE NEXT COUPLE OF DAYS AS IT
MOVES GENERALLY WESTWARD AT 10 TO 15 MPH OVER THE EASTERN
CARIBBEAN SEA. THIS WAVE WILL CONTINUE TO PRODUCE SQUALLY
WEATHER OVER PORTIONS OF THE WINDWARD AND SOUTHERN LEEWARD
ISLANDS TONIGHT AND SUNDAY.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 18N16W 9N33W 13N46 12N58W.
BESIDES THE CONVECTION MENTIONED ON THE TROPICAL WAVE
SECTION...SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS
FROM 7N-12N EAST OF 19W TO THE COAST OF W AFRICA. SCATTERED
MODERATE CONVECTION IS NEAR 8.5N30W.

...DISCUSSION...

THE GULF OF MEXICO...
FAY WEAKENED TO A DEPRESSION AT 0300 UTC. ALL TROPICAL STORM
WARNINGS ALONG THE NORTHEASTERN GULF OF MEXICO COAST WERE
DISCONTINUED...BUT HEAVY RAINS AND FLOODING COULD CONTINUE.
SEE SPECIAL FEATURES ABOVE. AN UPPER-LEVEL HIGH ANCHORED OVER NE
MEXICO DOMINATES THE WESTERN HALF OF THE GULF AND IS HELPING TO
INDUCE SCATTERED SHOWERS AND TSTMS OVER E MEXICO N OF 20N E OF
100W. THERE IS AN NARROW UPPER LEVEL TROUGH ALONG THE CENTRAL
GULF WHILE A SECOND UPPER-LEVEL HIGH CENTERED OVER WESTERN CUBA
EXTENDS A RIDGE NWD ACROSS THE E GULF AND THE FLORIDA PENINSULA.
A COUPLE OF RAINBANDS ASSOCIATED WITH T.D. FAY ARE SEEN OVER THE
NE QUADRANT OF THE GULF REGION. AT THE SURFACE...WINDS OF 15 TO
20 KT ASSOCIATED WITH THE CYCLONIC CIRCULATION OF FAY ARE
AFFECTING THE NORTHERN GULF WATERS E OF 90W AND N OF 27N. MAINLY
LIGHT WINDS ARE SEEN ACROSS THE REMAINDER OF THE AREA. A WEAK
SFC TROUGH IS ANALYZED OVER THE YUCATAN PENINSULA AT 0300
UTC.

THE CARIBBEAN SEA...
A TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN GENERATING A LARGE
BUT DISORGANIZED AREA OF SHOWERS AND THUNDERSTORMS...AND SURFACE
OBSERVATIONS SUGGEST THAT A BROAD SURFACE CIRCULATION COULD BE
FORMING OVER THE SE CARIBBEAN. PRES ARE FALLING 2 MB OVER THAT
AREA. WINDS ARE EXPECTED TO INCREASE TO 15-20 KT OVER THE
EASTERN CARIBBEAN TODAY THROUGH MON DUE TO THE PRESENCE OF THE
TROPICAL WAVE/LOW. SEE TROPICAL WAVE SECTION. AN UPPER-LEVEL
TROUGH ENTERS THE CARIBBEAN SEA THROUGH THE MONA PASSAGE THEN
CONTINUES TO N COLOMBIA.THIS TROUGH IS LIKELY PRODUCING AN AREA
OF SHOWERS AND TSTMS JUST SOUTH OF DOMINICAN REPUBLIC. THE
UPPER-LEVEL HIGH LOCATED OVER W CUBA COVERS MOST OF THE CENTRAL
AND WESTERN CARIBBEAN GIVING THE AREA ELY UPPER LEVEL FLOW. A
SECOND UPPER-LEVEL RIDGE ANCHORED OVER THE CENTRAL ATLC
DOMINATES THE E CARIBBEAN AND IS SUPPORTING THE CONVECTION
ASSOCIATED WITH THE TROPICAL WAVE.

THE ATLANTIC OCEAN...
THE SUBTROPICAL RIDGE ENVELOPS THE FORECAST AREA PRODUCING
MOSTLY EASTERLY SURFACE FLOW OVER THE ATLANTIC OCEAN FROM
23N-32N BETWEEN W AFRICA AND 80W. TIGHT PRES GRADIENT BETWEEN
THE SFC HIGH AND LOWER PRES OVER AFRICA IS PRODUCING A SWATH OF
MODERATE TO STRONG NELY WINDS BETWEEN THE MADEIRA/CANARY ISLANDS
AND THE AFRICAN COAST.
IN THE UPPER LEVELS...A TROUGH/RIDGE/TROUGH PATTERN DOMINATES
THE REGION WITH A COUPLE OF UPPER-LEVEL LOWS LOCATED NEAR 34N70W
AND OVER THE E ATLC NEAR 28N29W. THE CENTRAL ATLC IS UNDER THE
INFLUENCE OF AN UPPER-LEVEL HIGH THAT EXTENDS A RIDGE SOUTH OVER
THE N TROPICAL ATLC AND THE E CARIBBEAN.

$$
GR


This weather bulletin was brought to you by:
www.nashvilleweather.net