[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 170600
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU JUL 17 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...

TROPICAL STORM BERTHA IS CENTERED NEAR 35.4N 59.8W AT 17/0300
UTC MOVING SE AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 995
MB. MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT.
PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT2/WTNT22 KNHC AND THE PUBLIC ADVISORY UNDER
MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS. BERTHA IS MAINTAINING
TROPICAL STORM STRENGTH AND LARGE-SCALE GUIDANCE SUGGESTS THAT
THE ENVIRONMENT AROUND THE STORM SHOULD BE FAVORABLE ENOUGH TO
MAINTAIN THE INTENSITY FOR A DAY OR SO. THEREAFTER GRADUAL
WEAKENING IS EXPECTED AS OCEAN WATERS COOL AND UPPER LEVEL SHEAR
INCREASES. THE CYCLONE IS PRODUCING VERY LITTLE IN THE WAY OF
DEEP CONVECTION WITH A BROAD AREA OF SCATTERED SHOWERS FROM
33N-37N BETWEEN 57W-63W AND SE OF THE CENTER FROM WITHIN 120 NM
OF LINE FROM 30N50W TO 34N56W.

TROPICAL WAVE IS ALONG 60W S OF 17N MOVING W NEAR 20 KT WITH A
1009 MB LOW ANALYZED ALONG THE AXIS NEAR 12N. THIS WAVE WAS
INVESTIGATED BY AN AIR FORCE RECONNAISSANCE AIRCRAFT AND FOUND
A BROAD AREA OF LOW PRESSURE BUT NO WELL DEFINED CIRCULATION
CENTER. HOWEVER CONDITIONS IN THE E CARIBBEAN ARE CONDUCIVE FOR
FURTHER DEVELOPMENT AND IT COULD BECOME A TROPICAL DEPRESSION
LATER TODAY OR TOMORROW. REGARDLESS OF DEVELOPMENT...THE SYSTEM
IS EXPECTED TO BRING GUSTY WINDS AND LOCALLY HEAVY RAINS TO THE
WINDWARD ISLANDS OVER THE NEXT DAY OR SO. SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION IS FROM 11N-15N BETWEEN 61W-65W WITH
SCATTERED/LOCALLY HEAVY SHOWERS CONTINUING ACROSS THE WINDWARD
ISLANDS.

TROPICAL WAVE IS ALONG 80W S OF 21N MOVING W 15-20 KT. ALTHOUGH
THE CONVECTIVE ACTIVITY IS CURRENTLY POORLY ORGANIZED THE UPPER
LEVEL WINDS ARE FAVORABLE FOR DEVELOPMENT AND THIS COULD BECOME
A TROPICAL DEPRESSION BEFORE MOVING INTO CENTRAL AMERICA DURING
THE NEXT DAY OR SO. HEAVY RAINS AND GUSTY WINDS ARE LIKELY TO
MOVE OVER PORTIONS OF NICARAGUA AND HONDURAS TODAY AND TOMORROW
...WITH FLASH FLOODING AND MUDSLIDES POSSIBLE...ESPECIALLY IN THE
HIGHER TERRAIN. BROAD AREA OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS S OF 21N BETWEEN 74W-84W INCLUDING THE NW COAST OF
COLOMBIA THROUGH PANAMA INTO NICARAGUA AND HONDURAS. SCATTERED
MODERATE CONVECTION IS ALSO ACROSS HAITI...ERN CUBA AND THE
WINDWARD PASSAGE.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 40W S OF 18N MOVING W 15-20 KT. BROAD
INVERTED-V CURVATURE IS OBSERVED ON SATELLITE IMAGERY WITH NO
ASSOCIATED DEEP CONVECTION. WAVE IS MOVING INTO AN AREA OF DRIER
UPPER LEVEL AIR THUS ONLY A SMALL AREA OF SCATTERED MODERATE
SHOWERS IS WITHIN 60 NM OF THE POINT 14N38W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N12W 6N30W 4N40W 11N57W. SCATTERED
TO NUMEROUS STRONG CONVECTION IS FROM 4N-10N BETWEEN 11W-21W.
SCATTERED MODERATE CONVECTION IS FROM 5N-8N BETWEEN 51W-55W.

...DISCUSSION...

GULF OF MEXICO...
A 1015 MB LOW IS INLAND OVER EAST CENTRAL FLORIDA WITH A SURFACE
TROUGH EXTENDING SW TO JUST NORTH OF FORT MYERS FLORIDA. THIS
SYSTEM IS NOT EXPECTED TO DEVELOP BUT A LINE OF SCATTERED
SHOWERS WITH EMBEDDED THUNDERSTORMS ARE OVER THE CENTRAL FLORIDA
PENINSULA. A DEEP LAYERED TROUGH IS OFFSHORE THE NE U.S. SEABOARD
AND EXTENDS INTO THE NW ATLC. IT IS GRADUALLY MOVING NW OF THE
DISCUSSION AREA BUT A CUTOFF UPPER LOW REMAINS ACROSS THE NORTH
CENTRAL GULF EXTENDING FROM NEAR PENSACOLA FLORIDA S TO 25N92W.
AN UPPER RIDGE EXTENDS FROM MEXICO E INTO THE WRN GULF TO NEAR
THE YUCATAN PENINSULA. THIS FEATURE IS PROVIDING DIFFLUENCE
ALOFT TO GENERATE AN AREA OF SCATTERED SHOWERS IN THE WRN GULF
FROM 23N-26N BETWEEN 91W-95W. OTHERWISE THE REMAINDER OF THE
GULF REMAINS TRANQUIL WITH LIGHT WINDS CIRCULATING AROUND A WEAK
1018 MB SURFACE HIGH PRESSURE CENTERED NEAR 27N90W.

CARIBBEAN SEA...
THE FOCUS FOR THE CARIBBEAN SEA REMAINS THE TWO WELL-DEFINED
TROPICAL WAVES WITHIN THE BASIN...THE TROPICAL WAVE ALONG 80W...
AND THE SE CARIBBEAN WITH THE APPROACHING TROPICAL WAVE ALONG
60W. SEE SPECIAL FEATURES ABOVE. AN UPPER HIGH IS S OF PUERTO
RICO COVERING THE ERN CARIBBEAN AND INTO THE W TROPICAL ATLC NE
OF THE LEEWARD ISLANDS. ANOTHER UPPER LEVEL RIDGE IS ACROSS THE
CENTRAL CARIBBEAN NEAR 15N73W EXTENDING INTO THE NW CARIBBEAN
AND IS AIDING IN PROVIDING AMPLE UPPER DIFFLUENCE ACROSS A
MAJORITY OF THE BASIN W OF 72W TO SUPPORT CONVECTIVE SHOWERS AND
TSTMS ASSOCIATED WITH THE TROPICAL WAVES. UPPER LEVEL TROUGHING
EXTENDS FROM THE W ATLC ACROSS THE SE BAHAMAS...ERN CUBA AND THE
WINDWARD PASSAGE AND IS GENERATING ADDITIONAL SUPPORT FOR
SCATTERED SHOWERS AND TSTMS FROM 17N-21N BETWEEN 73W-79W.

ATLANTIC OCEAN...
A 1015 MB LOW IS INLAND OVER EAST CENTRAL FLORIDA WITH A SURFACE
TROUGH EXTENDING SW INTO THE ERN GULF OF MEXICO. THIS SYSTEM IS
NOT EXPECTED TO DEVELOP BUT AN AREA OF SCATTERED SHOWERS WITH
EMBEDDED THUNDERSTORMS ARE OVER THE CENTRAL FLORIDA PENINSULA.
THIS SURFACE LOW ALONG WITH UPPER LEVEL DIFFLUENCE IS PRODUCING
AN AREA OF SCATTERED SHOWERS AND TSTMS IN THE W ATLC FROM
28N-32N BETWEEN 74W-78W. AN AREA OF SURFACE HIGH PRESSURE IS
LOCATED S OF T.S. BERTHA CENTERED BY A 1021 MB HIGH NEAR 27N65W.
A DEEP LAYERED LOW IS TO THE E OF BERTHA AND N OF THE REGION
NEAR 35N50W WITH THE UPPER TROUGH EXTENDING S INTO THE REGION TO
15N BETWEEN 43W-57W WITH A SURFACE TROUGH EXTENDING THROUGH
32N52W TO 26N55W. BROAD UPPER HIGH COVERS THE ERN ATLC CENTERED
NEAR 30N31W. A SURFACE RIDGE COVERS THE ERN ATLC E OF 43W FROM A
1037 MB HIGH N OF THE AZORES.

$$
HUFFMAN


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