[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 171058
TWDAT

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

...SPECIAL FEATURES...

TROPICAL STORM BERTHA IS CENTERED NEAR 34.5N 59.2W AT 17/0900
UTC MOVING SE AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 997
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 KEEP BERTHA ABLE TO
MAINTAIN ITS INTENSITY FOR THE NEXT COUPLE DAYS BEFORE THE
SYSTEM BEGINS EXTRATROPICAL TRANSITION. THEREAFTER BERTHA IS
EXPECTED TO ACCELERATE NORTHEASTWARD AS UPPER LEVEL SHEAR
INCREASES. THE CYCLONE IS PRODUCING VERY LITTLE IN THE WAY OF
DEEP CONVECTION WITH ONLY A SMALL AREA OF SCATTERED MODERATE
SHOWERS AND TSTMS WITHIN 90 NM OF THE CENTER IN THE EASTERN
SEMICIRCLE. OTHER SCATTERED MODERATE SHOWERS WITH POSSIBLE
EMBEDDED TSTMS ARE ROTATING AROUND AN UPPER LEVEL LOW NEAR
37N50W.

TROPICAL WAVE IS ALONG 62W/63W S OF 19N MOVING W NEAR 20 KT WITH
A 1009 MB LOW ANALYZED ALONG THE AXIS NEAR 12N. THIS WAVE WILL
POSSIBLY BE INVESTIGATED LATER TODAY BY AN AIR FORCE
RECONNAISSANCE AIRCRAFT. CONDITIONS IN THE ERN 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 SRN WINDWARD ISLANDS...INCLUDING THE ABC ISLANDS...
OVER THE NEXT DAY OR SO. SCATTERED MODERATE CONVECTION IS FROM
10N-14N BETWEEN 62W-67W WITH SCATTERED/LOCALLY HEAVY SHOWERS
CONTINUING ACROSS THE WINDWARD ISLANDS AND NERN VENEZUELA.

TROPICAL WAVE IS ALONG 81W/82W S OF 22N MOVING W 15-20 KT WITH A
1011 MB LOW ANALYZED ALONG THE AXIS NEAR 12N. ALTHOUGH THE
CONVECTIVE ACTIVITY IS CURRENTLY POORLY ORGANIZED AND COVERS
MUCH OF THE WRN CARIBBEAN...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
20N BETWEEN 75W-84W.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 42W 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 NO ASSOCIATED SHOWER CLUSTERS.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N14W 7N24W 11N34W 11N41W 10N44W
7N53W 10N61W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM
4N-11N BETWEEN 14W-21W. SCATTERED MODERATE CONVECTION IS FROM
4N-7N BETWEEN 26W-33W. SIMILAR CONVECTION IS FROM 7N-10N BETWEEN
48W-52W.

...DISCUSSION...

GULF OF MEXICO...
A 1015 MB LOW IS INLAND OVER EAST CENTRAL FLORIDA WITH A SURFACE
TROUGH EXTENDING SW TO SARASOTA FLORIDA AND INTO THE ERN GULF
NEAR 27N84W. THIS SYSTEM IS NOT EXPECTED TO DEVELOP BUT AN AREA
OF SCATTERED SHOWERS WITH EMBEDDED THUNDERSTORMS ARE OVER THE
CENTRAL FLORIDA PENINSULA AND AN AREA WITHIN 90 NM OFFSHORE OF
FORT MYERS FLORIDA. 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 WSW TO 25N93W. AN UPPER RIDGE EXTENDS FROM MEXICO E INTO
THE FAR 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 24N-27N BETWEEN 91W-96W. OTHERWISE
THE REMAINDER OF THE GULF REMAINS TRANQUIL WITH LIGHT WINDS
CIRCULATING AROUND A WEAK 1019 MB SURFACE HIGH PRESSURE CENTERED
NEAR 26N92W.

CARIBBEAN SEA...
THE FOCUS FOR THE CARIBBEAN SEA REMAINS THE TWO WELL-DEFINED
TROPICAL WAVES WITHIN THE BASIN...THE TROPICAL WAVE ALONG
81W/82W...AND THE SE CARIBBEAN WITH THE APPROACHING TROPICAL
WAVE ALONG 62W/63W. SEE SPECIAL FEATURES ABOVE. AN UPPER RIDGE IS
S OF PUERTO RICO COVERING THE ERN CARIBBEAN AND IS ANCHORED ON
AN UPPER HIGH IN THE CENTRAL CARIBBEAN NEAR 15N73W. ANOTHER
UPPER LEVEL HIGH IS ACROSS THE NW CARIBBEAN NEAR 18N83W AND IS
AIDING IN PROVIDING AMPLE UPPER DIFFLUENCE ACROSS A MAJORITY OF
THE BASIN W OF 73W 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. UPPER LEVEL DIFFLUENCE E OF THE TROUGH IS
GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED TSTMS FROM
18N-20N BETWEEN 75W-81W.

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 ASSOCIATED
WITH TROUGHING LOCATED ALONG THE ERN U.S. SEABOARD IS PRODUCING
AN AREA OF SCATTERED MODERATE SHOWERS IN THE W ATLC FROM
29N-32N BETWEEN 73W-80W. AN WEAK RIDGE OF SURFACE HIGH PRESSURE
IS LOCATED S OF T.S. BERTHA WITH AXIS ALONG 23N60W 25N70W TO
ABACO ISLAND IN THE NW BAHAMAS. A DEEP LAYERED LOW IS TO THE E
OF BERTHA AND N OF THE REGION NEAR 37N50W WITH THE UPPER TROUGH
EXTENDING S INTO THE REGION TO 26N BETWEEN 42W-52W WITH A
SURFACE TROUGH EXTENDING THROUGH 32N51W TO 28N54W. BROAD UPPER
HIGH COVERS THE ERN ATLC CENTERED NEAR 30N33W. A SURFACE RIDGE
COVERS THE ERN ATLC E OF 43W FROM A 1034 MB HIGH N OF THE
AZORES.

$$
HUFFMAN




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