[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 160600
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED JUL 16 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 36.8N 61.6W AT 16/0300
UTC OR ABOUT 310 NM NORTH-NORTHEAST OF BERMUDA. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 996 MB. MAXIMUM SUSTAINED WIND SPEED
IS 55 KT WITH GUSTS TO 65 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
APPEARS LIKELY TO BE HEADED FOR A SLOW DEMISE AS IT TRAVERSES
OVER COOLER WATERS AND EXPERIENCES INCREASING SOUTHWESTERLY
SHEAR OVER THE NEXT COUPLE OF DAYS. WIDELY SCATTERED MODERATE
CONVECTION IS WITHIN 120 NM OF THE CENTER WITH A BROADER AREA OF
SCATTERED MODERATE CONVECTION IN THE NORTHWEST QUADRANT FROM
37N-39N BETWEEN 61W-63W.

STRONG TROPICAL WAVE IS ALONG 52W S OF 17N MOVING W NEAR 20 KT
WITH A 1012 MB LOW ANALYZED ALONG THE AXIS NEAR 12N MOVING
ROUGHLY WNW. THE SATELLITE PRESENTATION IS NOT AS WELL DEFINED
AS YESTERDAY BUT MAIN CONVECTIVE ACTIVITY REMAINS ROUGHLY
FOCUSED WITHIN 150 NM OF THE LOW CENTER. CLUSTERS OF SCATTERED
MODERATE CONVECTION ARE FROM 10N-14N BETWEEN 50W-55W. THIS
SYSTEM IS EXPECTED TO BRING GUSTY WINDS AND LOCALLY HEAVY
RAINFALL TO THE WINDWARD ISLANDS OVER THE NEXT COUPLE OF DAYS.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 33W S OF 17N MOVING W 15-20 KT. A MID
LEVEL LOW IS EMBEDDED WITHIN THE ITCZ ALONG THE WAVE AXIS NEAR
9N WITH INVERTED-V CURVATURE OBSERVED ON SATELLITE IMAGERY. THIS
WAVE EXHIBITS VERY LITTLE IN THE WAY OF DEEP CONVECTION WITH
ONLY SCATTERED SHOWERS ASSOCIATED WITH THE ITCZ ALONG 8N BETWEEN
32W-35W.

TROPICAL WAVE EXTENDS FROM THE WRN DOMINICAN REPUBLIC NEAR
19N71W TILTED ALONG 14N73W TO INLAND OVER NW VENEZUELA/NE
COLOMBIA MOVING W 15-20 KT. THIS FEATURE REMAINS WELL DEFINED
WITH AN INVERTED-V CURVATURE ON SATELLITE IMAGERY. SCATTERED
MODERATE CONVECTION IS FROM 18N-21N BETWEEN 72W-74W ACROSS HAITI
AND THE WINDWARD PASSAGE. SCATTERED MODERATE TO STRONG
CONVECTION IS
FARTHER SOUTH IN AN AREA FROM 7N-13N BETWEEN 68W-76W ACROSS NRN
COLOMBIA.

THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N13W 6N19W 9N26W 8N31W 8N36W 10N50W
10N55W ALONG THE N COAST OF SOUTH AMERICA ACROSS PANAMA INTO THE
E PACIFIC REGION. SCATTERED MODERATE CONVECTION IS FROM 4N-6N
BETWEEN 20W-24W AND FROM 1N-3N BETWEEN 39W-45W. SCATTERED
MODERATE TO STRONG CONVECTION IS INLAND AND WITHIN 60 NM ALONG
THE COAST OF SOUTH AMERICA AND PANAMA BETWEEN 71W-83W.

...DISCUSSION...

GULF OF MEXICO...
DEEP LAYERED TROUGH IS OVER THE E U.S. DIPPING S OVER THE N GULF
PROVIDING SUPPORT FOR A STATIONARY FRONT THAT IS SAGGING S INTO
THE N GULF FROM TALLAHASSEE FLORIDA JUST OFF SHORE OF ALABAMA
AND MISSISSIPPI INTO SE LOUISIANA NEAR NEW ORLEANS. A WEAK 1013
MB LOW IS ANALYZED WEST OF TAMPA FLORIDA NEAR 27N83W AT 16/0300
UTC WITH A SURFACE TROUGH EXTENDING WSW TO NEAR 24N87W. THIS
SURFACE LOW ALONG WITH DIFFLUENCE ALOFT OVER THE ERN GULF IS
PRODUCING SCATTERED SHOWERS AND THUNDERSTORMS FROM 24N-29N E OF
85W AND ACROSS THE WRN COAST OF THE FLORIDA PENINSULA. ELSEWHERE
AT THE SURFACE ACROSS THE GULF W OF 85W...IT REMAINS FAIRLY
TRANQUIL WITH LIGHT WINDS AS A WEAK SURFACE RIDGE BUILDS BACK
INTO THE WRN GULF BY LATE WED. AN UPPER LEVEL RIDGE EXTENDS E
FROM TEXAS/NRN MEXICO COVERING THE GULF W TO 90W PRODUCING ONLY
HIGH-MID LEVEL CLOUDINESS. THE SW GULF REMAINS RATHER CLEAR THIS
EVENING UNDER A NE UPPER FLOW REGIME.

CARIBBEAN SEA...
AN UPPER TROUGH DOMINATES THE CENTRAL CARIBBEAN DRYING THE AIR
NEAR ITS AXIS THAT EXTENDS FROM THE WINDWARD PASSAGE TO THE
NICARAGUA/HONDURAS BORDER AND KEEPING THE AREA N OF 15N W OF 76W
QUIET THIS EVENING. HOWEVER...UPPER DIFFLUENCE BETWEEN THIS
TROUGH AND THE UPPER RIDGE OVER THE WRN GULF OF MEXICO IS
PROVIDING AMPLE UPPER LEVEL MOISTURE ACROSS THE NW CARIBBEAN TO
GENERATE MID-HIGH LEVEL CLOUDINESS. THE ITCZ IS ALONG THE N
COAST OF SOUTH AMERICA AND PANAMA...SEE ABOVE. AN AREA OF
SCATTERED MODERATE CONVECTION IS FROM 12N-14N BETWEEN 79W-83W IN
ASSOCIATION WITH AN UPPER LEVEL DIFFLUENT PATTERN ACROSS THE SW
CARIBBEAN. AN UPPER LEVEL HIGH DOMINATES THE ERN CARIBBEAN INTO
THE W TROPICAL ATLC ANCHORED W OF THE WINDWARD ISLANDS NEAR
16N65W WHICH IS ENHANCING THE ACTIVITY ASSOCIATED WITH THE
TROPICAL WAVE.

ATLANTIC OCEAN...
BROAD UPPER LEVEL TROUGH IS OVER THE E U.S. AND INTO THE FAR W
ATLC WITH A NARROW UPPER RIDGE EXTENDING FROM SOUTH FLORIDA TO
NEAR 31N74W PROVIDING AMPLE DIFFLUENCE TO GENERATE SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 60 NM OF A LINE FROM
32N73W TO 28N80W. AN AREA OF SURFACE HIGH PRESSURE IS LOCATED S
OF T.S. BERTHA ANCHORED BY A 1022 MB HIGH NEAR 28N58W. A BROAD
DEEP LAYERED TROUGH IS OVER THE CENTRAL ATLC N OF 15N BETWEEN
42W-55W WITH A SURFACE TROUGH ENTERING THE REGION NEAR 32N45W TO
28N47W GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS WITHIN 120 NM EAST OF THE TROUGH. AN UPPER RIDGE
EXTENDS FROM THE UPPER HIGH IN THE ERN CARIBBEAN TO OVER THE W
ATLC W OF 56W. A LARGE UPPER LEVEL HIGH IS CENTERED OVER THE E
ATLC ANCHORED W OF THE CANARY ISLANDS NEAR 30N25W COVERING THE
AREA E OF 38W. A SURFACE RIDGE EXTENDS INTO THE E ATLC THROUGH
32N29W SW TO 19N40W.

$$
HUFFMAN




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