[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 161058
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...SPECIAL FEATURES...

TROPICAL STORM BERTHA IS CENTERED NEAR 36.4N 61.0W AT 16/0900
UTC OR ABOUT 310 NM 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 IS
CAUGHT BETWEEN BROAD UPPER TROUGHING ACROSS THE ERN CONUS TO ITS
EAST AND A DEEP-LAYERED UPPER LOW IN THE CENTRAL ATLANTIC TO ITS
WEST. IT APPEARS LIKELY TO BE HEADED FOR A SLOW DEMISE AS IT
TRACK SOUTH-SOUTHEASTWARD...TRAVERSES OVER MARGINAL OCEANIC
CONDITIONS AND GRADUALLY EXPERIENCES INCREASING SOUTHWESTERLY
UPPER SHEAR OVER THE NEXT COUPLE OF DAYS. SCATTERED MODERATE
CONVECTION IS WITHIN 150 NM OF THE CENTER BOUNDED FROM 35N-39N
BETWEEN 58W-64W.

STRONG TROPICAL WAVE IS ALONG 53W S OF 17N MOVING W NEAR 20 KT
WITH A 1011 MB LOW ANALYZED ALONG THE AXIS NEAR 13N MOVING
ROUGHLY WNW. THE SATELLITE PRESENTATION IS NOT AS WELL DEFINED
AS YESTERDAY BUT CONVECTIVE ACTIVITY THIS MORNING IS ON THE
INCREASE WEST OF THE WAVE AND REMAINS ROUGHLY FOCUSED WITH
SCATTERED MODERATE TO STRONG CONVECTION FROM 11N-14N BETWEEN
53W-58W. 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 34W/35W S OF 18N 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
33W-37W.

TROPICAL WAVE EXTENDS FROM HAITI NEAR 20N72W TILTED ALONG 15N74W
TO INLAND OVER NRN COLOMBIA MOVING W 15-20 KT. THIS FEATURE
REMAINS WELL DEFINED WITH AN INVERTED-V CURVATURE ON SATELLITE
IMAGERY. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS
FROM 12N-15N BETWEEN 72W-77W. SIMILAR CONVECTION IS ACROSS NRN
COLOMBIA NEAR 10N AND LIKELY EMBEDDED WITHIN THE ITCZ.

THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N13W 7N18W 11N27W 9N33W 7N36W 5N43W
11N51W 12N55W AND ALONG THE N COAST OF SOUTH AMERICA ACROSS
PANAMA INTO THE E PACIFIC REGION. SCATTERED MODERATE CONVECTION
IS WITHIN 60 NM OF A LINE FROM 5N10W TO 8N16W. SIMILAR
CONVECTION IS WITHIN 60 NM OF A LINE FROM 4N33W TO 2N47W.
SCATTERED MODERATE TO STRONG CONVECTION IS INLAND AND WITHIN 90
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
WITH A EMBEDDED SHORTWAVE NEAR 28N87W. THIS IS PROVIDING SUPPORT
FOR A STATIONARY FRONT THAT IS SAGGING S ACROSS CENTRAL FLORIDA
TO A 1013 MB SURFACE LOW PRESSURE WEST-SOUTHWEST OF TAMPA FLORIDA
NEAR 27N83W AT 16/0900 UTC WITH A SURFACE TROUGH EXTENDING WSW
TO NEAR 24N86W. THIS SURFACE LOW ALONG WITH DIFFLUENCE ALOFT E
OF THE SHORTWAVE IS GENERATING AN AREA OF SCATTERED SHOWERS AND
THUNDERSTORMS FROM 26N-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 MORNING UNDER A NORTHERLY UPPER
FLOW REGIME.

CARIBBEAN SEA...
AN UPPER TROUGH IS ACROSS THE NW CARIBBEAN DRYING THE AIR NEAR
ITS AXIS THAT EXTENDS FROM ERN CUBA TO THE NICARAGUA/HONDURAS
BORDER AND KEEPING THE AREA N OF 15N W OF 77W QUIET THIS
MORNING. THE ITCZ IS ALONG THE N COAST OF SOUTH AMERICA AND
PANAMA...SEE ABOVE. CLUSTERS OF SCATTERED MODERATE CONVECTION
ARE FROM 11N-14N BETWEEN 78W-84W 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 16N69W WHICH IS
ENHANCING THE ACTIVITY ASSOCIATED WITH THE TROPICAL WAVE ALONG
74W.

ATLANTIC OCEAN...
BROAD UPPER LEVEL TROUGH IS OVER THE E U.S. AND INTO THE FAR W
ATLC WITH A NARROW UPPER RIDGE EXTENDING ACROSS SOUTH FLORIDA TO
NEAR 30N77W PROVIDING AMPLE DIFFLUENCE TO GENERATE SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS FROM 28N-32N BETWEEN 76W-80W.
AN AREA OF SURFACE HIGH PRESSURE IS LOCATED S OF T.S. BERTHA
ANCHORED BY A 1023 MB HIGH NEAR 29N58W. A BROAD DEEP LAYERED
TROUGH IS OVER THE CENTRAL ATLC N OF 15N BETWEEN 40W-56W WITH A
SURFACE TROUGH ENTERING THE REGION NEAR 32N44W TO 27N50W
GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS
WITHIN 120 NM EAST OF THE TROUGH N OF 28N. AN UPPER RIDGE
EXTENDS FROM THE UPPER HIGH IN THE ERN CARIBBEAN TO OVER THE W
ATLC W OF 58W. A LARGE UPPER LEVEL HIGH IS CENTERED OVER THE E
ATLC ANCHORED W-NW OF THE CANARY ISLANDS NEAR 31N26W COVERING
THE AREA E OF 38W. A SURFACE RIDGE EXTENDS INTO THE E ATLC
THROUGH 32N31W S TO 22N35W.

$$
HUFFMAN




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