[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 151201
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE JUL 15 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 34.7N 63.2W AT 15/0900
UTC OR ABOUT 165 NM NORTH-NORTHEAST OF BERMUDA. THE MINIMUM
CENTRAL PRESSURE IS 995 MB. THE 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 STRONG TROPICAL STORM STRENGTH
AND IS FORECAST TO GRADUALLY INTENSIFY SLIGHTLY TO A HURRICANE
AGAIN DURING THE NEXT 24 HOURS. LARGE SWELLS AND HIGH SURF ARE
AFFECTING BERMUDA AND ARE EXPECTED TO GRADUALLY DECREASE DURING
THE NEXT COUPLE OF DAYS AS BERTHA TURNS EASTWARD AND MOVES
FARTHER AWAY FROM BERMUDA. DANGEROUS RIP CURRENTS ARE ALSO
OCCURRING ALONG THE U.S. EAST COAST FROM THE CAROLINAS THROUGH
SOUTHERN NEW ENGLAND. THE DEEPEST CONVECTION IS WITHIN 120 NM OF
THE CENTER OVER THE SOUTHERN AND EASTERN SEMICIRCLES WITH
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS COVERING
A BROAD AREA FROM 33N-36N BETWEEN 61W-64W.

STRONG TROPICAL WAVE IS ALONG 45W/46W S OF 18N MOVING W NEAR
10-15 KT WITH A 1009 MB LOW ANALYZED ALONG THE AXIS NEAR 12N
MOVING ROUGHLY WNW NEAR 15 KT. SATELLITE IMAGERY SHOWS A LARGE
WELL DEFINED ENVELOPE OF CYCLONIC ROTATION...FOCUSED NEAR THE
LOW CENTER. SCATTERED MODERATE CONVECTION IS FROM 11N-14N
BETWEEN 47W-50W. MAINLY SCATTERED SHOWERS ARE WITHIN 300 NM ON
EITHER SIDE OF THE AXIS FROM 10N-16N. THIS SYSTEM COULD BECOME A
TROPICAL DEPRESSION DURING THE NEXT DAY OR TWO.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM EASTERN PUERTO RICO ALONG 66W/67W TO
NEAR PUERTO CABELLO VENEZUELA MOVING W 15 KT. THIS FEATURE
REMAINS WELL DEFINED WITH IR SATELLITE IMAGERY SHOWING
INVERTED-V CURVATURE ALONG THE AXIS IN THE ERN CARIBBEAN.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE S OF 16N TO
INLAND OVER VENEZUELA BETWEEN 64W-72W INCLUDING THE ABC ISLANDS.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 14N17W 13N24W 5N34W 8N44W 11N48W
9N61W AND ACROSS THE SW CARIBBEAN. SCATTERED MODERATE TO STRONG
CONVECTION IS FROM 5N-7N BETWEEN 11W-13W. SIMILAR CONVECTION IS
FROM 5N-10N BETWEEN 27W-35W.

...DISCUSSION...

GULF OF MEXICO...
DEEP LAYERED TROUGH IS OVER THE ERN U.S. DIPPING S TO THE N GULF
COAST. A STATIONARY FRONTAL BOUNDARY AT THE SURFACE IS ANALYZED
ALONG THE N GULF COAST WITH A WEAK 1011 MB LOW ALONG THE
BOUNDARY NEAR TALLAHASSEE FLORIDA. THIS SURFACE LOW PRESSURE
COUPLED WITH THE DIFFLUENCE AHEAD OF THE UPPER TROUGH IS
GENERATING SCATTERED SHOWERS AND THUNDERSTORMS MAINLY OVER THE
NE GULF FROM 26N-29N BETWEEN 82W-87W. SCATTERED SHOWERS AND
ISOLATED TSTMS ARE ALSO WITHIN 90 NM OFFSHORE IN THE NW GULF E
OF THE PORT ARTHUR LOUISIANA AREA. SCATTERED SHOWERS ARE ALSO
ACROSS THE SE GULF AND SRN FLORIDA MOVING W TO E ACROSS THE
FLORIDA PENINSULA INTO THE W ATLC. STRONG SUBSIDENCE AND DRY
STABLE AIR ARE NORTH OF THE STATIONARY BOUNDARY THAT EXTENDS
ACROSS THE SE CONUS. A SURFACE RIDGE ENTERS THE CENTRAL AND WRN
GULF FROM THE NW CARIBBEAN AND IS ANCHORED IN THE GULF BY A
1016 MB HIGH NEAR 24N90W. AN UPPER HIGH IS OVER WEST TEXAS WITH
THE RIDGE AXIS EXTENDING SE OVER THE GULF OF MEXICO TO NEAR WRN
CUBA. THIS UPPER LEVEL DIFFLUENT PATTERN IS ENHANCING THE
TSTM ACTIVITY OVER THE NRN GULF AS WELL AS AIDING IN THE
AFOREMENTIONED CLUSTERS OF SCATTERED SHOWERS/THUNDERSTORMS OVER
THE ERN GULF E OF 87W.

CARIBBEAN SEA...
AN UPPER LOW IS IN THE NORTH CENTRAL CARIBBEAN COVERING THE AREA
N OF 15N FROM 70W-82W. THIS COMBINED WITH THE UPPER RIDGE THAT
COVERS THE GULF OF MEXICO IS PROVIDING ABUNDANT UPPER LEVEL
MOISTURE ACROSS THE NW CARIBBEAN SEA. THE ITCZ CROSSES THE SW
CARIBBEAN FROM NRN COLOMBIA ACROSS PANAMA INTO THE E PACIFIC
REGION GENERATING SCATTERED SHOWERS AND TSTMS ALONG COASTAL
PANAMA AND COSTA RICA BETWEEN 78W-84W. THE ERN CARIBBEAN IS
DOMINATED BY AN UPPER RIDGE ANCHORED OVER THE LEEWARD ISLANDS
WHICH IS ENHANCING THE CONVECTIVE ACTIVITY ASSOCIATED WITH THE
TROPICAL WAVE ALONG 66W/67W. THE CENTRAL CARIBBEAN REMAINS
TRANQUIL ALTHOUGH THERE ARE SOME HIGH LEVEL CLOUDS TRANSVERSING
THE AREA S OF 15N FROM W TO E BETWEEN 75W-82W.

ATLANTIC OCEAN...
TROPICAL STORM BERTHA CONTINUES TO INFLUENCE THE AREA N OF THE
REGION NEAR BERMUDA...SEE ABOVE. BROAD UPPER LEVEL TROUGHING IS
ACROSS THE ERN U.S. SEABOARD AND THE FAR W ATLC WATERS. IT
EXTENDS TO THE PREVIOUSLY MENTIONED UPPER LOW CENTERED OVER ERN
CUBA AND THE WINDWARD PASSAGE. THIS UPPER TROUGHING IS PROVIDING
AMPLE DIFFLUENCE TO GENERATE SCATTERED SHOWERS AND TSTMS WITHIN
90 NM OF A LINE FROM 30N75W ACROSS GRAND BAHAMA ISLAND TO NEAR
KEY LARGO FLORIDA. A NARROW UPPER RIDGE EXTENDS ALONG 60W FROM
NORTH OF THE DISCUSSION AREA SWD TO NEAR 24N60W. A BROAD DEEP
LAYERED TROUGH IS OVER THE CENTRAL ATLC N OF 18N BETWEEN 35W-55W
WITH A DISSIPATING ASSOCIATED COLD FRONT NORTH OF THE AREA AND
SURFACE TROUGH ENTERING THE AREA NEAR 32N41W TO 28N46W.
SCATTERED SHOWERS ARE WITHIN 60 NM OF THE TROUGH. A LARGE UPPER
LEVEL HIGH IS CENTERED OVER THE SOUTH CENTRAL AND WEST TROPICAL
ATLC NEAR 17N61W AND EXTENDS OVER THE ERN CARIBBEAN. A SECOND
UPPER LEVEL HIGH IS WEST OF THE CANARY ISLANDS NEAR 28N22W
COVERING THE ERN ATLC E OF 35W. A SURFACE RIDGE OF HIGH PRESSURE
EXTENDS ACROSS THE ERN ATLC ANCHORED ON A 1034 MB HIGH CENTERED
WELL N OF THE AZORES.

$$
HUFFMAN




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