[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 080516
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE JUL 08 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
0445 UTC.

...SPECIAL FEATURE....

HURRICANE BERTHA IS CENTERED NEAR 20.8N 52.8W AT 08/0300 UTC OR
ABOUT 605 NM ENE OF THE NORTHERN LEEWARD ISLANDS MOVING WNW AT
10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 952 MB. MAXIMUM
SUSTAINED WIND SPEED IS 105 KT WITH GUSTS TO 130 KT. SEE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT42
KNHC FOR MORE DETAILS. BERTHA REMAINS A CATEGORY THREE HURRICANE
ON THE SAFFIR-SIMPSON HURRICANE SCALE. BERTHA COULD FLUCTUATE IN
INTENSITY AS IT GOES THROUGH AN EYE-WALL REPLACEMENT CYCLE OVER
THE NEXT 12 TO 24 HOURS. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION SURROUNDS THE EYE WITHIN 60 NM IN ALL QUADRANTS AND
IS WITHIN 45 NM OF LINE FROM 21N50W TO 23N53W.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 40W S OF 13N MOVING W NEAR 20 KT. LOW
AMPLITUDE WAVE MOSTLY EMBEDDED WITHIN THE ITCZ. NO ASSOCIATED
DEEP CONVECTION.

TROPICAL WAVE IS ALONG 27N80W 17N83W TO 8N82W MOVING WNW NEAR 20
KT. WAVE REMAINS HIGHLY AMPLIFIED AND EXTENDS FROM PANAMA ACROSS
CUBA TO OVER S FLORIDA. WAVE IS NOW TO THE W OF THE UPPER LOW
OVER THE CARIBBEAN AND COUPLED WITH THE STRONG N UPPER FLOW IS
GENERATING SCATTERED NUMEROUS/SHOWERS/THUNDERSTORMS FROM 18N-27N
BETWEEN BETWEEN THE WAVE AXIS AND 86W.

TROPICAL WAVE IS ALONG 98W INLAND OVER MEXICO AND IS NO LONGER
IN THE ATLC BASIN.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 12N15W 7N29W 7N41W 6N45W 10N57W
ACROSS THE N PORTION OF SOUTH AMERICA INTO THE E PACIFIC REGION.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS MOVING OFF W
AFRICA FROM 11N-13N E OF 19W. SMALL CLUSTERS OF SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION ARE FROM 7N-12N BETWEEN
41W-46W AND FROM 5N-9N BETWEEN 47W-57W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LOW REMAINS INLAND OVER N/CENTRAL MEXICO WITH AN UPPER
RIDGE AXIS EXTENDING INTO THE GULF THROUGH THE BAY OF CAMPECHE
NEAR VERACRUZ MEXICO TO THE TEXAS COAST NEAR 30N97W. THE
DIFFLUENCE ALOFT BETWEEN THIS UPPER FEATURES COUPLED WITH THE
ABUNDANCE OF UPPER LEVEL MOISTURE IS GENERATING SCATTERED
SHOWERS/THUNDERSTORMS SW OF A LINE FROM BROWNSVILLE TEXAS TO
INTO THE BAY OF CAMPECHE NEAR 18N92W. AN UPPER LOW OVER NORTH
CAROLINA EXTENDS A WEAK BUT NARROW UPPER TROUGH INTO THE E GULF
THE BIG BEND AREA OF FLORIDA TO 25N84W WHERE AN INVERTED TROUGH
FROM THE S CONTINUES TO THE W TIP OF CUBA. THIS IS ENHANCING THE
SHOWERS/THUNDERSTORMS ASSOCIATED WITH THE TROPICAL WAVE. ALSO AT
THE SURFACE IS A WEAK RIDGE EXTENDING FROM THE W ATLC ACROSS
FLORIDA ALONG THE N GULF COAST TO TEXAS.

CARIBBEAN SEA...
ELONGATED UPPER LOW IS IN THE CENTRAL CARIBBEAN S OF W JAMAICA
NEAR 16N79W WITH STRONG N FLOW OVER THE W CARIBBEAN DUE TO THE
UPPER RIDGE OVER THE W GULF OF MEXICO AND WEAK UPPER FLOW OVER
THE E CARIBBEAN. ABUNDANCE OF UPPER LEVEL MOISTURE REMAINS OVER
THE W CARIBBEAN COUPLED WITH DIFFLUENCE ALOFT IS ENHANCING THE
SHOWERS/THUNDERSTORMS ASSOCIATED WITH THE TROPICAL WAVE. SIMILAR
ACTIVITY IS ACROSS THE SW CARIBBEAN S OF 11N ASSOCIATED WITH
THE CLOSE PROXIMITY OF THE ITCZ IN THE E PACIFIC REGION. STRONG
SUBSIDENCE AND DRY STABLE AIR REMAIN ACROSS THE E CARIBBEAN WITH
MODERATE/STRONG EASTERLY TRADE WINDS USHERING IN SOME SCATTERED
SHOWERS FROM 14N-18N E OF 69W ACROSS THE LESSER ANTILLES.

ATLANTIC OCEAN...
THE MAIN FOCUS TONIGHT IS HURRICANE BERTHA. OTHERWISE...AN UPPER
LOW IS OVER NORTH CAROLINA DRAWING THE UPPER LEVEL MOISTURE
ACROSS FLORIA TO ALONG THE US E COAST AND GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS N OF 30N W OF 77W TO COAST OF
GEORGIA AND SOUTH CAROLINA. A WEAK UPPER BUT INSIGNIFICANT UPPER
LOW IS NE OF THE BAHAMAS NEAR 28N65W EMBEDDED WITHIN MODERATE
SUBSIDENCE AND SOMEWHAT DRY AIR. THIS IS INDUCING A WEAK UPPER
RIDGE BETWEEN THESE UPPER LOWS AND PROVIDING ENOUGH DIFFLUENCE
ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
WITHIN 75 NM OF LINE FROM 28N76W ACROSS THE N BAHAMA ISLANDS TO
24N79W. STRONG SUBSIDENCE AND DRY STABLE AIR COVER THE REMAINDER
OF THE W ATLC INTO THE CENTRAL ATLC W OF BERTHA. WEAK UPPER
TROUGH EXTENDS INTO THE N/CENTRAL ATLC NE OF BERTHA WITH A
SECOND STRONG UPPER TROUGH EXTENDING INTO THE E ATLC OVER THE
MADEIRA ISLANDS W OF THE CANARY ISLANDS AND THE CAPE VERDE
ISLANDS TO NEAR 17N29W. IN ALL THESE ARE RATHER BENIGN UPPER
LEVEL FEATURES AS A BROAD SURFACE RIDGE DOMINATES THE ATLC WITH
A WEAKNESS INT HE VICINITY OF HURRICANE BERTHA. A 1025 MB HIGH
IS JUST S OF THE AZORES WITH A SECOND 1025 MB HIGH NEAR 32N45W
AND A 1026 MB HIGH JUST NE OF BERMUDA.

$$
WALLACE




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