000 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