000 AXNT20 KNHC 100009 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED JUL 09 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...SPECIAL FEATURE.... THE CENTER OF HURRICANE BERTHA AT 09/2100 UTC IS NEAR 24.8N 58.1W. BERTHA IS MOVING NORTHWEST OR 305 DEGREES AT 10 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 970 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE NOW 90 KT WITH GUSTS TO 110 KT MAKING BERTHA A CATEGORY 2 HURRICANE ON THE SAFFIR-SIMPSON SCALE. BERTHA IS LOCATED 560 MILES...900 KM...NORTHEAST OF THE NORTHERN LEEWARD ISLANDS AND ABOUT 660 MILES...1060 KM...SOUTHEAST OF BERMUDA. PLEASE REFER TO THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC AND THE PUBLIC ADVISORY UNDER MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS. THE OVERALL CLOUD PATTERN HAS BECOME MUCH MORE ORGANIZED WITH A WELL DEFINED 20 NM DIAMETER EYE EMBEDDED WITHIN A 45-60 NM WIDE RING OF STRONG CONVECTION. CLOUD TOP TEMPERATURES HAVE WARMED SLIGHTLY OVER THE PAST HOUR OR SO. HOWEVER THIS MAY BE TEMPORARY AS THE ATMOSPHERE IS EXPECTED TO REMAIN FAVORABLE FOR ADDITIONAL STRENGTHENING AND SEA SURFACE TEMPERATURES ARE SUFFICIENTLY WARM. THE LATEST INTENSITY FORECAST CALLS FOR BERTHA TO BECOME A MAJOR HURRICANE WITHIN THE NEXT 12 HOURS. INTERESTS IN BERMUDA SHOULD CLOSELY MONITOR THE PROGRESS OF BERTHA. ...TROPICAL WAVES... TROPICAL WAVE ALONG 32W SOUTH OF 14N MOVING WEST NEAR 15 KT. ALTHOUGH THE WAVE IS AT A FAIRLY LOW LATITUDE AND OF LOW AMPLITUDE IT CONSISTS OF A WELL ORGANIZED LOW LEVEL CIRCULATION WITH POCKETS OF MODERATE CONVECTION DEVELOPING. TROPICAL WAVE ALONG 51W SOUTH OF 13N MOVING WEST 10 TO 15 KT. CYCLONIC FLOW IN THE LOW CLOUDS ON VISIBLE SATELLITE IMAGERY AND QUIK-SCAT DATA HELP TO CONFIRM THIS POSITION. NEARBY PRECIPITATION IS IN THE ITCZ. SOUTHWESTERN GULF OF MEXICO TROPICAL WAVE HAS MOVED INLAND ALONG 97W SOUTH OF 22N AND CONTINUES MOVING WEST AT 15 KT. THIS WAVE IS MOVING THROUGH THE SOUTH SIDE OF AN UPPER LEVEL SHEAR AXIS WITH MODERATE TO STRONG NORTHWESTERLY WIND FLOW CUTTING ACROSS THE NORTHERN END OF THE WAVE. SHOWERS AND THUNDERSTORMS ARE DEVELOPING ALONG THE SIERRA MADRE IN MEXICO...WITH STRONGER ACTIVITY OVER THE ISTHMUS OF TEHUANTEPEC. ...THE ITCZ... 10N14W 9N30W 8N43W 7N59W. SCATTERED MODERATE TO STRONG SHOWERS AND THUNDERSTORMS ARE FROM 4N TO 6N BETWEEN 22W AND 31W...AND FROM 7N TO 11N BETWEEN 54W AND 60W. ISOLATED MODERATE SHOWERS AND THUNDERSTORMS ARE NOTED FROM 6N TO 8N BETWEEN 40W AND 45W. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS WERE MOVING OFF THE WEST AFRICAN COAST FROM 11N TO 14N BETWEEN 15W AND 16W...IN GUINEA AND GUINEA-BISSAU AND SENEGAL. ...DISCUSSION... THE GULF OF MEXICO... MIDDLE TO UPPER LEVEL ANTICYCLONIC FLOW EXTENDS FROM THE NORTHWEST ATLANTIC OCEAN INTO THE NORTHERN GULF OF MEXICO TO THE CENTRAL TEXAS GULF COAST. MIDDLE TO UPPER LEVEL TROUGH/SHEAR AXIS EXTENDS FROM CUBA WESTWARD ACROSS THE SOUTHERN GULF OF MEXICO. A WEAK CYCLONIC CIRCULATION WAS NOTED OVER THE BAY OF CAMPECHE NEAR 22N94W. MODERATE TO STRONG NORTHWESTERLY FLOW ON THE SOUTH SIDE OF THIS SHEAR AXIS WAS SWEEPING ACROSS THE NORTHERN END OF THE TROPICAL WAVE ALONG 97W. AT THE SURFACE WEAK RIDGE OF HIGH PRESSURE DOMINATED THE GULF. CLUSTERS OF MODERATE TO STRONG THUNDERSTORMS WERE MOVING OFF THE SW FLORIDA COAST BETWEEN MARCO ISLAND AND TAMPA BAY. ADDITIONAL ACTIVITY WAS MOVING OFF THE NORTHWEST YUCATAN PENINSULA. THE CARIBBEAN SEA... A MIDDLE TO UPPER LEVEL SHEAR AXIS COVERED THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA. ISOLATED MODERATE SHOWERS AND SOME THUNDERSTORMS ARE FROM 20N TO 22N BETWEEN 84W AND 85W...MOVING FROM THE WESTERN TIP OF CUBA INTO THE YUCATAN CHANNEL. UPPER LEVEL NORTHWESTERLY WIND FLOW S OF THE SHEAR AXIS CUTS ACROSS THE YUCATAN PENINSULA...THE GULF OF HONDURAS TO THE GREATER ANTILLES. ISOLATED MODERATE SHOWERS ARE FROM 17N TO 19N BETWEEN 66W AND 71W...FROM PUERTO RICO TO THE WATERS SOUTH OF THE WESTERN DOMINICAN REPUBLIC IN AN AREA OF UPPER LEVEL DIFFLUENT FLOW. A FLAT UPPER LEVEL RIDGE EXTENDS FROM 5N72W IN COLOMBIA TO 15N76W. SCATTERED MODERATE SHOWERS AND STRONG THUNDERSTORMS ARE OCCURRING FROM 15N TO 17N BETWEEN 80W AND 85W ALSO IN UPPER LEVEL DIFFLUENT FLOW IN THE FAR SOUTHWESTERN CARIBBEAN SEA. STRONG SHOWERS AND THUNDERSTORMS ARE SOUTH OF 11N75W 13N84W...UNDER THE UPPER LEVEL RIDGE...NORTH OF THE ITCZ...WITH BROAD MIDDLE LEVEL CYCLONIC WIND FLOW. THE ATLANTIC OCEAN... A STATIONARY MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 28N69W. CYCLONIC FLOW AROUND THIS CENTER COVERS THE ATLANTIC OCEAN FROM 22N TO 32N BETWEEN 65W AND 73W AND IS PROVIDING SOME OF THE STEERING FLOW FOR HURRICANE BERTHA. A MIDDLE TO UPPER LEVEL TROUGH IS DROPPING SOUTHWARD JUST TO THE NORTHEAST OF HURRICANE BERTHA...WITH AXIS THROUGH 34N50W TO 32N54W. THIS TROUGH SUPPORTS A COLD FRONT THAT IS GRAZING THE EXTREME NORTHERN PORTION OF THE AREA ALONG 32N AND 55W. ISOLATED SHOWERS ARE WITHIN 30 NM ON EITHER SIDE OF 31N BETWEEN 40W AND 52W. A SURFACE RIDGE PASSES THROUGH A 1023 MB HIGH PRESSURE CENTER NEAR 33N64W TO THE FLORIDA PANHANDLE NEAR 30N85W INTO SOUTHERN LOUISIANA. A MIDDLE TO UPPER LEVEL TROUGH IS IN THE EASTERN ATLANTIC OCEAN PASSING THROUGH 32N32W TO 22N39W. A SURFACE RIDGE PASSES THROUGH 32N26W TO 29N32W TO 24N44W TO 16N52W. MID TO UPPER LEVEL EASTERLY FLOW COVERS THE DEEP TROPICS E OF 50W. $$ COBB