000 AXNT20 KNHC 081750 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURE.... HURRICANE BERTHA IS CENTERED NEAR 22.1N 53.8W AT 08/1500 UTC OR ABOUT 570 NM ENE OF THE NORTHERN LEEWARD ISLANDS MOVING NW AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 970 MB. MAXIMUM SUSTAINED WIND SPEED IS 90 KT WITH GUSTS TO 110 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT42 KNHC FOR MORE DETAILS. BERTHA REMAINS A CATEGORY TWO HURRICANE ON THE SAFFIR-SIMPSON HURRICANE SCALE. A GRADUAL WEAKENING TREND IS EXPECTED OVER THE NEXT COUPLE OF DAYS AS BERTHA BEGINS TO FEEL THE EFFECTS OF A MODERATELY SHEARED UPPER ATMOSPHERIC ENVIRONMENT. SCATTERED MODERATE/ ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF THE CENTER OVER THE NORTH QUADRANT. SCATTERED MODERATE CONVECTION IS FROM 21N-25N BETWEEN 48W-52W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 45W/46W S OF 12N MOVING W NEAR 20 KT. THIS LOW AMPLITUDE WAVE REMAINS MOSTLY EMBEDDED WITHIN THE ITCZ. ISOLATED MODERATE CONVECTION IS WITHIN 150 NM E OF THE WAVE AXIS. TROPICAL WAVE IS ALONG 87W/88W S OF 22N MOVING W NEAR 20 KT. A PIECE OF ENERGY HAS BROKEN OFF THE NRN TIP OF THE WAVE AND IS ANALYZED AS A SURFACE TROUGH MOVING NW ACROSS THE NE GULF OF MEXICO...SEE BELOW. WAVE CONTINUES TO PROPAGATE W OF THE UPPER LOW OVER THE NW CARIBBEAN AND INTO THE REGION OF STRONG NLY UPPER FLOW GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ACROSS SRN MEXICO...BELIZE...GUATEMALA AND WRN HONDURAS. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 12N15W 12N22W 7N33W 9N43W 8N48W 7N58W. CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE FROM 6N-11N BETWEEN 15W-28W. SIMILAR CONVECTION IS FROM 4N-7N BETWEEN 47W-52W. ...DISCUSSION... GULF OF MEXICO... AN WEAK MID TO UPPER LEVEL DISTURBANCE REMAINS INLAND OVER THE NE MEXICO COAST WITH AN UPPER RIDGE AXIS EXTENDING FROM N CENTRAL MEXICO INTO TEXAS AND ALONG THE NW GULF COAST. THE DIFFLUENCE ALOFT OVER THE WRN GULF...COUPLED WITH THE ABUNDANCE OF UPPER LEVEL MOISTURE IS GENERATING SCATTERED SHOWERS AND TSTMS SW OF A LINE FROM CORPUS CHRISTI TEXAS TO NEAR CAMPECHE MEXICO. AN UPPER TROUGH EXTENDS FROM THE UPPER LOW IN THE NW CARIBBEAN THROUGH THE YUCATAN CHANNEL TO OVER THE CENTRAL AND ERN GULF. THE NRN PORTION OF THE TROPICAL WAVE IN THE NW CARIBBEAN IS ANALYZED AS A SURFACE TROUGH EXTENDING FROM ST. PETERSBURG FLORIDA SW TO NEAR 24N86W. THIS IS GENERATING AN AREA OF SCATTERED SHOWERS AND TSTMS ACROSS THE ERN GULF FROM 24N-29N BETWEEN 84W-88W. ALSO AT THE SURFACE IS A WEAK RIDGE EXTENDING FROM THE W ATLC ACROSS NRN FLORIDA ALONG THE N GULF COAST TO E TEXAS. CARIBBEAN SEA... ELONGATED UPPER LOW IN THE NW CARIBBEAN CENTERED NEAR 19N86W EXTENDS TROUGHING ACROSS THE S CENTRAL GULF OF MEXICO AND ACROSS TO THE CENTRAL CARIBBEAN. THIS ALONG WITH THE TROPICAL WAVE ALONG 87W/88W IS PRODUCING A SMALL CLUSTER OF SHOWERS/ISOLATED TSTMS IN THE YUCATAN BASIN FROM 19N-21N BETWEEN 84W-87W. AN ABUNDANCE OF UPPER LEVEL MOISTURE REMAINS OVER THE SW CARIBBEAN COUPLED WITH DIFFLUENCE ALOFT IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE SW CARIBBEAN S OF 11N E OF 81W TO INLAND OVER PANAMA AND COLOMBIA. STRONG SUBSIDENCE AND DRY STABLE AIR ARE ACROSS THE ERN CARIBBEAN WITH MODERATE/STRONG EASTERLY TRADE WINDS USHERING IN AN AREA OF SCATTERED SHOWERS AND POSSIBLE ISOLATED TSTMS FROM 14N-17N BETWEEN 68W-72W. ANOTHER AREA OF SCATTERED SHOWERS IS ACROSS THE LEEWARD ISLANDS AND IS ASSOCIATED WITH WEAK MID-LEVEL TROUGHING. ATLANTIC OCEAN... THE MAIN FOCUS REMAINS A GRADUALLY WEAKENING HURRICANE BERTHA. OTHERWISE...AN UPPER LOW IS OVER VIRGINIA DRAWING UPPER LEVEL MOISTURE ACROSS FLORIDA AND THE FAR W ATLC TO ALONG THE U.S. E COAST WHICH IS GENERATING SCATTERED SHOWERS/TSTMS N OF 28N W OF 75W TO THE FLORIDA AND GEORGIA COAST. A WEAK BUT INSIGNIFICANT UPPER LOW IS NE OF THE BAHAMAS NEAR 28N67W EMBEDDED WITHIN MODERATE SUBSIDENCE AND DRY AIR. 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 WEAKENING UPPER TROUGH EXTENDING INTO THE E ATLC OVER THE MADEIRA ISLANDS W OF THE CANARY ISLANDS TO THE CAPE VERDE ISLANDS. IN ALL THESE ARE RATHER BENIGN UPPER LEVEL FEATURES AS A BROAD SURFACE RIDGE DOMINATES THE ATLC WITH A WEAKNESS IN THE VICINITY OF HURRICANE BERTHA. A 1025 MB HIGH IS SE OF THE AZORES WITH A SECOND 1025 MB HIGH NEAR 31N40W AND A 1025 MB HIGH DIRECTLY OVER BERMUDA. $$ HUFFMAN