000 AXNT20 KNHC 042351 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI JUL 04 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 2315 UTC. ...SPECIAL FEATURE.... TROPICAL STORM BERTHA CENTERED NEAR 15.5N 31.6W AT 2100 UTC OR ABOUT 505 NM W OF THE CAPE VERDE ISLANDS MOVING WNW AT 16 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT42 KNHC FOR MORE DETAILS. CONVECTION IS PRESENTLY DECREASING NEAR BERTHA. SCATTERED MODERATE CONVECTION IS MOSTLY N OF THE CENTER FROM 15N-19N BETWEEN 29W-32W. BERTHA WILL BE PASSING OVER SLIGHTLY COOLER WATERS DURING THE NEXT 24 HOURS. ...TROPICAL WAVES... TROPICAL WAVE IS TILTED ALONG 57W S OF 22N MOVING W 20-25 KT. DESPITE THE HIGH AMPLIFICATION NOTED IN SATELLITE IMAGERY AND AN EARLIER QUIKSCAT PASS...THERE IS MINIMAL ASSOCIATED CONVECTION. SHALLOW SCATTERED SHOWERS ARE WITHIN 250 NM EITHER SIDE OF THE AXIS. TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN ALONG 71W/72W S OF 19N MOVING W 15-20 KT. SATELLITE IMAGERY SHOWS LOW CLOUD CYCLONIC TURNING WITH SCATTERED SHOWERS AND TSTMS FROM 15N-18N BETWEEN 67W-75W IN AN AREA MAINLY SOUTH OF HISPANIOLA. TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN ALONG 84W S OF 16N MOVING W 15 KT. THIS WAVE LIES IN AN UPPER DIFFLUENT ZONE ON THE S SIDE OF AN UPPER HIGH. THESE TWO FEATURES TOGETHER ARE PRODUCING SCATTERED MODERATE TO STRONG CONVECTION ALONG THE COASTS OF HONDURAS AND NICARAGUA FROM 13N-18N BETWEEN 80W-85W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 8N13W 9N20W 13N26W 7N40W 3N50W. NUMEROUS STRONG CONVECTION IS ALONG THE COAST OF W AFRICA FROM 10N-13N BETWEEN 13W-17W. ISOLATED MODERATE CONVECTION IS FROM 5N-12N BETWEEN 19W-22W. SCATTERED MODERATE CONVECTION IS FROM 6N-8N BETWEEN 31W-35W...AND FROM 5N-6N BETWEEN 48W-51W. ...DISCUSSION... THE GULF OF MEXICO... WEAK SURFACE RIDGING COVERS THE GULF OF MEXICO. 10-15 KT SELY SURFACE FLOW IS NOTED. CLUSTERS OF AIRMASS THUNDERSTORMS ARE OVER THE GULF OF MEXICO AND FLORIDA. WIDELY SCATTERED MODERATE CONVECTION IS OVER THE E FLORIDA FROM 26N-30N BETWEEN 80W-83W. SCATTERED MODERATE TO ISOLATED MODERATE CONVECTION IS OVER THE W GULF W OF 93W. IN THE UPPER LEVELS...A SMALL UPPER LEVEL LOW IS CENTERED OVER CENTRAL FLORIDA NEAR 28N83W ENHANCING THE CONVECTION OVER FLORIDA. THE ERN EXTENT OF AN UPPER LEVEL HIGH IS OVER THE W GULF OF MEXICO PRODUCING MAINLY NLY FLOW W OF 90W. CONSIDERABLE UPPER LEVEL MOISTURE COVERS THE ENTIRE GULF. EXPECT CONTINUED AIRMASS CONVECTION OVER MOST OF THE GULF DURING THE NEXT 24 HOURS. THE CARIBBEAN SEA... TWO TROPICAL WAVES ARE OVER THE CARIBBEAN AND CENTRAL AMERICA WITH CONVECTION. SEE ABOVE. MODERATE TO FRESH TRADEWINDS DOMINATE THE AREA. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS ALSO INLAND OVER CUBA BETWEEN 79W-85W. WIDELY SCATTERED MODERATE IS ALSO OVER THE SW CARIBBEAN AND PANAMA FROM 8N-12N BETWEEN 75W-85W. IN THE UPPER LEVELS...AN UPPER LEVEL HIGH IS CENTERED OVER THE W CARIBBEAN NEAR 15N80W. SIGNIFICANT UPPER LEVEL MOISTURE COVERS THE CARIBBEAN W OF 65W. EXPECT THE TROPICAL WAVES TO MOVE W WITH CONVECTION DURING THE NEXT 24 HOURS. THE ATLANTIC OCEAN... CLUSTERS OF WIDELY SCATTERED MODERATE CONVECTION IS OVER THE W ATLANTIC NEAR FLORIDA FROM 27N-30N BETWEEN 77W-80W. A 1028 MB HIGH IS OVER THE W ATLANTIC NEAR 34N60W. ANOTHER 1028 MB HIGH IS OVER THE CENTRAL ATLANTIC NEAR 36N41W. A SURFACE TROUGH IS OVER THE CENTRAL ATLANTIC FROM 32N46W TO 26N54W. SCATTERED MODERATE CONVECTION IS E OF THE WAVE AXIS FROM 30N-31N BETWEEN 44W-47W. SCATTERED SHOWERS ARE WITHIN 90 NM OF THE REMAINDER OF THE TROUGH. IN THE UPPER LEVELS...AN UPPER LEVEL RIDGE IS OVER THE W ATLANTIC W OF 68W. AN UPPER LEVEL LOW IS CENTERED OVER THE CENTRAL ATLANTIC NEAR 29N57W. A LARGE UPPER LEVEL HIGH IS CENTERED OVER THE TROPICAL ATLANTIC NEAR 19N48W. ANOTHER UPPER LEVEL HIGH IS CENTERED OVER THE CAPE VERDE ISLANDS NEAR 16N23W. $$ FORMOSA