000 AXNT20 KNHC 041751 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURE.... TROPICAL STORM BERTHA CENTERED NEAR 14.9N 29.7W AT 1500 UTC OR ABOUT 335 NM W OF THE CAPE VERDE ISLANDS MOVING WNW AT 14 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. BERTHA HAS MOVED W OF THE CAPE VERDE ISLANDS. A BURST OF ISOLATED STRONG CONVECTION IS LOCATED N OF THE CIRCULATION CENTER BETWEEN 29W-31W...WITH SCATTERED MODERATE CONVECTION WITHIN 180 NM N AND 90 NM S OF THE CENTER. BERTHA WILL BE PASSING OVER SLIGHTLY COOLER WATERS DURING THE NEXT 24 HOURS IN WHICH IT WILL MAINTAIN ITS INTENSITY WITH GRADUAL STRENGTHENING FORECAST THEREAFTER AS ATMOSPHERIC CONDITIONS APPEAR MORE FAVORABLE AND OCEANIC CONDITIONS REMAIN MARGINAL. ...TROPICAL WAVES... TROPICAL WAVE IS TILTED ALONG 54W/55W 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 S OF 19N MOVING W 15-20 KT. SATELLITE IMAGERY SHOWS CLASSIC INVERTED-V CURVATURE SIGNATURE ALONG WAVE AXIS NORTH OF 14N WITH SCATTERED SHOWERS AND TSTMS FROM 15N-18N BETWEEN 66W-73W IN AN AREA MAINLY SOUTH OF HISPANIOLA. TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN ALONG 82W/83W S OF 15N MOVING W 10-15 KT. THIS WAVE LIES IN AN UPPER DIFFLUENT ZONE ON THE S SIDE OF AN UPPER HIGH. THESE TWO FEATURES TOGETHER ARE PRODUCING WIDESPREAD SHOWERS AND SCATTERED STRONG TSTMS FROM 11N-16N BETWEEN 81W-85W WHICH INCLUDES FAR ERN HONDURAS AND NICARAGUA. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 10N14W 13N21W 8N31W 6N34W 5N52W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 5N-11N BETWEEN 14W-20W. SIMILAR CONVECTION IS FROM 6N-9N BETWEEN 27W-34W. ISOLATED MODERATE CONVECTION IS WITHIN 120 NM SOUTH OF THE AXIS BETWEEN 36W-42W AND BETWEEN 46W-51W. ...DISCUSSION... THE GULF OF MEXICO... THE LARGE SCALE PATTERN ACROSS THE GULF CONSISTS OF AN ELONGATED UPPER TROUGH EXTENDING FROM OFFSHORE OF THE ERN CONUS SW ACROSS NRN FLORIDA AND INTO THE ERN GULF WATERS..AND AN UPPER LOW SPINNING OVER SOUTHEAST TEXAS. BROAD RIDGING IS ACROSS CENTRAL MEXICO EXTENDING INTO THE WEST CENTRAL GULF WATERS. THIS PATTERN IS PRODUCING A FAIR AMOUNT OF MOISTURE OVER THE ENTIRE GULF. HOWEVER...LIGHTNING DATA INDICATES THAT ONLY THE MID TO UPPER LEVEL DIFFLUENCE E OF THE UPPER LOW ACROSS SE TEXAS IS SUSTAINING SCATTERED SHOWER AND TSTM ACTIVITY ACROSS THE WRN GULF SKIRTING COASTAL TEXAS AND MEXICO SWD INTO THE WRN BAY OF CAMPECHE. MOST OF THIS ACTIVITY REMAINS W OF 94W. AT THE SURFACE...RIDGE OF HIGH PRESSURE EXTENDING FROM THE W ATLC COVERS MUCH OF THE NE GULF KEEPING WINDS LIGHT AND VARIABLE N OF 25N AND E OF 90W. ELSEWHERE...WINDS REMAIN EAST TO SOUTHEASTERLY FROM 10-20 KT ACROSS THE WRN AND SRN GULF. THE CARIBBEAN SEA... A PAIR OF TROPICAL WAVES ARE PROPAGATING ACROSS THE SEA. THE EASTERN ONE ALONG 71W IS WELL DEFINED WITH CLUSTERS OF SCATTERED SHOWERS AND TSTMS N OF 15N TO THE SRN COAST OF HISPANIOLA BETWEEN 66W-73W. THE OTHER WAVE ALONG 82W/83W IS AIDING IN PRODUCING WIDESPREAD SHOWERS AND SCATTERED STRONG TSTMS ACROSS THE WRN CARIBBEAN AND ERN HONDURAS/NICARAGUA AS IT TRACKS UNDER AN UPPER DIFFLUENT AREA. THIS UPPER LEVEL DIFFLUENT AREA IS ANCHORED BY AN UPPER HIGH CENTERED NEAR 15N80W WHICH HAS CONTINUED TO CONCENTRATE HEAVY AMOUNTS OF RAINFALL ACROSS ERN NICARAGUA WHERE POTENTIAL FOR FLOODING AND MUDSLIDES REMAIN. ELSEWHERE...DEEP CONVECTION IS FAIRLY MINIMAL DUE TO NW FLOW AND DRIER AIR ALOFT ACROSS ERN CUBA/JAMAICA...AND STRONG UPPER LEVEL SUBSIDENCE/DRY AIR ACROSS THE FAR ERN CARIBBEAN AND LESSER ANTILLES. THE ATLANTIC OCEAN... THE UPPER PATTERN REMAINS DIFFLUENT OVER THE W ATLC IN ASSOCIATION WITH ELONGATED TROUGHING OVER THE ERN SEABOARD OF THE U.S. AND A NARROW SLIGHTLY AMPLIFIED RIDGE E OF THE BAHAMAS ALONG 70W. THIS PATTERN IS PRODUCING A LARGE SWATH OF CLOUDINESS WHICH EXTENDS FROM NEAR WEST PALM BEACH FLORIDA TO 32N75W AND NORTHEAST OF THE DISCUSSION AREA. SCATTERED SHOWERS WITH EMBEDDED TSTMS ARE OBSERVED N OF 26N AND W OF 76W. FARTHER E...A LARGE UPPER LOW IS SPINNING NEAR 33N54W WITH TROUGHING EXTENDING S TOWARDS THE NE CARIBBEAN. LARGE SCALE RIDGING HOLDS E OF THERE WITH AN UPPER HIGH POSITIONED NEAR 20N49W. OVERALL...THIS PATTERN IS PRODUCING LITTLE SENSIBLE WEATHER. AT THE SURFACE...A PAIR OF QUASI-STATIONARY HIGHS ARE OVER THE CENTRAL ATLC...ONE ANALYZED 1027 MB NEAR 35N39W...THE OTHER 1026 MB HIGH NEAR 33N59W. A SURFACE TROUGH IS WEAKENING THE RIDGE FROM 26N53W TO 33N47W. THIS TROUGH AND ASSOCIATED IMPULSE OF MID-LEVEL ENERGY APPEARS TO BE PARTLY ASSOCIATED WITH THE LARGE TROPICAL WAVE TO THE S AND THE UPPER LOW CENTERED TO THE NW. SCATTERED LOW-LEVEL SHOWERS ARE WITHIN 150 NM OF THE AXIS. $$ HUFFMAN