000 AXNT20 KNHC 162341 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED JUL 16 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 2245 UTC. ...SPECIAL FEATURES... TROPICAL STORM BERTHA IS CENTERED NEAR 36.1N 60.5W AT 16/2100 UTC MOVING SE AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 995 MB. MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC AND THE PUBLIC ADVISORY UNDER MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS. BERTHA IS MAINTAINING TROPICAL STORM STRENGTH AND LARGE-SCALE GUIDANCE SUGGESTS THAT THE ENVIRONMENT AROUND THE STORM SHOULD BE FAVORABLE ENOUGH TO MAINTAIN THE INTENSITY FOR A DAY OR SO. DEEP CONVECTION IS WEAKENING WITH A BROAD AREA OF SCATTERED SHOWERS FROM 34N-39N BETWEEN 58W-63W AND SE OF THE CENTER FROM WITHIN 90/120 NM OF LIEN FROM 30N53W TO 35N58W. TROPICAL WAVE IS ALONG 58W S OF 17N MOVING W NEAR 20 KT WITH A 1009 MB LOW ANALYZED ALONG THE AXIS NEAR 12N. THIS WAVE WAS INVESTIGATED BY AND FOUND A BROAD AREA OF LOW PRESSURE BUT NO WELL DEFINED CIRCULATION CENTER. HOWEVER CONDITIONS IN THE E CARIBBEAN ARE CONDUCTIVE FOR FURTHER DEVELOPMENT AND COULD BECOME A TROPICAL DEPRESSION LATER TODAY OR TOMORROW. REGARDLESS OF DEVELOPMENT...THE SYSTEM IS EXPECTED TO BRING GUSTY WINDS AND LOCALLY HEAVY RAINS TO THE WINDWARD ISLANDS OVER THE NEXT DAY OR SO. SCATTERED MODERATE/STRONG CONVECTION IS FROM 12N-14N BETWEEN 59W-62W WITH SCATTERED/LOCALLY HEAVY SHOWERS/ISOLATED THUNDERSTORMS S OF 14N BETWEEN 55W-64W. TROPICAL WAVE IS ALONG 78W S OF 21 MOVING W 15-20 KT. ALTHOUGH THE SHOWER ACTIVITY IS CURRENTLY POORLY ORGANIZED THE UPPER LEVEL WINDS ARE FAVORABLE FOR DEVELOPMENT AND THIS COULD BECOME A TROPICAL DEPRESSION BEFORE MOVING INTO CENTRAL AMERICA IN THE NEXT DAY OR SO. HEAVY RAINS AND GUSTY WINDS ARE LIKELY TO MOVE OVER PORTIONS OF NICARAGUA AND HONDURAS TOMORROW...WITH FLASH FLOODING AND MUDSLIDES POSSIBLE...ESPECIALLY IN HIGHER TERRAIN. BROAD AREA OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS S OF 18N BETWEEN 73W-85W INCLUDING THE NW COAST OF COLOMBIA THROUGH NICARAGUA MOVING INTO HONDURAS. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 38W S OF 18N MOVING W 15-20 KT. BROAD INVERTED-V CURVATURE IS OBSERVED ON SATELLITE IMAGERY WITH NO ASSOCIATED DEEP CONVECTION. WAVE IS MOVING INTO AN AREA OF DRIER AIR THUS NO ASSOCIATED SHOWER CLUSTERS. THE ITCZ... ITCZ AXIS IS CENTERED ALONG 8N12W 4N25W 5N43W 8N55W. SCATTERED/ NUMEROUS STRONG CONVECTION IS WITHIN 75 NM OF LINE FROM 7N12W TO 8N17W WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERING THE REMAINDER OF THE AREA FROM 5N-11N BETWEEN 11W-19W. CLUSTERS OF SIMILAR CONVECTION ARE FROM 5N-9N BETWEEN 49W-54W. DISCUSSION... GULF OF MEXICO... A BIG FOCUS THIS EVENING FOR THE GULF IS THE 1015 MB LOW INLAND OVER CENTRAL FLORIDA WITH A SURFACE TROUGH EXTENDING SW INTO THE FLORIDA BAY. THIS SYSTEM IS NOT EXPECTED TO DEVELOP BUT IS PRODUCING LOCALLY HEAVY RAINS WITH SCATTERED THUNDERSTORMS OVER THE FLORIDA PENINSULA AND THE FLORIDA KEYS. THE DEEP LAYERED TROUGH OVER THE NE U.S. AND INTO THE NW ATLC IS GRADUALLY MOVING OUT OF THE GULF BUT A SHORTWAVE UPPER TROUGH REMAINS EXTENDING FROM NEAR PENSACOLA FLORIDA S TO 25N89W. AN UPPER RIDGE EXTENDS FROM MEXICO E INTO THE GULF JUST S OF THE SHORTWAVE UPPER TROUGH AND IS PROVIDING DIFFLUENCE ALOFT TO GENERATE AN AREA OF SCATTERED SHOWERS/THUNDERSTORMS IN THE CENTRAL GULF FROM 23N-27N BETWEEN 86W-94W. OTHERWISE THE REMAINDER OF THE GULF REMAINS TRANQUIL THIS EVENING. CARIBBEAN SEA... THE FOCUS THIS EVENING FOR THE W CARIBBEAN IS TWO FOLD...THE TROPICAL WAVE ALONG 78W AND THE SE CARIBBEAN WITH THE APPROACHING TROPICAL WAVE ALONG 58W. SEE SPECIAL FEATURES ABOVE. AN UPPER HIGH IS JUST S OF PUERTO RICO COVERING THE E CARIBBEAN AND INTO THE W TROPICAL ATLC E OF THE LEEWARD ISLANDS. THIS UPPER RIDGE IS ENHANCING THE SCATTERED SHOWERS/THUNDERSTORMS THAT HAVE DEVELOPED INLAND OVER HISPANIOLA WITH THE HEAVIEST CONCENTRATION OVER HAITI. THE REMAINDER OF THE CARIBBEAN IS RATHER TRANQUIL THIS EVENING WITH NEAR CLEAR SKIES. ATLANTIC OCEAN... A 1015 MB LOW IS INLAND OVER CENTRAL FLORIDA WITH A SURFACE TROUGH EXTENDING SW INTO THE FLORIDA BAY. THIS SYSTEM IS NOT EXPECTED TO DEVELOP BUT IS PRODUCING LOCALLY HEAVY RAINS WITH SCATTERED THUNDERSTORMS OVER THE FLORIDA PENINSULA MOVING INTO THE THE FAR W ATLC WITHIN 120 NM OF LINE FROM 32N76W TO FLORIDA NEAR WEST PALM BEACH. AN AREA OF SURFACE HIGH PRESSURE IS LOCATED S OF T.S. BERTHA CENTERED BY A 1022 MB HIGH NEAR 27N65W. A DEEP LAYERED LOW IS TO THE E OF BERTHA AND N OF THE REGION NEAR 35N51W WITH THE UPPER TROUGH EXTENDING S INTO THE REGION TO 22N BETWEEN 43W-55W WITH A SURFACE TROUGH EXTENDING THROUGH 32N48W TO 26N53W. BROAD UPPER HIGH COVERS THE E ATLC CENTERED NEAR 30N26W. A SURFACE RIDGE COVERS THE E ATLC E OF 43W FROM A 1038 MB HIGH N OF THE AZORES. $$ WALLACE