000 AXNT20 KNHC 171058 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU JUL 17 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...SPECIAL FEATURES... TROPICAL STORM BERTHA IS CENTERED NEAR 34.5N 59.2W AT 17/0900 UTC MOVING SE AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 997 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 KEEP BERTHA ABLE TO MAINTAIN ITS INTENSITY FOR THE NEXT COUPLE DAYS BEFORE THE SYSTEM BEGINS EXTRATROPICAL TRANSITION. THEREAFTER BERTHA IS EXPECTED TO ACCELERATE NORTHEASTWARD AS UPPER LEVEL SHEAR INCREASES. THE CYCLONE IS PRODUCING VERY LITTLE IN THE WAY OF DEEP CONVECTION WITH ONLY A SMALL AREA OF SCATTERED MODERATE SHOWERS AND TSTMS WITHIN 90 NM OF THE CENTER IN THE EASTERN SEMICIRCLE. OTHER SCATTERED MODERATE SHOWERS WITH POSSIBLE EMBEDDED TSTMS ARE ROTATING AROUND AN UPPER LEVEL LOW NEAR 37N50W. TROPICAL WAVE IS ALONG 62W/63W S OF 19N MOVING W NEAR 20 KT WITH A 1009 MB LOW ANALYZED ALONG THE AXIS NEAR 12N. THIS WAVE WILL POSSIBLY BE INVESTIGATED LATER TODAY BY AN AIR FORCE RECONNAISSANCE AIRCRAFT. CONDITIONS IN THE ERN CARIBBEAN ARE CONDUCIVE FOR FURTHER DEVELOPMENT AND IT 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 SRN WINDWARD ISLANDS...INCLUDING THE ABC ISLANDS... OVER THE NEXT DAY OR SO. SCATTERED MODERATE CONVECTION IS FROM 10N-14N BETWEEN 62W-67W WITH SCATTERED/LOCALLY HEAVY SHOWERS CONTINUING ACROSS THE WINDWARD ISLANDS AND NERN VENEZUELA. TROPICAL WAVE IS ALONG 81W/82W S OF 22N MOVING W 15-20 KT WITH A 1011 MB LOW ANALYZED ALONG THE AXIS NEAR 12N. ALTHOUGH THE CONVECTIVE ACTIVITY IS CURRENTLY POORLY ORGANIZED AND COVERS MUCH OF THE WRN CARIBBEAN...THE UPPER LEVEL WINDS ARE FAVORABLE FOR DEVELOPMENT AND THIS COULD BECOME A TROPICAL DEPRESSION BEFORE MOVING INTO CENTRAL AMERICA DURING THE NEXT DAY OR SO. HEAVY RAINS AND GUSTY WINDS ARE LIKELY TO MOVE OVER PORTIONS OF NICARAGUA AND HONDURAS TODAY AND TOMORROW...WITH FLASH FLOODING AND MUDSLIDES POSSIBLE...ESPECIALLY IN THE HIGHER TERRAIN. BROAD AREA OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS S OF 20N BETWEEN 75W-84W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 42W 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 UPPER LEVEL AIR THUS NO ASSOCIATED SHOWER CLUSTERS. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 10N14W 7N24W 11N34W 11N41W 10N44W 7N53W 10N61W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 4N-11N BETWEEN 14W-21W. SCATTERED MODERATE CONVECTION IS FROM 4N-7N BETWEEN 26W-33W. SIMILAR CONVECTION IS FROM 7N-10N BETWEEN 48W-52W. ...DISCUSSION... GULF OF MEXICO... A 1015 MB LOW IS INLAND OVER EAST CENTRAL FLORIDA WITH A SURFACE TROUGH EXTENDING SW TO SARASOTA FLORIDA AND INTO THE ERN GULF NEAR 27N84W. THIS SYSTEM IS NOT EXPECTED TO DEVELOP BUT AN AREA OF SCATTERED SHOWERS WITH EMBEDDED THUNDERSTORMS ARE OVER THE CENTRAL FLORIDA PENINSULA AND AN AREA WITHIN 90 NM OFFSHORE OF FORT MYERS FLORIDA. A DEEP LAYERED TROUGH IS OFFSHORE THE NE U.S. SEABOARD AND EXTENDS INTO THE NW ATLC. IT IS GRADUALLY MOVING NW OF THE DISCUSSION AREA BUT A CUTOFF UPPER LOW REMAINS ACROSS THE NORTH CENTRAL GULF EXTENDING FROM NEAR PENSACOLA FLORIDA WSW TO 25N93W. AN UPPER RIDGE EXTENDS FROM MEXICO E INTO THE FAR WRN GULF TO NEAR THE YUCATAN PENINSULA. THIS FEATURE IS PROVIDING DIFFLUENCE ALOFT TO GENERATE AN AREA OF SCATTERED SHOWERS IN THE WRN GULF FROM 24N-27N BETWEEN 91W-96W. OTHERWISE THE REMAINDER OF THE GULF REMAINS TRANQUIL WITH LIGHT WINDS CIRCULATING AROUND A WEAK 1019 MB SURFACE HIGH PRESSURE CENTERED NEAR 26N92W. CARIBBEAN SEA... THE FOCUS FOR THE CARIBBEAN SEA REMAINS THE TWO WELL-DEFINED TROPICAL WAVES WITHIN THE BASIN...THE TROPICAL WAVE ALONG 81W/82W...AND THE SE CARIBBEAN WITH THE APPROACHING TROPICAL WAVE ALONG 62W/63W. SEE SPECIAL FEATURES ABOVE. AN UPPER RIDGE IS S OF PUERTO RICO COVERING THE ERN CARIBBEAN AND IS ANCHORED ON AN UPPER HIGH IN THE CENTRAL CARIBBEAN NEAR 15N73W. ANOTHER UPPER LEVEL HIGH IS ACROSS THE NW CARIBBEAN NEAR 18N83W AND IS AIDING IN PROVIDING AMPLE UPPER DIFFLUENCE ACROSS A MAJORITY OF THE BASIN W OF 73W TO SUPPORT CONVECTIVE SHOWERS AND TSTMS ASSOCIATED WITH THE TROPICAL WAVES. UPPER LEVEL TROUGHING EXTENDS FROM THE W ATLC ACROSS THE SE BAHAMAS...ERN CUBA AND THE WINDWARD PASSAGE. UPPER LEVEL DIFFLUENCE E OF THE TROUGH IS GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED TSTMS FROM 18N-20N BETWEEN 75W-81W. ATLANTIC OCEAN... A 1015 MB LOW IS INLAND OVER EAST CENTRAL FLORIDA WITH A SURFACE TROUGH EXTENDING SW INTO THE ERN GULF OF MEXICO. THIS SYSTEM IS NOT EXPECTED TO DEVELOP BUT AN AREA OF SCATTERED SHOWERS WITH EMBEDDED THUNDERSTORMS ARE OVER THE CENTRAL FLORIDA PENINSULA. THIS SURFACE LOW ALONG WITH UPPER LEVEL DIFFLUENCE ASSOCIATED WITH TROUGHING LOCATED ALONG THE ERN U.S. SEABOARD IS PRODUCING AN AREA OF SCATTERED MODERATE SHOWERS IN THE W ATLC FROM 29N-32N BETWEEN 73W-80W. AN WEAK RIDGE OF SURFACE HIGH PRESSURE IS LOCATED S OF T.S. BERTHA WITH AXIS ALONG 23N60W 25N70W TO ABACO ISLAND IN THE NW BAHAMAS. A DEEP LAYERED LOW IS TO THE E OF BERTHA AND N OF THE REGION NEAR 37N50W WITH THE UPPER TROUGH EXTENDING S INTO THE REGION TO 26N BETWEEN 42W-52W WITH A SURFACE TROUGH EXTENDING THROUGH 32N51W TO 28N54W. BROAD UPPER HIGH COVERS THE ERN ATLC CENTERED NEAR 30N33W. A SURFACE RIDGE COVERS THE ERN ATLC E OF 43W FROM A 1034 MB HIGH N OF THE AZORES. $$ HUFFMAN