000 AXNT20 KNHC 170605 AAA TWDAT TROPICAL WEATHER DISCUSSION...UPDATE ON HURRICANE DEAN NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT FRI AUG 17 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0415 UTC. ...SPECIAL FEATURES... HURRICANE DEAN IS CENTERED NEAR 14.3N 59.8W AT 17/0600 UTC OR ABOUT 74 NM ESE OF MARTINIQUE AND 78 NM NNW OF BARBADOS MOVING W AT 22 KT. ON THIS TRACK DEAN WILL BE PASSING VERY NEAR THE ISLANDS OF ST. LUCIA AND MARTINIQUE WITHIN THE NEXT SIX HOURS. ESTIMATED MINIMUM CENTRAL PRESSURE IS 976 MB. MAXIMUM SUSTAINED WIND SPEED IS 85 KT WITH GUSTS TO 105 KT...MAKING DEAN A CATEGORY TWO HURRICANE. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC OR THE INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT4/WTNT34 FOR MORE DETAILS. DEAN CONTINUES TO MOVE RATHER QUICKLY ALONG THE SOUTHERN PERIPHERY OF A MID LEVEL RIDGE THAT HAS MOVED IN TANDEM WITH DEAN. DEAN IS EXPECTED TO CONTINUE TO STRENGTHEN AS IT CROSSES THE LESSER ANTILLES LATER TODAY AND THROUGH THE CARIBBEAN. OUTER RAINBANDS HAVE ALREADY REACHED THE CENTRAL LESSER ANTILLES WITH HEAVY SHOWERS AND EMBEDDED THUNDERSTORMS FROM GRENADA TO GUADELOUPE. SCATTERED MODERATE/ ISOLATED STRONG CONVECTION IS FROM 12N-17N BETWEEN 55W-60W WITH CLUSTERS OF SIMILAR CONVECTION COVERING A BROADER AREA FROM 11N-17N BETWEEN 52W-65W. TROPICAL DEPRESSION ERIN CONTINUES TO WEAKEN AND MOVE FARTHER INLAND OVER SOUTH TEXAS. ERIN IS PRODUCING HEAVY RAINS ACROSS S/CENTRAL AND SE TEXAS. FURTHER INFORMATION ON ERIN CAN BE FOUND IN PUBLIC ADVISORIES ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER...UNDER AWIPS HEADER TCPAT5 AND WMO HEADER WTNT35 KWNH. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 26W S OF 20N MOVING W 15-20 KT. BROAD LOW/MID LEVEL ROTATION IS OBSERVED WITH NO ASSOCIATED SHOWERS/CONVECTION. TROPICAL WAVE IS ALONG 39W S OF 19N MOVING W 15-20 KT. BROAD LOW/MID LEVEL SLIGHTLY TILTED CURVATURE REMAINS MOSTLY TO THE W OF THE WAVE AXIS. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 11N-13N BETWEEN 39W-43W. TROPICAL WAVE OVER THE CENTRAL CARIBBEAN IS ALONG 71W/72W S OF 19N MOVING W NEAR 20 KT. WEAK BUT WELL DEFINED LOW LEVEL INVERTED-V CURVATURE IS IN THE CENTRAL CARIBBEAN. NO ASSOCIATED DEEP CONVECTION WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN A 45 NM RADIUS OF 16N73W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 16N16W 12N29W 10N37W 9N42W 14N54W BECOMING DISTORTED DUE TO HURRICANE DEAN. SEE SPECIAL FEATURES ABOVE. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90/120 NM OF A LINE FROM 10N16W 10N21W TO 7N27W WITH CLUSTERS OF SIMILAR CONVECTION CONTINUING W TO 7N45W. DISCUSSION... GULF OF MEXICO... THE W GULF OF MEXICO REMAINS UNDER DENSE CLOUDINESS AND WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS IN THE WAKE OF TROPICAL DEPRESSION ERIN THAT MOVED INLAND OVER S TEXAS ON THU. AN UPPER LEVEL RIDGE FROM THE UPPER HIGH NEAR ERIN EXTENDS S OVER E MEXICO INDUCING AN INVERTED TROUGH ACROSS THE CENTRAL GULF. LARGE UPPER LOW IN THE W ATLC EXTENDS ACROSS FLORIDA GENERATING SCATTERED SHOWERS/THUNDERSTORMS WITHIN 75 NM OF THE W COAST OF FLORIDA FROM FLORIDA KEYS TO N OF TAMPA. THE SURFACE RIDGE FROM THE ATLC EXTENDS ACROSS FLORIDA AND OVER THE E GULF GIVING THE REMAINDER OF THE E GULF MOSTLY CLEAR SKIES TONIGHT. CARIBBEAN SEA... THE LARGE UPPER LOW DIPS S ACROSS CUBA AND HISPANIOLA INTO THE N CARIBBEAN N OF 16N W OF 70W TO THE YUCATAN PENINSULA GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS MAINLY IN THE YUCATAN CHANNEL N OF 20N W OF 83W. THE MAIN CONCERN TONIGHT IS HURRICANE DEAN AS IT APPROACHES THE LESSER ANTILLES AND IS ALREADY BRINGING HEAVY SHOWERS WITH EMBEDDED THUNDERSTORMS TO THE ISLANDS...SEE SPECIAL FEATURES ABOVE. THE ITCZ ENTERS THE E PACIFIC REGION JUST S OF THE PANAMA BUT IS PRODUCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS TO THE SW CARIBBEAN S OF 11N FROM COLOMBIA TO COSTA RICA. THE REMAINDER OF THE AREA REMAINS RATHER CLEAR TONIGHT BUT CONDITIONS WILL DETERIORATE AS HURRICANE DEAN CROSSES THE AREA DURING NEXT FEW DAYS. ATLANTIC OCEAN... LARGE UPPER LOW IS CENTERED IN THE W ATLC NEAR 28N75W COVERING THE AREA W OF 68W TO ACROSS FLORIDA AND INTO THE N CARIBBEAN BUT WITH THE DRY NEAR STABLE AIR IS ONLY ABLE TO PRODUCE SOME SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER HISPANIOLA TO OVER THE TURKS AND CAICOS. AN UPPER HIGH IS NEAR 26N60W AND AN UPPER LOW IS NEAR 27N48W BUT BOTH ARE RATHER BENIGN UPPER FEATURES. BROAD UPPER RIDGE EXTENDS E/W FROM OFF AFRICA TO 40W WITH THE AXIS ALONG 19W/20W. DRY STABLE AIR DOMINATES THE ATLC WITH THE EXCEPTION OF HURRICANE DEAN. A BROAD SURFACE RIDGE ALSO DOMINATES THE ATLC INTO THE E GULF OF MEXICO ANCHORED BY A 1030 MB HIGH JUST W OF THE AZORES AND A 1029 MB HIGH JUST N OF THE AZORES GIVING THE ATLC FAIR WEATHER AND MODERATE TRADE WINDS E OF 60W. $$ WALLACE