000 AXNT20 KNHC 212355 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE AUG 21 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURE... HURRICANE DEAN IS CENTERED NEAR 19.7N 92.2W...OR 95 NM W OF CAMPECHE MEXICO AT 22/0000 UTC MOVING W AT 17 KT. MAXIMUM SUSTAINED WIND SPEED IS 70 KT WITH GUSTS TO 90 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 970 MB. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC AND THE LATEST PUBLIC ADVISORY UNDER MIATCPAT4/WTNT34 KNHC FOR MORE DETAILS. HURRICANE DEAN AS EMERGED INTO THE S GULF OF MEXICO IN THE BAY OF CAMPECHE LOSING STRENGTH AS IT CROSSED THE YUCATAN PENINSULA. DEAN RETAINS ITS INNER CORE AND COULD BECOME A MAJOR HURRICANE AGAIN BEFORE MAKING LANDFALL OVER MEXICO LATE WED. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS S OF 20N TO INLAND OVER S MEXICO FROM 90W-95W. OUTER RAINBANDS WITH SCATTERED THUNDERSTORMS ARE OVER THE W GULF S OF 28N W OF 91W TO THE COAST OF MEXICO AND SE TEXAS. ...TROPICAL WAVES... TROPICAL WAVE IS FROM 5N51W TO 21N56W MOVING W 15-20 KT. ALTHOUGH THIS WAVE HAS A WELL DEFINED INVERTED-V CURVATURE TO A RATHER HIGH AMPLITUDE THERE IS NO ASSOCIATED DEEP CONVECTION. TROPICAL WAVE IS ALONG 69W S OF 29N MOVING W 15-20 KT. VERY BROAD HIGH AMPLITUDE WAVE WITH A WELL DEFINED INVERTED-V CURVATURE. THIS IS HAS MOVED INTO AN AREA NOT FAVORABLE FOR FURTHER DEVELOPMENT. CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 120/150 NM OF LINE FROM 19N61W 28N68W TO THE BAHAMAS NEAR 23N75W. NO ASSOCIATED CONVECTION IN THE CARIBBEAN. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 12N15W 10N31W 8N43W 10N50W 7N59W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 7N TO THE ITCZ AXIS BETWEEN 15W-26W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 5N-10N BETWEEN 32W-50W AND FROM 9N-13N BETWEEN 52W-55W. DISCUSSION... GULF OF MEXICO... THE MAIN FOCUS THIS EVENING REMAINS HURRICANE DEAN THAT HAS MOVED OFF THE YUCATAN PENINSULA INTO THE BAY OF CAMPECHE. SEE SPECIAL FEATURES ABOVE. AN UPPER RIDGE EXTENDS ACROSS THE W GULF FROM THE UPPER HIGH LOCATED NEAR DEAN TO OVER LOUISIANA ENHANCING THE ACTIVITY OF THE OUTER RAINBANDS ASSOCIATED DEAN. A WEAK UPPER HIGH IN THE W ATLC EXTENDS ACROSS FLORIDA TO OVER THE E GULF GIVING THE AREA DRY STABLE AIR. SOME LATER AFTERNOON LOW LEVEL THUNDERSTORMS HAVE DRIFTED OFF THE SW COAST OF FLORIDA INTO FLORIDA BAY AND OFF W CUBA INTO THE YUCATAN CHANNEL. OTHERWISE...THE E GULF E OF 90W IS CLEAR THIS EVENING. CARIBBEAN SEA... IN THE WAKE OF DEAN...THE WINDS ARE BEGINNING TO DIMINISH WITH THE SEAS SUBSIDING OVER THE NEXT 12 TO 24 HOURS. A BROAD UPPER LOW DOMINATES THE CARIBBEAN AND IS CENTERED OFF THE S COAST OF HAITI NEAR 18N74W EXTENDING AN UPPER TROUGH N OVER THE W ATLC WITH A WEAKER UPPER TROUGH EXTENDING WSW TO NEAR 16N81W. THIS UPPER LOW IS DRAWING TROPICAL MOISTURE ACROSS THE S CARIBBEAN GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 14N W OF 78W WITH SOME MID LEVEL CYCLONIC ROTATION OFF THE COAST OF COLOMBIA NEAR 12N78W. ATLANTIC OCEAN... WEAK UPPER HIGH IS OVER THE W ATLC NEAR 30N79W COVERING THE AREA W OF 75W AND EXTENDING INTO THE E GULF OF MEXICO. DRY STABLE AIR COVERS THE FAR W ATLC W OF 75W WITH SOME LOW LEVEL ISOLATED SHOWERS/THUNDERSTORMS BROUGHT IN BY MODERATE EASTERLY SURFACE FLOW OVER THE N BAHAMA ISLANDS. BROAD UPPER TROUGH EXTENDS FROM THE UPPER LOW JUST S OF HAITI TO NEAR 28N67W. A TROPICAL WAVE IS BENEATH THIS UPPER TROUGH ENHANCING SHOWERS/THUNDERSTORMS ASSOCIATED WITH THE TROPICAL WAVE. A BENIGN UPPER HIGH/LOW ARE OVER THE CENTRAL ATLC WHILE TYPICAL UPPER RIDGING EXTENDS E FROM AFRICA OUT TO 27W. LARGE SURFACE RIDGE REMAINS IN CONTROL OF THE ATLC TO ACROSS THE SE US AND N GULF OF MEXICO. ALL OF THIS IS PRODUCING ABUNDANT STABLE CONDITIONS AND MODERATE TRADE WINDS ACROSS THE ATLC WITH THE EXCEPTION OF THE AREA ASSOCIATED WITH THE TROPICAL WAVE. $$ WALLACE