000 AXNT20 KNHC 192355 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN AUG 19 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 2330 UTC. ...SPECIAL FEATURE... AS OF 20/0000 UTC THE EYE OF EXTREMELY DANGEROUS HURRICANE DEAN WAS LOCATED NEAR LATITUDE 17.5 NORTH...LONGITUDE 77.8 WEST OR ABOUT 70 MILES...115 KM...WEST-SOUTHWEST OF KINGSTON JAMAICA AND ABOUT 265 MILES...425 KM...EAST-SOUTHEAST OF GRAND CAYMAN. DEAN IS MOVING TOWARD THE WEST NEAR 20 MPH...32 KM/HR. A MOTION BETWEEN WEST AND WEST-NORTHWEST IS EXPECTED OVER THE NEXT 24 HOURS. ON THE FORECAST TRACK...THE CENTER OF DEAN WILL BE PASSING VERY NEAR THE SOUTHWESTERN COAST OF JAMAICA DURING THE NEXT SEVERAL HOURS...AND JUST SOUTH OF THE CAYMAN ISLANDS ON MONDAY. MAXIMUM SUSTAINED WINDS REMAIN NEAR 125 KT WITH GUSTS TO 155 KT...THIS MAKES DEAN A STRONG CATEGORY FOUR HURRICANE. THE ESTIMATED MINIMUM CENTRAL PRESSURE WAS 930 MB. FLUCTUATIONS IN INTENSITY ARE COMMON IN MAJOR HURRICANES AND ARE POSSIBLE DURING THE NEXT 24 HOURS. DEAN HAS THE POTENTIAL TO BECOME A CATEGORY FIVE HURRICANE IN THE NORTHWESTERN CARIBBEAN SEA ON MONDAY ...LIKE GILBERT IN 1988 AND WILMA IN 2005. ALL INTERESTS IN THE WESTERN CARIBBEAN SEA...AND THE GULF OF MEXICO SHOULD CLOSELY MONITOR THE PROGRESS OF THIS POWERFUL HURRICANE. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC AND THE LATEST PUBLIC ADVISORY UNDER MIATCPAT4/WTNT34 KNHC FOR THE MOST RECENT WATCH AND WARNING INFORMATION. FOR STORM INFORMATION SPECIFIC TO YOUR AREA...INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS...PLEASE MONITOR PRODUCTS ISSUED BY YOUR LOCAL WEATHER OFFICE. KINGSTON JAMAICA REPORTED SUSTAINED WINDS OF 70 KT AT 21Z IN THE NE EYEWALL. THE SATELLITE APPEARANCE OF DEAN REMAINS VERY IMPRESSIVE WITH GOOD SYMMETRY TO IT'S EYE...EYEWALL...SPIRAL RAINBANDS AND OUTFLOW. NUMEROUS MODERATE TO STRONG CONVECTION IS WITHIN 90 NM OF THE CENTER. OUTER BANDS OF DEAN SPREAD MUCH FARTHER AND ROUGHLY COVER THE REGION FROM 15N-21N BETWEEN 71W-80W. ...TROPICAL WAVES... LARGE TROPICAL WAVE IS TILTED ALONG 23N50W 5N55W MOVING W NEAR 20 KT OVER THE PAST 24 HOURS. THE ASSOCIATED SFC CYCLONIC TURNING SHOWS UP NICELY IN THE SURROUNDING BUOY/SHIP DATA. A 1009 MB LOW IS ALONG THIS WAVE NEAR 12N54W. THE LOW IS RATHER WEAK AT THE MOMENT WITH THE CENTER PARTIALLY EXPOSED TO THE NE OF AN AREA OF DENSER CLOUDS. DEVELOPMENT...ASSOCIATED WITH THIS SMALL LOW...APPEARS UNLIKELY. THE REMAINDER OF THE AXIS IS EMBEDDED WITHIN A LARGE CYCLONIC GYRE. THE NRN PORTION OF THE WAVE IS THE ACTIVE REGION...IN TERMS OF CONVECTION...WITH IR IMAGERY AND LIGHTNING DATA SHOWING SCATTERED SHOWERS AND TSTMS FROM 18N-23N BETWEEN 48W-55W. THIS ACTIVITY IS BEING ENHANCED BY AN ELONGATED UPPER TROUGH. THIS PORTION OF THE WAVE WILL CONTINUE TO BE MONITORED AS SLOW DEVELOPMENT APPEARS POSSIBLE AS IT TRACKS WNW OVER THE NEXT COUPLE OF DAYS. THE NRN PORTION OF A TROPICAL WAVE ALONG 91W/92W EXTENDS INTO THE BAY OF CAMPECHE S OF 21N MOVING W 10-15 KT. VIS IMAGES SHOW A WEAK AREA OF CYCLONIC TURNING EVIDENT ALONG THE S PORTION OF THE WAVE OVER THE EPAC WATERS. THE INTERACTION BETWEEN THIS WAVE AND AN UPPER LOW IN THE MID-GULF IS PRODUCING SCATTERED SHOWERS AND TSTMS OVER THE YUCATAN PENINSULA AND OVER THE CENTRAL GULF WATERS...SEE GULF DISCUSSION BELOW FOR MORE DETAILS. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 12N15W 7N27W 14N49W 9N61W. ISOLATED MODERATE CONVECTION IS WITHIN 120 NM S OF THE AXIS BETWEEN 24W-29W. SCATTERED MODERATE IS FROM 9N-11N BETWEEN 43W-47W. DISCUSSION... THE GULF OF MEXICO... AN UPPER LOW CONTINUES TO PUSH W ACROSS THE GULF CENTERED NEAR 25N91W. AS WAS WELL PREDICTED BY MANY OF THE MODELS...THIS UPPER CIRCULATION HAS BEEN MOVING W 15-20 KT WHICH IS LIMITING IT'S IMPACTS ON DEAN. INSTABILITY NEAR THIS UPPER LOW ALONG WITH SOME INTERACTION WITH A TROPICAL WAVE IN THE BAY OF CAMPECHE IS PRODUCING SCATTERED SHOWERS AND TSTMS ACROSS THE CENTRAL GULF FROM 22N-29N BETWEEN 87W-95W...AS INDICATED BY LIGHTNING DATA. AT THE SFC...THE WRN EXTENT OF AN ATLC SUBTROPICAL RIDGE CONTINUES TO HOLD IT'S PLACE ACROSS THE GULF. THIS IS ALLOWING WINDS TO BE FAIRLY LIGHT OUT OF THE E TO SE ACROSS THE AREA. HOWEVER...THIS WILL NOT BE THE CASE FOR LONG AS POWERFUL DEAN TRACKS TOWARD THE SW PORTION OF THE AREA. SEE SPECIAL FEATURE SECTION FOR DETAILS. THE CARIBBEAN SEA... ATTENTION REMAINS FOCUSED ON POWERFUL CATEGORY FOUR HURRICANE DEAN. DEAN WILL CONTINUE TO HAVE SIGNIFICANT IMPACTS ON THE CENTRAL AND WESTERN CARIBBEAN AS WELL AS THE YUCATAN PENINSULA THROUGH TUE NIGHT. KINGSTON JAMAICA RECENTLY REPORTED 70 KT SUSTAINED WINDS AT 21Z. FOR DETAILS REFER TO THE SPECIAL FEATURE ABOVE. A CURIOUS FEATURE IS A NARROW SQUALL/FEEDER LINE WELL AHEAD OF THE HURRICANE'S CENTER...PRESSING W ACROSS THE NW CARIB. THE ATLANTIC OCEAN... A STRONG MID LEVEL RIDGE IS PARKED ACROSS THE WRN ATLC NEAR 31N76W. THIS IS THE FEATURE STEERING DEAN FAIRLY QUICKLY TO THE W OR WNW ACROSS THE WESTERN CARIBBEAN. DEAN'S STRONG CIRCULATION IS CAUSING DISTINCT SINKING/DRYING BEYOND IT'S OUTFLOW ACROSS THE CENTRAL BAHAMAS AND REGIONS FURTHER N. ELY WINDS ARE QUITE STRONG...25 TO 30 KT WITH HIGHER GUSTS ACROSS THE EXTREME SW ATLC NEAR DEAN. THESE WINDS ARE DRIVING SOME SHOWER/TSTMS STREAMERS ACROSS THE BAHAMAS AND S FLORIDA. FURTHER E...A LARGE TROPICAL WAVE IN THE CENTRAL ATLC LOOKS MORE INTERESTING THIS EVENING. FOR DETAILS REFER TO THE TROPICAL WAVES SECTION ABOVE. AN UPPER LOW/ELONGATED TROUGH RUNS N-S ALONG 57W...ANOTHER UPPER LOW IS CENTERED NEAR 31N30W. RIDGING DOMINATES THE REGION TO THE S AND E OF THE UPPER LOWS EXTENDING FROM AN ANTICYCLONE OVER AFRICA NEAR 24N7W. AT THE SFC...A LARGE SCALE RIDGE DOMINATES THE ATLANTIC DISCUSSION AREA ANCHORED BY A 1032 MB HIGH NEAR THE AZORES. THIS IS AIDING IN THE WIDESPREAD FAIR WEATHER AND PRODUCING MODERATE TRADES...EXCEPT STRONGER WINDS NEAR DEAN (AS DISCUSSED ABOVE) AND NEAR THE LARGE TROPICAL WAVE. $$ CANGIALOSI