000 AXNT20 KNHC 111202 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST TUE DEC 11 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1130 UTC ...SPECIAL FEATURE... SUBTROPICAL STORM OLGA CONTINUES WWD ACROSS THE MONA PASSAGE. AT 12Z...OLGA WAS CENTERED NEAR 18.4N 67.6W OR ABOUT 40 NM EAST OF CABO ENGANO IN THE DOMINICAN REPUBLIC MOVING WEST AT 13 KT. MAXIMUM SUSTAINED WIND SPEED REMAINS 35 KT WITH GUSTS TO 45 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC AND THE NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS. OLGA HAS BEEN GRADUALLY LOSING CONVECTION THIS MORNING BASED ON THE WARMING CLOUD TOPS ON IR IMAGERY AND THE DECREASE IN LIGHTNING DETECTIONS. WHILE CONVECTION IS ON THE SLIGHT DECLINE...THE OVERALL CLOUD STRUCTURE HAS BECOME SOMEWHAT MORE SYMMETRIC AS SEEN IN SHORTWAVE IR IMAGES AND BANDS OF SHOWER/TSTM ACTIVITY EVIDENT ON SAN JUAN DOPPLER RADAR...THOUGH CLEARLY THE HEAVIEST RAINS REMAIN N OF THE CENTER. CURRENTLY...SCATTERED MODERATE CONVECTION IS FROM 19N-22N BETWEEN 64W-69W. BANDS OF SCATTERED SHOWERS AND TSTMS ARE ELSEWHERE FROM 16N-23N BETWEEN 63W-70W. HEAVY RAINFALL REMAINS A HIGH CONCERN WITH LIFE-THREATENING FLASH FLOODS AND MUDSLIDES POSSIBLE OVER THE ISLANDS OF PUERTO RICO AND HISPANIOLA. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 6N11W 5N19W 7N39W 5N50W 4N55W. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM EITHER SIDE OF THE AXIS BETWEEN 29W-36W AND BETWEEN 43W-49W. ISOLATED MODERATE IS ELSEWHERE WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN 27W-50W. DISCUSSION... GULF OF MEXICO... A MID TO UPPER LEVEL RIDGE REMAINS PARKED OVER AND JUST E OF THE AREA ALLOWING THE FLOW ALOFT TO BE RATHER LIGHT AND THE ATMOSPHERE FAIRLY STABLE. AT THE SFC...RIDGING EXTENDS SW INTO THE GULF FROM A 1028 MB HIGH NEAR BERMUDA. MAINLY MODERATE E TO SE WINDS ARE TRANSPORTING PATCHES OF LOW TO MID LEVEL CLOUDINESS FROM THE ATLC ACROSS THE REGION. MOSAIC DOPPLER RADAR SHOWS EMBEDDED LIGHT ISOLATED SHOWERS OVER THE FLA STRAITS AND ONE OR TWO IN THE NW GULF. THE FRONT THAT WAS NEAR THE SE TEXAS COAST YESTERDAY IS PUSHING BACK INLAND AS IT LACKS UPPER SUPPORT. THE NEXT FRONT...HOWEVER...SHOULD HAVE A SUFFICIENT PUSH TO TRACK ACROSS THE AREA LATER THIS WEEK. CARIBBEAN SEA... NUMEROUS SQUALLS OF SHOWERS AND TSTMS ASSOCIATED WITH SUBTROPICAL STORM OLGA IS ROTATING THROUGH THE DOMINICAN REPUBLIC...PUERTO RICO AND THE VIRGIN ISLANDS AS NOTED IN SAN JUAN DOPPLER RADAR AND SATELLITE IMAGERY. THESE HEAVY RAINS COULD CAUSE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES. DOPPLER DERIVED ACCUMULATED PRECIP SHOWS PEAK AMOUNTS OF 6-8 INCHES ALONG AND JUST TO THE N OF THE CORDILLERA CENTRAL...WHERE THE FLOW HAS BEEN ONSHORE AND UPSLOPE FOR MOST OF THE EVENING AND OVERNIGHT HOURS. NOW THAT THE STORM IS MOVING W OF THE ISLAND...THE HEAVIEST RAINS WILL LIKELY SHIFT ALONG AND JUST S OF THE MOUNTAIN CHAIN IN THE SAME FLOW REGIME. SEE THE SPECIAL FEATURE SECTION FOR MORE DETAILS. THE REMAINDER OF THE REGION IS EXPERIENCING MOSTLY FAIR WEATHER BENEATH MODERATE TO STRONG SUBSIDENCE ESPECIALLY N OF 17N W OF 72W WHERE THE UPPER FLOW IS CONFLUENT BETWEEN AN UPPER LOW IN THE BAHAMAS AND AN ELONGATED RIDGE STRETCHING FROM COLOMBIA THRU THE YUCATAN CHANNEL. TRADE WIND FLOW IS QUITE STRONG ACROSS THE REGION AS A RECENT SCAT PASS SHOWED A LARGE AREA OF 20-25 KT E TO NE WINDS N OF 10N W OF 70W...EVEN TO 30 KT IN THE EXPOSED ATLANTIC PASSAGES. ATLANTIC OCEAN... SUBTROPICAL STORM OLGA IS THE ONLY AREA OF ACTIVE WEATHER ACROSS THE ENTIRE ATLC DISCUSSION AREA...BESIDES FOR PORTIONS OF THE ITCZ. SEE ABOVE FOR DETAILS. STACKED SFC AND MID LEVEL RIDGING CONTROLS THE PATTERN IN THE W ATLC. TIGHT PRES GRADIENT BETWEEN THE SFC RIDGE ALONG 32N AND OLGA IS PRODUCING WINDS TO TROPICAL STORM FORCE WITHIN 175 NM N OF THE STORM CENTER. DEBRIS STREAMS OF LOW TO MID LEVEL CLOUDINESS IS BEING ADVECTED ACROSS THE W ATLC BY THE STRONG LOW-LEVEL FLOW. UPPER TROUGHING LIES OVER THE BAHAMAS ANCHORED BY AN UPPER LOW NEAR 23N75W AND A SMALLER ONE NEAR OLGA. SLY FLOW ON THE E SIDE IS SPREADING DEBRIS HIGH LEVEL MOISTURE WELL TO THE N AND NE OF THE SYSTEM. THE CENTRAL AND E ATLC IS VERY TRANQUIL WITH SFC RIDGING DOMINATING THE PATTERN SUPPORTED BY THE BERMUDA HIGH AND A 1026 MB ABOUT 250 NM W OF THE IBERIAN PENINSULA NEAR 38N15W. THE MID AND UPPER FLOW IS FAIRLY ZONAL ACROSS THIS PORTION OF THE ATLC AIDING IN THE TRANQUILITY. THE ONLY PERTURBATION IN THIS PATTERN IS A WEAK UPPER LOW CENTERED NEAR 29N25W. AN ASSOCIATED WEAK SFC TROUGH LIES UNDERNEATH THE UPPER SYSTEM ALONG 26W FROM 26N-31N. IR IMAGERY SUGGESTS A FEW SHOWERS WITHIN 90 NM OF THE UPPER LOW CENTER. $$ CANGIALOSI