000 AXNT20 KNHC 142359 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE OCT 14 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... TROPICAL STORM OMAR IS CENTERED NEAR 14.1N 68.3W AT 15/0000 UTC OR ABOUT 290 NM SOUTH-SOUTHWEST OF SAN JUAN PUERTO RICO MOVING E-NE AT 6 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 980 MB. MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. PLEASE SEE LATEST NHC PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT5/WTNT35 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. NUMEROUS STRONG CONVECTION IS WITHIN 150 NM OF THE CENTER WITH SCATTERED MODERATE/STRONG CONVECTION COVERING THE REMAINDER OF THE AREA FROM 10N-19N BETWEEN 61W-73W...INCLUDING AN OUTER CONVECTIVE BAND INLAND OVER NE VENEZUELA. OMAR IS FORECAST TO TRACK NE BY EARLY WEDNESDAY WITH A GRADUAL INCREASE IN FORWARD SPEED BRINGING THE CYCLONE OVER OR NEAR THE NRN LEEWARD ISLANDS BY WEDNESDAY NIGHT. TROPICAL DEPRESSION SIXTEEN IS CENTERED NEAR 16.2N AND 83.5W AT 15/0000 UTC OR ABOUT 140 NM NORTH-NORTHWEST OF CABO GRACIAS A DIOS ON THE NICARAGUA/HONDURAS BORDER MOVING W-NW AT 6 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1003 MB. MAXIMUM SUSTAINED WIND SPEED IS 25 KT WITH GUSTS TO 35 KT. PLEASE SEE LATEST NHC PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVER A LARGE AREA OF THE WRN CARIBBEAN FROM 12N-21N BETWEEN 77W-88W. A SIMILAR AREA OF CONVECTION IS ACROSS THE YUCATAN PENINSULA N OF 17N. T.D. SIXTEEN IS FORECAST TO TRACK TOWARD THE WEST WITH A GENERAL WESTWARD MOTION EXPECTED DURING THE NEXT COUPLE OF DAYS AS THE CENTER OF THE DEPRESSION PARALLELS THE NRN HONDURAS COAST. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 36W S OF 14N MOVING W NEAR 10-15 KT. THIS LOW AMPLITUDE WEAK PERTURBATION EMBEDDED WITHIN THE ITCZ IS GENERATING SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 5N-11N BETWEEN 34W-41W. A WEAK TROPICAL WAVE IS ALONG 54W/55W S OF 17N MOVING W NEAR 10 KT. THE WAVE IS EMBEDDED IN AN AREA OF MODERATE TO STRONG SUBSIDENCE THUS NO SIGNIFICANT DEEP CONVECTION SURROUNDS THE WAVE AXIS. HOWEVER...LAST VISIBLE SATELLITE IMAGES DEPICT A WEAK LOW-LEVEL INVERTED-V CLOUD SIGNATURE ASSOCIATED WITH THE WAVE. A TROPICAL WAVE IS IN THE FAR ERN CARIBBEAN ALONG 62W S OF 18N MOVING W NEAR 5-10 KT. LOW-LEVEL CYCLONIC CURVATURE IS NOTED ACROSS THE ERN CARIBBEAN AS THE WAVE IS BECOMING EMBEDDED WITHIN THE LARGER CYCLONIC SURFACE FLOW AROUND T.S. OMAR. SCATTERED MODERATE/ISOLATED STRONG CONVECTION...MOST LIKELY ASSOCIATED WITH THE OUTER CONVECTIVE BANDS OF OMAR...ARE FROM 12N-19N BETWEEN 58W-65W BRINGING HEAVY RAINFALL TO THE LESSER ANTILLES. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 12N16W 8N34W 8N38W 7N42W 9N52W 9N56W 10N61W. IN ADDITION TO CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE/STRONG CONVECTION IS ALONG COASTAL W AFRICA FROM 5N-14N BETWEEN 9W-18W. ELSEWHERE...SCATTERED MODERATE CONVECTION IS FROM 7N-10N BETWEEN 25W-32W. ...DISCUSSION... GULF OF MEXICO... AN UPPER-LEVEL LOW IS CENTERED OVER ERN MEXICO NEAR 19N98W AND EXTENDS CYCLONIC FLOW NWD TO ACROSS DEEP SRN TEXAS AND THE WRN GULF W OF 91W. LOW-LEVEL INSTABILITY AND MOIST SOUTHERLY MID-HIGH LEVEL FLOW EAST OF THIS FEATURE IS HELPING TO INDUCE SCATTERED SHOWERS AND TSTMS OVER THE WRN GULF THIS EVENING FROM 25N-29N W OF 92W. A SURFACE TROUGH...LIKELY A REFLECTION OF THE UPPER FEATURE...IS ANALYZED ALONG 93W S OF 26N. SHIP AND BUOY OBSERVATIONS FROM THE PAST 6-12 HOURS CONFIRM THE WIND SHIFT ASSOCIATED WITH THIS SURFACE TROUGH. SCATTERED SHOWERS AND TSTMS ARE ALSO ACROSS THE YUCATAN PENINSULA AND EXTEND INTO THE S/CENTRAL GULF WATERS S OF 22N BETWEEN 86W-92W. THESE ARE BEING GENERATED DUE TO THE UPPER LEVEL RIDGE ASSOCIATED WITH T.D. SIXTEEN IN THE WRN CARIBBEAN. A HIGH PRESSURE CENTER OVER THE SE CONUS DOMINATES MUCH OF THE GULF E OF 90W...INCLUDING THE FLORIDA PENINSULA AND STRAITS OF FLORIDA. THE PRESSURE GRADIENT BETWEEN THIS HIGH AND T.D. SIXTEEN IS GENERATING MODERATE TO STRONG ELY WINDS OVER THE CENTRAL AND ERN GULF. CARIBBEAN SEA... A TROPICAL WAVE AND TWO TROPICAL CYCLONES ARE IN THE CARIBBEAN SEA...SEE THE SPECIAL FEATURES AND TROPICAL WAVES SECTION FOR MORE DETAILS. AN UPPER-LEVEL RIDGE IS CENTERED OVER T.D. SIXTEEN COVERING MUCH OF THE CARIBBEAN W OF 73W. THIS UPPER RIDGE IS PROVIDING UPPER LEVEL DIFFLUENCE TO GENERATE THE CONVECTIVE ACTIVITY ASSOCIATED WITH T.D. SIXTEEN. WATER VAPOR IMAGERY REVEALS A DEEP LAYERED TROUGH ACROSS THE W ATLC DIGGING SWD INTO THE NRN CARIBBEAN. THIS TROUGH WILL PLAY A ROLE IN TRACKING OMAR TO THE NE OVER THE NEXT FEW DAYS. UPPER DIFFLUENCE E OF THE UPPER TROUGH ACROSS THE ERN CARIBBEAN IS PROVIDING AMPLE OUTFLOW FOR THE CONVECTIVE ACTIVITY ASSOCIATED WITH OMAR E OF 71W. SCATTERED SHOWERS AND TSTMS EXTEND NEWD FROM OMAR ACROSS PUERTO RICO...THE US/UK VIRGIN ISLANDS AND MUCH OF THE LESSER ANTILLES THIS EVENING. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE IS ACROSS THE SE CONUS EXTENDING ACROSS THE W ATLC WATERS W OF 71W. MODERATE TO STRONG SUBSIDENCE IS ASSOCIATED WITH THIS UPPER RIDGE BRINGING DRY AIR ACROSS THE FLORIDA PENINSULA...NRN CUBA AND THE BAHAMAS. A DEEP LAYERED TROUGH IS ACROSS THE REMAINDER OF THE W ATLC EXTENDING EWD INTO THE CENTRAL ATLC W OF 50W. A SURFACE TROUGH EXTENDS INTO THE DISCUSSION AREA NEAR 32N47W SW TO 20N67W. A LARGE AREA OF DEEP-LAYERED MOISTURE CONTINUES TO STREAM NE ACROSS THE CENTRAL ATLC WITH EMBEDDED SHOWERS FROM 20N-32N BETWEEN 51W-62W. ANOTHER SURFACE TROUGH CLIPS THE REGION NEAR 31N58W. SCATTERED MODERATE/ ISOLATED STRONG CONVECTION IS ALSO MOVING NE ACROSS PUERTO RICO AND THE LEEWARD ISLANDS IN ASSOCIATION WITH OMAR. A 1008 MB LOW...REMNANTS OF NANA...CENTERED NEAR 19N45W IS DRIFTING N-NW INTO THE DEEP LAYERED TROUGH ACROSS THE CENTRAL ATLC. SCATTERED SHOWERS AND TSTMS ARE FROM 19N-22N BETWEEN 43W-46W. TO THE SE... A 1009 MB LOW IS GENERATING LITTLE SENSIBLE WEATHER UNDER DRIER AIR ALOFT. THE E ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED ON A 1026 MB HIGH CENTERED SOUTH OF THE AZORES NEAR 35N26W. A BROAD UPPER-LEVEL RIDGE ANCHORED ON AN HIGH NEAR 10N25W DOMINATES THE TROPICAL ATLC E OF 50W AND IS ENHANCING CONVECTION ALONG THE ITCZ. $$ HUFFMAN