000 AXNT20 KNHC 141803 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... TROPICAL DEPRESSION FIFTEEN IN THE EASTERN CARIBBEAN SEA STRENGTHENS INTO TROPICAL STORM OMAR. AT 14/1800 UTC OMAR IS CENTERED NEAR 13.8N 68.9W OR ABOUT 325NM...600 KM...SOUTH- SOUTHWEST OF SAN JUAN PUERTO RICO AND ABOUT 95 NM...180 KM... NORTH OF CURACAO MOVING SE AT 4 KT. A GRADUAL TURN TO THE EAST IS FORECAST TO OCCUR LATER TODAY...WITH A GRADUAL INCREASE IN FORWARD SPEED AND A TURN TO THE NORTHEAST EXPECTED ON WEDNESDAY. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1001 MB. MAXIMUM SUSTAINED WIND SPEED HAS INCREASED TO 35 KT WITH GUSTS TO 40 KT. GRADUAL STRENGTHENING IS FORECAST OVER THE NEXT 48 HOURS...WITH OMAR REACHING HURRICANE STATUS. 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. RECENT DEVELOPMENT OF A CDO-LIKE AREA OF CENTRAL DEEP CONVECTION SUGGESTS THAT OMAR MAY BE STARTING A PERIOD OF RAPID STRENGTHENING. BANDS OF MODERATE TO STRONG CONVECTION ARE SEEN TO THE N AND SE OF OMAR'S CENTER. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE AFFECTING THE ABC ISLANDS. THIS MORNING CURACAO REPORTED 1.70 INCHES OF RAIN IN 24 HOURS. GUSTY WINDS AND HEAVY RAIN WILL CONTINUE TO AFFECT ARUBA...BONAIRE AND CURACAO THE REST OF TODAY. SATELLITE AND SURFACE OBSERVATIONS INDICATE THAT THE AREA OF LOW PRESSURE OVER THE WESTERN CARIBBEAN SEA HAS ACQUIRED ENOUGH ORGANIZATION TO BE DESIGNATED A TROPICAL DEPRESSION. AT 14/1800 UTC...T.D. SIXTEEN IS CENTERED NEAR 15.6N AND 83.2W OR ABOUT 35 NM...65 KM...NORTH-NORTHEAST OF CABO GRACIAS A DIOS ON THE NICARAGUA/HONDURAS BORDER MOVING W-NW AT 4 KT. A TURN TOWARD THE WEST IS EXPECTED LATER TODAY AND A GENERAL WESTWARD MOTION IS FORECAST WEDNESDAY AND WEDNESDAY NIGHT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WIND SPEED IS 25 KT WITH GUSTS TO 35 KT. AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT IS SCHEDULED TO INVESTIGATE THE DEPRESSION THIS AFTERNOON. SOME STRENGTHENING IS EXPECTED DURING THE NEXT COUPLE OF DAYS AS LONG AS THE CENTER OF DEPRESSION REMAINS OFFSHORE...AND THE DEPRESSION IS FORECAST TO BECOME A TROPICAL STORM BY WEDNESDAY. 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. BANDING FEATURES WITH MODERATE TO ISOLATED STRONG CONVECTION ARE OBSERVED WITHIN 240 NM NW QUADRANT AND WITHIN 200 NM E SEMICIRCLE. ...TROPICAL WAVES... A TROPICAL WAVE IS ADDED TO THE 1200 UTC SURFACE MAP ALONG 33W SOUTH OF 13W BASED ON SATELLITE PHOTOS AND SURFACE OBSERVATIONS. IN ADDITION...THE HOVMOLLER DIAGRAM SHOWS VERY CLEAR THE WWD PROPAGATION OF THE CLOUDINESS AND THE TPW PRODUCT FROM CIMSS INDICATES A BULGE OF MOISTURE ALONG THE WAVE AXIS. SCATTERED MODERATE CONVECTION IS SEEN EITHER SIDE OF THE WAVE AXIS COVERING A LARGE AREA FROM 5N-13N BETWEEN 28W-38W. A WEAK TROPICAL WAVE IS ALONG 53W/54W S OF 17N MOVING W NEAR 10 KT. THE WAVE IS EMBEDDED IN AN AREA OF MODERATE TO STRONG SUBSIDENCE KEEPING ANY ASSOCIATED SHOWERS CONFINED TO THE ITCZ NEAR 11N54W. THE WAVE SHOWS UP ON THE SSMI-TPW PRODUCT FROM CIMSS...AND VIS SATELLITE IMAGERY DEPICTS A WEAK INVERTED V-SIGNATURE ASSOCIATED WITH THIS FEATURE. A TROPICAL WAVE IS OVER THE LESSER ANTILLES ALONG 61W/62W SOUTH OF 18N MOVING WEST NEAR 10 KT. THE WAVE IS GENERATING SOME SHOWER/TSTM ACTIVITY BETWEEN MARTINIQUE AND BARBADOS. GUADELOUPE REPORTED 1.17 INCHES OF RAIN THIS MORNING FOR THE PAST 24 HOURS. THIS WAVE IS EXPECTED TO BECOME ABSORBED INTO T.S. OMAR PRETTY SOON AS IT TRACKS WESTWARD. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 11N16W 9N30W 8N40W 9N50W 10N60W. A 1008 MB LOW IS EMBEDDED WITHIN THE ITCZ NEAR 13N42W. IN ADDITION TO CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS INLAND OVER WEST AFRICA FROM 9N-15N BETWEEN 10W-17W. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM N OF AXIS BETWEEN 24W-30W. ...DISCUSSION... GULF OF MEXICO... THE UPPER-LEVEL LOW THAT WAS CENTERED OVER THE BAY OF CAMPECHE YESTERDAY NIGHT HAS CONTINUED TO MOVE WWD AND NOW IS ROTATING OVER MEXICO NEAR 19N98W. LOW-LEVEL INSTABILITY AND MOIST SOUTHERLY MID-HIGH LEVEL FLOW TO THE EAST OF THIS FEATURE IS HELPING TO INDUCE SCATTERED SHOWERS AND TSTMS OVER THE WESTERN GULF PARTICULARLY FROM 23N-27N WEST OF 90W. A SFC TROUGH... LIKELY A REFLECTION OF THE UPPER FEATURE IS ANALYZED ALONG 93W SOUTH OF 26N. A QSCAT PASS FROM AROUND 1230 UTC SHOWED THE WIND SHIFT ASSOCIATED WITH THIS SFC TROUGH. A HIGH PRESSURE CENTER OVER THE MID-ATLANTIC STATES DOMINATES THE SE CONUS...THE FLORIDA PENINSULA AND THE NORTHERN GULF WATERS. THE PRESSURE GRADIENT BETWEEN THIS HIGH AND T.D. SIXTEEN ACROSS THE WRN CARIBBEAN SEA IS GENERATING MODERATE TO STRONG ELY WINDS OVER THE MIDDLE AND ERN GULF. CARIBBEAN SEA... A TROPICAL WAVE AND TWO TROPICAL CYCLONES ARE IN THE CARIBBEAN SEA...ONE IS T.S. OMAR IN THE ERN CARIBBEAN...AND THE SECOND ONE IS T.D. SIXTEEN IN THE WRN CARIBBEAN...SEE SPECIAL FEATURES FOR MORE DETAILS. UPPER-LEVEL RIDGE IS OVER T.D. SIXTEEN COVERING MUCH OF THE BASIN WHICH IS AIDING IN GENERATING THE CONVECTIVE ACTIVITY ASSOCIATED WITH BOTH TROPICAL SYSTEMS. WV IMAGERY REVEALS A DEEP LAYER TROUGH DIGGING INTO THE WEST AND CENTRAL ATLC. THIS TROUGH WILL PLAY A ROLE IN THE FUTURE MOVEMENT OF OMAR...WHICH IS FORECAST TO BE EMBEDDED IN THE ELY FLOW AHEAD OF THIS TROUGH. AS A RESULT...OMAR IS EXPECTED TO MOVE TO THE EAST DURING THE NEXT 12 HOURS. HIGH CLOUDS ASSOCIATED WITH THE OUTFLOW OF T.D. SIXTEEN ARE REACHING CUBA. SCATTERED TO NUMEROUS SHOWERS WITH EMBEDDED TSTMS ARE AFFECTING THE VIRGIN ISLANDS AND NE PUERTO RICO WHILE AN OUTER RAINBAND ASSOCIATED WITH T.S. OMAR IS SLOWLY APPROACHING THE SOUTH COAST OF PUERTO RICO. ST.THOMAS REPORTED THIS MORNING 3.85 INCHES OF RAIN IN 24 HOURS. ATLANTIC OCEAN... THE LAST PUBLIC ADVISORY ON T.D. NANA WAS ISSUED BY THE NATIONAL HURRICANE CENTER AT 14/0900 UTC. SLOW WEAKENING OF THE SYSTEM IS FORECAST UNTIL THE REMNANT LOW OF NANA DISSIPATES IN A COUPLE OF DAYS. AT 14/1500 UTC...THE EXPOSED LOW LEVEL CENTER OF WHAT WAS NANA IS NEAR 18.5N44.5W. ANOTHER EXPOSED LOW LEVEL CENTER IS TO THE SE OF NANA'S REMNANT NEAR 16.5N41.5N. THIS LOW CONTINUES TO PRODUCE SOME THUNDERSTORM ACTIVITY MAINLY TO THE EAST OF THE CENTER...BUT THIS SYSTEM IS FORECAST TO ENCOUNTER UNFAVORABLE UPPER-LEVEL WINDS AS IT MOVES SLOWLY NORTH-NORTHEASTWARD OVER THE NEXT DAY OR TWO...AND SIGNIFICANT DEVELOPMENT IS NOT ANTICIPATED. A SURFACE TROUGH...ASSOCIATED WITH BROAD UPPER TROUGHING ACROSS THE W-CENTRAL ATLC...EXTENDS INTO THE DISCUSSION AREA NEAR 31N47W TO 20N66W. A LARGE AREA OF CLOUDINESS WITH EMBEDDED SHOWERS IS MAINLY AHEAD OF THE TROUGH AXIS FROM 20N-27N BETWEEN 50W-62W. ANOTHER SURFACE TROUGH CLIPS THE REGION NEAR 31N63W. THE E ATLC IS UNDER THE INFLUENCE OF A SFC RIDGE ANCHORED ON A 1026 MB HIGH CENTERED EAST OF THE AZORES NEAR 35N22W. SURFACE OBSERVATIONS ALSO SHOW THE PRESENCE OF A 1011 MB LOW INLAND OVER WEST AFRICA NEAR 14N15W. A BROAD UPPER-LEVEL RIDGE ANCHORED ON AN HIGH NEAR 11N28W DOMINATES THE TROPICS AND IS ENHANCING CONVECTION ALONG THE ITCZ. $$ GR