WTPA41 PHFO 210243 TCDCP1 TROPICAL STORM OMEKA DISCUSSION NUMBER 4 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP012010 500 PM HST MON DEC 20 2010 A COUPLE OF CBS MANAGED TO POP UP NEAR THE CENTER OF OMEKA BETWEEN NOON AND 2PM. THESE CBS HAVE SINCE WEAKENED AND NOW MOVED NORTH AND EAST OF THE LOW LEVEL CIRCULATION CENTER. NO CHANGES TO SAB AND HFO DVORAK FIXES OF 2.0 AND 2.5 RESPECTIVELY. JTWC DVORAK FIX WAS LOWERED TO 1.5 BASED ON SUBTROPICAL TECHNIQUE. ASCAT PASS INDICATED A SMALL AREA OF 35 KT WINDS IN THE SOUTHEAST QUADRANT OF OMEKA WHILE RAMMB/CIRA MULTIPLATFORM SATELLITE SURFACE WIND ANALYSIS INDICATES MAX WINDS AT 32 KT IN THE SAME AREA. INITIAL INTENSITY IS WEIGHTED TOWARD HFO FIX AND ASCAT WINDS AND HELD AT 35 KT. INITIAL POSITION IS VERY CLOSE TO POSITION ESTIMATES FROM ALL FIX AGENCIES. FORECAST ISSUE IS WHETHER OR NOT OMEKA REMAINS TROPICAL OR IS TRANSITIONING TO EXTRATROPICAL. RAMMB/CIRA T ANOMALY CROSS SECTION FROM 16 UTC INDICATED A WARM CORE SYSTEM. WITHOUT CONVINCING ARGUMENT TO GO AGAINST THIS...EVEN 12 PLUS HOURS LATER...WILL MAINTAIN THE WEAKENING TREND DUE TO SHEAR AND LOWERING SSTS ALONG THE FORECAST TRACK WHILE KEEPING OMEKA AS A TROPICAL SYSTEM THROUGH 24 HOURS BEFORE WEAKENING IT INTO A REMNANT LOW. THE LATEST FORECAST TRACK WAS NUDGED SLIGHTLY BACK TOWARD THE EAST GIVEN THE 2PM POSITION WAS FURTHER EAST THAN ANTICIPATED. THIS TRACK TAKES OMEKA JUST EAST OF LISIANSKI ISLAND AT THE CLOSEST POINT OF BETWEEN 9 AND 10 PM TONIGHT. GIVEN THE FORECAST WEAKENING...MAINTAIN THE EARLIER DECISION NOT TO ISSUE A TROPICAL STORM WARNING FOR THIS PORTION OF THE NW HAWAIIAN ISLANDS. IN THE ABSENCE OF THE CB ACTIVITY NEAR THE CENTER...A SHEAR PATTERN BASED ON THE LAST COUPLE OF SATELLITE IMAGES SUGGESTS OMEKA MIGHT ALREADY BE BELOW TROPICAL STORM STRENGTH. FORECAST POSITIONS AND MAX WINDS INITIAL 21/0300Z 24.6N 174.3W 35 KT 12HR VT 21/1200Z 27.1N 173.3W 30 KT 24HR VT 22/0000Z 30.2N 172.1W 30 KT 36HR VT 22/1200Z 33.7N 170.6W 25 KT...POST-TROP/REMNT LOW $$ FORECASTER TANABE