000 WTPZ44 KNHC 240848 TCDEP4 HURRICANE CELIA DISCUSSION NUMBER 21 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042010 200 AM PDT THU JUN 24 2010 CELIA APPEARS TO BE GOING THROUGH YET ANOTHER RE-STRENGTHENING PHASE BASED ON A SIGNIFICANT INCREASE IN THE AREAL COVERAGE OF COLD CLOUD TOPS IN THE CENTRAL DENSE OVERCAST FEATURE. DEEP CONVECTION ...WITH SOME TOPS AS COLD AS -86C...HAS DEVELOPED IN THE PREVIOUSLY CONVECTION-VOID WESTERN SEMICIRCLE. SATELLITE INTENSITY ESTIMATES ARE T5.5/102 KT FROM TAFB AND T5.0/90 KT FROM SAB USING THE EMBEDDED CENTER TECHNIQUE. SINCE THE 06Z FIXES...DEEP CONVECTION HAS CONTINUED TO EXPAND IN ALL QUADRANTS AND UPPER-LEVEL OUTFLOW HAS ALSO BECOME MORE SYMMETRICAL. HOWEVER...I WOULD PREFER TO SEE AN EYE APPEAR IN INFRARED IMAGERY BEFORE BRINGING CELIA BACK UP TO MAJOR HURRICANE STATUS. THE OFFICIAL INTENSITY OF 95 KT IS A BLEND OF THE TWO DVORAK SATELLITE INTENSITY ESTIMATES. THE INITIAL MOTION ESTIMATE IS 285/11. THERE IS NO CHANGE TO THE PREVIOUS FORECAST TRACK REASONING. FOR THE NEXT 3-4 DAYS...CELIA IS EXPECTED TO MOVE IN A GENERAL WEST-NORTHWESTWARD DIRECTION TOWARD A DEVELOPING WEAKNESS IN THE DEEP-LAYER RIDGE TO THE NORTH OF THE CYCLONE. BY DAYS 4 AND 5...THE MID- TO UPPER-LEVEL TROUGH THAT WEAKENS THE RIDGE IS FORECAST TO LIFT OUT TO THE NORTHEAST AND ALLOW THE RIDGE TO BUILD BACK WESTWARD TO THE NORTH OF THE HURRICANE...WHICH SHOULD FORCE CELIA ON A MORE WESTWARD TRACK. THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY AND IS ALONG THE LEFT SIDE OF THE GUIDANCE ENVELOPE. A 24/0215Z SSMI-S WATER VAPOR IMAGE INDICATED A NARROW BAND OF DRY AIR HAD BEEN DRAWN INTO THE WESTERN SEMICIRCLE...WHICH LIKELY LED TO THE EARLIER EROSION OF CONVECTION IN THAT PART OF THE STORM. HOWEVER...BASED ON THE RECENT RE-DEVELOPMENT OF CENTRAL DEEP CONVECTION...IT WOULD SEEM THAT THE DRY AIR HAS BEEN MIXED OUT. CELIA IS EXPECTED TO REMAIN OVER 28C OR WARMER SSTS AND IN A LOW WIND SHEAR ENVIRONMENT FOR THE NEXT 24 HOURS...WHICH WOULD FAVOR SOME ADDITIONAL STRENGTHENING TO OCCUR. THE PROXIMITY TO DRY AIR JUST TO THE WEST OF THE CYCLONE...HOWEVER...COULD RESULT IN ADDITIONAL FLUCTUATIONS IN INTENSITY DURING THAT PERIOD WHICH CAN NOT BE SPECIFICALLY FORECAST. BY 48 HOURS...CELIA WILL BEGIN TO MOVE OVER COOLER WATER AROUND 25C...WHICH SHOULD INDUCE SLOW BUT STEADY WEAKENING FOR THE REMAINDER OF THE PERIOD. THE INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY THROUGH 24 HOURS... AND AFTERWARD CLOSELY FOLLOWS THE DOWNWARD TREND OF THE SHIPS AND LGEM INTENSITY MODELS. FORECAST POSITIONS AND MAX WINDS INITIAL 24/0900Z 12.6N 112.8W 95 KT 12HR VT 24/1800Z 13.0N 114.6W 100 KT 24HR VT 25/0600Z 13.7N 117.0W 100 KT 36HR VT 25/1800Z 14.4N 119.1W 95 KT 48HR VT 26/0600Z 15.1N 120.9W 85 KT 72HR VT 27/0600Z 16.2N 123.9W 60 KT 96HR VT 28/0600Z 16.5N 125.5W 50 KT 120HR VT 29/0600Z 16.5N 126.5W 35 KT $$ FORECASTER STEWART