Flhurricane.com - Central Florida Hurricane Center - Tracking Storms since 1995Hurricanes Without the Hype! Since 1995
The Atlantic is quiet
|
Show Selection: |
| #463184 (Received by flhurricane at: 4:47 AM 30.Sep.2011) TCDAT1 HURRICANE OPHELIA DISCUSSION NUMBER 31 NWS NATIONAL HURRICANE CENTER MIAMI FL AL162011 500 AM AST FRI SEP 30 2011 OPHELIA HAS BEEN RAPIDLY STRENGTHENING DURING THE PAST 12 HOURS BASED ON AN EYE FEATURE OCCASIONALLY APPARENT ON BOTH INFRARED AND NIGHT-VISIBLE SATELLITE IMAGES. MICROWAVE IMAGERY INDICATES A WELL-DEVELOPED AND CLOSED DEEP-LAYER EYE...ALBEIT TILTED SLIGHTLY TO THE NORTHEAST. A BLEND OF SATELLITE INTENSITY ESTIMATES OF T5.0/90 KT FROM SAB...T4.5/77 KT FROM TAFB...AND UW-CIMSS AVERAGE ADT OF T4.7/82 KT IS THE BASIS FOR THE 85-KT ADVISORY INTENSITY. THE INITIAL MOTION ESTIMATE IS 345/08 KT. THERE IS NO SIGNIFICANT CHANGE TO THE PREVIOUS FORECAST TRACK REASONING. OPHELIA IS CURRENTLY ROUNDING THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE SITUATED ALONG 32N LATITUDE. AN UNSEASONABLY STRONG MID-TROPOSPHERIC TROUGH IS FORECAST TO DEEPEN AND MOVE EASTWARD TO THE U.S. EAST COAST BY 48 HOURS...AND WILL ACT TO ACCELERATE AND LIFT OPHELIA NORTHWARD OVER THE NEXT 72 HOURS. BY DAYS 3-4...OPHELIA IS FORECAST TO MERGE WITH A FRONTAL SYSTEM AND BE OVER MUCH COLDER WATER...WHICH WILL RESULT IN THE CYCLONE BECOMING A STRONG POST-TROPICAL WINTER-TYPE LOW PRESSURE SYSTEM THAT WILL TURN EASTWARD NEAR THE CANADIAN MARITIMES. THE ONLY NOTICEABLE CHANGE IN THE MODEL GUIDANCE IS A SOUTHWARD SHIFT IN THE GUIDANCE TRACKS AFTER 72 HOURS. IN FACT...THE NEW ECMWF RUN BARELY TAKES OPHELIA AS FAR NORTH AS 45N LATITUDE. THE OFFICIAL FORECAST TRACK WAS NUDGED SLIGHTLY TO THE LEFT THROUGH 72 HOURS...AND THEN BROUGHT FARTHER SOUTH IN LINE WITH THE CONSENSUS MODEL...TVCN...BUT NOT AS FAR SOUTH AS THE ECMWF MODEL TRACK. THE OUTFLOW OF OPHELIA REMAINS QUITE IMPRESSIVE...EXCEPT THAT THE WESTERN EDGE OF THE CIRRUS OUTFLOW HAS STARTED TO FLATTEN AND DISSIPATE AS WESTERLY UPPER-LEVEL WINDS ENCROACH ON THE CYCLONE. HOWEVER...THE LIGHT TO MODERATE WESTERLY VERTICAL WIND SHEAR THAT IS CURRENTLY AFFECTING THE CYCLONE IS FORECAST TO TURN MORE FROM SOUTH-SOUTHWEST BY 36-48 HOURS...WHICH SHOULD ALLOW FOR SOME ADDITIONAL STRENGTHENING TO OCCUR. ALTHOUGH FURTHER RAPID STRENGTHENING IS A POSSIBILITY...THE VERTICAL SHEAR IS FORECAST BY THE SHIPS MODEL TO FLUCTUATE BETWEEN 5 AND 15 KT DURING THE NEXT 48 HOURS...WHICH SHOULD ACT TO KEEP THE EYE TILTED AT TIMES AND LIKELY DISRUPT THE RAPID INTENSIFICATION PROCESS. AS A RESULT...ONLY MODEST STRENGTHENING IS FORECAST UNTIL OPHELIA REACHES 22C AND COLDER SSTS SHORTLY AFTER THE 48-HOUR TIME PERIOD...WHICH IS ALSO COINCIDENT WITH AN EXPECTED SHARP INCREASE IN THE VERTICAL SHEAR. THE INTENSITY FORECAST IS SIMILAR TO THE INTENSITY CONSENSUS MODEL...ICON...THROUGH 72 HOURS...AND THEN LEANS CLOSE TO THE LGEM MODEL AFTER THAT. IT IS WORTH NOTING THAT SOME OF THE GLOBAL MODELS ARE NOW HOLDING ON TO OPHELIA AS A ROBUST EXTRATROPICAL LOW PRESSURE SYSTEM BEYOND 96 HOURS. FORECAST POSITIONS AND MAX WINDS INIT 30/0900Z 22.4N 62.6W 85 KT 100 MPH 12H 30/1800Z 24.2N 63.1W 90 KT 105 MPH 24H 01/0600Z 27.0N 63.4W 90 KT 105 MPH 36H 01/1800Z 30.1N 62.9W 95 KT 110 MPH 48H 02/0600Z 34.6N 61.7W 95 KT 110 MPH 72H 03/0600Z 44.3N 57.0W 65 KT 75 MPH...POST-TROP/EXTRATROP 96H 04/0600Z 51.5N 38.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 05/0600Z...DISSIPATED $$ FORECASTER STEWART |
