|
Show Selection: |
| #222765 (Received by flhurricane at: 4:37 AM 18.Oct.2008) TCDAT5 TROPICAL STORM OMAR DISCUSSION NUMBER 20 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL152008 500 AM EDT SAT OCT 18 2008 CENTRAL CONVECTION...AND I USE THAT TERM QUITE LOOSELY IN THIS CASE...HAS CONTINUED TO RAPIDLY DECREASE AND INNER-CORE CLOUD TOPS ARE BARELY -20C...WITH MOST TOPS WARMER THAN -10C. ONE COULD CERTAINLY ARGUE THAT OMAR MAY NOT EVEN BE A TROPICAL CYCLONE. HOWEVER...I DON'T LIKE DROPPING SYSTEMS AT NIGHT OVER THE OPEN OCEAN JUST IN CASE A BRIEF FLARE UP OF CONVECTION REDEVELOPS. THE INITIAL INTENSITY ESTIMATE OF 50 KT IS BASED THE WELL-DEFINED EYE-LIKE FEATURE AND A DVORAK CI NUMBER OF T3.0/45 KT FROM TAFB. THE INITIAL MOTION ESTIMATE IS 045/14. THERE IS NO SIGNIFICANT CHANGE TO THE PREVIOUS FORECAST TRACK OR REASONING. OMAR IS EXPECTED TO CONTINUE TO MOVE NORTHEASTWARD AND EVENTUALLY EAST-NORTHEASTWARD AROUND THE THE NORTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE LOCATED TO THE EAST OF THE CYCLONE FOR THE NEXT 2 DAYS. BY 48 HOURS...THE STEERING FLOW IS FORECAST TO BECOME MORE WESTERLY AHEAD OF A LARGE EXTRATROPICAL LOW FORECAST TO DEVELOP OFF THE U.S.EAST COAST...WHICH IS EXPECTED TO FORCE OMAR ON A MORE EASTERLY TRACK. BY 72 HOURS...OMAR IS FORECAST BY MOST OF THE MODELS TO BE PULLED SLOWLY POLEWARD UNDER THE INFLUENCE OF THE APPROACHING LARGER EXTRATROPICAL TO THE WEST...AND EVENTUALLY BE ABSORBED BY THE LOW IN 96-120 HOURS. THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY AND IS IN THE MIDDLE OF THE NHC MODEL GUIDANCE SUITE. OMAR WILL CONTINUE TO MOVE OVER SUB-26C SSTS AND BENEATH INCREASING SOUTHWESTERLY VERTICAL WIND SHEAR...SO ADDITIONAL WEAKENING APPEARS LIKELY. IF THE RECENT CONVECTIVE DEGENERATION TREND CONTINUES... THEN OMAR COULD BECOME EXTRATROPICAL IN 24 HOURS OR LESS. FORECAST POSITIONS AND MAX WINDS INITIAL 18/0900Z 32.9N 51.5W 50 KT 12HR VT 18/1800Z 34.3N 49.8W 45 KT 24HR VT 19/0600Z 36.1N 47.3W 40 KT 36HR VT 19/1800Z 37.6N 44.6W 35 KT...BECOMING EXTRATROPICAL 48HR VT 20/0600Z 38.7N 42.1W 30 KT...EXTRATROPICAL 72HR VT 21/0600Z 40.3N 38.2W 30 KT...EXTRATROPICAL 96HR VT 22/0600Z 43.0N 35.4W 30 KT...EXTRATROPICAL 120HR VT 23/0600Z...ABSORBED BY LARGER EXTRATROPICAL LOW $$ FORECASTER STEWART |
