|
Show Selection: |
| #130914 (Received by flhurricane at: 10:49 AM 10.May.2007) TCDAT1 SUBTROPICAL DEPRESSION ANDREA DISCUSSION NUMBER 5 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL012007 1100 AM EDT THU MAY 10 2007 DEEP CONVECTION IS DISAPPEARING QUICKLY AND ONLY A FEW THUNDERSTORMS REMAIN IN THE NORTHEASTERN QUADRANT. IT IS THEREFORE NO SURPRISE THAT THE STRONGEST FLIGHT-LEVEL WINDS MEASURED AT 1000 FT BY THE AIR FORCE RECONNAISSANCE AIRCRAFT THIS MORNING WERE LESS THAN 40 KT. ANDREA IS DOWNGRADED TO A SUBTROPICAL DEPRESSION WITH 30 KT MAXIMUM WINDS. A COMEBACK SEEMS UNLIKELY IN THE DRY AND STABLE ENVIRONMENT...COMBINED WITH NORTHWESTERLY WIND SHEAR...DEPICTED IN WATER VAPOR IMAGERY. A CONTINUED DECLINE IS FORECAST...AND UNLESS DEEP CONVECTION REDEVEOPS SOON...ANDREA WILL PROBABLY NO LONGER QUALIFY AS A DEPRESSION BY TOMORROW OR PERHAPS EARLIER. A REMNANT LOW CIRCULATION MIGHT PERSIST FOR A COUPLE OF DAYS BEYOND THEN. IT IS WORTH NOTING THAT ALL OF THE DYNAMICAL MODELS FORECAST EXTRATROPICAL CYCLOGENESIS FARTHER NORTH OVER THE WESTERN ATLANTIC IN ABOUT THREE DAYS. THE GFDL IS THE ONLY ONE THAT KEEPS ANDREA INTACT LONG ENOUGH TO MOVE NORTHEASTWARD AND EVENTUALLY BECOME THIS EXTRATROPICAL CYCLONE...AND WHILE THIS SOLUTION IS NOT IMPOSSIBLE...IT IS DISCOUNTED IN THE OFFICIAL FORECAST. ANDREA CONTINUES TO DRIFT SOUTHWARD AND MOST MODELS INDICATE THIS WILL CONTINUE FOR THE NEXT DAY OR TWO. THE OFFICIAL FORECAST NOW HINTS AT AN EASTWARD MOTION BEGINNING ON DAY TWO AS THE LONGWAVE SYNOPTIC PATTERN BECOMES A LITTLE MORE PROGRESSIVE...BUT THE OVERALL MOTION THROUGH 48 HOURS IS EXPECTED TO BE MINIMAL. THE TROPICAL STORM WATCH ALONG THE SOUTHEAST U.S. COAST IS BEING DISCONTINUED. FORECAST POSITIONS AND MAX WINDS INITIAL 10/1500Z 29.9N 79.9W 30 KT 12HR VT 11/0000Z 29.6N 79.9W 30 KT 24HR VT 11/1200Z 29.3N 79.8W 25 KT...DISSIPATING 36HR VT 12/0000Z 29.2N 79.6W 25 KT...REMNANT LOW 48HR VT 12/1200Z 29.5N 79.3W 20 KT...REMNANT LOW 72HR VT 13/1200Z...DISSIPATED $$ FORECASTER KNABB |
