Flhurricane.com - Central Florida Hurricane Center - Tracking Storms since 1995Hurricanes Without the Hype! Since 1995
The Atlantic is quiet
|
Show Selection: |
| #512112 (Received by flhurricane at: 4:47 PM 20.May.2012) TCDAT1 TROPICAL STORM ALBERTO DISCUSSION NUMBER 5 NWS NATIONAL HURRICANE CENTER MIAMI FL AL012012 500 PM EDT SUN MAY 20 2012 ALBERTO DOES NOT HAVE THE TYPICAL VERTICAL WIND PROFILE OF A HEALTHY TROPICAL CYCLONE. THE AIR FORCE PLANE THAT SAMPLED THE STORM ONLY MEASURED MAXIMUM 850-MB FLIGHT-LEVEL WINDS OF 37 KT...YET SFMR VALUES WERE AS HIGH AS ABOUT 50 KT. THE SFMR ESTIMATES ARE LIKELY TOO HIGH BASED ON COINCIDENT SPIKES IN THE RAIN RATE AND A WELL-DOCUMENTED HIGH BIAS AT LOW-END TROPICAL STORM WIND SPEEDS. IN ADDITION...DROPSONDE DATA FROM THE AIRCRAFT DO NOT SUPPORT WINDS OF 50 KT NEAR THE SURFACE. THE INTENSITY IS THEREFORE BEING HELD AT 40 KT. THE AIRCRAFT DATA SUGGEST THAT THE BOUNDARY LAYER HAS DECOUPLED...AND THE SURFACE CIRCULATION MAY NOW BE TAKING SOME TIME TO SPIN DOWN. ALBERTO IS INGESTING DRY AIR...AND IT HAS MOVED OVER SHELF WATERS THAT ARE COLDER THAN 26C. IN ADDITION...WESTERLY VERTICAL WIND SHEAR IS EXPECTED TO INCREASE MARKEDLY DURING THE NEXT 24 HOURS. ALTHOUGH THE CYCLONE WILL TRAVERSE THE GULF STREAM AGAIN WHEN IT ACCELERATES NORTHEASTWARD ON MONDAY...THE OTHERWISE HOSTILE CONDITIONS SUGGEST THAT SIGNIFICANT INTENSIFICATION IS UNLIKELY. SMALL FLUCTUATIONS IN INTENSITY ARE POSSIBLE THROUGH TUESDAY DEPENDING ON THE BEHAVIOR OF DEEP CONVECTION...BUT OVERALL LITTLE CHANGE IN STRENGTH IS ANTICIPATED. THIS SCENARIO IS SUPPORTED BY THE BULK OF THE INTENSITY GUIDANCE. ALBERTO COULD BECOME POST- TROPICAL BY WEDNESDAY AS IT MOVES TOWARDS EVEN COLDER WATER...WITH DISSIPATION POSSIBLE BY THURSDAY. THE MOTION HAS BECOME SOUTHWESTWARD DURING THE DAY...AND IT APPEARS THAT ALBERTO IS BEGINNING ITS ANTICIPATED COUNTER-CLOCKWISE LOOP. THE BLOCKING PATTERN IN PLACE OVER THE EASTERN U.S. IS STILL EXPECTED TO BREAKDOWN THROUGH MONDAY...AND ALBERTO WILL RESPOND BY ACCELERATING NORTHEASTWARD AHEAD OF AN APPROACHING LONGWAVE TROUGH. THE 12Z ECMWF MODEL RUN...LIKE THE PREVIOUS ONE...IS STILL A LITTLE SOUTH OF THE REST OF THE TRACK GUIDANCE ENVELOPE. THE OFFICIAL FORECAST IS CLOSE TO THE VARIOUS CONSENSUS MODELS THROUGH 48 HOURS BUT A LITTLE FARTHER SOUTH AT 72 HOURS...HEDGING TOWARD THE ECMWF SOLUTION. FORECAST POSITIONS AND MAX WINDS INIT 20/2100Z 30.9N 80.0W 40 KT 45 MPH 12H 21/0600Z 30.8N 79.8W 40 KT 45 MPH 24H 21/1800Z 31.2N 78.6W 40 KT 45 MPH 36H 22/0600Z 32.5N 76.6W 40 KT 45 MPH 48H 22/1800Z 34.7N 73.8W 40 KT 45 MPH 72H 23/1800Z 38.0N 66.5W 35 KT 40 MPH...POST-TROP/EXTRATROP 96H 24/1800Z...DISSIPATED $$ FORECASTER BERG |
