|
Show Selection: |
| #355977 (Received by flhurricane at: 4:58 AM 29.Jun.2010) TCDAT1 TROPICAL STORM ALEX DISCUSSION NUMBER 15 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL012010 400 AM CDT TUE JUN 29 2010 A 0525Z AIR FORCE RESERVE RECON FLIGHT FOUND TWO PEAK 925 MB FLIGHT-LEVEL WINDS OF 73 KT LOCATED ABOUT 20 AND 45 NMI NORTHEAST OF THE CENTER. RELIABLE SFMR SURFACE WINDS ALONG THAT LEG WERE AROUND 57 KT...AND THE CENTRAL PRESSURE WAS 985 MB. SINCE THAT RECON FLIGHT...DEEP CONVECTION IN THE EASTERN SEMICIRCLE OF THE SMALL DEVELOPING EYE HAS ALSO INCREASED. SATELLITE INTENSITY ESTIMATES AT 06Z WERE T4.0/65 KT FROM TAFB AND T3.5/55 KT FROM SAB. BASED ON A BLEND OF THESE DATA...THE INITIAL INTENSITY IS SET AT 60 KT FOR THIS ADVISORY. THE INITIAL MOTION ESTIMATE IS 340/07 BASED ON RECON AND MICROWAVE SATELLITE FIX POSITIONS OVER THE PAST 8 HOURS. THE LATEST MODEL GUIDANCE SUITE...INCLUDING THE CONSENSUS MODELS...HAS SHIFTED SOUTHWARD. HOWEVER...ALEX HAS SHOWN NO SIGNS OF MAKING ANY SIGNIFICANT WESTWARD PROGRESS LIKE THE ECMWF...NOGAPS...GFS...AND GFDL MODELS HAVE BEEN AND ARE STILL FORECASTING TO OCCUR. THE MODELS ARE CONSISTENT...HOWEVER...ON BUILDING A SUBTROPICAL RIDGE TO THE NORTH AND EAST OF ALEX OVER THE NEXT 3 DAYS...WHICH IS EXPECTED TO GRADUALLY STEER THE CYCLONE ON A WEST-NORTHWESTWARD OR WESTWARD TRACK WITH TIME. HOWEVER...WATER VAPOR IMAGERY INDICATES THE UPPER-LEVEL OUTFLOW PATTERN IS STRONGLY ELONGATED IN A NORTH-SOUTH ORIENTATION. THIS IS A GOOD SHORT-TERM MOTION INDICATOR ...WHICH WOULD SUGGEST THAT ALEX SHOULD MAINTAIN ITS CURRENT NORTH-NORTHWESTWARD MOTION FOR ANOTHER 6-12 HOURS BEFORE TURNING TOWARD THE NORTHWEST. THIS MOTION VECTOR WOULD KEEP ALEX ALONG OR JUST OUTSIDE THE RIGHT SIDE OF THE GUIDANCE ENVELOPE. SINCE THERE IS NO OBVIOUS PHYSICAL JUSTIFICATION TO SHIFT THE TRACK SOUTHWARD AT THIS TIME...THE OFFICIAL FORECAST IS JUST AN UPDATE OF THE PREVIOUS TRACK AND IS WELL TO THE RIGHT OF THE MODEL CONSENSUS. MICROWAVE DATA FROM 0114Z SSMIS AND 0243Z AMSU OVERPASSES INDICATED A SMALL MID-LEVEL EYE FEATURE VERY NEAR THE LOW-LEVEL RECON CENTER POSITION. THIS INDICATES THAT ALEX HAS A NEARLY VERTICALLY ALIGNED INNER CORE CIRCULATION...WHICH WOULD FAVOR STEADY INTENSIFICATION GIVEN THE VERY CONDUCIVE UPPER-LEVEL AND OCEANIC ENVIRONMENTS THAT THE CYCLONE IS FORECAST TO INTERACT WITH RIGHT UP UNTIL LANDFALL IN ABOUT 48 HOURS. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND IS A BLEND OF THE SHIPS AND LGEM MODELS. FORECAST POSITIONS AND MAX WINDS INITIAL 29/0900Z 21.7N 91.9W 60 KT 12HR VT 29/1800Z 22.8N 92.7W 65 KT 24HR VT 30/0600Z 24.0N 94.2W 75 KT 36HR VT 30/1800Z 24.8N 95.9W 80 KT 48HR VT 01/0600Z 25.3N 97.4W 85 KT...NEAR NE MEXICAN COAST 72HR VT 02/0600Z 26.0N 100.0W 35 KT...INLAND 96HR VT 03/0600Z 27.5N 102.5W 20 KT...DISSIPATING INLAND 120HR VT 04/0600Z...DISSIPATED INLAND $$ FORECASTER STEWART |
