Flhurricane.com - Central Florida Hurricane Center - Tracking Storms since 1995Hurricanes Without the Hype! Since 1995
The Atlantic is quiet
|
Show Selection: |
| #442510 (Received by flhurricane at: 4:55 AM 18.Jul.2011) TCDAT2 TROPICAL STORM BRET DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL022011 500 AM EDT MON JUL 18 2011 THE AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INVESTIGATING BRET OVERNIGHT FOUND THAT THE CYCLONE HAS CONTINUED TO SLOWLY STRENGTHEN ...WITH THE CENTRAL PRESSURE FALLING TO 1001 MB. THE INITIAL INTENSITY IS RAISED TO 45 KT BASED ON A PEAK 850-MB FLIGHT-LEVEL WIND OF 54 KT AND SOME BELIEVABLE 45 TO 50 KT SFMR WINDS OUTSIDE AREAS OF HEAVY RAIN AND SHALLOW WATERS NEAR THE ABACOS ISLANDS. SATELLITE AND RADAR IMAGERY SHOW THAT DEEP CONVECTION HAS INCREASED NEAR THE CENTER AND IN A PROMINENT BAND IN THE EASTERN SEMICIRCLE OVER THE PAST FEW HOURS...HOWEVER DRY AIR IS STILL IMPINGING ON THE WESTERN HALF OF THE CIRCULATION. ALSO...AN UPPER-LEVEL SHEAR AXIS SITUATED JUST NORTHWEST OF BRET APPEARS TO BE HINDERING OUTFLOW IN THE WESTERN SEMICIRCLE AND THE AIRCRAFT NOTED A 3 TO 5 NM SOUTHEASTWARD TILT BETWEEN THE SURFACE AND 850-MB CENTERS. THE INTENSITY GUIDANCE IS CONSISTENT WITH THIS MARGINAL ENVIRONMENT AND SUGGESTS THAT BRET HAS A PERIOD OF 24 TO 36 HOURS TO STEADILY STRENGTHEN BEFORE THE SHEAR INCREASES MARKEDLY AND THE CYCLONE BEGINS TO MOVE OVER COOLER WATERS. THE OFFICIAL FORECAST HAS BEEN NUDGED UPWARD IN AGREEMENT WITH THE SHIPS MODEL THROUGH 48 HOURS AND A BLEND OF THE SHIPS AND LGEM BEYOND THAT TIME. BRET JOGGED SOUTH-SOUTHEASTWARD OVERNIGHT...ALTHOUGH THE LATEST AIRCRAFT FIXES AND DOPPLER RADAR IMAGERY FROM MIAMI SUGGEST THAT THE CYCLONE HAS TURNED TOWARD THE EAST IN THE PAST COUPLE OF HOURS... POSSIBLY COMPLETING A CYCLONIC LOOP. THE LATEST AIRCRAFT FIXES YIELD AN INITIAL MOTION ESTIMATE OF 090/03 KT. ALL OF THE GUIDANCE INSISTS THAT BRET WILL BEGIN TO MOVE SLOWLY NORTH-NORTHEASTWARD BY TONIGHT AS THE CYCLONE COMES UNDER THE INFLUENCE OF A BUILDING MID-LEVEL RIDGE TO ITS SOUTHEAST. BY 48 HOURS AND BEYOND THE GLOBAL MODELS SUGGEST THAT A BROAD MID-LEVEL TROUGH OFFSHORE OF THE NORTHEASTERN U.S. WILL DEEPEN ENOUGH TO CAPTURE BRET AND ACCELERATE THE CYCLONE INTO THE WESTERLIES BY THE END OF THE PERIOD. GIVEN THE EASTWARD MOVEMENT OF THE CYCLONE OVERNIGHT AND A GENERAL WESTWARD TREND IN THE GUIDANCE ENVELOPE...THE NEW OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS ONE THROUGH 48 HOURS AND LIES CLOSE TO A BLEND OF THE ECMWF...UKMET...GFS...GFDL...AND HWRF MODELS. AFTER THAT TIME...THE NHC FORECAST IS ADJUSTED TOWARD THIS MODEL BLEND AND IS LEFT OF AND A LITTLE SLOWER THAN THE PREVIOUS PACKAGE. FURTHER ADJUSTMENTS IN THIS DIRECTION MAY BE NECESSARY NEAR THE END OF THE PERIOD IF THIS TREND IN THE GUIDANCE CONTINUES. FORECAST POSITIONS AND MAX WINDS INIT 18/0900Z 27.2N 77.7W 45 KT 50 MPH 12H 18/1800Z 27.6N 77.7W 50 KT 60 MPH 24H 19/0600Z 28.6N 77.2W 55 KT 65 MPH 36H 19/1800Z 29.7N 76.5W 55 KT 65 MPH 48H 20/0600Z 30.7N 75.4W 50 KT 60 MPH 72H 21/0600Z 32.5N 71.5W 45 KT 50 MPH 96H 22/0600Z 35.0N 67.0W 35 KT 40 MPH 120H 23/0600Z 38.0N 59.0W 30 KT 35 MPH $$ FORECASTER BRENNAN |
