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#44222 (Received by flhurricane at: 11:20 PM 05.Sep.2005) TCDAT5 TROPICAL STORM NATE DISCUSSION NUMBER 2 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT MON SEP 05 2005 CONVECTION HAS CONSOLIDATED AND DEEPENED WITHIN AN INCREASINGLY ROBUST AND WELL-DEFINED CIRCULATION DURING THE PAST FEW HOURS. CONVECTIVE TOPS HAVE COOLED TO NEAR -80C. THE 00Z DVORAK INTENSITY ESTIMATES SUPPORT 30-35 KT... AND THE CLOUD PATTERN HAS BECOME MORE IMPRESSIVE SINCE THEN... SO THE ADVISORY INTENSITY IS INCREASED TO 35 KT... WHICH IS ALSO SUPPORTED BY A VERY RECENT BUOY REPORT OF 30 KT TO THE WEST OF THE CENTER AND OUTSIDE OF THE CONVECTION. WHILE THE GFDL DOES NOT EVEN FORECAST THE SYSTEM TO EVER REACH TROPICAL STORM STATUS... WHICH IS OBVIOUSLY UNDERDONE... THE SHIPS MODEL FORECASTS STRENGTHENING TO A HURRICANE BY ABOUT 60 HOURS. THE NEW OFFICIAL FORECAST WILL NOT BE QUITE THAT AGGRESSIVE... BUT GIVEN THE RECENT STRENGTHENING TREND... IT IS ADJUSTED UPWARD FROM THE PREVIOUS ADVISORY AS SHOWS NATE NEARING HURRICANE STRENGTH WITHIN THE NEXT THREE DAYS. NATE HAS NOT BEEN MOVING MUCH DURING THE PAST SEVERAL HOURS... AND THE CENTER IS SOMEWHAT DIFFICULT TO LOCATE. THE SMALL LOW LEVEL CENTER SEEN EARLIER ON VISIBLE IMAGERY APPEARS TO HAVE ROTATED EASTWARD INTO THE LARGER CIRCULATION ENVELOPE WHICH IS CENTERED FARTHER EAST. AN SSMI OVERPASS NEAR 23Z ALSO SUGGESTED THIS LARGER CIRCULATION IS CENTERED FARTHER EAST... AND RECENT SHORTWAVE IR IMAGERY HINTS AT A VERY SLOW WESTWARD MOTION. THE MODEL GUIDANCE IS ALL OVER THE PLACE... WITH NOGAPS SHOWING CONTINUED WESTWARD MOTION... AS DOES GFDL BUT NOT UNTIL SOME MEANDERING IS COMPLETED DURING THE NEXT 24 HOURS... ALL WITHIN A WEAK STEERING ENVIRONMENT LEFT BEHIND BY THE MID LATITUDE TROUGH PUSHING MARIA FARTHER OUT TO SEA. WHILE A WEAK RIDGE SHOULD INDUCE SLOW WESTWARD MOTION FOR THE NEXT 2-3 DAYS... THE RIDGE IS FORECAST BY MOST MODELS TO THEN BREAK DOWN AND FORCE NATE NORTHEASTWARD. THE NEW OFFICIAL FORECAST FOLLOWS THIS GENERAL SCENARIO AND IS AN EASTWARD ADJUSTMENT OF THE PREVIOUS ADVISORY TRACK. IT IS SAFE TO SAY THIS IS A LOW CONFIDENCE TRACK FORECAST. FORECASTER KNABB FORECAST POSITIONS AND MAX WINDS INITIAL 06/0300Z 28.0N 66.8W 35 KT 12HR VT 06/1200Z 28.1N 67.1W 40 KT 24HR VT 07/0000Z 28.3N 67.8W 45 KT 36HR VT 07/1200Z 28.6N 68.6W 50 KT 48HR VT 08/0000Z 29.1N 69.7W 55 KT 72HR VT 09/0000Z 30.5N 70.5W 60 KT 96HR VT 10/0000Z 31.5N 70.0W 60 KT 120HR VT 11/0000Z 32.5N 67.5W 60 KT |