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#98423 (Received by flhurricane at: 5:03 AM 19.Jul.2006) TCDAT2 TROPICAL STORM BERYL DISCUSSION NUMBER 4 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022006 500 AM EDT WED JUL 19 2006 THE CENTER WOBBLED A BIT TO THE NORTH-NORTHWEST A FEW HOURS AGO BUT A RECENT FIX FROM THE AIR FORCE HURRICANE HUNTERS INDICATE THAT THE MOTION IS TOWARD THE NORTH...I.E. 360/6. A MID-TROPOSPHERIC SHORTWAVE TROUGH IS CURRENTLY PASSING BY THE LONGITUDE OF BERYL AND GLOBAL MODELS INDICATE THAT ANOTHER ONE WILL BE APPROACHING THE SYSTEM IN 36-48 HOURS...WITH A STRONG SUBTROPICAL RIDGE HOLDING IN PLACE TO THE EAST-SOUTHEAST. THIS STEERING PATTERN SHOULD CAUSE THE TROPICAL CYCLONE TO GRADUALLY TURN TOWARD THE NORTHEAST. THE OFFICIAL FORECAST TRACK HAS BEEN SHIFTED SOMEWHAT TO THE LEFT FROM THE PREVIOUS ADVISORY...OUT OF RESPECT FOR A LEFTWARD SHIFT IN THE GFDL AND GFS TRACKS. HOWEVER BOTH OF THESE MODELS SHOW A VERY WEAK SYSTEM IN A COUPLE OF DAYS AND IN FACT THE GFS SUGGEST THAT BERYL WILL BEGIN TO MERGE WITH AN APPROACHING EXTRATROPICAL CYCLONE IN 2-3 DAYS. THE OFFICIAL FORECAST IS CLOSEST TO THE U.K. MET. OFFICE TRACK WHICH APPEARS TO BE A REASONABLE SOLUTION BASED ON THE STEERING SCENARIO DESCRIBED ABOVE. BERYL IS LIKELY TO MERGE WITH THE AFOREMENTIONED MID-LATITUDE SYSTEM BY THE END OF THE FORECAST PERIOD...IF NOT SOONER. THE HURRICANE HUNTERS FOUND THE CENTRAL PRESSURE HOLDING STEADY NEAR 1005 MB...AND PEAK 850 MB FLIGHT-LEVEL WINDS WERE 45 KT OVER THE SOUTHEAST QUADRANT. THIS JUST SUPPORTS TROPICAL STORM STRENGTH. SOME DEEP CONVECTION HAS DEVELOPED AROUND THE BROAD CENTER BUT THE TOPS ARE NOT VERY COLD. SEA SURFACE TEMPERATURES WILL BE IN 25-27 DEG C RANGE ALONG THE TRACK OF BERYL FOR THE NEXT 24-36 HOURS SO THERE IS STILL THE POSSIBILITY OF SOME STRENGTHENING. HOWEVER ANIMATION OF INFRARED IMAGES SHOW CIRRUS ELEMENTS MOVING NORTHEASTWARD ACROSS THE CENTER OF THE STORM...INDICATIVE OF SOUTHWESTERLY SHEAR. GIVEN THE MARGINAL UPPER-LEVEL ENVIRONMENT...A SUBSTANTIAL INCREASE IN STRENGTH APPEARS UNLIKELY. THE TROPICAL STORM WATCH FOR THE NORTH CAROLINA COAST IS BEING KEPT AS A PRECAUTION AT THIS TIME. FORECAST POSITIONS AND MAX WINDS INITIAL 19/0900Z 34.7N 73.7W 35 KT 12HR VT 19/1800Z 35.7N 73.7W 40 KT 24HR VT 20/0600Z 36.9N 73.7W 45 KT 36HR VT 20/1800Z 38.6N 72.8W 50 KT 48HR VT 21/0600Z 40.3N 70.7W 50 KT 72HR VT 22/0600Z 44.0N 64.0W 45 KT...EXTRATROPICAL 96HR VT 23/0600Z 47.0N 55.0W 35 KT...EXTRATROPICAL 120HR VT 24/0600Z...MERGED WITH EXTRATROPICAL CYCLONE |