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| #199536 (Received by flhurricane at: 5:08 PM 06.Jul.2008) TCDAT2 TROPICAL STORM BERTHA DISCUSSION NUMBER 15 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022008 500 PM EDT SUN JUL 06 2008 A COUPLE OF MICROWAVE IMAGES JUST RECEIVED SUGGEST THAT BERTHA'S VORTEX IS TILTED A LITTLE. THE IMAGES INDICATE THAT THE LOW-LEVEL CENTER IS LOCATED JUST SOUTHWEST OF THE MID-LEVEL CENTER. HOWEVER...THESE IMAGES ALSO SUGGEST THAT THE OVERALL STRUCTURE HAS IMPROVED WITH THE APPEARANCE OF AN EYE FEATURE...SUGGESTING THAT BERTHA IS STRENGTHENING. DVORAK INTENSITY ESTIMATES WERE 45 KT AT 18Z...BUT WITH THE IMPROVING STRUCTURE THE INITIAL INTENSITY IS INCREASED TO 50 KT. CONDITIONS APPEAR CONDUCIVE FOR STRENGTHENING DURING THE NEXT COUPLE OF DAYS AND BERTHA COULD BECOME A HURRICANE. HOWEVER...INDICATIONS ARE THAT BEYOND 48 HOURS...WESTERLY SHEAR COULD HALT ANY ADDITIONAL STRENGTHENING AS SUGGESTED BY THE SHIPS MODELS. BERTHA IS MOVING WEST-NORTHWESTWARD OR 285/17 KT. ALL OF THE AVAILABLE GUIDANCE SHOWS A NORTHWEST TURN AS THE RIDGE OVER THE WESTERN ATLANTIC WEAKENS IN A FEW DAYS. HOWEVER...THERE REMAINS SOME SPREAD IN THE GUIDANCE AS TO WHEN THE TURN OCCURS. THE HWRF AND GFDL...WHICH DEPICT A STRONG TROPICAL CYCLONE REMAINS ALONG THE EASTERN EDGE OF THE MODEL ENVELOPE. THE UKMET WHICH KEEPS BERTHA WEAKER IS ALONG THE WESTERN EDGE. THE NEW TRACK FORECAST IS ADJUSTED SLIGHTLY EASTWARD...BUT STILL REMAINS WEST OF THE MODEL CONSENSUS. FORECAST POSITIONS AND MAX WINDS INITIAL 06/2100Z 18.1N 47.0W 50 KT 12HR VT 07/0600Z 18.7N 49.6W 55 KT 24HR VT 07/1800Z 19.5N 52.3W 60 KT 36HR VT 08/0600Z 20.2N 54.6W 65 KT 48HR VT 08/1800Z 20.9N 56.7W 70 KT 72HR VT 09/1800Z 23.0N 60.5W 70 KT 96HR VT 10/1800Z 26.0N 64.0W 70 KT 120HR VT 11/1800Z 29.0N 65.5W 70 KT $$ FORECASTER BROWN |
