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| #111036 (Received by flhurricane at: 4:43 PM 15.Sep.2006) TCDAT3 TROPICAL STORM HELENE DISCUSSION NUMBER 14 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006 500 PM EDT FRI SEP 15 2006 HELENE IS DEFINITELY STRENGTHENING AT THIS TIME AND IS VERY NEAR HURRICANE STATUS. SATELLITE IMAGES SHOW AN IMPRESSIVE CYCLONICALLY-CURVED CONVECTIVE BAND WRAPPING AROUND THE CENTER. THE OUTFLOW IS WELL-ESTABLISHED AND IS MOST IMPRESSIVE TO THE WEST AND SOUTH OF THE CYCLONE. ALL INDICATIONS ARE THAT HELENE WILL CONTINUE IN A LOW-SHEAR ENVIRONMENT AND WILL BE MOVING OVER WARMER WATERS...ACCORDING TO BUOY DATA NEARBY. THERE ARE NO OTHER APPARENT CONDITIONS THAT COULD HALT ADDITIONAL STRENGTHENING OVER THE NEXT 2 TO 3 DAYS. HELENE IS MOVING TOWARD THE WEST-NORTHWEST OR 300 DEGREES...BACK AT THE EARLIER SPEED OF 13 KNOTS...AROUND THE PERIPHERY OF THE SUBTROPICAL RIDGE. A STRONG MID-LATITUDE TROUGH...WHICH IS FORECAST TO BE OVER THE WESTERN ATLANTIC...WILL LIKELY ERODE THE RIDGE. THE EXPECTED STEERING PATTERN WILL FORCE HELENE TO GRADUALLY TURN TO THE NORTHWEST AS INDICATED IN THE OFFICIAL FORECAST. THIS IS THE GENERAL SOLUTION PROVIDED BY MOST OF THE GUIDANCE BUT MODELS VARY IN HOW FAR WEST THEY BRING HELENE DEPENDING ON EACH MODEL'S FORECAST REPRESENTATION OF THE RIDGE. NEVERTHELESS...NO MODEL BRINGS HELENE PAST 60W LONGITUDE IN FIVE DAYS IN THE LATEST MORNING RUN...AND IN FACT...MOST OF THEM TURN THE CYCLONE NORTHWARD. FORECAST POSITIONS AND MAX WINDS INITIAL 15/2100Z 16.7N 42.8W 60 KT 12HR VT 16/0600Z 17.7N 44.5W 70 KT 24HR VT 16/1800Z 18.6N 46.0W 75 KT 36HR VT 17/0600Z 19.5N 47.5W 85 KT 48HR VT 17/1800Z 20.5N 49.0W 95 KT 72HR VT 18/1800Z 22.0N 51.0W 100 KT 96HR VT 19/1800Z 24.0N 54.0W 95 KT 120HR VT 20/1800Z 26.0N 56.5W 90 KT $$ FORECASTER AVILA |
