ZCZC MIATCDAT2 ALL TTAA00 KNHC DDHHMM TROPICAL STORM HELENE DISCUSSION NUMBER 10 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072012 1000 PM CDT FRI AUG 17 2012 A HURRICANE HUNTER PLANE INVESTIGATED HELENE FOR SEVERAL HOURS THIS EVENING AND FOUND THAT THE DEVELOPMENT TREND OBSERVED EARLIER TODAY IS NO LONGER OCCURRING. HELENE IS EITHER WEAKER OR ON A STEADY STATE WITH MAXIMUM WINDS OF 35 KNOTS. THE CYCLONE STILL HAS A WELL DEFINED CIRCULATION AS INDICATED BY THE RECONNAISSANCE PLANE BEFORE IT LEFT THE AREA...AND ALTHOUGH THE SATELLITE PRESENTATION HAS DETERIORATED...ENVIRONMENTAL CONDITIONS ARE SOMEWHAT FAVORABLE FOR HELENE TO REGAIN SOME STRENGTH BEFORE IT MOVES INLAND IN ABOUT 24 HOURS OR EARLIER. AFTER LANDFALL...A STEADY WEAKENING IS ANTICIPATED. FIXES FROM THE RECONNAISSANCE PLANE INDICATE THAT HELENE WAS MEANDERING OR DRIFTING NORTHWARD DURING THE PAST COUPLE OF HOURS. HOWEVER...THERE IS ENOUGH RIDGING TO THE NORTH OF THE CYCLONE TO FORCE HELENE SLOWLY NORTHWESTWARD AT ABOUT 6 KNOTS TOWARD THE COAST OF MEXICO. ALTHOUGH THIS IS THE MOST LIKELY SCENARIO AS INDICATED IN THE OFFICIAL FORECAST...ONE SHOULD NOTE THAT VARIOUS MODELS INCLUDING THE GFS AND THE ECMWF KEEP A LOW...OR PERHAPS THE MODEL REPRESENTATION OF HELENE DRIFTING NORTHWARD VERY CLOSE TO THE COAST OF MEXICO FOR SEVERAL DAYS...AND IN FACT...THE GFS RESTRENGTHENS THIS FEATURE. NEVERTHELESS...THE MAIN THREAT FROM HELENE WILL BE HEAVY RAINFALL...WHICH WILL CONTINUE EVEN AS THE CYCLONE SLOWLY MOVES INLAND AND WEAKENS. FORECAST POSITIONS AND MAX WINDS INIT 18/0300Z 21.0N 96.4W 35 KT 40 MPH 12H 18/1200Z 21.7N 97.2W 40 KT 45 MPH 24H 19/0000Z 22.2N 97.8W 45 KT 50 MPH...ON THE COAST 36H 19/1200Z 23.0N 98.0W 30 KT 35 MPH...INLAND 48H 20/0000Z 24.0N 98.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 21/0000Z...DISSIPATED $$ FORECASTER AVILA NNNN
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Page last modified: Monday, 31-Dec-2012 12:09:20 UTC