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| #102152 (Received by flhurricane at: 11:00 AM 04.Aug.2006) TCDAT3 TROPICAL DEPRESSION CHRIS DISCUSSION NUMBER 16 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032006 1100 AM EDT FRI AUG 04 2006 NORTHEASTERLY SHEAR HAS CONTINUED TO TAKE ITS TOLL ON CHRIS THIS MORNING. IN FACT...BETWEEN 0900 UTC AND 1130 UTC...RECONNAISSANCE AIRCRAFT ONLY MEASURED 29 KT WINDS AT FLIGHT LEVEL. THEREFORE... CHRIS WAS DOWNGRADED TO A 30 KT DEPRESSION ON THE INTERMEDIATE ADVISORY AND WILL RETAIN THIS INTENSITY FOR THIS ADVISORY. THIS COULD EVEN BE A LITTLE GENEROUS GIVEN THE AIRCRAFT DATA AND A QUIKSCAT PASS THAT ONLY INDICATED ABOUT 25 KT WINDS. CHRIS REMAINS SQUEEZED BETWEEN TWO UPPER-LEVEL LOWS AND IT DOES NOT APPEAR IN THE SHORT-TERM THAT THE SHEAR WILL RELAX. HOWEVER...IT WOULD NOT TAKE MUCH FOR CHRIS TO RESTRENGHTEN BACK TO TROPICAL STORM STATUS IF NEW CONVECTION DEVELOPS NEAR THE CENTER. THE INTENSITY FORECAST KEEPS IN THIS POSSIBILITY. THEREAFTER...THE FORECAST MAINTAINS CHRIS AS MINIMAL TROPICAL STORM AS IT MOVES ALONG THE NORTH COAST OF CUBA. BOTH THE SHIPS AND GFDL MODELS INDICATE THAT IF CHRIS SURVIVES THE NEXT DAY OR SO...WHICH IT MAY NOT...IT MIGHT ENTER A LITTLE MORE FAVORABLE ENVIRONMENT OVER THE GULF OF MEXICO. THE INTENSITY FORECAST ALLOWS FOR STRENGTHENING OVER THE GULF OF MEXICO BUT IS A BIT MORE CONSERVATIVE THAN BOTH OF THESE MODELS. CHRIS TOOK A NORTHWESTWARD JOG EARLY THIS MORNING BUT A 12-HOUR MOTION YIELDS 280/11 KT. CHRIS IS FORECAST TO REMAIN SOUTH OF A STRONG MID-LEVEL RIDGE FOR THE NEXT 5 DAYS. IN FACT...THE RIDGE IS FORECAST TO STRENGTHEN OVER THE SOUTHERN UNITED STATES BEYOND DAY 3 WHICH SHOULD KEEP CHRIS ON A GENERAL WEST TO WEST-NORTHWESTWARD HEADING. THE TRACK GUIDANCE IS IN FAIRLY GOOD AGREEMENT ON THIS SCENARIO AND THE OFFICIAL FORECAST WAS NUDGED JUST NORTH OF THE PREVIOUS TRACK. IT LIES JUST NORTH OF THE MODEL CONSENSUS. FORECAST POSITIONS AND MAX WINDS INITIAL 04/1500Z 21.3N 71.6W 30 KT 12HR VT 05/0000Z 21.6N 73.5W 30 KT 24HR VT 05/1200Z 22.0N 76.1W 35 KT 36HR VT 06/0000Z 22.5N 78.6W 35 KT...NEAR CUBA 48HR VT 06/1200Z 23.2N 81.3W 35 KT...NEAR CUBA 72HR VT 07/1200Z 24.3N 86.5W 40 KT 96HR VT 08/1200Z 25.0N 91.5W 45 KT 120HR VT 09/1200Z 25.5N 97.0W 50 KT |
