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#31624 (Received by flhurricane at: 11:14 PM 09.Jul.2005) TCDAT4 HURRICANE DENNIS DISCUSSION NUMBER 23 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 10 PM CDT SAT JUL 09 2005 AFTER DEEPENING AT A RATE THAT BORDERED ON INSANE DURING THE AFTERNOON...DENNIS HAS CONTINUED TO STRENGTHEN AT A MORE NORMAL RATE THIS EVENING. REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT SHOW THAT THE CENTRAL PRESSURE HAS FALLEN TO 941 MB...WITH MAXIMUM FLIGHT-LEVEL WINDS OF 122 KT IN THE NORTHEAST QUADRANT. BASED ON THIS...THE INITIAL INTENSITY IS 110 KT. IT IS EXPECTED THAT WHEN THE AIRCRAFT AGAIN SAMPLES THE NORTHEAST EYEWALL THAT IT WILL FIND STRONGER WINDS THAT WILL JUSTIFY UPGRADING DENNIS TO A CATEGORY FOUR HURRICANE. IT SHOULD BE NOTED THAT ALTHOUGH DENNIS HAS A VERY LARGE OUTER WIND FIELD... THE HURRICANE FORCE WINDS ARE CONFINED TO A VERY SMALL AREA NEAR THE CENTER. THERE IS NO CHANGE TO THE TRACK FORECAST PHILOSOPHY. DENNIS IN ON THE SOUTHWEST SIDE OF A MID/UPPER LEVEL RIDGE EXTENDING FROM THE WESTERN ATLANTIC NORTHWESTWARD INTO THE OHIO VALLEY...AND EAST OF A MID/UPPER-LEVEL TROUGH EXTENDING FROM ARKANSAS SOUTH-SOUTHWESTWARD TO JUST OFF THE TEXAS COAST. THIS COMBINATION SHOULD KEEP DENNIS ON A GENERAL NORTHWESTWARD TO NORTH-NORTHWESTWARD TRACK FOR AT LEAST 2 DAYS...WITH THIS MOTION BRINGING THE STORM INLAND ON SUNDAY. TRACK MODEL GUIDANCE IS TIGHTLY CLUSTERED IN CALLING FOR LANDFALL IN THE PENSACOLA FLORIDA-PASCAGOULA MISSISSIPPI AREA...AND THE OFFICIAL FORECAST TRACK IS BASICALLY DOWN THE MIDDLE OF THE CLUSTER JUST A LITTLE TO THE LEFT OF THE PREVIOUS FORECAST. AFTER LANDFALL...DENNIS SHOULD SLOW AND GRADUALLY RECURVE INTO THE WESTERLIES OVER THE MID-MISSISSIPPI AND OHIO VALLEYS. THE COMBINATION OF TIGHT INNER CORE...GOOD TO EXCELLENT OUTFLOW OVER THE NORTHEASTERN SEMICIRCLE...WARM SEA SURFACE TEMPERATURES...AND COLD CONVECTIVE TOPS SUGGESTS THAT DENNIS HAS NOT YET FINISHED STRENGTHENING. THE INTENSITY FORECAST CALLS FOR THE SYSTEM TO REACH 120 KT IN 12 HR. AFTER THAT...CONCENTRIC EYEWALL CYCLES ALONG WITH POSSIBLE DRY AIR INTRUSION AND POSSIBLY INCREASING SHEAR WILL LIKELY END STRENGTHENING. DENNIS WILL WEAKEN AFTER LANDFALL AND EVENTUALLY BECOME A LOW PRESSURE AREA. 34 KT WINDS IN THE SOUTHEASTERN QUADRANT HAVE BEEN REVISED OUTWARD BASED ON OBSERVATIONS AT KEY WEST. FORECASTER BEVEN FORECAST POSITIONS AND MAX WINDS INITIAL 10/0300Z 26.6N 85.3W 110 KT 12HR VT 10/1200Z 28.2N 86.6W 120 KT 24HR VT 11/0000Z 30.6N 87.9W 120 KT...INLAND 36HR VT 11/1200Z 32.9N 89.0W 65 KT...INLAND 48HR VT 12/0000Z 34.8N 89.8W 30 KT...INLAND 72HR VT 13/0000Z 37.5N 89.0W 25 KT...INLAND DISSIPATING 96HR VT 14/0000Z 38.0N 86.5W 20 KT...INLAND REMNANT LOW 120HR VT 15/0000Z 38.5N 82.5W 20 KT...INLAND REMNANT LOW |