ZCZC MIATCDEP4 ALL TTAA00 KNHC DDHHMM TROPICAL STORM IGNACIO DISCUSSION NUMBER 8 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2 PM PDT SAT AUG 23 2003 LATEST DVORAK CLASSIFICATIONS ARE T3.5 FROM BOTH TAFB AND SAB. A RECENT OBJECTIVE DVORAK ESTIMATE WAS T4.0. A FORMATIVE EYE HAS BEEN INTERMITTENTLY VISIBLE IN SATELLITE IMAGERY AND A MICROWAVE PASS AT 1820Z SHOWED A PARTIAL EYEWALL. BASED ON THE ABOVE...THE ADVISORY INTENSITY IS SET JUST BELOW HURRICANE STRENGTH...AND THE ONGOING RECORD FOR LATEST FIRST HURRICANE OF THE EAST PACIFIC SEASON IS EXTENDED FOR ANOTHER THREE HOURS. THE INITIAL MOTION IS ESTIMATED AT 310/5...ALTHOUGH THERE HAS BEEN LITTLE MOTION OVER THE PAST THREE HOURS. THERE HAS BEEN LITTLE CHANGE TO THE TRACK FORECAST IN THE SHORT TERM. MODEL GUIDANCE HAS CONVERGED...WITH THE NOGAPS NO LONGER AN OUTLIER WITH A NORTHWARD TRACK. THE OFFICIAL FORECAST IS A BLEND OF THE GFS...UKMET...AND GFDL MODELS. THERE IS A WEAK MID-LEVEL RIDGE TO THE NORTH OF THE CYCLONE THAT IS NUDGING IGNACIO NORTHWESTWARD. THIS RIDGE IS FORECAST BY GLOBAL MODELS TO GRADUALLY WEAKEN OVER THE NEXT FEW DAYS AND THIS IS EXPECTED TO RESULT IN SOME SLOWING OF THE MOTION AND A PROLONGED PASSAGE OF IGNACIO OVER OR VERY NEAR THE BAJA PENINSULA. ONE CONCERN WITH THIS WOULD BE THE POSSIBILITY FOR VERY LARGE AMOUNTS OF RAINFALL. FORTUNATELY...IGNACIO IS A RATHER SMALL STORM AND THIS MAY MITIGATE THE RAINFALL DANGER SOMEWHAT. LATE IN THE FORECAST PERIOD THE TRACK WAS ADJUSTED NORTHWARD BECAUSE THE CYCLONE IS EXPECTED TO BE STRONGER AND RESPOND TO DEEPER LAYER STEERING LONGER. THE SHIPS INTENSITY GUIDANCE BRINGS IGNACIO TO NEARLY 80 KT BEFORE PRESUMED LANDFALL...BUT A BIG CONTRIBUTOR TO THIS IS PERSISTENCE... THE RECENT RAPID DEVELOPMENT. THE GFDL BRINGS IGNACIO TO ABOUT 85 KT IN 24 HOURS. WHILE THE WATERS ARE VERY WARM...WATER VAPOR IMAGERY SUGGESTS THAT THE OUTFLOW FROM THE CYCLONE IS INHIBITED TO THE SOUTHWEST AND NORTHEAST...WITH NO ANTICYCLONE ESTABLISHED OVER IGNACIO. AS A RESULT...THE OFFICIAL FORECAST IS LESS AGGRESSIVE THAN THE GUIDANCE. WHILE THE OFFICIAL FORECAST CALLS FOR A CATEGORY ONE HURRICANE...A CATEGORY TWO LANDFALL IS A DISTINCT POSSIBILITY. FORECASTER FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 23/2100Z 21.9N 108.7W 60 KT 12HR VT 24/0600Z 22.5N 109.4W 70 KT 24HR VT 24/1800Z 23.3N 110.2W 70 KT...INLAND 36HR VT 25/0600Z 24.0N 111.0W 60 KT...ALONG THE COAST 48HR VT 25/1800Z 24.6N 111.7W 45 KT...ALONG THE COAST 72HR VT 26/1800Z 25.5N 113.0W 35 KT...OVER WATER 96HR VT 27/1800Z 27.0N 113.5W 25 KT...INLAND 120HR VT 28/1800Z 28.5N 114.0W 20 KT...DISSIPATING INLAND NNNN
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Page last modified: Monday, 07-Feb-2005 16:49:57 UTC