Tropical Storm IGNACIO

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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
 
 
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