Tropical Storm IGNACIO

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TROPICAL STORM IGNACIO DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP122009
200 AM PDT TUE AUG 25 2009
 
A SERIES OF MICROWAVE IMAGES RECEIVED DURING THE PAST FEW HOURS
INDICATE THAT THE LOW-LEVEL CENTER OF IGNACIO WAS A LITTLE BIT TO
THE NORTH THAN PREVIOUSLY INDICATED AND REMOVED FROM THE MAIN
CONVECTION.  HOWEVER...A NEW AREA OF DEEP CONVECTION IS CURRENTLY
DEVELOPING NEAR THE CENTER.  THE OUTFLOW IS ESTABLISHED IN THE
SOUTHERN SEMICIRCLE ONLY...SUGGESTING THAT THERE IS SOME NORTHERLY
SHEAR AFFECTING THE CYCLONE. DVORAK T-NUMBER HAVE NOT CHANGED AND
THE INITIAL INTENSITY IS KEPT AT 35 KNOTS.  IN FACT...AN ASCAT PASS
JUST CAME IN AND SHOWS 35-KT WINDS...THE DATA HELPED TO ADJUST THE
INITIAL WIND RADII.  IGNACIO HAS THE POTENTIAL TO GATHER SOME
STRENGTH BEFORE IT MOVES OVER COOLER WATER IN A COUPLE OF DAYS.
THEREAFTER... A WEAKENING IS INDICATED AND BY DAYS 4 AND 5
IGNACIO SHOULD HAVE BECOME A REMNANT LOW.
 
WITH THE SMALL RELOCATION OF THE CENTER...THE INITIAL MOTION IS NOW
295 DEGREES OR WEST-NORTHWEST AT 10 KNOTS...WHICH IS NOT TOO
DIFFERENT FROM THE PREVIOUS ADVISORY MOTION. IGNACIO IS ALREADY ON
THE WESTERN EDGE OF THE SUBTROPICAL RIDGE WHILE A LARGE MID-LEVEL
TROUGH IS APPROACHING THE CYCLONE FROM THE NORTHWEST. THIS PATTERN
CALLS FOR IGNACIO TO GRADUALLY TURN MORE TO THE NORTHWEST DURING
THE NEXT 2 TO 3 DAYS. THEREAFTER...IGNACIO SHOULD TURN TO THE WEST
STEERED BY THE LOW-LEVEL FLOW AS IT BECOMES A SHALLOW REMNANT LOW.
THIS IS THE SOLUTION PROVIDED BY MOST OF THE GUIDANCE AND THE
OFFICIAL FORECAST IS IN THE MIDDLE OF THE TRACK GUIDANCE ENVELOPE.
THE NEW FORECAST TRACK WAS ADJUSTED NORTHWARD A LITTLE BIT DUE TO
THE SMALL RELOCATION OF THE CENTER AND NOT BECAUSE OF A CHANGE IN
THE STEERING PATTERN.
 
 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      25/0900Z 18.1N 118.5W    35 KT
 12HR VT     25/1800Z 18.7N 119.9W    40 KT
 24HR VT     26/0600Z 19.7N 122.0W    45 KT
 36HR VT     26/1800Z 21.0N 123.5W    50 KT
 48HR VT     27/0600Z 23.0N 125.0W    40 KT
 72HR VT     28/0600Z 26.5N 128.5W    30 KT
 96HR VT     29/0600Z 27.5N 131.5W    25 KT...REMNANT LOW
120HR VT     30/0600Z 28.0N 135.5W    20 KT...REMNANT LOW
 
$$
FORECASTER AVILA
 
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