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TROPICAL DEPRESSION ERIN DISCUSSION NUMBER  19
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT THU SEP 06 2001

INFRARED IMAGES SUGGEST LITTLE IMPROVEMENT IN THE ORGANIZATION OF 
ERIN SO FAR.  HOWEVER THE UPPER-LEVEL FLOW APPEARS TO BE FAVORABLE 
FOR EVENTUAL STRENGTHENING.  THE UPPER LOW TO THE WEST OF THE 
TROPICAL CYCLONE HAS DEGENERATED INTO A CYCLONIC SHEAR AXIS...AND 
HIGH CLOUD MOTIONS SHOW SHOW SOUTHEASTERLIES OVER THE SOUTHERN 
SEMICIRCLE OF ERIN.  THIS INDICATES THAT UPPER-LEVEL OUTFLOW IS 
BECOMING ESTABLISHED.  HOWEVER...EVEN WITH THE FAVORABLE SIGNS IN 
THE ENVIRONMENT...THE OFFICIAL INTENSITY FORECAST IS CONSERVATIVE 
SINCE ERIN HAS BEEN SO FICKLE UP TO THIS POINT.

THE CENTER IS DIFFICULT TO LOCATE ON NIGHT-TIME IMAGES.  MY BEST 
GUESS FOR INITIAL MOTION IS 330/6...SLIGHTLY TO THE RIGHT OF THE 
PREVIOUS ESTIMATE.  ERIN MAY BE ROTATING AROUND THE UPPER LOW 
REMNANTS AT THIS TIME.  A LARGE MID-LATITUDE TROUGH IS CURRENTLY 
BYPASSING THE TROPICAL CYCLONE...AND THE NCEP GLOBAL MODEL SHOWS A 
MID-TROPOSPHERIC RIDGE BUILDING OVER THE WESTERN ATLANTIC OVER THE 
NEXT COUPLE OF DAYS.  HOWEVER THERE IS ALSO A LOW- TO MID-LEVEL 
VORTEX ON THE SOUTHWEST SIDE OF THE RIDGE...JUST OFF THE SOUTHEAST 
U.S. COAST.  THE OFFICIAL TRACK FORECAST...WHICH IS SIMILAR TO THE 
PREVIOUS ONE...STEERS SLOWLY ERIN TOWARD THE NORTH-NORTHWEST AND 
NORTHWEST BETWEEN THE RIDGE AND THE VORTEX.  THIS IS ON THE LEFT 
EDGE OF THE TRACK GUIDANCE SUITE.

ANOTHER HURRICANE HUNTER AIRCRAFT IS SCHEDULED TO INVESTIGATE ERIN 
AROUND 06Z.

FORECASTER PASCH
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     07/0300Z 24.0N  58.7W    25 KTS
12HR VT     07/1200Z 24.8N  59.4W    30 KTS
24HR VT     08/0000Z 25.6N  60.2W    40 KTS
36HR VT     08/1200Z 26.3N  61.0W    50 KTS
48HR VT     09/0000Z 27.2N  62.0W    60 KTS
72HR VT     10/0000Z 29.0N  64.0W    65 KTS
 
 
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