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TROPICAL STORM ERIN DISCUSSION NUMBER 22
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT FRI SEP 07 2001
DATA FROM A RECONNAISSANCE PLANE INDICATE THAT THE CENTRAL PRESSURE
HAS FALLEN TO 1004 MB...ACTUALLY VERY CLOSE TO LATEST PRESSURE
REPORTED BY THE UNIVERSITY OF WISCONSIN EXPERIMENTAL TROPICAL
CYCLONE ESTIMATE FROM THE AMSU INSTRUMENT. MAXIMUM FLIGHT LEVEL
WINDS WERE 46 KNOTS TO THE NORTHEAST OF THE CENTER...SO INITIAL
INTENSITY IS ADJUSTED TO 35 KNOTS. ERIN IS ONCE AGAIN A TROPICAL
STORM. I GUESS THIS HAS BEEN THE YEAR OF THE INTERRUPTED TROPICAL
CYCLONES.
CONVECTION IS NOT DEEP BUT THERE IS A WELL DEFINED LOW-LEVEL
CIRCULATION WITH BANDING FEATURES...AND THE OUTFLOW IS FAIR. SHEAR
IS FORECAST TO BE LOW OR MARGINAL AND THE OCEAN IS WARM. SO ERIN IS
EXPECTED TO BECOME A HURRICANE BY THE END OF THE FORECAST PERIOD.
ERIN IS MOVING SLOWLY TOWARD THE NORTH-NORTHWEST BUT ONCE THE TROUGH
TO THE NORTH IS GONE...THE RIDGE IS EXPECTED TO BUILD AGAIN AND ERIN
SHOULD TURN MORE TO THE NORTHWEST AND INCREASE IN FORWARD SPEED FOR
A WHILE. THEREAFTER...ANOTHER TROUGH IS FORECAST TO APPROACH THE
AREA AND WEAKEN THE STEERING CURRENTS. ERIN SHOULD SLOW DOWN AGAIN.
FORECASTER AVILA
FORECAST POSITIONS AND MAX WINDS
INITIAL 07/2100Z 25.7N 58.1W 35 KTS
12HR VT 08/0600Z 26.7N 58.5W 40 KTS
24HR VT 08/1800Z 28.5N 59.3W 45 KTS
36HR VT 09/0600Z 30.5N 60.0W 50 KTS
48HR VT 09/1800Z 32.5N 62.0W 55 KTS
72HR VT 10/1800Z 34.5N 63.5W 65 KTS
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