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HURRICANE ERIN DISCUSSION NUMBER  27
NATIONAL WEATHER SERVICE MIAMI FL
11 PM AST SAT SEP 08 2001

THE LAST FIX FROM THE AIR FORCE RESERVE HURRICANE HUNTER FOUND A
CENTRAL PRESSURE OF 992 MB AND FLIGHT LEVEL WINDS OF 84 KT IN THE
NORTHEAST QUADRANT.  SINCE THAT TIME...ERIN HAS DEVELOPED AN
IRREGULAR 35-40 NM WIDE EYE AND SATELLITE INTENSITY ESTIMATES
FROM TAFB AND SAB HAVE INCREASED TO 77 KT.  THE INITIAL INTENSITY
IS THUS RAISED TO 75 KT.  THE NEXT AIRCRAFT IS SCHEDULED TO ARRIVE
IN THE STORM AT ABOUT 06Z TO EITHER CONFIRM OR REFUTE THE ESTIMATES.

THE INITIAL MOTION IS 335/13.  SATELLITE DATA SUGGESTS THAT A
SIGNIFICANT LOW/MID LEVEL RIDGE IS NORTH OF ERIN...WHICH WOULD
FAVOR A MORE NORTHWESTERLY TRACK THAN WHAT IS CURRENTLY OCCURRING.
NHC HURRICANE GUIDANCE SUGGESTS A SLOWING NORTHWESTERLY MOTION
THROUGH 48 HR...FOLLOWED BY A TURN TO THE NORTH DUE TO AN UPPER
LEVEL LOW WEST OF THE HURRICANE AND A LARGER DEEP LAYER TROUGH
MOVING INTO THE EASTERN U.S.  THE OFFICIAL FORECAST TRACK FOLLOWS
THIS SCENARIO DOWN THE CENTER OF THE GUIDANCE AND IS ONLY SLIGHTLY
CHANGED FROM THE PREVIOUS FORECAST.  IT SHOULD BE NOTED THAT NONE
OF THE NHC GUIDANCE MOVES ERIN WEST OF 68W AT THIS TIME.

ERIN IS SHOWING GOOD ANTICYCLONIC OUTFLOW...ESPECIALLY TO THE NORTH.
HOWEVER...SOME CIRRUS CLOUDS WEST OF THE HURRICANE ARE BLOWING
STRAIGHT TOWARD IT...HINTING THAT SHEAR MAY NOT YET BE THROUGH
WITH ERIN.  WATER VAPOR IMAGERY INDICATES THESE WESTERLIES ARE DUE
TO THE DEVELOPING UPPER-LEVEL LOW OFF THE NORTH CAROLINA COAST...
AND THE MODELS FORECAST THESE WINDS TO BECOME SOUTHERLY AS THE
LOW DEVELOPS FURTHER AND A RIDGE DEVELOPS NEAR OR OVER ERIN.
SHOULD THIS HAPPEN...ERIN WILL REMAIN IN A FAVORABLE ENVIRONMENT
AND STRENGTHEN.  THE GFDL AND SHIPS MODELS INDICATE THIS WILL
HAPPEN...AND THE INTENSITY FORECAST WILL FOLLOW ALONG.  THERE IS A
CHANCE THAT ERIN COULD STRENGTHEN MORE THAN FORECAST HERE IF THE
SHEAR REMAINS LIGHT.

THE 12 FT SEAS RADII HAVE BEEN EXPANDED BASED ON COORDINATION WITH
THE MARINE PREDICTION CENTER.  WHILE ERIN IS NOT CURRENTLY FORECAST
TO THREATEN THE UNITED STATES...SWELLS FROM THE HURRICANE MAY 
EVENTUALLY AFFECT PORTIONS OF THE ATLANTIC COAST.
 
FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     09/0300Z 30.1N  60.6W    75 KTS
12HR VT     09/1200Z 31.7N  61.8W    85 KTS
24HR VT     10/0000Z 33.4N  63.7W    90 KTS
36HR VT     10/1200Z 34.8N  65.2W    95 KTS
48HR VT     11/0000Z 36.5N  66.0W    95 KTS
72HR VT     12/0000Z 38.0N  66.0W    90 KTS
 
 
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