[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 152027
TCDAT4
HURRICANE IRENE DISCUSSION NUMBER  45
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT MON AUG 15 2005

AN EYE HAS OCCASIONALLY BEEN EVIDENT ON SATELLITE IMAGES.  DVORAK
ANALYSES SUPPORT A CURRENT INTENSITY NEAR 80 KT.  THE HURRICANE
CONTINUES TO SHOW STRONG UPPER-LEVEL OUTFLOW...EXCEPT TO THE
NORTHWEST.  IRENE HAS CONTINUED TO MOVE A LITTLE MORE TO THE
RIGHT...AT LEAST TEMPORARILY DUCKING THE BELT OF WESTERLIES AND
MUCH STRONGER SHEAR THAT LIES TO ITS NORTH.  THE SHIPS
MODEL...WHICH USES THE GFS UPPER-LEVEL FORECAST FIELDS...PREDICTS
THAT THE SHEAR WILL INCREASE TO 35 KT WITHIN 36 HOURS.  WEAKENING
IS EXPECTED TO COMMENCE IN 12 HOURS OR SO.  WITHIN A COUPLE OF
DAYS...IRENE IS FORECAST TO TRANSFORM INTO A VIGOROUS
EXTRATROPICAL STORM.  BY THE END OF THE FORECAST PERIOD IT IS
LIKELY TO BE ABSORBED BY ANOTHER BAROCLINIC CYCLONE.  SOME OF THE
GUIDANCE...SUCH AS THE U.K. MET. OFFICE GLOBAL MODEL...SUGGEST THAT
IRENE'S EXTRATROPICAL REMNANTS COULD MERGE WITH ANOTHER SYSTEM NEAR
THE CANADIAN MARITIMES AS SOON AS 48-72 HOURS FROM NOW.

AS NOTED ABOVE...IRENE'S TRACK HAS BENT A LITTLE MORE TO THE RIGHT
AND THE ESTIMATED MOTION IS NOW 070/10.  THERE HAS BEEN NO INCREASE
IN FORWARD SPEED YET...BUT THE CYCLONE IS FORECAST TO BEGIN
ACCELERATING TOWARD THE EAST-NORTHEAST AS IT ENCOUNTERS A
SIGNIFICANTLY STRONGER WESTERLY STEERING CURRENT OVER THE NEXT DAY
OR SO.  A GRADUAL TURN TO THE LEFT IS PREDICTED OVER THE NEXT FEW
DAYS...DUE TO AN APPROACHING 500 MB MID-LATITUDE TROUGH.  BASED ON
THE INITIAL MOTION...THE CURRENT NHC FORECAST IS A LITTLE TO THE
RIGHT AND A LITTLE SLOWER THAN THE PREVIOUS ONE.  THIS IS FASTER
THAN THE DYNAMICAL CONSENSUS...BUT FAIRLY CLOSE TO THE GFS ENSEMBLE
MEAN.

WIND RADII FOR THE EXTRATROPICAL PHASE HAVE BEEN EXPANDED BASED ON
INPUT FROM OCEAN PREDICTION CENTER.

FORECASTER PASCH


FORECAST POSITIONS AND MAX WINDS

INITIAL      15/2100Z 36.7N  66.0W    80 KT
 12HR VT     16/0600Z 37.3N  64.0W    80 KT
 24HR VT     16/1800Z 38.4N  61.5W    70 KT
 36HR VT     17/0600Z 40.0N  58.5W    60 KT
 48HR VT     17/1800Z 43.0N  54.0W    55 KT...EXTRATROPICAL
 72HR VT     18/1800Z 50.5N  43.5W    50 KT...EXTRATROPICAL
 96HR VT     19/1800Z 58.0N  35.0W    45 KT...EXTRATROPICAL
120HR VT     20/1800Z...ABSORBED

$$
This weather bulletin was brought to you by:
www.nashvilleweather.net