[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 110845
TCDAT4
TROPICAL STORM IRENE DISCUSSION NUMBER  27
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT THU AUG 11 2005

THE ORGANIZATION OF IRENE APPEARS TO BE GRADUALLY IMPROVING...WITH A
LITTLE MORE CONVECTIVE BANDING IN THE NORTHEAST QUADRANT OF THE
CYCLONE AND IN INCREASE IN CONVECTION NEAR MY ESTIMATED CENTER
POSITION. THE UPPER-LEVEL OUTFLOW PATTERN ALSO APPEARS STRONG.
HOWEVER...A GOOD LOW-LEVEL CENTER IS STILL HARD TO FIND...WITH 06Z
FIXES FROM THE THREE AGENCIES SPREAD BY ABOUT 90 NMI...AND THE
CIRCULATION APPEARS TO BE ELONGATED FROM SOUTHEAST TO NORTHWEST.
DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB ARE 35 KT AND THE
ADVISORY INTENSITY WILL REMAIN 35 KT. SHEAR IS NOT EXPECTED TO BE
AN INHIBITING FACTOR OVER THE NEXT FEW DAYS...AND THE OFFICIAL
FORECAST FOLLOWS THE PREVIOUS ADVISORY IN FORECASTING A GRADUAL
INTENSIFICATION TO HURRICANE STRENGTH. THIS FORECAST IS CLOSE TO
THE SHIPS GUIDANCE.

WITH THE UNCERTAINTY IN THE LOCATION OF THE CENTER...THE INITIAL
MOTION IS ALSO UNCERTAIN...BUT IT APPEARS TO BE NEAR 295/12. 00Z
RAOB DATA AND GLOBAL ANALYSES SHOW A 500 MB SHORT-WAVE TROUGH IS
MOVING EASTWARD JUST OFF THE CAROLINAS...WITH THE SUBTROPICAL RIDGE
CENTER JUST EAST OF BERMUDA. AS THE SHORT WAVE LIFTS OUT...HEIGHTS
WILL BUILD NEAR AND JUST EAST OF THE U.S. MID-ATLANTIC STATES...AND
IRENE'S TRACK COULD TAKE A MORE WESTWARD BEND IN A COUPLE OF DAYS.
HOWEVER...MOST OF THE GLOBAL MODEL GUIDANCE SHOWS MID-LEVEL
SOUTHWESTERLY FLOW RETURNING OVER THE SOUTHEASTERN STATES BY DAYS 4
AND 5...AND THIS FLOW COULD TURN IRENE NORTHWARD BEFORE IT REACHES
THE COAST.  THIS IS THE SOLUTION FAVORED BY THE UKMET...GFDL...AND
NOGAPS MODELS.  EVEN THE BAM MODELS...WHICH EARLIER HAD BEEN WELL
TO THE LEFT OF THE GLOBAL MODELS...NOW FAVOR A RECURVING TRACK
OFFSHORE.  THE GFS...ALTHOUGH IT ESSENTIALLY DISSIPATES
IRENE...KEEPS ITS REMNANTS UNDERNEATH THE RIDGE...AND THE GFDN ALSO
TAKES THE CYCLONE INLAND.  THERE IS SUBSTANTIAL UNCERTAINTY IN THE
4 AND 5 DAY POINTS AND IT IS STILL TOO SOON TO TELL WHAT KIND OF
THREAT IRENE COULD POSE FOR THE UNITED STATES.  THE OFFICIAL
FORECAST HAS BEEN ADJUSTED JUST A BIT TO THE RIGHT OF THE PREVIOUS
TRACK...BUT IS STILL WELL TO THE LEFT OF MOST OF THE MODEL
GUIDANCE.

FORECASTER FRANKLIN


FORECAST POSITIONS AND MAX WINDS

INITIAL      11/0900Z 24.2N  61.0W    35 KT
 12HR VT     11/1800Z 24.9N  62.8W    40 KT
 24HR VT     12/0600Z 26.0N  64.9W    45 KT
 36HR VT     12/1800Z 27.0N  66.7W    50 KT
 48HR VT     13/0600Z 27.9N  68.3W    55 KT
 72HR VT     14/0600Z 29.5N  71.0W    60 KT
 96HR VT     15/0600Z 31.5N  73.0W    65 KT
120HR VT     16/0600Z 34.0N  75.0W    70 KT


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