[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 142032
TCDAT4
TROPICAL STORM IRENE DISCUSSION NUMBER  41
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT SUN AUG 14 2005

THERE WERE 2 AIR FORCE HURRICANE HUNTER PLANES INVESTIGATING IRENE
THIS AFTERNOON.  THEY FOUND THAT THE CENTRAL PRESSURE HAD DROPPED
TO 992 MB AND THE HIGHEST 850 MB FLIGHT LEVEL WIND WAS 72 KNOTS.
THESE DATA INDICATE THAT IRENE IS JUST BELOW HURRICANE STRENGTH.
THE TROPICAL CYCLONE'S CLOUD PATTERN IS THE BEST ORGANIZED IT HAS
EVER BEEN...WITH A FAINT EYE FEATURE AND GOOD SYMMETRY TO THE CDO.
UPPER-LEVEL OUTFLOW IS WELL-DEFINED IN ALL QUADRANTS EXCEPT THE
NORTHEAST.  SINCE IRENE WILL BE TRAVERSING THE WARM GULF STREAM
WATERS OVER THE NEXT 12-24 HOURS...IT MAY VERY WELL BECOME A
HURRICANE TONIGHT OR EARLY MONDAY...BEFORE VERTICAL SHEAR BEGINS TO
INCREASE SIGNIFICANTLY.

NO CHANGE IN THE ESTIMATED MOTION...020/10.  IRENE HAS MOVED NORTH
OF THE AXIS OF THE SUBTROPICAL RIDGE AND WILL LIKELY TURN TOWARD
THE NORTHEAST AND EAST-NORTHEAST AS IT INTERACTS WITH THE
WESTERLIES.  SIGNIFICANT ACCELERATION IS LIKELY IN ABOUT 72 HOURS
AS A 500 MB TROUGH APPROACHES FROM SOUTHEASTERN CANADA.  SOME OF
THE MODELS HAVE NOT INITIALIZED THE TROPICAL CYCLONE VERY WELL AND
THERE HAS PROBABLY CAUSED SOME DIVERGENCE IN THE TRACK FORECAST
GUIDANCE.  THE OFFICIAL FORECAST IS BASED ON A COMPROMISE OF THE
TRACK MODELS...AND CONTINUITY.  IRENE IS LIKELY TO BECOME
EXTRATROPICAL AND MERGE WITH A LARGER BAROCLINIC LOW LATE IN THE
FORECAST PERIOD.

FORECASTER PASCH


FORECAST POSITIONS AND MAX WINDS

INITIAL      14/2100Z 34.5N  69.8W    60 KT
 12HR VT     15/0600Z 35.7N  68.8W    65 KT
 24HR VT     15/1800Z 37.1N  66.5W    65 KT
 36HR VT     16/0600Z 38.4N  64.0W    60 KT
 48HR VT     16/1800Z 39.5N  61.0W    55 KT
 72HR VT     17/1800Z 43.0N  54.0W    50 KT...EXTRATROPICAL
 96HR VT     18/1800Z 52.0N  42.0W    40 KT...EXTRATROPICAL
120HR VT     19/1800Z...ABSORBED

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