[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 132022
TCDAT4
TROPICAL STORM IRENE DISCUSSION NUMBER  37
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT SAT AUG 13 2005

AS MENTIONED IN THE PREVIOUS DISCUSSION...IRENE HAS NOT BEEN ABLE TO
MAINTAIN A STEADY AND SYMMETRIC CLOUD PATTERN DURING ITS LIFETIME.
ONCE AGAIN THIS AFTERNOON THE CONVECTION HAS DECREASED AND THE
LOW-LEVEL CENTER IS BECOMING EXPOSED BUT REMAINS VERY VIGOROUS. IN
FACT...THE RECONNAISSANCE PLANE JUST MEASURED 70 KNOTS AT FLIGHT
LEVEL ON THE EAST SIDE OF THE CYCLONE. THE MINIMUM PRESSURE HAS
BEEN OSCILLATING BETWEEN 1000 AND 999 MB SINCE 1500 UTC. INITIAL
INTENSITY IS KEPT AT 60 KNOTS AND...ALTHOUGH THE WATER IS WARM AND
THE SHEAR IS LOW...THE LOW-LEVEL ENVIRONMENT REMAINS HOSTILE AS
SUGGESTED BY THE SHIPS MODEL. THEREFORE...ONLY A SMALL INCREASE IN
INTENSITY IS INDICATED.

BEST ESTIMATE OF THE INITIAL MOTION IS 320 DEGREES AT 9 KNOTS. THERE
HAS BEEN NO CHANGE IN THE FORECAST STEERING PATTERN SO IRENE SHOULD
GRADUALLY TURN TO THE NORTH AROUND THE SUBTROPICAL RIDGE. THE
CYCLONE WILL LIKELY BE EMBEDDED WITHIN THE SOUTHWESTERLY FLOW IN A
COUPLE OF DAYS AND SHOULD BEGIN TO MOVE TOWARD THE NORTHEAST WITH
AN INCREASE IN FORWARD SPEED. IRENE IS EXPECTED TO BE EXTRATROPICAL
BY 120 HOURS OVER THE COOLER WATERS OF THE NORTH ATLANTIC.

FORECASTER AVILA

FORECAST POSITIONS AND MAX WINDS

INITIAL      13/2100Z 31.2N  69.5W    60 KT
 12HR VT     14/0600Z 32.5N  70.0W    60 KT
 24HR VT     14/1800Z 34.5N  70.0W    65 KT
 36HR VT     15/0600Z 36.5N  69.0W    65 KT
 48HR VT     15/1800Z 38.5N  66.5W    60 KT
 72HR VT     16/1800Z 40.5N  60.0W    55 KT
 96HR VT     17/1800Z 43.5N  53.0W    50 KT...BECOMING EXTRATROPICAL
120HR VT     18/1800Z 48.0N  42.0W    40 KT...EXTRATROPICAL


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