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Tropical Storm Irwin Discussion Number 8
NWS National Hurricane Center Miami FL EP102023
1100 AM HST Mon Aug 28 2023
Deep convection has been fading away, and Irwin is getting closer to
becoming a post-tropical cyclone. Satellite imagery suggests
mid-level dry air is wrapping around much of circulation and an area
of decaying convection remains over the northern portion of storm.
The initial intensity remains at 35 kt based on recent ASCAT passes.
Irwin has yet to make its much anticipated westward turn and is
still moving west-northwestward at 9 kt. Still, model guidance
insists the cyclone will go to the west shortly and remains tightly
clustered. The general westward motion, with a increase in forward
speed, is expected to continue through the forecast period. The
latest track forecast has shifted to the north and lies between the
previous forecast and the simple consensus aids.
The storm appears to be in the process of weakening. The extent of
tropical-storm-force winds in the northeast quadrant has decreased
significantly based on the satellite-derived surface wind data. Sea
surface temperatures and mid-level relative humidities are expected
to decrease along the forecast track and Irwin is expect weaken
further in the next day or so. The storm is still forecast to
become a remnant low within 48 hours, though this could happen
sooner.
FORECAST POSITIONS AND MAX WINDS
INIT 28/2100Z 18.6N 124.2W 35 KT 40 MPH
12H 29/0600Z 19.0N 126.3W 30 KT 35 MPH
24H 29/1800Z 19.0N 129.0W 30 KT 35 MPH
36H 30/0600Z 18.9N 131.7W 30 KT 35 MPH
48H 30/1800Z 19.0N 134.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
60H 31/0600Z 19.0N 136.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 31/1800Z 19.2N 137.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 01/1800Z 19.3N 140.2W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 02/1800Z 19.2N 142.4W 25 KT 30 MPH...POST-TROP/REMNT LOW
$$
Forecaster Bucci
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