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Tropical Storm Irwin Discussion Number   6
NWS National Hurricane Center Miami FL       EP102023
1100 PM HST Sun Aug 27 2023
 
Irwin is struggling as a tropical cyclone. Although a small burst
of convection has recently been noted near Irwin's center, little
organized deep convection associated with the tropical storm has 
been observed during the past 12 h or so. SSTs under 26 deg C are 
likely responsible for Irwin's lack of deep convection. A pair of 
ASCAT passes around 0600 UTC did not capture the center of Irwin, 
but did sample an area to the cyclone's northeast where winds above 
30 kt were noted.  Allowing for some undersampling, Irwin's 
intensity remains 35 kt based on that data.
 
Only small  adjustments were made to the NHC forecast, the most
visible of which was moving up the point where Irwin will become
post-tropical. While it is a little hard to believe based on
Irwin's current lack of convective activity, all available
dynamical models continue to indicate that Irwin will generate
sufficient convection to be classified as a tropical cyclone for
a couple more days. Regardless of Irwin's exact classification, 
only small fluctuations in intensity are expected as the large 
cyclone gradually spins down.

Irwin is still expected to turn westward by tomorrow morning and 
then continue on that general heading for the next 5 days. The NHC 
track forecast remains on the south side of the model guidance, but 
is very close to the previous advisory official forecast track 
forecast.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  28/0900Z 17.6N 123.0W   35 KT  40 MPH
 12H  28/1800Z 18.0N 124.3W   35 KT  40 MPH
 24H  29/0600Z 18.4N 126.9W   35 KT  40 MPH
 36H  29/1800Z 18.4N 129.7W   35 KT  40 MPH
 48H  30/0600Z 18.3N 132.4W   30 KT  35 MPH
 60H  30/1800Z 18.4N 134.7W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  31/0600Z 18.6N 136.6W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  01/0600Z 19.0N 139.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  02/0600Z 19.0N 142.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster D. Zelinsky
 
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