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Post-Tropical Cyclone Isaias Discussion Number 33


Issued Active alert

Start Time

Wed 08/05/2020 05:00 AM EDT

End Time

Wed 08/19/2020 05:00 AM EDT



Full Alert Message

Post-Tropical Cyclone Isaias Discussion Number 33 NWS National Hurricane Center Miami FL AL092020 500 AM EDT Wed Aug 05 2020 Surface observations indicate that Isaias continues to gradually weaken over southeastern Quebec. There have been a couple of observing sites with marine exposure along the St. Lawrence River that have reported winds of around 35 kt within the past few hours. Therefore, the initial intensity is set at that value for this advisory. The post-tropical cyclone should continue to weaken today, and the system is expected to be absorbed by a larger extratropical low over eastern Canada on Thursday. The cyclone has begun to decelerate and is now moving 015/24 kt. The post-tropical cyclone should continue on a general north-northeastward motion with an additional decrease in forward speed over the next 12-24 hours. The updated NHC track forecast is similar to previous advisory and is near the middle of the tightly clustered dynamical model guidance. This is the last NHC advisory on Isaias. Additional information on the post-tropical cyclone can be found in products issued by the Canadian Hurricane Center at: FORECAST POSITIONS AND MAX WINDS INIT 05/0900Z 47.5N 71.8W 35 KT 40 MPH...POST-TROPICAL 12H 05/1800Z 50.7N 70.6W 30 KT 35 MPH...POST-TROP/EXTRATROP 24H 06/0600Z 53.3N 69.0W 25 KT 30 MPH...POST-TROP/EXTRATROP 36H 06/1800Z...DISSIPATED