Tropical Cyclone Isaias
Last Updated: Wednesday, August 5, 2020 @ 11:30:03 AM

Storm Origin: Atlantic
Wind Speed: 40 mph
Pressure: 1000 mb
Movement: 28 mph NNE
Latitude: 47.5 N
Longitude: 71.8 W
Tropical Storm Wind Extent: 104 miles
TROPICAL CYCLONE ISAIAS ADVISORY / FORECAST
ADVISORY from National Hurricane Center:
Expires:No;;962156
WTNT34 KNHC 050837
TCPAT4
 
BULLETIN
Post-Tropical Cyclone Isaias Advisory Number  33
NWS National Hurricane Center Miami FL       AL092020
500 AM EDT Wed Aug 05 2020
 
...RAIN AND GUSTY WINDS CONTINUE TO SPREAD OVER EASTERN QUEBEC...
...THIS IS THE LAST NHC ADVISORY...


SUMMARY OF 500 AM EDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...47.5N 71.8W
ABOUT 55 MI...90 KM NNW OF QUEBEC CITY
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...NNE OR 15 DEGREES AT 28 MPH...44 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES
 
 
WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.
 
 
DISCUSSION AND OUTLOOK
----------------------
At 500 AM EDT (0900 UTC), the center of Post-Tropical Cyclone Isaias
was located near latitude 47.5 North, longitude 71.8 West. The
post-tropical cyclone is moving toward the north-northeast near 28
mph (44 km/h), and this general motion is expected with a decrease
in forward speed through tonight.
 
Maximum sustained winds are near 40 mph (65 km/h) with higher gusts.
Weakening is expected, and the winds are expected to drop below
tropical-storm force this morning.  The post-tropical cyclone is
expected to dissipate over southeastern Canada on Thursday.
 
Tropical-storm-force winds extend outward up to 140 miles (220 km) 
to the northeast and east of the center primarily over and near 
the St. Lawrence River. 
 
The estimated minimum central pressure is 1000 mb (29.53 inches).
 
 
HAZARDS AFFECTING LAND
----------------------
WIND:  Gale-force winds will continue over and near the St. 
Lawrence River this morning. Gale-force wind gusts are possible 
elsewhere over southeastern Quebec today.  See products issued by 
Environment Canada for more information.
 
RAINFALL: Rainfall accumulations of 1 to 3 inches are expected along
and near the track of Isaias across southern Quebec.
 
Even though the rainfall has ended, scattered minor to moderate and
isolated major river flooding is ongoing across portions of the
Mid-Atlantic with most rivers expected to fall below flood stage
by later today.
 
SURF:  Swells generated by Isaias will affect the coast of the
Northeast United States through this morning. These swells are
likely to cause life-threatening surf and rip current conditions.
Please consult products from your local weather office.
 
 
NEXT ADVISORY
-------------
This is the last public advisory issued by the National Hurricane
Center on this system.  Additional information on the post-tropical 
cyclone can be found in products issued by the Canadian Hurricane 
Center at https://weather.gc.ca/hurricane/index_e.html


DISCUSSION from National Hurricane Center:
Expires:No;;962172
WTNT44 KNHC 050838
TCDAT4
 
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: 
https://weather.gc.ca/hurricane/index_e.html


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