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Post-Tropical Cyclone Isaias Advisory Number 32
NWS National Hurricane Center Miami FL AL092020
1100 PM EDT Tue Aug 04 2020
...ISAIAS BECOMES A POST-TROPICAL CYCLONE AS IT MOVES INTO
...TROPICAL STORM CONDITIONS EXPECTED FOR A FEW MORE HOURS ALONG
PORTIONS OF THE NEW ENGLAND COAST...
SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION
ABOUT 45 MI...70 KM ESE OF MONTREAL QUEBEC
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...NNE OR 20 DEGREES AT 38 MPH...61 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
The Tropical Storm Warning has been discontinued south of the
Merrimack River, Massachusetts.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Tropical Storm Warning is in effect for...
* Merrimack River Massachusetts to Stonington Maine
A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area, in this case
during the next few hours.
For storm information specific to your area, including possible
inland watches and warnings, please monitor products issued by your
local National Weather Service forecast office.
DISCUSSION AND OUTLOOK
At 1100 PM EDT (0300 UTC), the center of Post-Tropical Cyclone
Isaias was located near latitude 45.3 North, longitude 72.5 West.
The post-tropical cyclone is moving toward the north-northeast near
38 mph (61 km/h), and this general motion is expected with a
decrease in forward speed through Wednesday night.
Maximum sustained winds have decreased to near 45 mph (75 km/h) with
higher gusts, mainly over water to the southeast of the center.
Continued weakening is expected, and the winds are expected to drop
below tropical-storm force during the next few hours. The
post-tropical cyclone is expected to dissipate over southeastern
Canada Wednesday night or Thursday.
Tropical-storm-force winds extend outward up to 175 miles (280 km)
to the southeast of the the center. The NOAA automated station at
Isle of Shoals, New Hampshire recently reported sustained winds of
46 mph (74 km/h) and a wind gust of 51 mph (81 km/h) at an
elevation of 63 ft (19 m).
The estimated minimum central pressure is 1000 mb (29.53 inches).
HAZARDS AFFECTING LAND
Key messages for Isaias can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT4, WMO header WTNT44 KNHC,
and on the web at www.hurricanes.gov/text/MIATCDAT4.shtml.
WIND: Tropical-storm conditions are expected for a few more
hours in the tropical storm warning area in southern New England.
These winds could cause significant tree damage and power outages.
Gale-force winds are possible over portions of southeastern Quebec
for a few more hours. 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. Additional
rainfall of up to an inch is possible across western and northern
As the rainfall exits the United States, scattered minor to moderate
and isolated major river flooding is ongoing or forecast across
portions of the Mid-Atlantic with most rivers falling below flood
stage Wednesday. Quick-responding rivers in the Northeast will also
be susceptible to minor and possible moderate river flooding.
TORNADOES: A couple of tornadoes are possible across central and
eastern Maine for the next several hours.
SURF: Swells generated by Isaias will affect the mid-Atlantic and
Northeast coasts of the United States through tonight. These swells
are likely to cause life-threatening surf and rip current
conditions. Please consult products from your local weather office.
Next intermediate advisory at 200 AM EDT.
Next complete advisory at 500 AM EDT.