ATL: ISAIAS - Advisories

[cycloneye]

BULLETIN
Tropical Storm Isaias Intermediate Advisory Number 31A
NWS National Hurricane Center Miami FL AL092020
800 PM EDT Tue Aug 04 2020

...CENTER OF ISAIAS NOW MOVING THROUGH THE NEW ENGLAND STATES...


SUMMARY OF 800 PM EDT...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...43.6N 73.0W
ABOUT 5 MI...10 KM NNW OF RUTLAND VERMONT
MAXIMUM SUSTAINED WINDS...50 MPH...80 KM/H
PRESENT MOVEMENT...NNE OR 20 DEGREES AT 40 MPH...65 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

The Tropical Storm Warning has been discontinued west of Watch
Hill, Rhode Island, including Long Island and Long Island Sound.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Watch Hill Rhode Island to Stonington Maine
* Martha's Vineyard, Nantucket, and Block Island

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area, in this case
within the next 6 to 12 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 800 PM EDT (0000 UTC), the center of Tropical Storm Isaias was
located by NOAA Doppler weather radars and surface observations near
latitude 43.6 North, longitude 73.0 West. Isaias is moving toward
the north-northeast near 40 mph (65 km/h), and this general motion
is expected through tonight. On the forecast track, the center of
Isaias will continue to move farther inland over eastern New York
and Vermont this afternoon and evening, and over southern Canada
tonight.

Data from Doppler weather radars along with surface observations
indicate that maximum sustained winds have decreased to near 50 mph
(80 km/h) with higher gusts. Continued weakening is expected this
evening, and Isaias is forecast to become post-tropical tonight or
early Wednesday.

Tropical-storm-force winds extend outward up to 205 miles (335 km)
from the center. During the past few hours, there have been numerous
reports of wind gusts of 40-50 mph (65-80 km/h) across portions of
Rhode Island, eastern Massachusetts, and southeastern New Hampshire.

The estimated minimum central pressure based on surface
observations is 997 mb (29.44 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: Widespread tropical-storm conditions are expected tonight in
the tropical storm warning area in southern New England. These
winds could cause significant tree damage and power outages.

Gale-force winds are expected to spread into southeastern Quebec
tonight and Wednesday. 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 northeast New York, northern
Vermont, northern New Hampshire, and Southern Quebec.

Heavy rainfall near the path of Isaias could result in flash
flooding, particularly through urban areas and the surrounding
terrain of the Adirondack and Green Mountain Ranges through tonight.
Scattered minor to moderate and isolated major river flooding is
ongoing or forecast across portions of the Mid-Atlantic.
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 southern New
England through this evening.

SURF: Swells generated by Isaias will spread northward along 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 ADVISORY
-------------
Next complete advisory at 1100 PM EDT.

$$
Forecaster Beven

[cycloneye]

BULLETIN
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
SOUTHEASTERN CANADA...
...TROPICAL STORM CONDITIONS EXPECTED FOR A FEW MORE HOURS ALONG
PORTIONS OF THE NEW ENGLAND COAST...


SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...45.3N 72.5W
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 http://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
Maine overnight.

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 ADVISORY
-------------
Next intermediate advisory at 200 AM EDT.
Next complete advisory at 500 AM EDT.

$$
Forecaster Beven



Post-Tropical Cyclone Isaias Discussion Number 32
NWS National Hurricane Center Miami FL AL092020
1100 PM EDT Tue Aug 04 2020

Satellite and radar data, along with surface observations, indicate
that Isaias has lost its tropical cyclone characteristics as it
merges with a weak baroclinic zone over New England and
southeastern Canada. Thus, it is being designated a post-tropical
cyclone. The initial intensity is reduced to 40 kt based mainly on
a recent observation at the Isle of Shoals, New Hampshire, and
these winds are occurring over the Gulf of Maine well to the
southeast of the center. The post-tropical cyclone is expected to
weaken further, with winds dropping below 35 kt early tomorrow.
After that, the system is forecast to be absorbed into a large
baroclinic low over southeastern Canada between 36-48 h.

The initial motion remains north-northeastward or 020/33 kt. A
continued general north-northeastward motion with a decrease in
forward speed is expected until the cyclone is absorbed by the
larger low. The new NHC track forecast is similar to the previous
forecast and is in the center of the tightly-clustered track
guidance models.

While Isaias is now post-tropical, the National Hurricane Center
will continue to issue advisories until the Tropical Storm Warning
can be discontinued along the coast of the United States.


Key Messages:

1. Tropical storm force winds that could cause tree damage and power
outages will continue over portions of New England for a few more
hours.

2. 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.

3. The threat of tornadoes will continue over portions of Maine
for a few more hours.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0300Z 45.3N 72.5W 40 KT 45 MPH...POST-TROP/EXTRATROP
12H 05/1200Z 49.1N 71.1W 30 KT 35 MPH...POST-TROP/EXTRATROP
24H 06/0000Z 52.6N 70.0W 25 KT 30 MPH...POST-TROP/EXTRATROP
36H 06/1200Z 54.0N 68.2W 25 KT 30 MPH...POST-TROP/EXTRATROP
48H 07/0000Z...DISSIPATED

$$
Forecaster Beven

[cycloneye]

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

$$
Forecaster Brown