1. Tropical storm force winds that could cause tree damage and poweroutages will continue over portions of New England for a few morehours.

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.

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.

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: Tropicalstorm 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.

Galeforce 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 MidAtlantic with most rivers falling below flood stage Wednesday. Quickresponding 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 midAtlantic and Northeast coasts of the United States through tonight. These swells are likely to cause lifethreatening surf and rip current conditions. Please consult products from your local weather office.

At 1100 PM EDT (0300 UTC), the center of PostTropical Cyclone Isaias was located near latitude 45.3 North, longitude 72.5 West. The posttropical cyclone is moving toward the northnortheast 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 tropicalstorm force during the next few hours. The posttropical cyclone is expected to dissipate over southeastern Canada Wednesday night or Thursday.

Tropicalstormforce 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).

Satellite and radar data, along with surface observations, indicatethat Isaias has lost its tropical cyclone characteristics as itmerges with a weak baroclinic zone over New England andsoutheastern Canada. Thus, it is being designated a post-tropicalcyclone. 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. Acontinued general north-northeastward motion with a decrease inforward speed is expected until the cyclone is absorbed by thelarger low. The new NHC track forecast is similar to the previousforecast and is in the center of the tightly-clustered trackguidance models.

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