Good evening! This update will focus on what has (for the moment) strengthened into Hurricane Isaias as it makes landfall in the Carolinas. The forecast hasn’t changed a whole ton this morning – just some tweaks.
Hurricane Isaias – Monday Evening Update:
TROPICAL STORM WARNING IN EFFECT for Dracut.
The warning also includes all of MA/CT/RI, southern and central NH, and coastal western Maine. A Tropical Storm Watch also is in effect for northern NH and the rest of Maine.
Hazards: Strong winds and heavy rain are the primary hazards. Isolated severe thunderstorms are possible Tuesday evening and early overnight, with a few isolated tornadoes the main threat in addition to enhanced wind gusts.
Winds: Southeast wind 5-10 mph during the day Tuesday, turning south-southeast at 25-35 mph with gusts up to 55 mph Tuesday evening and early overnight, then turning south-southwest 10-20 mph during the later overnight hours, gusting up to 30 mph. Note that there is at least some potential that sustained winds could exceed 40 mph, hence the issuance of the Tropical Storm Warning from the National Weather Service – the first time the Dracut area has been under a warning since Hurricane Irene in 2011. (This same historical stat applied to the tropical storm watch from this morning.) Regardless of whether we reach the official tropical storm criteria in terms of sustained winds, frequent tropical storm force gusts are likely for a time Tuesday evening and early overnight.
Rainfall: Anywhere from 0.75″ to 2″ of rain is most likely in the Dracut area, though I would lean toward the lower end of that range. The heaviest and steadiest rain (over 3″) will stay in far western New England into New York state, but minor flooding problems are still possible locally.
Impacts: Scattered power outages are likely, along with some wind damage to trees and other outdoor objects. Unsecured outdoor objects will likely be blown around at times. Given the south-southeast wind direction during the strongest wind gusts, there is at least some potential for significant damage from wind levels that cause less damage during the Nor’easters that we are used to. The October 29-30, 2017 wind and rain storm also had a southeasterly wind, and despite gusts generally only being in the 50s in our area, that storm produced a tremendous amount of damage in large part due to the wind direction along with the fully leaved trees.
A few isolated tornadoes are possible in southern New England, with the chance being a little higher for Isaias than most other landfalling tropical cyclones given impressive dynamics. Any locations that see a tornado would obviously be prone to much higher end wind damage; a few severe storms could also produce some enhanced straight line wind damage. Those threats are very much hit or miss, though.
Heavy rain may cause localized minor flooding issues; significant flooding problems are unlikely in our area of New England.
Timing: The earliest associated rain bands may move in overnight tonight. Rain will occur at times throughout the day Tuesday; rain may be heavy at times, with a chance of thunderstorms in the afternoon, evening, and early overnight. Wind will not likely be a factor until the evening hours; the strongest wind gusts will occur tomorrow evening and early overnight. Rain should be done shortly after midnight. It will remain on the windy side through most of tomorrow overnight, however.
Temperatures: mainly in the 70s. High 81 tomorrow, low 71 tomorrow night.
Uncertainty: slight shifts in the track could dramatically affect the final rain total.
NHC 8 PM Forecast Path; Summary Graphic; Tropical Storm Watches and Warnings:
I plan to have another full update tomorrow morning. As for realtime updates during Isaias, I had the misfortune of being scheduled to work tomorrow evening and night through 8-9 pm, which doubly stings since I have had Tuesdays off all spring and summer to this point. I can attempt to deliver updates during my shift since hopefully it will be slow, but of course no promises on that one.
Have a great day!