Tuesday 8/4/20 – TS Isaias Update #3

Good morning! This update will focus on Tropical Storm Isaias as it begins to make its presence felt in the region. The rain forecast has changed significantly since yesterday.

Tropical Storm Isaias – Tuesday Morning Update:
TROPICAL STORM WARNING IN EFFECT for Dracut.
The warning also includes all of MA/CT/RI/NH, all of the Maine coast, and all of interior western Maine. 
A Tropical Storm Watch also is in effect for the rest of Maine.

Hazards: Strong winds are the main hazard here in eastern Massachusetts, with brief heavy rain and a few tornadoes also possible.

Winds: Southeast wind 5-15 mph during the day today, gusting up to 25 mph;, turning south-southeast at 25-35 mph with gusts up to 55 mph this evening and early overnight, then turning southwest 5-15 mph during the later overnight hours. 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. Regardless of whether we reach the official tropical storm criteria in terms of sustained winds, frequent tropical storm force gusts are likely for a few hours this evening and early overnight.

Rainfall: Up to 1″ possible for the Dracut area as well as most locations in eastern New England. 1-3″ possible in western New England. New York State gets more rain. Just like with Tropical Storm Fay, we get hosed out of a decent rainfall right before the storm. Oh well, at least this means no flooding issues are expected in our area. Some brief heavy rain is still likely at times though, especially this evening.

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 a limited potential for widespread significant damage from wind levels that would cause far 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 peak 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. I’m not calling for a repeat of that system by any means – just saying that there is at least some chance that we could be in for a surprising amount of damage. Hopefully we end up on the lower side of potential winds and peak gusts, and the chance of that has ticked up a little overnight as Isaias ticked a little further west.

A few tornadoes are possible to even likely in southern New England, with the chance being much for Isaias than most other landfalling tropical cyclones given impressive helicity dynamics and interaction with a jet (which is why we may see some of those very strong gusts to begin with). Any locations that see a tornado would obviously be prone : 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. The best chance for a tornado is west of Worcester, but tornadoes are a threat anywhere today. There’s already been a tornado warning issued in western Massachusetts and another one in southwest New Hampshire.

Timing: Showers at times throughout the day today, with the most frequent showers likely in the evening. Wind picks up during the later stages of the evening hours (after 5 pm), with the strongest winds through midnight. Any rain should be over by around midnight, and winds back off significantly after midnight as Isaias pulls away. This gives way to what looks to be a beautiful Wednesday.

Temperatures: high 85 today. Low 70 tonight.

Wednesday forecast: High 88. Mostly sunny, with a very, very low risk of an isolated thunderstorm in the afternoon; I would expect dry conditions all day in most places. Southwest wind 5-10 mph. Low 62 Wednesday night; mostly clear with a light west wind.

NHC 8 AM Forecast Path/Summary Graphic; Dracut Two Day Forecast:
weather 2020-08-04.001.jpeg

weather 2020-08-04.002

Have a great day!
-Nathan

Published by Nathan Coram

Hello! I'm Nathan Coram, a 19 year old meteorology student and weather geek, and am going into my junior year at UMass Lowell as a meteorology major. I am the current Vice President of the UML American Meteorological Society Local Student Chapter. Prior to at UML, I attended the Dracut school system for my K-12 years, having graduated from Dracut High in 2018. I first got into weather with the December 2008 ice storm, which knocked out my electricity for 4 days. I had no idea how it could be raining and becoming ice immediately, and how rain can knock out power. (Now I do - warm layer aloft, cold air at surface). But I didn't really get into it until the heat of July 2010 and specifically a few severe weather events during that month, followed by the year 2011, which featured several high profile weather events. Since then I have had a growing interest, and am hoping to make it into the meteorology field, preferably with NOAA/NWS. But for now, I'm blogging here, helping with the UML Weather Center social media, and tweeting about the weather on my own account as well. Thanks for visiting!

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