Possible Heavy Rain Tomorrow

Good evening! This post will cover tomorrow’s heavy rain threat.

Wednesday Heavy Rain Threat

First, it needs to be pointed out that this is only a threat of heavy rain and not all locales will see said heavy rain. Nonetheless, showers and storms are likely late tomorrow morning into the afternoon. An area of showers and storms exists in eastern Ohio and western Pennsylvania ahead of that short wave that will move NE overnight and reach the area late tomorrow morning: (radar courtesy NWS)

Capture.PNG

 

There is a distinct possibility that the cluster will expand, and the HRRR portrays this nicely as the area moves in late tomorrow morning and early afternoon (last frame is at noon tomorrow, this is the 1Z HRRR, courtesy of Weatherbell):

hrrr_2016081001_ref_neng

Again, moderate to isolated heavy rain is possible with the cluster but the larger heavy rain threat is behind it. Later in the day, dependent on how much clearing occurs, there is a chance of showers and storms forming. With high dewpoints and high PWAT values, heavy rain is likely in any storm that forms – PWATs over 2″ are likely in much of southern New England and all of New England sees greater than 1″ PWATs (as depicted with the 0Z 4km NAM at 2 PM tomorrow, courtesy Pivotal Weather):

pwat 0z nam 4k.png

The shortwave acts as a trigger, and high humidity gives some instability as dewpoints rise into the 60s and low 70s. There is a question of how much clearing does occur – lots of clouds, hindered storm development but even in that situation at least a few storms should form given marginal instability, and once you have a storm in such a highly juiced atmosphere, heavy rain becomes a risk, with localized urban flooding possible. In the afternoon heavy rain will be hit or miss as with any storm threat but the more clearing there is, the more likely it is that storms form. Additionally, strong winds are possible in the strongest storms, and the risk is increased a little bit if there is more clearing to equal more instability. Wind shear of 30-40kt in the 0-6km layer supports a strong wind threat in the strongest storms (0Z NAM at 2 PM tomorrow, courtesy of Accuweather Pro):

0z nam 0-6 shear.png

The threat will be dwindling by the evening hours.

More tomorrow morning on this threat, and the heat to come.

-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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