While Joaquin looms, sizeable heavy rain threat next 24 hours too

Hello everyone!

First post for me here covering what is shaping up to be an extraordinary rainfall event for Maine and New Hampshire (as well as most of the rest of the Northeast). Will this be historic? Unlikely. WIll it be devastating? Probably not. Will it be a big headache? Absolutely. Let’s dive right in.

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6:30 PM Radar

Current radar shows a broad area of heavy rain over the Mid Atlantic associated with developing low pressure and another batch of rain along and ahead of a cold front sagging south. Rain is already moving through western ME and NH and is rather heavy in spots and this will continue through the evening increasing in coverage and intensity.The threat of heavy rain has begun.

12Z GFS Model Idea Showing Torrential Rain  Tomorrow Map Credit: Weatherbell, Additions By Me.

12Z GFS Model Idea Showing Torrential Rain Tomorrow Map Credit: Weatherbell, Additions By Me.

The low currently over the Mid Atlantic will move NE along the front and end up in the Gulf of Maine tomorrow. The above image shows the position of the low at 2PM tomorrow afternoon and precip totals from 8AM to 2PM. While I think this model is a bit overdone with its 3-4″ in 6 hours idea, it goes to show a larger idea of very heavy rain in the morning and early afternoon tomorrow. Flash flooding is definitely a threat with this torrential type of rain so be prepared for that threat on the AM commute tomorrow.

Total rainfall looks to be in the 2-4″ range for most with isolated 3-6″ amounts where the most intense storms pop up. The greatest likelihood for something like this to happen is south of route 2 closer to the low and the front.

The front briefly moves offshore Thursday for a period of nice(ish) weather as the sun could make an appearance but NE winds will likely be gusty so it will still feel a tad raw.

Looking ahead towards the weekend, the front appears to move back north which would likely provide focus for another round of rain Friday into Saturday at which point things get very interesting with Tropical Storm Joaquin. At this point in time it looks like the bulk of the impacts stay to our south as an upper level low pulls it into the Mid Atlantic though this is still far out and, as usual, can and will likely change. I’ll have more updates on that in the coming days.

Regardless of Joaquin’s involvement in the latter part of the forecast, the next 24 hours is shaping up to be a wet one so that’s where our attention will be focused for now.

I’ll have another update in the morning.

-Jack

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