Another Round of Heat, Storms

Monday’s weather could get interesting.

First, there’s the heat.  Most of us got a nice break from the heat on Sunday.  Boston didn’t get above 79.  Worcester peaked at 84.  The heat and the humidity make a big comeback on Monday.  Temperatures will soar into the 90s for most of the area.  There will be a brisk offshore wind, enough to prevent any sea breeze.  So even the Seacoast, the North Shore, and the South Shore beaches will be hot.  Only the Cape and the Islands will escape the 90s on Monday.   At the same time, dew points will be in the upper 60s.  Bri did an awesome job explaining just how muggy that is in her blog last night.  Bottom-line, that means there will be enough humidity to make it feel like its in the upper 90s.  The record high temp in Boston for Monday is 98 set in 1982.  That record should be safe.  But, it will be too close for comfort, literally, and it certainly might feel that hot.

Good news…there is a cold front coming.  Bad news…there is a cold front coming.  That brings me to the second thing we need to keep an eye on.  The cold front will bring a line of showers and thunderstorms to the area late in the day.  It now looks more likely that the thunderstorms could be on the strong to severe side.  The Storm Prediction Center, the government agency responsible for tracking severe storms and tornadoes, has placed the western part of the area in the “slight risk” category for severe weather and the eastern part of the area in the “marginal risk.”  Here’s how the risk categories break down…

To put that into perspective, on Sunday we were in the “marginal risk” category.  There were two severe thunderstorms across southern New England Sunday afternoon and evening.  One of them downed several trees, produced coin size hail, and produced several cloud to ground lightning strikes causing spotty damage across Bristol and Plymouth Counties.  Along with that there was torrential rain.  Taunton got just over 1″ in less than 30 minutes!  That’s like getting about 7-10 days worth of average rain in under a half an hour.  That was a “marginal risk.”  On Monday there is a “slight risk” for much of the area.  In other words, the risk of severe weather is a bit higher on Monday than it was on Sunday.

So what are we worried about?  The same type of thing we saw on Sunday afternoon, only potentially more widespread.  Any storms that do form will produce torrential rain and frequent cloud to cloud lightning much like Sunday’s storms.  The next concern is straight-line winds.  Some of the stronger storms could produce 50-70 mph gusts.  The risk for seeing large hail will be low.  Don’t get me wrong, the storms will likely produce large hail.  But, with near record heat, the hail will at least partially melt before hitting the ground.  So the heat mitigates the risk of damaging hail a bit.  Perfect example…Florida is the most thunderstorm prone area of the county, and is the second most thunderstorm prone area of the world…yet large hail is rare in Florida.  The risk for tornadoes is very low here on Monday, but not zero.

As for the timing, that is a bit uncertain.  The storms will form out ahead of the front, but how far ahead of the front could mean the difference between the storms arriving early in the afternoon or late in the evening.  Right now the best guess is sometime between 2-8 pm.  But stay tuned!  Its also possible that the storms could weaken as they travel from New York into New England and push toward the coast.  That’s part of the reason the risk for severe weather is higher in western New England.  Since there is some uncertainty, the best advice is to just be weather aware and keep in touch with Chris and Bri for the latest updates.

Now the good news…the air behind the front is cooler AND less humid!!  That means the weather will be much more pleasant Tuesday into Thursday.  Wednesday is my pick of the week!  Wednesday might even be the best day of the month!

Don’t get too used to the pleasant weather.  The heat and humidity return along with the afternoon storms this weekend.