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Heat, severe weather threat will build this week

Yesterday we wrote that “summer weather was finally here”. Well, if you’ve been here long enough you know that “summer weather” refers to sunshine and warmth, but also brings the potential for thunderstorms, heavy rain, and strong winds. We were able to luck out on Monday, as strong and severe thunderstorms (which produced widespread reports of damaging winds) stayed off to our west. Tuesday will be first day which storms will move through our area.

While the storms on Tuesday aren’t expected to be quite as severe as the ones which brought wind damage to the interior Northeast on Monday, they will still have the potential to produce gusty winds, small hail, and heavy rain. Lightning will, of course, also be a threat in any storms that develop. Instability will be a bit less than ideal for widespread storms, but wind shear may help them organize. The Storm Prediction Center has issued a Slight Risk for severe thunderstorms, mainly to the north of NYC into New England. 

The interesting twist in the story this week will come after Tuesday’s storms. Atypical to these storms events, the heat will actually build further on Wednesday and Thursday. High temperatures will reach into the upper 80’s and lower 90’s by Thursday afternoon. After a dry day on Wednesday (maybe isolated popcorn type storms), a boundary sinking toward the area on Thursday will become the focal point for more thunderstorms.

The difference between Thursday and eery other event so far this year will be instability. It’s going to be hot. The atmosphere will be primed for the development of thunderstorms, with plenty of instability to work with if updrafts can develop. Think of it this way: Our area will be on the northern periphery of a heat ridge, which will be building on the East Coast. At the same time, a disturbance will be swinging through Southeast Canada and New England. The result will be a boundary from Pennsylvania through New Jersey, Southeast New work, and Connecticut, where instability is juxtaposed with favorable wind shear.

NAM model showing impressive instability across the area on Thursday afternoon.

NAM model showing impressive instability across the area on Thursday afternoon.

If storms can develop along this axis of instability, they could very quickly go severe. Heavy rain with dangerous lightning, gusty winds, and hail will be possible. Making matters worse will be the fact that they will shift southeastward from Northwest NJ and Southeast NY toward NYC, NJ and Long Island. With a northwest-to-southeast component to the storms movement, the influence of the coastal waters and marine layer will be mitigated. So, yes, these storms could be severe all the way to the coastal plain.

For now, the Storm Prediction Center has placed the area in a “Marginal” Risk for severe storms. But forecast models remain quite bullish with the juxtaposition of instability and shear — so we’re willing to bet that an upgrade to Slight Risk will eventually come if the forecast models continue to advertise the same threat.

Stay tuned throughout the week for updates on the threat for strong thunderstorms — with additional threats possible this weekend as well.