Heat wave, severe storms highlight upcoming weekend

Stock up on the sunscreen.

Forecast models are in good agreement that a large, anomalous ridge over the Central United States will build eastward toward the Mid Atlantic and Northeast states during the middle to latter part of this week. As it does so, very warm temperatures in the mid and low levels of the atmosphere will surge toward the area, and high temperatures at the surface will climb fairly rapidly as the weekend approaches — a heat wave.

By the weekend itself, high temperatures may approach or exceed 100 degrees in many locations, with a piece of the core of the aforementioned ridge settling overhead. West winds — even with a northwesterly component at times — will help to suppress any seabreeze or ocean influence, and keep the air extremely hot, and even dry for a day or two.

Mentioned in long range forecasts for a few weeks now, this large ridge over the Central US has been well forecast. It will become the dominant feature in the weather pattern throughout the United States during the time period that it is established, with all atmospheric disturbances riding along its northern periphery — from the International Border near the Northern Plains, through the Great Lakes and into the Northeast.

On the south side of this gradient, the heat will be maximized near the Northeast US this weekend. Temperatures at the 850mb level — around 5000 feet above the ground — will surge to between +22 and +24 celsius, supportive of surface temperatures near 100 degrees, especially when considering the low dew points drawn in by west winds.

As the weekend approaches, the heat will build, as high temperatures reach into the upper 90s — but notably, dew points increase. A more unstable environment is gradually expected to develop each day from Friday onward. This will be aided by an Elevated Mixed Layer — or a layer of drier air in the mid levels of the atmosphere — which will surge eastward from the Rockies late this week.

The ridge gradient mentioned earlier will serve as a “highway”, of sorts, for disturbances in the atmosphere — and the positioning of that ridge takes the disturbances right into the Northeast United States. Multiple disturbances are forecast by model guidance to surge through the Northeast this weekend — and some of them, depending on timing and intensity, could aid in the development of strong and severe thunderstorms.

GFS showing very high instability levels in the atmosphere on Friday afternoon.

GFS showing very high instability levels in the atmosphere on Friday afternoon.

The first “Attention grabbing” disturbance comes on Friday, dropping into the Northeast US from Southeast Canada. But forecast models have beens struggling with its orientation, speed, and intensity — so confidence is quite low. The main takeaway, however, is that severe thunderstorm potential will come along with the heat this weekend.

Stay tuned over the next few days as the details of this weather pattern become more apparent — our forecasters will have the latest information over on the Premium Dashboard, complete with videos and discussions multiple times per day.