Tricky Saturday Forecast

Happy Saturday!

It is early as I write, and the sun is shining and temperatures are quite pleasant. Temperatures and dew points dipped in the later parts of the week, making for a nice close to what began as a hot and humid week. Here's a photo of last night's sunset over Lake Quassapaug in Middlebury, CT, where my family and I had a nice picnic for dinner.

Sunset over Lake Quassapaug last night

I mentioned in my last post on June 25 (link here) that we were in need of some rain here in New England and that Saturday would be the best chance for some new precipitation. I still think that we will see some rain today, though it's a tricky forecast (as storms in the summer tend to be). The NWS Storm Prediction Center's (SPC) convective outlook for today places parts of Southern New England in a slight risk for severe thunderstorms.

Day one convective outlook (NWS)

Any convective storms that do form could contain damaging wind gusts and hail, particularly in areas in the center of the yellow polygon in the above map like Pennsylvania and New Jersey. I am fairly confident that areas in Southern New England will see a storm today, though the timing and exact locations where the storms will be most intense are quite hard to pin down.

I think that some rain will begin to enter the region in the early afternoon hours, with potential stronger storms occurring in the late afternoon to early evening. Here is a look at the 4:00 p.m. ET HRRR model, showing an area of stronger storms in Southwest Connecticut.

2:00 p.m. HRRR (Tropical Tidbits)

That area of red in Southern Connecticut is a stronger storm, though you can see that it is a small, isolated area, and even a shift 15 miles in any one direction could lead to some not seeing a significant storm. Wind shear, which is the difference in wind speed and direction at given levels of the altitude (like a wind gradient) is quite high today, providing an ideal environment for storms to pop up. At the same time, CAPE, which is a measure of instability in the atmosphere, is not quite as high as the impressive wind shear value. This is part of what makes the forecast tricky.

The NAM 3 km model (a higher resolution view of the NAM that I will typically share images of), seems to agree with the HRRR, although the storms are slightly more widespread, including Northwest Connecticut as well.

2:00 p.m. NAM (Tropical Tidbits)

Overall, I think that most areas in Southern New England will see some much-needed rain today, with the timing being in the late afternoon hours and the exact locations of heavy storms being hard to predict. None of the heavy storms will last too long, but I'd avoid being outside for a lengthy period of time in the afternoon, if you are in Connecticut. As always, on days of potential convective storms, keep your eye on RADAR (link here) to see where precipitation is at the moment. Have a nice Saturday!