For yet another day, a stubborn low pressure spun high up above New England, stuck in place since the start of the week. And for another day, a few scattered showers and thunderstorms developed and rotated around our low pressure and slid on through parts of eastern Pennsylvania and New Jersey. The storms were hit or miss again today, but some locally heavy downpours resulted in the few spots that were hit. With more clouds than sun, temperatures were kept down in the low to mid 80s, but while it wasn't that hot, it was rather humid. As our pesky low weakens and finally slides east of New England and farther away from our area, the thunderstorm chances will go down over most of the next two days as temperatures go up to around and above 90 degrees. By Friday night, a cold front will drop from north to south through the Mid-Atlantic, an unusual direction for a cold front in early summer and more like a back door cold front, more common during the early spring. It will likely produce a few late day or nighttime showers and thunderstorms late Friday and Friday night. Behind that front, it won't be as hot for the Fourth of July holiday weekend, but it will still be seasonably warm (mid 80s), somewhat humid, and mostly dry outside of a stray thunderstorm either Saturday or Sunday.
Like the past few evenings, any lingering shower or thunderstorm activity that spills over into the evening hours should diminish after sunset. Skies should average out partly cloudy for the rest of the night, with perhaps a little patchy fog in areas that saw some heavier daytime rains. It will be seasonably mild and a bit muggy overnight with lows in the mid 60s, similar to last night.
As that New England low begins its departure, it loses its influence on our area. As a result, Thursday should be a sunnier day with plenty of sunshine mixed with just some patchy clouds. While a shower or thunderstorm still can't entirely be ruled out given the heat and humidity, it should be the exception to the rule as highs surge into the upper 80s and flirt with 90 degrees for some. Humidity levels remain moderate with dew points in the mid 60s.
We're saving the hottest for last this week, with mostly sunny skies for a good part of Friday sending highs into the low 90s for many, and perhaps mid 90s for a few. Some clouds will bubble up and mix in with the sun in the afternoon, especially north of the Lehigh Valley. And as a cold front approaches from the north late in the day, a few showers and thunderstorms will develop across upstate New York and drop south into northeastern Pennsylvania and northwestern New Jersey late in the day. So the best thunderstorm chances late Friday will be north of Interstate 78, with that shower and storm chance moving south in the evening and overnight but gradually diminishing as the night progresses. Humidity levels remain moderate and could even inch up a bit into the mid to perhaps upper 60s in spots, which will drive the heat index higher into the 90s.
SATURDAY (FOURTH OF JULY) AND SUNDAY
It looks like our cold front will settle south of the area for the start of the holiday weekend, which will suppress the 90 degree heat farther to our south as well. So seasonably warm mid 80s are expected for high temperatures for the holiday, thanks to a cooler east to northeast wind behind our front. While the front will mark a change in temperatures, it won't bring a refreshingly comfortable air mass in its wake, so expect the humidity to linger into the weekend but perhaps ease a bit compared to Friday's higher levels. A stray shower or thunderstorm can't entirely be ruled out, but most of the Fourth of July looks dry. The same can be said for Sunday with one small difference, as temperatures may inch up into the upper 80s.