The sky early Thursday morning was relatively clear, and there should be plenty of sunshine again. Temperatures, which were mostly in the lower 90s Wednesday, should mostly reach the lower 90s again. There’ll still be a bit of a breeze, and it won’t be all that humid (dewpoint temperatures will still be mostly in the 50s). However, that will be changing late Thursday night and early Friday morning.
Thursday night, there’ll be a complex of thunderstorms that will be blowing up over the Great Lakes region. Along the leading edge of much more humid air, these storms will probably develop later Thursday afternoon and evening over Michigan and Ohio before pushing to the east and south later on Thursday and Friday morning.
Therefore, the showers and thunderstorms associated with a “warm front,” or our gateway to hot and more humid air
that’s on the way for Friday, will probably trigger a couple of showers and a thunderstorm in areas north and west of Baltimore prior to midnight Thursday night, and then in the City and along the coast late Thursday and into Friday morning.
We’re going to go with a high temperature of 100 at the BWI airport Friday. Despite some clouds, a shower and thunderstorm in the area very early, all forms of guidance show high temperatures very close to 100 degrees, so the two-degree change appears to be warranted. There was also a decision made between 6 a.m. and noon Wednesday to make Friday’s thunderstorm “a morning occurrence only.” This timing, and the rationale was based on the concept that the warm front would be the catalyst which will cause these showers and thunderstorms, and AS LONG AS THAT FRONT PUSHES THROUGH by mid-morning, then there’s no reason to believe it can’t approach 100 in the afternoon. Although the surface maps are showing a so-called “cool front” reaching the area late Friday afternoon, we must remember that there isn’t going to be very much of a change in the air mass associated with this front as it reaches the area late Friday. It will probably, if anything, be slightly less humid late Friday afternoon and evening, but temperatures on both Saturday and Sunday will be in the mid and upper 90s, and the humidity will be moderately high as well. So, it will “Feel Like” it’s closer to 100 both days this weekend, and we’ll need to address the possibility of a couple of
thunderstorms, especially during the afternoon and evening.