Middle of the week-- middle of the heat!
Another day in mid-summer form today, with a southwesterly flow continue to stream in the same heat and humidity. The probability of hitting 90 in the afternoon rests solely with the prevalence of the scattered shower and storm. There will be more out there today than the past few days. Here's the NAM on this one:
Given the dewpoints back in the 70s, there's plenty of ready-to-go moisture in the air. Any storm that does pop should be well on its way to fostering a downpour. Now it should be noted that the models have been whiffing a bit on these storms, as the past few days have yielded little convection even during the prime heating hours of the day. Nevertheless, I've still been calling for today (and moreso Thursday) as the better opportunities for these showers.
The Front Approaches... And Changes Begin
On Thursday, we'll see a system arrive from the west. This one has ample vertical support along with some good surface forcing as well. In a way, summer is out ahead of the front, with fall on the back-side. Here's the GFS model on this:
GFS - Thursday Evening
There's a big vort-max rotating around the base of that upper-level trough driving the surface front forward and through our region. When these things come around, they also elongate the trough itself, making it meaner and deeper. The contrast of air masses and wind direction on either side of the front (and from the surface aloft) makes me think we'll have to be on the lookout for a strong or even severe storm later Thursday. The best dynamics and energy for this is north of us however, but I always keep in mind that you can't go from Point A (summer) to Point B (fall) in this amount of time without some energy expenditure (thunderstorms, winds, etc.). It's not just going to politely happen without any notice.
TANGENT --- Hurricane Season --- Feel Free To Skip
...Speaking about 'politely happening without any notice', how about that tropical season this year. It was predicted to be an above-average year with all sorts of "cue dire music" earlier this year. And now, we got about as long as ever in history before getting a single hurricane to form in the entirety of the Atlantic. Here's the best the season's had to offer this year so far:
Hurricane or not... kind of a big fat nothing. We're now just past the half-way mark of the season, so the experts are still saying, "don't count [our prediction] out just yet!" I treat hurricanes like this like a tree falling in the woods: Borrrring!
--- /END TANGENT ---
I've got to tell you, it's been a rare thing this summer that the weekend has looked so great on models for so long in advance... but perhaps we should talk about this weekend in the context of fall instead :-) Following this front, we'll see some solid sunshine AND break new ground in cooler temperatures on our way to autumn. Check out this continual confirmation from the latest runs of the GFS:
GFS - Saturday Morning
I often like to use the 700mb charts to look for solid areas of cloud-cover/moisture and dry skies in the mid-range forecast time-frame. Here we see again (at left) the establishment of region-wide cloud-level humidities of less than 10%. That'll mean some good sunshine. But add to that the right-hand map of projeted minimum temperatures for the same morning. Lower humidities extend onward to the surface resulting in low-to-mid 40s in the cities and the upper 30s (!) in some of those sheltered WV valleys. [Yes, that is a projection of upper 20s in the Canaan Valley area of the WV mountains]. Sometimes these get overdone on the models, but suffice it to say there will be a chill in the air for the early soccer games.
Summer weather fans may still yet get one last run before the seasons officially change. CPC is still projecting a return to above-average temperatures in the week beyond:
Have a great day everyone!