Very Warm & Very Humid Weather Continues Through Sat; Possible Strong/Severe Storms Sat Afternoon

For The Rest Of This Afternoon: Sunny to partly sunny skies with very warm and very humid conditions are expected throughout the rest of this afternoon. Temperatures will be in the 84 to 89 Degree range. Wind will be West at 5 to 10 mph. Tonight: A warm and very humid night is expected across the region under clear to partly cloudy skies. Low temperatures will be between 70 and 75 Degrees. Winds will be Southwest at 5 to 10 mph. Saturday: A fairly robust cold front will push through the region during Saturday afternoon. This front will set off some thunderstorm activity during the afternoon across much of the area. The question is how severe will the thunderstorms be and which areas of Western and Central Mass have the highest chance of seeing strong to severe thunderstorms. The high resolution weather forecast guidance is of no help in determining tomorrow’s severe weather risk as they are all over the place. Some guidance show a scenario that shows much of the severe weather affecting Connecticut and Rhode Island and completely missing Western and Central Mass. Other just as reliable guidance point to a scenario that has scattered strong to severe thunderstorms occurring across much of Western and Central Mass during the afternoon. The reason for the uncertainty is due to the uncertainty of the progression and track of thunderstorm complexes that occur this afternoon and tonight across the Midwestern United States and the Ohio Valley. These large thunderstorm complexes are always very difficult to forecast a day out and because of this, my confidence in how the thunderstorm development Saturday afternoon shakes out is very low. Unfortunately, we may not really know how things will progress until almost “game time” tomorrow. That said, My Current Thinking Is That the cold front will press southward into the upper Pioneer Valley and the northern Worcester Hills during the early afternoon hours and should make it to about the Mass Pike by late afternoon Saturday. The environment ahead of the front is expected to be strongly unstable with wind shear values that will support organized thunderstorms to develop within areas that are ahead of the front. I think that we’ll see thunderstorms develop across the region around the midday hour potentially first across Western Mass and the northern Worcester Hills with these storms gradually pushing southward towards the Mass Pike around mid-afternoon. These storms look to exit the region by about the 5-7 pm time frame. Based on my analysis, I think the area of greatest risk of seeing strong to severe thunderstorms Saturday afternoon will be areas that are located south of the Mass Pike. In fact, much of, if not all of the severe weather may occur across Connecticut, Rhode Island and across the Cape. Any strong to severe thunderstorms across areas that are located south of the Mass Pike will contain 50-70 mph wind gusts, dime size hail, torrential downpours and frequent lightning. For areas near and north of the Mass Pike, which includes a large percentage of Western and Central Mass, while I expect scattered thunderstorms Saturday afternoon which move from northwest to southeast, I think a majority of them should remain just below severe limits, but still may produce wind gusts of 25-45 mph, pea size hail, torrential downpours and frequent lightning. With all of that said, I will be monitoring things closely to determine whether changes to the forecast may be needed or not. Again, Saturday afternoon’s thunderstorm forecast and especially the extent of strong to severe thunderstorms, has a high amount of uncertainty and changes to the forecast are likely. High temperatures Saturday will be between 85 and 90 Degrees. Winds will be West to Southwest at 10 to 20 mph. Sunday Through Wednesday: A much cooler and much less humid air mass will infiltrate the region on Sunday and remain in place for a large part of next week. This is, obviously, welcome relief to the hot and very humid air that we’ve endured for the last 6 weeks. I know all members, both two legged and four legged, of our house is looking forward to the cooler and much less humid air. I’m also looking forward to the break in having to forecast heavy rain and thunderstorms every other day! Sunday will be sunny to partly sunny with high temperatures between 75 and 80 Degrees with very comfortable humidity levels. Monday, Tuesday and Wednesday all look sunny to partly sunny with very comfortable humidity levels. High temperatures all three days will be between 75 and 80 Degrees. In fact, Monday night and Tuesday night may see low temperatures of 50 to 55 Degrees, which is going to feel downright chilly as compared to what we’ve seen lately. Late Next Week: It looks like a frontal boundary will push its way into the region for Thursday night and next Friday bringing with it widespread showers and scattered thunderstorms, along with an increase in humidity levels. Thursday looks partly sunny with high temperatures near 80 Degrees. Next Friday is expected to feature widespread showers and scattered thunderstorms with high temperatures between 75 and 80 Degrees.