Today’s Weather Journal column focuses on the hottest July on record just completed in Roanoke and the trend toward warmer summertime low temperatures locally. (It was also Blacksburg’s 4th warmest July, dating to 1952, which I discuss in comment No. 4 at 8:38 a.m. below.) It was the consistently warm lows, more than the sometimes very hot, sometimes not-so-hot, highs that drove the record average of 80.8 degrees, after all. Because June averaged near-normal (the 104 and 102 at the end was more than offset by several sub-80 highs and sub-60 lows), it is unlikely that this summer as a whole will overtake 2010 for hottest summer or even 2011 for second hottest. To catch 2010, August would need to average 81.3 degrees — hotter than every August on record except 2007. Above-normal temperatures appear likely to dominate in days and weeks ahead, and without strong Canadian air masses to flush out the atmosphere, sticky humidity most nights will hold our low temperatures upward even if some days are not as hot. So a new hottest summer record can’t be ruled out just yet, but those 70s/50s days in June may be what holds it back.
As for today’s weather — more of the same. The atmosphere is a like a big soaked towel of humidity that will pour out water with only a little wringing. An approaching (though weakening, and likely never-to-arrive) cold front, outflow boundaries from Tuesday’s storms (rumbling and flashing outside my window well into the overnight as I type this), terrain effects and daytime heating (mostly 80s) will be more than sufficient to trigger another round of scattered to numerous storms across Southwest Virginia on Wednesday. Once again, flooding rain is possible in the heaviest downpours, while some folks hear thunder in the distance with little or no rain. A few downbursts of gusty wind are also possible. The front will not be able to push through with any significant cooling. Expect hot days (mid 80s to low 90s, mostly) and gradual drying through the latter half of the week — though there will probably be some scattered afternoon showers and storms each day.