And that’s what we’re about to experience, again. After Tuesday morning’s scattered frost, temperatures are likely to be 15-20 degrees warmer to start Wednesday … and then shoot up into the 80s by Wednesday afternoon. It wouldn’t be totally out of the question for Roanoke to record its second 90-degree high of 2013 on Wednesday, though the forecast high is just a tad cooler. After a record-breaking low of 35 at Roanoke and record-tying low of 31 in Blacksburg on Tuesday morning, May 15 record highs of 92 at Roanoke (1962) and 88 at Blacksburg (1985) will probably be just a wee bit out of reach — but not inconceivable. Westerly winds blowing down the slopes of the Appalachians will enhance the effects of the strong warm air advection rolling in from the west to produce the high temperatures 10-15 degrees above normal for mid-May. We’re not the only part of the country experiencing temperature whiplash, or even the part experiencing it most severely — some parts of Nebraska, South Dakota and Iowa soared past 100 on Tuesday, just a couple of days after sub-freezing lows and less than 2 weeks after abnormally late and in some cases record-large snow for May. Omaha, Neb., for instance, has recorded its earliest 100-degree temperature and its heaviest May snow just 11 days apart.
Some hard-to-time disturbances and ill-defined fronts will begin to affect our weather by Thursday continuing well into next week. That’s why you see forecasts with chances of showers and thunderstorms stretching out for days. In time, those forecasts may become a little more focused on particular periods with higher chances of showers and storms.
The Hokie Storm Chasers, who left chilly Blacksburg on Tuesday morning, may see some severe storm action Wednesday afternoon/evening in north-central Texas, or somewhere reasonably nearby. Targets sometimes easily shift 100+ miles as new data develops on these trips. We’ll see if they come up with any memorable storm photos on the second day of this first trip.