UPDATE 12:45 AM, 4/7: Freeze warning issued Saturday morning for first of several cold mornings in next week
UPDATE 12:45 AM, 4/7: Dry air in place will help temperatures rebound quickly from chilly morning lows into the 60s. Easter Sunday will be even a little warmer. Nice Easter weekend ahead. END UPDATE
As expected, the National Weather Service has placed much of the western and central Virginia under a freeze warning for Saturday morning, with lows in the upper 20s/low 30s expected.
Franklin, (UPDATE 4:25 PM: Franklin County included in freeze warning). Henry and Patrick counties and several counties west of Interstate 77 are under a frost advisory with not-quite-as-cold temperatures expected (though don’t be surprised if some spots in those areas also hit freezing). Roanoke/Salem city may squeak out with slightly above-freezing temperatures, too, as surrounding county areas go below 32, but the point is that everywhere in our region will have temperatures at or very near a level capable of doing some damage to plants that have bloomed or greened early in March’s record warmth. It doesn’t appear likely that any more than a very few isolated locations (and if you’re a farmer or gardener, you probably already know if your local microclimate is one of those that typically gets a little colder) will experience a “hard freeze,” with 3 or more hours of temperatures below 28 degrees. But, nevertheless, it’s advisable for anyone with sensitive outdoor plants to take precautions overnight. Cold, dry Canadian air over the region will allow for maximum radiational cooling overnight, with clear skies and calm winds.
We are entering what I would describe as an April cool spell — not quite a cold snap or hard freeze — for about the next week or so. Temperatures will average 5 degrees or so below-normal on many days, but it does not appear likely prolonged winterlike chill similar to April 2007 will develop. A deep southerly dip in the jet stream over the eastern U.S. will allow a repeated series of cold fronts to reinforce the cool, dry air mass, with most days seeing chilly lows in the 30s (some 20s) and frost on many mornings followed by fairly mild afternoon highs in the upper half of the 50s and 60s. Easter Sunday appears likely to be the warmest day of the next week, with sunny skies and westerly downsloping winds pumping highs into the upper 60s to mid 70s after a cold start in the 30s to low 40s. With low humidities and strong breezes behind a weak reinforcing cold front, there may be an enhanced fire danger for a few hours on Sunday afternoon, so be aware of that if you have outdoor plans. Some upper-air impulses along with new shots of Canadian air in the early to mid part of next week may be sufficient to trigger a few snow showers, as limited moisture is squeezed out on northwesterly winds lifting over the Appalachians, primarily in the overnight and morning hours in the higher elevations (3.000-plus) west of Interstate 81.