The Washington Region remains under a “slight risk” for severe thunderstorms this afternoon. Increasing lapse rates out ahead of an approaching upper level trough along with ample daytime heating will produce the ingredients necessary for storms capable of producing damaging winds in excess of 60 – 70 mph. Cloud to ground lightning, torrential rain and hail are also possible in these storms.
The high resolution NAM model (image above courtesy Tropical Tidbits) predicts that a line of thunderstorms will approach the Shenandoah Valley around 2pm, pushing eastward into the Washington Region between 3 and 6 pm. I would not be surprised to see a Severe Thunderstorm Watch issued for our region during the early afternoon hours.
Storms will fire again this afternoon with about 50% coverage, meaning about half of us will remain dry and half of us will get relief from the heat. Yesterday’s storms put down some pretty good rainfall totals across Annandale, Burke, Springfield, Newington and Alexandria in Fairfax County with some locations picking up over an inch of rain there.
The image below is from the latest high-resolution North American Model showing where storms may fire this afternoon.
If you didn’t get wet yesterday afternoon and miss out on the storms today in your back yard, storms are forecast to be more widespread on Wednesday afternoon.
The Storm Prediction Center (SPC) has placed the Mid-Atlantic (image below, courtesy NOAA) under a “slight risk” for severe storms on Wednesday afternoon and evening with the primary threat being damaging winds.
While the Washington Area isn’t technically in a drought, the dog days of summer aren’t helping out our local lawns. There may be some relief during the middle portion of next week when a potent disturbance crosses our region during peak afternoon heating touching off some more widespread showers and storms.
In the meantime, Sunday will be another sizzler with highs reaching the upper 90s. The image below (courtesy Pivitol Weather) is from the latest high-resolution North American Model showing a line of scattered storms approaching the Blue Ridge during the afternoon hours and possibly surviving the trip to the interstate 95 corridor.
Storms Most Likely Wednesday and Thursday
The image below shows vorticity (spin) in the atmosphere crossing our area Wednesday afternoon and evening. The darker orange “line” in the image below moving eastward out of Ohio into PA, WV, MD and eventually northern Virginia should provide enough lift to induce more numerous showers and thunderstorms. Another disturbance may cross again on Thursday touching off some showers and storms.
Upper Level Ridge May Break Down Late Week across Mid-Atlantic Coast
The upper level ridge of high pressure responsible for sinking air and extreme heat may begin to retrograde westward next weekend allowing for more of a northwesterly flow aloft. If this materializes our region may see temps relax with highs near 90 and a chance of showers and storms as opposed to dry, hot conditions.