Much cooler Wed.
9:15 p.m. update: Scattered showers and storms are moving into the northwest suburbs. A larger batch of showers/storms is to the southwest and should move into the metro region in the next couple hours. None of this activity is severe and even the severe thunderstorm watch to the northwest has been canceled. Still, some heavy downpours, thunder and lightning are possible through the night. Around 0.5” of rain is most likely with isolated heavier amounts.
4 p.m. update: A severe thunderstorm watch has been issued west of both Loudoun and Frederick counties until 10 p.m. We’ll keep an eye on these storms and update if any severe weather nears the area.
From 3:30 p.m.: Tuesday delivered for warm weather fans, with partly sunny skies, a little mugginess, and high temps in the low 80s. The heat and humidity will fuel a line of storms developing along a cold front in West Virginia headed toward the metro region. On the plus side, the rain should hold off until after the evening commute.
Through Tonight: It remains dry and mild through the evening commute. Around 8 p.m., a line of showers and thunderstorms likely reaches the western suburbs and is into the eastern suburbs by around 11 p.m. Particularly north and northwest of the District ( where the Storm Prediction Center has indicated a severe thunderstorm or tornado watch may be issued), a few of thunderstorms may be severe with damaging winds (10-15 percent chance), large hail (10-15 percent chance) and even an isolated tornado (2-5 percent chance). After around 11 p.m., the risk of severe thunderstorms diminishes but showers and thundershowers continue intermittently overnight, with lows around 50.
Tomorrow (Wednesday): Much cooler and unsettled. Rain showers are likely (60 percent chance) in the morning, holding on longest east of town. Some partial sunshine may emerge in the afternoon, but a scattered shower can’t be ruled out (20-30 percent chance) in the late afternoon or evening as a weak disturbance swings through. Highs only reach around 60.
Walter Reed Pollen update: Grass pollen is in the MODERATE range (NAB) at 13.74 gr/cubic meter, this is HIGH for our area range. Tree pollen is HIGH at 233.55 gr/cubic meter, weeds are LOW at 0.32 gr/cubic meter and mold spores are in the LOW range at 1823.27 spores/cubic meter.
Final summary of DC/MD/VA tornado outbreak from 4/27-4/28: The National Weather Service Office in Sterling has developed a nice website which lists the attributes of 11 tornadoes that affected the region in a useful table. It also has a nifty graphic which shows the various tornado tracks.
Congressional hearing on disaster preparedness: The Senate Commerce Committee is (as I write this) holding a hearing on the effectiveness of Federal programs in protecting citizens from unforeseen natural disasters. Witnesses include WJLA meteorologist Bob Ryan, and the American Meteorological Society’s Policy Program Director Bill Hooke. It’s streaming on CSPAN...