Two words describe what we’ve seen on this Friday the 13th: Pattern change. Gone are the sunny 70s, now replaced by clouds, highs today only in the mid-60s, and occasional showers and thunder into next week. Of course, the change comes just in time for a busy outdoor weekend (e.g., the Nats and United at home, festivals at National Harbor and Bethesda, etc.). Fortunately, it won’t rain all the time. Unfortunately, with this pattern it’s almost impossible to say when it will and won’t rain.
Through Tonight: Some places probably stay dry, but anyone could see a passing shower, maybe a rumble of thunder, now through morning. Any showers are mainly light, with the best chance of anything heavier to the west of D.C. Temps don’t fall very far with cloudy skies and somewhat muggy air, hanging within a few degrees of 60 through the night.
Saturday & Sunday: Have the umbrella handy as a shower or storm could strike at any time. Truth is it’s hard to say when and where it’ll rain. Best chance for drier periods looks to be mid-morning to mid-afternoon each day, with a greater shower/storm threat late afternoon to early morning. Skies are mostly cloudy throughout with highs near 70 Saturday and perhaps mid-70s Sunday, when an isolated storm could turn severe.
Coastal Flooding: Prolonged onshore winds have prompted a Coastal Flood Warning, in effect from midnight tonight to 6 a.m. Saturday, along the west side of the Chesapeake Bay in Anne Arundel County, with a Coastal Flood Advisory is in effect before then and again from 6 a.m. to 8 p.m. Saturday. Moderate flooding is possible near high tide early Saturday (2:54 a.m. at Annapolis) with minor flooding a concern near high tide Saturday afternoon (3:01 p.m.). A Coastal Flood Advisory also remains in effect ‘til 8 p.m. Saturday elsewhere along the Bay and the Potomac, including at Alexandria (high tides at 5:26 p.m. today, 5:55 a.m. and 6:27 p.m. Saturday).
Pollen update: Walter Reed says trees remain in the HIGH range (but lowest this week) at 173.16 gr/cubic meter. Grass is HIGH for our area at 7.35 gr/cubic meter. Weed pollen is LOW at 2.24 gr/cubic meter and mold spores are in the LOW range at 3104.65 spores/cubic meter.