Another pleasant fall day is in the books. We managed to reach the 70s despite cloud cover ahead of the next storm system. A comfortable and dry PM commute precedes the incoming storm’s first drops of rain, unlikely to reach the region until after 2 a.m. Wednesday is unsettled with showers and possible thunderstorms.
Through Tonight: Just cloudy this evening with no rain until quite late tonight. The most likely timing for the onset of rain is between 2 and 5 a.m. Overnight rainfall should generally be under a quarter inch. Lows are mild, ranging from 53-59 (suburbs-city).
Wednesday: Two areas of low pressure - one passing to the east and one passing to the west paint a complicated weather picture. Confidence is pretty high that we’ll have rain showers (80% chance) and possibly a rumble of thunder from the morning commute through midday. After that, as the coastal low to the east passes to our north, we may well get dry slotted, meaning decreasing rain in the afternoon. So I’ll call for just a 40-50% chance of scattered showers and thunderstorms during the afternoon. I can’t even rule out some breaks in the cloud cover. Rainfall potential is on the order of 0.5-1”, with higher amounts possible especially east. High temperatures are probably in the mid-to-upper 60s with increasing winds from the east reach 10-20 mph, with some higher gusts possible.
Pollen update from Walter Reed: Trees, grasses, and weeds are LOW. Mold spores are HIGH.
Storm will pack bigger punch west and east: We look to catch somewhat of a break from this complex storm system compared to impacts on either side of us. Along the eastern shore of Md./De./Va., 1-2”+ of rain and winds to near gale force (especially Wednesday night and Thursday) are possible. And then well to the west, cold, wind-driven rains are likely over the Ohio Valley and eastern Great Lakes. In Chicago, strong north winds are forecast to gust up to 50 mph. This has prompted a Lakeshore Flood Warning as waves on Lake Michigan may build to 17 to 22 feet Wednesday night.