Active Weather
No watches, warnings, or advisories are in effect in the District of Columbia, Delaware, Maryland, Pennsylvania, Virginia, or West Virginia. A test message was posted for Montgomery County, Maryland overnight, which is a routine systems check and not a weather product.
The forecast is the useful part today. The Storm Prediction Center, which forecasts severe thunderstorms nationally, places a slight risk of severe storms for Wednesday afternoon running from eastern Ohio into western New York, and the southern edge of that area reaches into northwest Pennsylvania. A slight risk is the second of five levels and means scattered severe storms are expected somewhere in the area.
For northwest Pennsylvania specifically, the center carries a 2 percent tornado probability alongside the wind threat. Two percent is low, and it is the lowest tornado category the center draws, but it is not zero and it is worth knowing today rather than at 4 PM. The forecaster's note is that storms should form into a line, and a line produces damaging straight line wind far more often than it produces a tornado.
Further south and east, a marginal risk covers a broader area including more of Pennsylvania, West Virginia, and Kentucky. Marginal is the lowest level. Philadelphia, Baltimore, Washington, northern Virginia, and Delaware sit outside both risk areas.
If you are in Erie, Pittsburgh, or the northwest corner of Pennsylvania, the useful steps before the afternoon are ordinary ones. Secure anything light in the yard, charge phones, and check that you can find a flashlight without opening a drawer in the dark. This outlook was issued Tuesday afternoon as a day 2 product and the Storm Prediction Center will refresh it Wednesday morning at spc.noaa.gov.
Infrastructure
Nothing active. No outage events, water system notices, or transportation disruptions are reported across the six jurisdictions.
No large wildfires are burning in the region in the National Interagency Fire Center's September 8 situation report.
West Virginia has an open Federal Emergency Management Agency major disaster declaration, DR-4932, issued August 3 for flooding, and it carries Individual Assistance. Individual Assistance is the category that pays money directly to households rather than to local government, and it can cover temporary housing, home repair, and some uninsured losses. If you were flooded in a designated West Virginia county and have not applied, disasterassistance.gov is the place to check whether your county is included and whether the application window is still open.
Public Health
No active air quality alerts in any of the six jurisdictions.
The Centers for Disease Control and Prevention Health Alert Network archive index could not be read again this morning, so we are not able to confirm either way whether a new national health advisory has posted. The most recent notice we could open directly was issued August 11 and is written for clinicians rather than households. If you want to check for yourself, the archive lives at emergency.cdc.gov/han.
Watch Item
The Weather Prediction Center's day 2 excessive rainfall outlook, valid from Wednesday morning through Thursday morning, places a marginal risk across Pennsylvania, West Virginia, and westward through Ohio and Kentucky. Marginal is the lowest of the four levels and means isolated flash flooding is possible where storms line up over the same ground.
The center's day 3 outlook, valid Thursday into Friday, raises that to a slight risk over the upper Ohio Valley and the central Appalachians. That is a step up, and it is the single thing in this region worth tracking over the next 48 hours. Terrain does most of the work in a West Virginia or western Pennsylvania flash flood: water that falls on a ridge arrives in the hollow below faster than anywhere flat, which is why these events give so little warning.
If that materializes, the rule is the National Weather Service's Turn Around, Don't Drown guidance. Do not drive into water across a road, and do not walk into it either. In hill country the road surface under moving water is often gone.
The National Hurricane Center's Atlantic tropical weather outlook, issued at 2 AM Eastern time this morning, says tropical cyclone formation is not expected during the next seven days. This is the climatological peak of the Atlantic season, so an empty basin is worth noticing rather than assuming.
For the Chesapeake and Delaware coasts that is the number to hold onto in September. It makes this a good week for the parts of hurricane preparation that take time rather than money: photographing what you own for an insurance claim, finding your policy and reading the flood exclusion, and making sure your important documents are somewhere you could grab in five minutes.
Explore Today
Why hill country flooding arrives faster than the forecast makes it sound.
The five minute version of what you would need if you had to leave.
What to do before an afternoon line of storms, and what is not worth doing.