The week at a glance
Keep the rain gear handy. Several weather systems will cross Central Appalachia through the middle of the week, bringing repeated rain and a few thunderstorms.
The greatest immediate concern is flooding Monday. Official Flood Watches cover much of southeastern Ohio, northern and central West Virginia, southwestern Pennsylvania and areas near and south of Pittsburgh. Another half-inch to inch and a half of rain is possible in parts of the region, with narrow corridors potentially receiving more.
Rain becomes lighter and less organized after Monday, but additional showers through Wednesday could keep streams elevated and cause slower river rises. Temperatures will also turn sharply cooler. Many communities from eastern Ohio through western Pennsylvania may remain in the 60s for several days.
Drier weather should return late Thursday or Friday. The weekend currently looks cool, pleasant and much quieter.
Full technical briefing
Seven-day forecast for Central Appalachia
This outlook covers western Pennsylvania, eastern Ohio, northern West Virginia, western Maryland and nearby portions of Central Appalachia.
| Day | Expected pattern | Main concern | What CAWA should do |
|---|---|---|---|
| Monday, Sept. 21 | Periods of rain with embedded storms | Flash flooding, standing water and isolated strong wind | Plan for active flood coverage through the morning |
| Tuesday, Sept. 22 | Cool, cloudy and damp | Additional rain; elevated streams and rivers | Continue checking rainfall totals and water levels |
| Wednesday, Sept. 23 | More widespread showers | Longer-duration flooding; poor visibility | Keep flood messaging available even if rain is lighter |
| Thursday, Sept. 24 | Lingering showers, gradually improving | Gusty wind east; isolated remaining water issues | Confirm the upper low and coastal system are moving away |
| Friday, Sept. 25 | Drier with partial clearing | Chilly morning temperatures | Routine monitoring should be enough |
| Saturday, Sept. 26 | Dry and seasonably cool | No significant hazard expected | Routine monitoring is enough |
| Sunday, Sept. 27 | Mainly dry with increasing clouds possible | No organized hazard identified | Watch for changes in the next approaching system |
Monday: Flooding is the main concern
Official NWS Flood Watches extend through Monday morning across much of southeastern Ohio, northern and central West Virginia, southwestern Pennsylvania and counties near and south of Pittsburgh.
A moisture-rich system will produce another round of rain overnight into Monday morning. NWS Pittsburgh expects a general half-inch to inch and a half near and south of the city, but high-resolution guidance shows the possibility of narrow two- to three-inch corridors. The exact placement will depend on where the slow-moving front settles.
The ground is already wet in many locations. That raises the risk of flash flooding along small streams, in low spots and in poor-drainage areas. NWS Charleston notes that places hit by heavy rain Sunday will be particularly vulnerable.
A few thunderstorms may produce strong wind, especially across southeastern Ohio and West Virginia. Widespread severe weather is not the primary concern; extensive clouds and limited instability should keep that threat isolated.
Confidence is high that more rain occurs and moderate on the flash-flood threat. Confidence is lower on exactly where the heaviest stripe sets up.
Plan for active flood coverage through Monday morning. Track observed rainfall, road closures and stream responses instead of relying on the regional forecast alone.
Sources: NWS Pittsburgh forecast discussion, NWS Charleston forecast discussion
Tuesday: Cooler, with lingering rain
Canadian high pressure pressing south will bring much cooler air into eastern Ohio and western Pennsylvania. Highs there may struggle to leave the lower or middle 60s. West Virginia will remain somewhat warmer, particularly south of the stalled boundary.
Clouds, scattered showers and low ceilings will continue. Rainfall rates should generally be lower than Monday, reducing the immediate flash-flood threat. Even so, runoff from several days of rain may keep streams elevated.
Western Maryland could receive steadier rain Monday night into early Tuesday as moist easterly flow strengthens against the terrain.
Continue checking rainfall totals, river forecasts and any extensions of the Flood Watch. Public messaging should separate ongoing river or stream responses from the lower risk of new, rapid flash flooding.
Sources: NWS Cleveland forecast discussion, NWS Baltimore/Washington forecast discussion
Wednesday: Another round of showers
An upper-level trough will move into the Ohio Valley, bringing another period of widespread showers. Thunder is possible, but cool temperatures and limited instability should keep severe-weather potential low.
NWS Pittsburgh notes that longer-duration rainfall may produce river rises or overflow flooding through Wednesday, even as the risk of intense short-term rainfall decreases. Areas along and south of the Pennsylvania–West Virginia border deserve particular attention.
It will feel distinctly autumnal. Lower elevations in western Pennsylvania and eastern Ohio should remain in the lower or middle 60s, while some higher ridges may struggle to reach 60.
Keep flood messaging available Wednesday. If water problems develop, emphasize that flooding can continue after the heaviest rain ends.
Thursday: Slow improvement
The upper trough may close off before finally moving east. Scattered showers could linger, particularly over West Virginia, the higher terrain and western Maryland.
A coastal low moving north near the Mid-Atlantic coast may also produce gusty northerly or northeasterly winds in western Maryland. The stronger wind and coastal-flood threat should remain east of CAWA’s primary coverage area, but gusts may become noticeable along exposed ridges.
Confidence in gradual improvement is moderate; the main uncertainty is how quickly the upper and coastal lows depart.
Confirm that the systems are pulling away before dropping rain and wind coverage. Otherwise, routine monitoring should become sufficient later in the day.
Source: NWS Baltimore/Washington forecast discussion
Friday: Drying out
High pressure should begin taking control, bringing clearing skies and a welcome break from the rain.
Morning temperatures may fall into the 40s across inland northeastern Ohio, northwestern Pennsylvania and the higher terrain. Widespread frost or freezing conditions are not currently expected.
Routine monitoring should be enough. Check sheltered valleys for lower temperatures if skies clear more quickly than forecast.
Saturday and Sunday: A quieter fall weekend
The weekend currently looks dry and seasonably cool. Afternoon temperatures should generally reach the upper 60s or lower 70s, with chilly nights in the 40s and lower 50s.
Forecast confidence is moderate to high for Saturday and somewhat lower by Sunday. No organized hazardous-weather signal is evident at this range.
Routine monitoring is enough, with a check Sunday for the timing of the next system beyond the seven-day period.
Additional operational concerns
Lake Erie remains hazardous early in the week
NWS Cleveland has issued Beach Hazards Statements for portions of the Ohio and Pennsylvania Lake Erie shoreline through Wednesday evening. Small Craft Advisories are also in effect.
Persistent northeast winds may gust around 30 mph in northwestern Ohio, with higher waves and dangerous currents along the lakeshore. These are official NWS hazards and are separate from the inland flood threat.
If CAWA’s coverage includes Erie County or the northeastern Ohio lakeshore, keep the beach and marine message visible through Wednesday.
Source: NWS Cleveland forecast discussion and active headlines
Operational meteorology and communication updates
No major new national product change was identified this week
No consequential new NWS, SPC, WPC, NCEP, MRMS or AWIPS change relevant to CAWA operations was identified since the previous briefing. Several previously announced deadlines still require attention.
CAP transition comments close September 21
Status: Proposal under review
The NWS comment period on potentially making Common Alerting Protocol messages its primary alert format closes Monday.
This remains an early proposal, not an implementation notice. A future transition could affect any CAWA automation that depends on raw VTEC strings to identify warning actions, event numbers, extensions or cancellations.
If CAWA has concerns about migration time, alert tracking or access to legacy text products, Monday is the last scheduled day to provide initial feedback.
Source: NWS CAP transition proposal
Verify the completed NEXRAD Level II migration
Status: Scheduled change date has passed
NWS scheduled the old NOMADS directory for NEXRAD Level II data to be discontinued September 15. Identical files are available through TGFTP, and Level III products were not affected.
Any CAWA tool using Level II data should now be checked for both connectivity and freshness. A successful request is not enough; confirm that file timestamps continue advancing and that all expected radar sites are present.
Source: NEXRAD Level II migration notice
WPC precipitation portal approaches operational status
Status: Operational transition planned around October 1
WPC’s Probabilistic Precipitation Portal is scheduled to move from experimental to operational status around October 1.
This week’s repeated-rain setup is a good example of where probabilistic information can add value. A single rainfall-total map may obscure uncertainty in the location of a narrow heavy-rain corridor. Threshold probabilities can better show how likely a location is to receive one, two or three inches.
When sharing probabilistic rainfall information publicly, always include the accumulation threshold, valid period and geographic context.
Source: NWS service-change notices
RRFS/REFS transition is about two weeks away
Status: Implementation scheduled for October 6
RRFS and REFS remain scheduled to become operational October 6. NAM, SREF, HREF, HiresW and NAM MOS production is expected to end with the transition.
CAWA should be beyond the inventory stage by now. Any dashboard, automated download, bookmark or forecast process using the retiring systems should have a tested replacement or a documented plan for temporary loss of that component.
Source: RRFS and REFS implementation notice
This briefing is planning guidance, not an official warning or substitute for current forecasts. Follow watches, warnings and advisories issued by the National Weather Service. This post was created with AI assistance.