The week at a glance
Monday will feel noticeably cooler and less humid across Central Appalachia. That break will not last long: temperatures and humidity climb Tuesday, with hot conditions returning to West Virginia by Wednesday.
Thunderstorms may begin near Lake Erie and northeastern Ohio Tuesday night. Scattered storms remain possible Wednesday and Thursday as a front wavers across the region. Another front may bring additional showers and storms from Thursday into the weekend.
The forecast supports keeping an eye on storms, but it does not yet point to a widespread or high-confidence severe-weather event. The more certain concern is heat across the West Virginia lowlands Wednesday and Thursday, where heat-index values may approach 100 degrees.
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. 14 | Cooler and less humid | Breezy conditions; early clouds or fog south | Routine monitoring is enough |
| Tuesday, Sept. 15 | Dry and quickly warmer | Storms may approach northeastern Ohio at night | Watch northern Ohio Tuesday evening |
| Wednesday, Sept. 16 | Hot and humid; scattered storms | Heat in West Virginia; isolated strong storms | Publish heat reminders and monitor afternoon storms |
| Thursday, Sept. 17 | Humid with on-and-off storms | Heat, gusty storms and locally heavy rain | Keep coverage plans flexible |
| Friday, Sept. 18 | Front crossing or nearby | Scattered showers and storms | Follow the front before scaling back |
| Saturday, Sept. 19 | Front may linger south and east | Additional showers or storms | Focus monitoring on West Virginia and western Maryland |
| Sunday, Sept. 20 | Unsettled in some guidance | Scattered storms; timing uncertain | Check updated guidance before weekend messaging |
Monday: Cooler air settles in
A cold front departing early Monday will leave behind a cooler, drier air mass. Highs should range from near 70 in northeastern Ohio and northwestern Pennsylvania to the middle and upper 70s farther south. Mountain locations will be cooler.
Northwest winds may gust between 20 and 25 mph in western Maryland and the higher terrain. That falls short of a significant land-based wind hazard, but it will make the day feel more autumnal. Low clouds or fog could briefly affect parts of West Virginia early in the morning.
NWS Cleveland has issued Beach Hazards Statements along portions of Lake Erie through Monday morning, along with Small Craft Advisories for the lake. These are official NWS alerts, primarily affecting marine and lakeshore interests.
Routine monitoring is enough away from Lake Erie. Mention the lakeshore hazard if CAWA’s morning coverage reaches northwestern Pennsylvania or northeastern Ohio.
Sources: NWS Cleveland forecast discussion, NWS Baltimore/Washington forecast discussion
Tuesday: Temperatures rebound
High pressure shifts east and return flow develops, allowing temperatures to climb quickly. Many lower elevations should return to the lower and middle 80s. The West Virginia lowlands may become hotter, although humidity should remain below its midweek peak.
A warm front near Lake Erie may produce showers or thunderstorms Tuesday night across northern Ohio. Confidence decreases farther south, where most of the day should remain dry.
Watch northeastern Ohio Tuesday evening. Broader active-weather coverage probably will not be necessary unless storms become more organized than currently expected.
Sources: NWS Cleveland forecast discussion, NWS Pittsburgh forecast discussion
Wednesday: Heat south, scattered storms possible
Wednesday brings summer back to the region. Temperatures should reach the middle and upper 80s across much of western Pennsylvania, eastern Ohio and western Maryland. Lower elevations in West Virginia may reach the lower 90s.
NWS Charleston expects heat-index values in the middle and upper 90s across much of the lowlands, with readings approaching 100 in urban parts of the Kanawha Valley. That is the clearest impact signal in the current forecast. This is not a statement that a Heat Advisory has been issued.
A nearly stationary boundary could also support scattered thunderstorms. NWS Pittsburgh notes early guidance suggesting a low-end severe and flooding signal Wednesday and Thursday, but that signal remains uncertain. NWS Cleveland has not yet identified a focused severe threat and plans to reevaluate the convective environment as the event gets closer.
Publish a straightforward heat reminder for West Virginia. Monitor afternoon storm development, but wait for stronger support from SPC or later local NWS forecasts before advertising an organized severe threat.
Sources: NWS Charleston forecast discussion, NWS Pittsburgh forecast discussion
Thursday: Humid with several possible hazards
A front may remain near northeastern Ohio and western Pennsylvania while another disturbance approaches. Scattered or periodically more numerous thunderstorms are possible.
The main concerns are locally gusty wind, downpours and lightning. Repeated storms could create isolated drainage or poor-drainage flooding, but the available guidance does not support presenting a widespread flash-flood event as likely.
Hot weather may continue in the West Virginia lowlands, where afternoon heat indices could again reach the middle or upper 90s. Farther north, clouds and storms may hold temperatures down.
Confidence is moderate that some part of the region receives storms, but lower on their timing, coverage and strength. Keep coverage plans flexible and review the newest SPC convective outlook and WPC excessive-rainfall outlook before drawing a specific risk area.
Friday: Frontal timing becomes important
Forecast guidance generally brings a cold front through part of the region late in the week. Showers and thunderstorms may accompany it, particularly from western Pennsylvania southward into West Virginia and western Maryland.
Severe probabilities currently appear limited in the eastern coverage area. The front’s timing is still unsettled, and an earlier passage would reduce both instability and storm intensity.
Follow the front rather than committing to a full-day storm message. If it clears early, much of eastern Ohio and western Pennsylvania may turn cooler and quieter.
Source: NWS Baltimore/Washington forecast discussion
Saturday and Sunday: Lower-confidence storm chances
The weekend forecast depends on how quickly the late-week front clears the Appalachians. Western Pennsylvania and eastern Ohio have the better chance of turning cooler and drier first. Showers and thunderstorms could linger or redevelop across West Virginia and western Maryland.
NWS Charleston also notes that passing upper-level disturbances may provide daily opportunities for storms as the ridge weakens. At this range, neither day stands out as a defined severe-weather day.
Focus Saturday monitoring on the southern and eastern coverage area. Reassess Sunday after the front’s position becomes clearer.
Operational meteorology and communication updates
NEXRAD Level II data moves off NOMADS Monday
Scheduled change — September 15, 2026
NWS plans to discontinue the existing NEXRAD Level II directory on the NOMADS server at 1200 UTC Monday. Identical data are already available from the replacement TGFTP directory. Level III data are not included in this change.
Any CAWA script that still retrieves Level II files from:
should be moved to:
The file format, frequency, filenames and directory structure are unchanged. After migrating, verify timestamps rather than merely confirming that the downloader runs successfully.
Source: NWS NEXRAD Level II migration notice
WPC’s Probabilistic Precipitation Portal is going operational
Scheduled implementation — on or about October 1, 2026
NWS Service Change Notice 26-75 says WPC’s experimental Probabilistic Precipitation Portal will transition to operational status around October 1.
The portal presents precipitation probabilities in a form that can help answer questions that a single deterministic QPF map cannot—for example, the chance of exceeding a particular rainfall amount at a location. That can be useful when CAWA needs to explain uncertainty around localized heavy-rain or flooding setups.
CAWA should evaluate the portal as an internal briefing and forecast-confidence tool. If its graphics are eventually used publicly, include the threshold and valid period prominently; a probability without those details is easy to misread.
Source: NWS service-change notices and announcements
CAP transition feedback remains open
Proposal — comments due September 21, 2026
NWS is gathering early feedback on making Common Alerting Protocol messages its primary watch, warning and advisory format, potentially ending traditional VTEC-formatted dissemination later.
This remains a proposal, with no implementation date. It still deserves attention because CAWA’s alert poster and other automated tools must correctly follow warning updates, cancellations and event identifiers.
Document every place where CAWA relies directly on VTEC strings. If the alert poster primarily consumes the NWS API, confirm which structured fields it uses and whether any event-tracking logic still parses raw product text.
Source: NWS CAP transition proposal
RRFS and REFS appear in local forecast operations
NWS Pittsburgh’s September 13 forecast discussion directly compared HREF and parallel REFS guidance while assessing the day’s severe-weather environment. That is a useful real-world sign that forecasters are already evaluating REFS alongside established convection-allowing guidance ahead of the planned October 6 operational transition.
CAWA can do the same during this week’s less-certain storm periods: compare REFS probabilities with HREF, observed instability and actual radar evolution. Keep the comparisons internal until there is enough experience to understand each field’s strengths and biases.
RRFS and REFS are still scheduled to become operational October 6, when NAM, SREF, HREF, HiresW and NAM MOS production is expected to end.
Sources: NWS Pittsburgh forecast discussion, 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.