Area Forecast Discussion

WHAT HAS CHANGED

Have lowered PoPs for tonight, with isolated showers in and near the higher terrain expected at this point through the first half of tonight. Some valley fog is expected to develop overnight, especially across the lowlands given less cloud cover. Updated 00Z Aviation Discussion.

KEY MESSAGES

1) A cluster of severe thunderstorms will be possible Monday night into Tuesday. Damaging winds and flash flooding appear to be the main concerns with a bowing line of thunderstorms.

2) Beyond Tuesday, quieter weather should settle in for the rest of the week with seasonable temperatures.

DISCUSSION

KEY MESSAGE 1...

In previous forecasts, we mentioned the potential for a cluster of thunderstorms late Sunday night into Monday morning. In recent runs, high- resolution forecast guidance has backed off on this idea for our local forecast area.

Instability will build Monday afternoon, particularly across southeast Ohio and northern West Virginia, with 1,000 to 2,000 J/kg of CAPE expected during that timeframe. Isolated to scattered thunderstorms may develop Monday afternoon across these areas as rounds of vorticity flow northwest to southeast from the Great Lakes.

Models have been consistently showing the potential for a thunderstorm complex to impact the area Monday night into Tuesday, but they are still having a difficult time agreeing on a consistent track and location.

The best potential for thunderstorms will occur in the early morning hours of Tuesday, ahead of a few robust vort. maxes and an advancing cold front. High- resolution mesoscale models are continuing to show the potential for a bowing cluster of thunderstorms approaching from the Great Lakes during this time. The synoptic pattern will feature a strong 250-mb jet streak aligning northwest to southeast from Wisconsin to northern Ohio, placing the middle and upper Ohio Valley region in the favorable exit region for upward motion. In addition, robust 500-mb vorticity will approach from the Great Lakes. 0-6km shear will be robust at 45-50 kts, and some models still show a fairly high amount of instability during the predawn hours of Tuesday (1,000 to 1,500 J/kg from northeast KY through northern WV). A low-level jet will advect 65 to 70 degree dew points into the region, and precipitable water values will range from 2.00 to 2.25 inches.

The atmospheric setup early Tuesday morning does not look favorable for catastrophic flooding like what was seen last week because storms should be moving at a fairly quick pace. However, localized flash flooding will certainly be a concern, especially in areas that were recently hit hard with flooding last week.

Depending on how quickly storms exit Tuesday morning, there may be an opportunity for the atmosphere to destabilize again Tuesday afternoon before the main cold front approaches between 18Z Tuesday and 00Z Wednesday. This is highly uncertain at this time, but another round of thunderstorms Tuesday afternoon is not out of the question.

KEY MESSAGE 2...

Wednesday through Friday should be fairly quiet as ridging brings dry weather. However, chances of showers and thunderstorms will return next weekend as another mid-level disturbance approaches. Temperatures will range from the middle to upper 70s in the mountains and the middle to upper 80s in the lowlands from Wednesday through next weekend.

AVIATION /00Z MONDAY THROUGH FRIDAY/

VFR conditions continue into tonight amid the chance for ISOLD showers in and near the higher terrain. Dry conditions then return later tonight, amid some developing valley fog and stratus. Valley fog is expected to be more so confined to the lowlands, while stratus is favored across the higher terrain. MVFR or worse is currently progged for all terminals later tonight in Monday morning, with VFR expected to return area-wide by mid morning amid a developing FEW/SCT Cu field. ISOLD showers/storms could occur Monday afternoon/evening across the north, but confidence in timing/placement remains low.

Surface flow goes calm at most sites tonight, with light WSW (lowlands) to WNW (higher terrain) flow developing during the day on Monday.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z TUESDAY... FORECAST CONFIDENCE: Low to medium tonight, medium on Monday.

ALTERNATE SCENARIOS: Restrictions with fog/stratus later tonight into Monday morning may vary from the forecast. Brief MVFR VSBY could occur Monday afternoon/evening if any thunderstorms were to occur.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

DATE MON 07/27/26 UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 CRW CONSISTENCY H H H H H M L L L L L M HTS CONSISTENCY H H H H H H M L L L L L BKW CONSISTENCY H H H H H H L L M M M M EKN CONSISTENCY H H H H H M L L M M M M PKB CONSISTENCY H H H H H H M L M H M M CKB CONSISTENCY H H H H H M L L M M M M

AFTER 00Z TUESDAY... IFR conditions are possible with showers and thunderstorms Monday night through Tuesday. IFR conditions are also possible with valley fog and/or stratus Wednesday through Friday mornings.

RLX WATCHES / WARNINGS / ADVISORIES

WV...None. OH...None. KY...None. VA...None.