Area Forecast Discussion

WHAT HAS CHANGED

...745 PM Aviation discussion updated. In addition, the threat for severe thunderstorms has diminished, therefore the Severe Thunderstorm Watch has been cancelled.

KEY MESSAGES

1. Severe thunderstorms capable of damaging wind gusts and localized flash flooding are possible this afternoon and evening.

2. A cold front will bring better chances for more numerous showers and thunderstorms Friday afternoon into Friday evening. Some storms could contain damaging wind gusts and hail.

3. Drier and cooler weather returns for Saturday before another frontal system brings rain chances back to the region on Sunday.

DISCUSSION

KEY MESSAGE 1... Surface observations early this afternoon show temperatures climbing into the upper 80s to near 90 degrees F with dew points in the lower 70s. While mid-level lapse rates are poor, this strong surface heating and moisture pooling will yield MLCAPE values of 2000 to 2500 J/kg by peak heating with little to no convective inhibition.

The forecast area is initially under weak subsidence behind a departing shortwave, but a secondary wave approaching this afternoon will provide the necessary forcing for convective initiation. Deep layer shear is weak, generally 15 to 25KTs, which supports a multicellular storm mode. Given steep low level lapse rates and water-loaded soundings featuring precipitable water values near 1.8 inches, the primary threat will be isolated damaging wind gusts and locally heavy rainfall.

There is some potential for cold pools to congeal, allowing convection to grow upscale as it progresses eastward late this afternoon into this evening. A Severe Thunderstorm Watch is in effect through 8 PM for the northern counties where convective coverage and the threat for upscale growth is highest. While the best convective coverage is largely expected to stay away from areas that have seen upwards of 3 to 4 inches in the past few days, should any heavy rain work its way down into these areas, isolated high water issues may occur.

KEY MESSAGE 2... Remnant convection from a large system over the Midwest is expected to approach the western counties by early Friday morning, potentially bringing lingering gusty winds as it dissipates.

Strong surface heating during the day will allow the boundary layer to become uncapped by noon. While isolated convection could develop on remnant outflow boundaries, the first half of the day should remain largely dry under weak subsidence. A cold front will approach the Middle Ohio Valley by 1 to 2 PM, blossoming showers and thunderstorms into a broken line that will bisect the forecast area from southwest to northeast by late afternoon. Kinematics lag the frontal boundary, with deep layer shear of 20 to 25KTs coincident with the expected storm footprint. This will once again favor a multicellular mode. Fairly straight hodographs suggest a low end threat for a split into supercells, with any left-splits posing a marginal severe hail threat. However, the primary hazard remains damaging wind gusts driven by steep low level lapse rates. Brief but intense heavy rainfall is expected, but the progressive nature of the front will limit hydro issues.

KEY MESSAGE 3... In the post frontal environment, drier and slightly cooler conditions are forecast for Saturday. Highs will drop back toward normal values in the lower to mid 80s for the lowlands and 70s for the mountains, providing a brief reprieve from the humidity. Moisture quickly returns on Sunday ahead of another approaching cold front. Kinematics with this system are stronger, featuring deep layer shear of 30 to 40KTs. Current timing of the frontal passage places the best forcing largely east of the region by peak heating, limiting the severe risk primarily to the northeastern mountains.

AVIATION /00Z FRIDAY THROUGH TUESDAY/

Earlier showers and thunderstorms are waning with only isolated showers and storms in southern Randolph and portions of Pocahontas County. These will continue to push east, exiting the area in the next hour or so. Elsewhere, VFR prevails with a mix of SCT/BKN decks with even some SKC across portions of the region.

Patchy fog development is possible overnight, but modest boundary layer flow should limit widespread dense fog. As for now, any mention of FG is excluded from TAFS due to low confidence and low probability of occurrence.

Another round of showers/storms expected tomorrow afternoon, mainly along/east of I-79. Any showers/storms could result in brief reductions in CIGS/VSBYs.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY... FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Could be some isolated FG development tonight.

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 FRI 06/12/26 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 H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H M L L M M M M M PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H

AFTER 00Z SATURDAY... Brief periods of IFR visibility possible in thunderstorms Friday and Sunday. IFR conditions in fog is possible early Saturday and Monday mornings, as high pressure builds in behind cold fronts that cross Friday and Sunday.

RLX WATCHES / WARNINGS / ADVISORIES

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