Area Forecast Discussion

WHAT HAS CHANGED

12Z Aviation Forecast Discussion update...

A Heat Advisory was issued for this afternoon for central portions of the County Warning Area, which encompasses much of the WV lowlands. The faster timing of the cold front limits the potential for excessive heat on Friday. There is increasing confidence a clean passage of a cold front late this weekend, allowing for dry weather at least for the start of the upcoming work week.

KEY MESSAGES

- 1) Scattered afternoon thunderstorms today may organize into a small complex over the lowlands, bringing a threat for damaging wind gusts and localized high water.

- 2) A progressive cold front will cross the region Friday afternoon, triggering a broken line of thunderstorms capable of producing damaging wind gusts.

- 3) Hot and humid conditions build Thursday and Friday, driving heat index values into the mid and upper 90s across the lowlands, even around 100 early this afternoon across portions of the WV lowlands.

- 4) Saturday brings a break the very warm, humid and active weather pattern, then a cold fronts crosses Sunday afternoon, bringing cooler and less humid weather at least for the start of the upcoming work week.

DISCUSSION

KEY MESSAGE 1...

A mid/upper-level ridge over the area early this morning is flattened by a weak flat wave coming out of a long wave trough out west today, before rebuilding over the area tonight. The flat wave is associated with a cluster of showers and thunderstorms approaching from the midwest early this morning. This activity continues to fall apart this morning, and then reforms just west of and over the area this afternoon, as is suggested by most guidance including the Convective Allowing Models. Storms could then organize into a small cluster or two.

Central Guidance has been close or even a bit low on dew points, which have been in the mid to even upper 70s at ASOS sites. With heating taking temperatures up to around 90 degrees this afternoon, and the -10 C level just above h5, this generates CAPE up around 3500. Coupled with 30 kts mid-level flow north with the flat wave, thunderstorms, once formed, can tower quickly and produce heavy downpours, and strong to damaging wind gusts including microbursts.

The Storm Prediction Center has a Slight Risk for Severe Thunderstorms in and near the mountains, with a Marginal Risk back over the middle Ohio Valley and down along the Tug Fork, for this afternoon and early this evening. This is based on the timing of the flat wave relative to diurnal heating. As such, thunderstorms should weaken and move east, out of the northeast mountains, around sunset this evening. The main threat with thunderstorms this afternoon and early this evening is damaging wind, but hail is also possible.

The Weather Prediction Center has a Marginal Risk for Excessive Rainfall for much of the area today given the convective potential amid PW values of 1.75 inches. Localized flash flooding is possible with stronger cores this afternoon and early this evening. Southern and central portions of the area and into the northeast mountains are the most saturated, with 1 to 3 inches rainfall over the past 3 days.

KEY MESSAGE 2...

A broad long wave trough drifts eastward across the center of the continent today through Friday, and then eastward to the central to eastern portion of the continent this weekend. The ridge rebuilding over the area tonight gives way to the lead mid/upper-level short wave trough associated with the long wave trough, which pushes a surface cold front toward the area.

However, models are faster with the front, which is now progged to cross the Ohio River as early as midday Friday.

The Storm Prediction Center has a Slight Risk for Severe Thunderstorms east of the Ohio river Friday, with a narrow Marginal Risk sliver along the Ohio River. Further, most of the increase in bulk shear occurs behind the cold front, so the Severe Weather Threat level for Friday is not necessarily much higher compared with today.

Weather Prediction Center has been carrying a Marginal Risk for Excessive Rainfall for the forecast area, in a long ribbon all along and ahead of the approaching cold front, for the Appalachians and Ohio Valley, and then back westward through the south-central Plains States.

KEY MESSAGE 3...

With the mid/upper-level ridge ahead of the flat wave crossing this afternoon, temperatures today climb to around 90 at least east of the Ohio River, to go along with the high humidity of late. This pushes heat indices to around 100 F for several hours this afternoon, and have issued a Heat Advisory for central portions of the County Warning Area, which is much of the WV lowlands.

The faster timing of the cold front on Friday is fast-closing the window of opportunity for excessive heat that afternoon.

KEY MESSAGE 4...

The cold front crossing the area Friday, driven by the forward progress of the long wave trough into the eastern U.S., brings the promise of dry weather Saturday, complete with lower dew points, breaking the ad nauseum of active summer weather. However, high pressure building in behind the cold front as early as overnight Friday night, along with the previous rain, could lead to areas of dense fog early Saturday morning.

The next cold front brings showers and possible thunderstorms on Sunday. Models are coming into agreement on the cold front pushing cleanly through the area as early as Sunday afternoon, allowing high pressure to bring dry, cooler and less humid weather for the early portion of the upcoming work week, with the next cold front due next Thursday.

Probabilistic-based Central guidance has begun to tease out a dry interlude early next week across the middle Ohio Valley, but leaves chance PoPs in and near the mountains until Tuesday.

AVIATION /09Z THURSDAY THROUGH MONDAY/

While very warm and humid air in place and weak mid/upper- level disturbances could result in showers and thunderstorms forming this morning, there is greater confidence in a cluster of thunderstorms forming in the area early this afternoon.

The Storm Prediction Center has a Slight Risk for Severe Thunderstorms in and near the mountains, with a Marginal Risk back over the middle Ohio Valley and down along the Tug Fork, for this afternoon and early this evening. The main threat is damaging wind, but hail is also possible. MVFR/IFR conditions are possible on direct hits of heavier showers and storms.

Thunderstorms should weaken and move east, out of the northeast mountains, around sunset this evening.

Light southwest surface flow this morning will be a bit stronger and could become gusty for a time this afternoon. Thunderstorms this afternoon can produce strong to damaging wind gusts. Light west flow aloft this morning will become light southwest this afternoon, and then moderate southwest tonight.

Clearing overnight tonight with locally heavy rainfall that falls today, could induce at least patchy fog, but given the aforementioned flow, any fog that does form will be limited.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY... FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Shower and thunderstorm timing could vary. More substantial fog could develop overnight tonight if winds can completely decouple under clear sky.

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 THU 06/11/26 UTC 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18 EDT 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14 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 M M H H H H H 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 12Z FRIDAY... 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...Heat Advisory from noon today to 6 PM EDT this evening for WVZ006>008-013>019-026-027-029. OH...None. KY...None. VA...None.