textproduct: Charleston

SYNOPSIS

High pressure brings dry weather Wednesday through Thursday, with a warming trend. Low pressure brings a return to unsettled weather for Friday and the weekend amid warm, humid conditions.

NEAR TERM /THROUGH TONIGHT/

As of 145 AM Wednesday...

High pressure was allowing overnight valley fog formation that can become dense early this Wednesday morning. Otherwise, it will maintain dry weather through the near term period, with a few cumulus atop the mixing layer during the day Wednesday. Valley fog formation is likely overnight Wednesday night, and can become dense again during the predawn hours of Thursday.

The HRRR integrated smoke suggests haze becoming more noticeable again Wednesday.

Despite the passage of the cold front, Wednesday will actually be warmer than Tuesday, with highs slightly above normal, although lows Wednesday night will be slightly below normal.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/

As of 400 AM Wednesday...

High pressure continues to provide dry weather Thursday and Thursday night. However, as it moves east, giving way to a return south to southwest flow of warmer and more humid air, the chance for mainly diurnally driven showers and thunderstorms returns on Friday, although the approach of a mid/upper-level short wave trough may keep showers and thunderstorms going Friday night.

PW values climb to around 1.75 inches Friday, with surface dew points peaking in the lower 70s across the lowlands late Friday morning and Friday evening. While a slow moving downpour could cause flash flooding in this soupy environment, low precipitation coverage through this period should keep the threat isolated.

Lowlands highs near 90 are expected Thursday and Friday, as h85 temperatures approach 20C across the north as early as Wednesday night. Nights will warm to the lower to mid 60s Thursday night, then up to the mid to upper 60s for Friday night.

LONG TERM /SATURDAY THROUGH TUESDAY/

As of 400 AM Wednesday...

A roughly west to east oriented boundary remains stuck to the north of the area this weekend, and even into early next week, leaving the area in a stuck mojo of very warm, humid and active weather.

A southern stream mid/upper level short wave trough and surface low pressure center become increasingly diffuse as they cross over the weekend. Nonetheless, with PW values of 1.75 to nearly 2 inches, and evening and late morning surface dew points peaking in the lower 70s across the lowlands, shower and thunderstorm coverage is likely to become widespread enough for a marginal flash flood risk. However, the light flow that keeps storm motion slow enough to enhance the flash flood threat also keeps bulk shear light to modest, and the severe threat low.

The front remains north of the area early next week, although it may dip down the east side of the Appalachians, a prospect that has been delayed. Mainly but not exclusively diurnally driven showers and thunderstorms will continue to pose an isolated flash flood threat, although the threat may lower a bit at least into the middle Ohio Valley Monday or Tuesday of next week. The severe threat should remain low in the light flow regime, even amid elevated CAPE.

The active weather keeps lowland highs limited to the lower to mid 80s, while lows languish in the mid to upper 60s.

AVIATION /07Z WEDNESDAY THROUGH SUNDAY/

As of 145 AM Wednesday...

GOES-R nighttime imagery was showing vally fog formation which was already beginning to impact some of the TAF sites, and all TAF sites outside BKW are likely to have conditions as low as VLIFR 07-12Z CRW and EKN, 08-~11Z CKB and 09-12Z along the Ohio River HTS and PKB. BKW may experience brief MVFR mist. Otherwise high pressure will bring VFR conditions this period.

Surface flow will be generally calm by night and light west to northwest in the mountains and light west to southwest in the lowlands during the day on Wednesday. Light west flow aloft through Wednesday will become light southwest Wednesday night.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY MODEL CONSISTENCY NOT AVAILABLE DURING THE AWIPS UPGRADE.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY... FORECAST CONFIDENCE: High. ALTERNATE SCENARIOS: The timing and extent of fog/low stratus overnight into early Wednesday morning may vary from the forecast. Valley fog may begin to form by the end of the TAF period, 06Z Thursday. The return of a smoky haze may lower visibility toward or into MVFR late Wednesday or Wednesday night.

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.

UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18 CRW CONSISTENCY L L L L L L L L L L L L HTS CONSISTENCY L L L L L L L L L L L L BKW CONSISTENCY L L L L L L L L L L L L EKN CONSISTENCY H L L L L L L L L L L L PKB CONSISTENCY L L L L L L L L L L L L CKB CONSISTENCY L L L L L L L L L L L L

AFTER 06Z THURSDAY... Brief IFR possible in showers and thunderstorms late Friday and on Saturday.

RLX WATCHES/WARNINGS/ADVISORIES

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