textproduct: Charleston

WHAT HAS CHANGED

Active today with strong storms and heavy downpours ahead of a front. Briefly drier behind the front then another system brings potential for heavy rain and strong storms Tuesday into Tuesday night.

KEY MESSAGES

1) Rain and thunderstorms are expected during the day, and as a front crosses tonight into Sunday. Strong to severe storms could produce damaging wind gusts today. Heavy rain could also prompt localized flash flooding.

2) Impacts from wildfire smoke decrease today.

3) Next chance of heavy rain and strong storms arrives Tuesday.

DISCUSSION

KEY MESSAGE 1...

A low traverses southern Ontario and Quebec today and then continues onward to the Maritime Provinces and Gulf of St. Lawrence on Sunday. A cold front trailing this system will descend into the Middle Ohio Valley tonight and then sink south towards the Virginia/North Carolina border Sunday and Sunday night.

The presence of a warm, moist, and unstable environment ahead of the front, combined with a passing shortwave, should facilitate development of showers and thunderstorms across the area today. Precipitable water values in excess of an inch and a half should support heavy downpours which could prompt localized flooding in poor drainage areas or locations impacted by multiple storms. Scattered strong to severe storms could also be capable of producing damaging wind gusts this afternoon and evening.

A brief lull in activity may occur after sundown, then another round of activity is expected to accompany the front across the area overnight. Precipitation coverage tapers off from north to south as the front recedes south on Sunday.

KEY MESSAGE 2...

Canadian wildfires will have less of an impact on the area as smoke is swept northward today. That being said, an air quality alert remains in effect for portions of northwest and north- central West Virginia where some impacts could linger through tonight.

KEY MESSAGE 3...

Drier for much of the area on Monday, then another low swings across southern Ontario while an upper trough digs down into the eastern US. This system is projected to bring the next chance of strong storms and heavy rain to the area Tuesday and Tuesday night. SPC has already highlighted a 15 percent risk of severe weather on Tuesday while WPC has placed much of the area within a slight risk of excessive rainfall.

Surface high pressure builds as the trough shifts east, allowing quieter weather to take hold later in the week. This dry spell may be rather short-lived as the first in a series of disturbances is expected to approach the area this weekend.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

A mix of MVFR to VFR ceilings will persist across the area while showers and thunderstorms prompt sub-VFR visibilities at times today. Conditions are expected to further deteriorate as a front moves through overnight, bringing more rain and storms. Fog may also develop behind the front early Sunday morning. Conditions should then slowly improve to VFR during the day Sunday.

Winds will generally be southwesterly today, then pivot to the north behind the front overnight. In addition to sporadic gusts into the teens to low 20s, stronger gusts will be possible within storms.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY... FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Expect flight conditions to fluctuate in RA/TS. Timing of improvements on Sunday may vary from the forecast.

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 17 18 19 20 21 22 23 00 01 02 03 04 EDT 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00 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 H H H H H H H 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 18Z SUNDAY... IFR valley fog possible Sunday/Monday mornings.

RLX WATCHES/WARNINGS/ADVISORIES

WV...Air Quality Alert until midnight EDT tonight for WVZ007>011- 016>020-029>032-039-040. OH...None. KY...None. VA...None.