Area Forecast Discussion
Issued by NWS Charleston, WV
Issued by NWS Charleston, WV
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717 FXUS61 KRLX 041738 AFDRLX AREA FORECAST DISCUSSION National Weather Service Charleston WV 138 PM EDT Thu Jul 4 2024 .SYNOPSIS... Stationary front becomes diffuse today. Showers and thunderstorms expected today and Friday. Drier weather is in store for the weekend. && .NEAR TERM /THROUGH FRIDAY/... As of 757 AM Thursday... Isolated heavy showers have popped up across central WV and the Kanawha Valley this morning, and forecast PoPs through early this afternoon have been updated to reflect this. As of 308 AM Thursday... While a frontal boundary remains stationary northeast of the area today, very unstable conditions will emerge this afternoon with SB CAPE exceeding 3,500 J/Kg, PWATs from 2.0 to 2.2 inches, and dewpoints in the low the mid 70s. Without a trigger, strong convection may not materialize until the arrival of upper level short waves. Models brings a vorticity maxima around 21Z Thursday to 00Z Friday. This wave will provide deep layered shear from 35 to 55 knots mainly across the northern half of the area. Hi-res CAMs show convection arriving to the Middle OH valley and NE KY around 19Z this afternoon, spreading east into WV into the evening hours. The aforementioned unstable conditions will allow for long lived thunderstorms, some strong to severe into this evening. The main threat will be damaging winds. Locally heavy downpours are also anticipated with the potential for localized flooding if thunderstorms begin to train over the same areas. A marginal risk for severe thunderstorms and for excessive rainfall exist over the entire area through tonight. For tonight, the environment remains unstable and humid with a near stationary frontal boundary becoming diffuse nearby. Any upper level shortwave could trigger nocturnal convection. Therefore, precipitation will remain likely Thursday night. Guidance suggest low stratus formation across northern SE OH, and northern and northeast WV late tonight. Some areas may experience post-rain dense fog, but confidence is growing. Abundant cloud cover will allow afternoon temperatures to reach the upper 80s across the lowlands, ranging into the mid 70s higher elevations. Very humid night is anticipated Thursday night with dewpoints in the low to mid 70s. Lows will range from the mid 70s lowlands, into the lowe 60s northeast mountains. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... As of 250 AM Thursday... Cold front moves northward as a warm front, allowing for above normal temperatures to move back in with southwesterly/southerly flow taking precedence. Temperatures will be in the upper 80s to around 90 for the lowlands with mid 70s to the upper 80s being reached in the mountains. There is currently a marginal risk for severe weather and excessive rainfall across the area Friday with a cold front. The marginal risk for severe being situated across the western portions of the forecast area along the Ohio River Valley, most likely due to the timing of the frontal passage. Excessive rainfall risk is shifted farther to the east and along the mountains to cover overnight stratiform rainfall with this front. There could be some strong to severe storms that achieve damaging winds in the afternoon and evening. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... As of 125 PM Thursday... Southwest flow returns on Monday, along with a shot of heat and humidity, and some showers and storms may start to creep into the higher terrain and the southern coalfields that evening. However, the bulk of shower and storm potential looks to hold off until Tuesday or Tuesday night, when a stronger upper-level trough should push a front through the area. However, with uncertainty on just how much dry air will be behind the front, a chance for precip lingers into Wednesday as we may have some air mass convection. Monday will be quite hot, with highs mainly low to mid-90s in the lower elevations, and we`ll have to monitor the dew point forecast closely for Heat Advisory potential. Temps may get knocked down towards normal on Tuesday and Wednesday due to the expected precip and frontal passage. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... As of 629 AM Thursday... Radar imagery is showing how showers and thunderstorms dissipated as they move overhead. However, an H500 shortwave arrives to the Tri-state area (OH/KY/WV) around 12Z. Under a very unstable environment, this wave will likely trigger showers and thunderstorms this morning. Convection will be ongoing by mid morning mainly across the southern half of the area to affect HTS, CRW and BKW through this afternoon. Have coded IFR conditions in TEMPO groups for this morning activity. Another shortwaves will arrive this afternoon and evening enhancing afternoon convection areawide. Have timed convection at different terminals mainly across the northern terminals closer to the Hi-res HRRR solution, using PROB30 groups for now. Expect brief periods of IFR conditions under heavy rain. Strong gusty winds may occur at and nearby stronger storms. An area of MVFR ceilings may develop overnight tonight along the eastern mountains and western foothills of WV. Despite general guidance suggesting dense fog, believe low stratus will develop instead due to H850 winds about 20 knots. Winds will continue to be light from the southwest, except variable and gusty nearby stronger storms. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing of convection and associated restrictions may vary from 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 15 16 17 18 19 20 21 22 23 00 01 02 EDT 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY M 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 M H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H M H H H H H H H H H H AFTER 18Z FRIDAY... Brief IFR possible in showers and thunderstorms Friday. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...FK/ARJ/JMC NEAR TERM...ARJ/JMC SHORT TERM...LTC LONG TERM...FK AVIATION...ARJ