Area Forecast Discussion
Issued by NWS Charleston, WV

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807 FXUS61 KRLX 261851 AFDRLX AREA FORECAST DISCUSSION National Weather Service Charleston WV 251 PM EDT Sun May 26 2024 .SYNOPSIS... Showers and storms through Memorial Day weekend in response to a cold front. Damaging wind gusts, hail, and locally heavy downpours will be possible. Remaining unsettled Tuesday and Wednesday. && .NEAR TERM /THROUGH MONDAY/...
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As of 250 PM Sunday... Key Points: * Bowing line of thunderstorms arriving soon to the western flank of the forecast area this afternoon. * Strong to severe thunderstorms possible with potential for damaging wind gusts, large hail, and brief spin up tornadoes. * Heavy downpours associated with convection may produce localized flash flooding. What was a beautiful and quiet morning around the Central Appalachians has quickly grown active as we await a bowing convective segment encroaching on eastern Kentucky and Ohio and the time of writing. This line of storms has had history of producing very strong winds on the upwards of 60+ mph gusts throughout the morning and early afternoon upstream in the Tennessee Valley, with a few spin up tornadoes noted by neighboring offices currently facing the southern end of this system. A Severe Thunderstorm Watch is already in place for the vast majority of the forecast area this afternoon as we monitor storms dashing across the region. Mesoanalysis depicts storms have outran the favorable sheared environment that was present earlier today in western and central Kentucky, denoting more of a wind threat now, but still would not rule out quick QLCS tornadoes that become embedded in the descending notch. Warm and muggy conditions here in our forecast area will aid in sustaining storms as they travel into West Virginia and perhaps up into the northeastern mountains. In addition to the potential for winds, hail, and tornadoes, there will be the increasing concern for heavy downpours as convection ventures overhead. With PWATs projected to rise to around 1.5-1.8 inches today and tall, skinny CAPE profiles denoted by forecast soundings, it is certainly not out of the question to observe rainfall rates on the upwards of 1-2 inches per hour. This would impede on recovering ground conditions from antecedent rain and lead to flash flooding concerns. Convective trends this afternoon and evening will be the catalyst for how overnight activity will fare. Hi-res guidance for this afternoon suggests a secondary line of showers and storms forming upstream that will maintain active weather for the overnight period. This could become primarily outflow driven and take a southward trajectory away from the Ohio River Valley tonight, but held onto likely POPs once again crossing the CWA overnight into early Monday morning. However, this first line of convection could overwork our environment and impose less of a severe threat late tonight. Regardless, rain and flooding concerns stretch into the overnight hours, especially in the event of training. Unsettled weather triumphs into Memorial Day as a low pressure system and its attendant cold front drift further eastward. While a break in activity seems plausible during the morning hours Monday, isolated to possibly scattered showers and storms return to the forecast once more for the afternoon and evening. Temperatures will be a few degrees cooler on Monday, but dew points remain well into the 60s, leading to another muggy day across the area. The cold front will continue eastward progress through the region at the conclusion of the near term period. As of 248 AM Sunday... Key Points: * Hot and humid today. * Enhanced risk for severe storms NE Kentucky through tonight. * Slight risk for severe storms rest of the area, except NE mountains through tonight. * Slight risk for excessive rainfall over the southern two thirds of the area through tonight. Widespread river valley dense fog will gradually dissipate early this morning. Frontal boundary, oriented west to east across our north, lifts north as a warm front this morning, leaving the area under a warm sector of an approaching cold front. Winds increase from the southwest, bringing strong moisture advection with boundary layer theta-e values exceeding 340K by this afternoon. A mid level shortwave crosses the area this afternoon, providing upper forcing to enhance convection. Local bufkit soundings show a tall/skinny CAPE signature with dry air at the mid levels by this afternoon. Guidance suggests deep layered shear will limited over most parts of the area, except far west across NE KY where values of 50 to 60 knots are anticipated. These ingredients will allow for strong to severe updrafts /downdrafts, the strongest; farther west where the best dynamics will be present. With PWATs increasing from 1.3 to 1.7 inches by this evening, very heavy downpours are likely, some capable to produce flash flooding. Hi-res CAMs suggest a strong line of convection arriving to the Tri-state area (OH/KY/WV) around 3 PM spreading east as some elements weaken. A second batch of convection is forecasted right behind it, but it seems to weaken as well as the reach NE KY and portions of the Mid Ohio valley. However, strong to severe storms may be able to survive and spread east further into WV with the passing of another upper level shortwave around midnight as convective parameters become more active, with deep layered shear increasing to 55 knots, PWATs around 1.7 inches and CAPE about 1200 J/Kg. SPC maintains an enhanced risk for severe thunderstorms over NE KY, a slight risk roughly across the rest of the area, except for the northern mountains through tonight. Therefore, expecting scattered to possibly numerous severe storms around the Tri- State area this afternoon and evening, with damaging gusty wind, large hail, and the possibility of tornadoes being the main threats. WPC has a slight risk for excessive rainfall across the southern two thirds of the area, and a marginal risk across the northern third. This translates to the possibility of very heavy rain and associated flash flooding. Despite clouds and convection expected, highs will manage to reach the mid to upper 80s across the lowlands, ranging into the lower 70s across the higher elevations of our northeast mountains. Lows tonight will generally be in the 60s.
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&& .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 1137 AM Sunday... Showers and a few isolated thunderstorms will remain possible Tuesday and Wednesday with shortwave energy flowing around the base of a 500-mb trough. Areas with the best chance at seeing showers will be in northern parts of the area and in the mountains. Severe weather is not anticipated at this time. For both Tuesday and Wednesday, temperatures will be a bit lower than recent days with highs only in the 70s in the lowlands and the upper 60s to 70s in the mountains. Wednesday night might even feel chilly to some with temperatures dropping into the 40s and lower 50s for lows. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As of 1137 AM Sunday... The long term forecast period looks largely dry with high pressure building into the region from the west. Temperatures will remain comfortably cool Thursday and Friday with highs in the 70s for most. The summer-like warmth will return next weekend as high pressure slides east and southerly flow returns. There is a slight chance of showers or thunderstorms Saturday with 500-mb shortwave energy approaching from the west, but confidence is low at this time. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/...
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As of 1234 PM Sunday... Approaching line of showers and thunderstorms will reach our western terminals around or just shortly after the 18Z TAF issuance, then follow a northeasterly trajectory through the forecast area. This trend continues into tonight, with all airfields having a high potential to see a strong to possibly severe thunderstorm pass overhead or near the site. Any storm that does become severe could yield damaging wind gusts, large hail, and a quick spin up tornado. A secondary line of convection scrapes the area late tonight into the overnight hours. Additional lightning is possible overnight, with focus gradually becoming more on the heavy downpours associated with this renewed precipitation. Ceilings will also lower in the process for the Ohio River Valley and up the mountains for Monday morning. While gradually improving on Monday along the higher terrain, MVFR cigs will fester over southeast Ohio as a frontal boundary is tucked in close quarters to our airspace. That front is progged to pass through the region late Monday evening into Tuesday morning. Additional convection is possible during the second half of the day Monday. Winds begin out of the southwest today, but could grow breezy to gusty in response to convection. Low level jet snakes through the area late tonight, and could promote a few instances of LLWS around HTS or CRW. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY... FORECAST CONFIDENCE: High. ALTERNATE SCENARIOS: Timing of thunderstorms and weather 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 19 20 21 22 23 00 01 02 03 04 05 06 EDT 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02 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 M H 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 M H H H H H H AFTER 18Z MONDAY... IFR possible at times in showers and storms through the first half of the week.
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