Area Forecast Discussion
Issued by NWS Charleston, WV
Issued by NWS Charleston, WV
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738 FXUS61 KRLX 101044 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 644 AM EDT Mon Aug 10 2026 .WHAT HAS CHANGED... Forecast thinking has sharpened around a multi-day northwesterly-flow train of convective complexes. The primary upgrade is coordination with WPC on a Day 2 Moderate Risk of excessive rainfall across much of southeast Ohio and central West Virginia. As of 640 AM Monday... Updated 12Z aviation discussion. && .KEY MESSAGES... 1.) Substantial flash flooding is possible early Tuesday through Thursday night across southeast Ohio, central West Virginia, northeast Kentucky, and the southern coalfields as repetitive convective complexes move through the region. 2.) Multiple rounds of severe thunderstorms capable of producing primarily damaging wind gusts are possible this evening through Wednesday/Thursday evening. 3.) A brief transition to drier and calmer weather is expected by Friday night into the start of the weekend as upper-level ridging shifts east and moves the storm track out of the area. && .DISCUSSION... KEY MESSAGE 1... The primary meteorological concern through mid to late week is a train of mesoscale convective systems (MCSs) tracking southeastward in northwesterly flow aloft around the northeastern periphery of an amplifying ridge over the middle of the country. While the individual MCSs are expected to maintain a fairly progressive forward propagation, repetitive rounds of convection over the same corridors present a high-impact flash flooding and river flooding threat. Precipitable water values across the region will hover between 1.6 and 2.0 inches, representing the 90th to 95th percentile for mid-August climatology. Confluent low-level westerly flow intersecting an east-west oriented instability axis will support hourly rainfall rates exceeding 2 to 4 inches per hour within deeper convective cores. While the current lush state of summer vegetation and intervening intervals allow soils to handle moderate water loads initially, localized extreme rainfall rates can quickly exceed soil infiltration capacity. Any mesoscale backbuilding to the northwest or west, or any convective line orienting east-to-west parallel to steering flow, will produce prolonged dwell times of extreme rainfall rates, leading to localized life-threatening flash flooding regardless of antecedent soil conditions and with pre-moistening soils these threats will emerge event quicker. The threat is heightened during overnight hours when flash flooding is hardest to detect and react to. In coordination with WPC, a Day 2 Moderate Risk for Excessive Rainfall has been placed over much of southeast Ohio and central West Virginia for Tuesday. Given low confidence in the exact spatiotemporal track of individual convective complexes due to upstream cold pool evolution and environmental modification, Flash Flood Watch issuance is deferred for now. However, a Flash Flood Watch encompassing most or all of the forecast area will almost certainly become necessary for the Tuesday through Thursday period. It is important to note that this scenario is not guaranteed to be widespread or even occur at all, but this setup does leave the potential open to locally extreme flash flooding impacts. Multi-day cumulative precipitation totals of 3 to 6 inches across larger river basins will drive significant rises, which could lead to river flooding, especially downstream of any localized extreme rainfall totals. The key takeaway is: Residents in hollows, floodplains, and low- lying terrain should have multiple ways to receive warnings and have a plan of action to move to higher ground this week if conditions warrant. KEY MESSAGE 2... A lesser but still substantial hazard involves severe weather associated with the daily convective complexes through Wednesday evening. The primary severe hazard will be damaging straight- line wind gusts driven by consolidated MCS cold pools, though bowing line segments and mesoscale boundary interactions will also support an embedded tornado risk. The conditional threat for more semi-discrete or discrete supercellular convection capable of all severe modes will be highest during peak heating late this afternoon (although this may remain north of us and already be congealed by the time it arrives) and again Wednesday afternoon and evening. Forecast soundings across the region display strong thermodynamic support, with MLCAPE reaching 2000 to 3000J/kg and DCAPE values between 800 and 1200J/kg. Deep-layer 0-6km bulk shear of 35 to 45KTs and 0-3km SRH near 100 to 200m2/s2 support organized convective modes given discrete convection. In Appalachia and steep terrain, full tree canopy foliage combined with rapidly saturating topsoil lowers severe wind damage thresholds significantly. Sub-severe wind gusts of 40 to 50 mph, especially when sustained over several minutes typical within cold pool driven gusts corridors, can easily uproot trees and knock down power lines. SPC maintains a Slight Risk for severe storms daily through Wednesday. An upgrade to risk levels may be warranted, especially on Tuesday/Wednesday as confidence increases. For today, an ongoing MCS over Illinois and Indiana will weaken as it approaches western counties late this morning. Resulting morning cloud cover and stabilization across northern counties may limit convective coverage there this afternoon (displacing convective initiation farther north). This developing complex could drop south overnight bringing forth the first round of severe storms. KEY MESSAGE 3... A temporary break in this persistent fire hose of MCS pattern is possible by Friday night and the start of the weekend. Upper- level ridging over the south-central states is forecast to shift slightly eastward, pushing the primary shortwave track and moisture plume east of the central Appalachians. This transition will yield a trend toward drier and calmer conditions for Friday night through Saturday. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... Remnant cloudiness associated with former convective activity will overspread the region from the northwest this morning. Could see some revitalization of this activity this afternoon and have included VCTS at the western terminals. Additional storms may fire late this afternoon into evening across the north and progress south overnight. IFR conditions are possible in any convection. Outside of convection, prevailing VFR conditions will dominate with southwest winds around 5 to 10KTs FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Afternoon convection could see less coverage than advertised, overnight activity could be more substantial than advertised. 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 10 11 12 13 14 15 16 17 18 19 20 21 EDT 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 CRW CONSISTENCY M M L 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 M H H H H H H H H H EKN CONSISTENCY M L L H H H H H H H H H PKB CONSISTENCY M L H H H M H H H H H H CKB CONSISTENCY L L H H H H H H H H H H AFTER 12Z TUESDAY... Tuesday through Friday, additional convective complexes favor daily chances of showers and thunderstorms with MVFR or IFR in heavy rain. Morning valley fog or low stratus may return after wetting rains, especially at EKN and other sheltered sites. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ DISCUSSION...JP AVIATION...JP