FXUS61 KRNK 031104 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 704 AM EDT Sat May 3 2025 .SYNOPSIS... A large, slow moving low pressure system will stall the Ohio Valley today through Monday. This system will push a cold front through the area Sunday and Monday, and will trigger multiple rounds of showers and thunderstorms today through Tuesday. Temperatures will stay above normal for the next several days. && .NEAR TERM /THROUGH TONIGHT/... As of 340 AM EDT Saturday... Key messages: - High confidence of thunderstorms this afternoon through late tonight - Threat of severe thunderstorms this afternoon and flooding tonight Cluster of showers as shown on the National Weather Service radar early this morning will continue to move northeast. Enough clearing is expected later this morning for modest instability to develop. The environment will have enough shear to support thunderstorms that are capable of producing damaging wind and/or large hail. Hi-res guidance was in good agreement with timing of the storms this afternoon and evening. Expecting showers and thunderstorms to develop between 2pm-5pm over the mountains and foothills and evolve into a more organized line of storms in the piedmont before 8PM. Then a second band of showers and thunderstorms will cross from west to east across the region tonight. The FV3 and 3KM NAM depicted this scenario and probability of precipitation was largely based on the timing in these models. Accumulated rainfall from the repeated rounds of thunderstorms will heighten the threat of urban and small stream flooding, as well as localized flash flooding along and east of the Blue Ridge. Precipitable water values above 1.5 inches will be advected into the area lift will be enhanced by jet stream dynamics and upper diffluence. Only minor changes to temperature forecast for today and tonight. && .SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/... As of 230 AM EDT Saturday... Key Messages: 1) Showers and widely scattered thunderstorms expected through Tuesday, with drier conditions possible Tuesday night. 2) Any storms during the period will be capable of hail, gusty winds and localized heavy rain, though the overall threat is low. The Mid-Atlantic into North Carolina will remain under the influence of an upper level low pressure system that will drift across the central Ohio River Valley into the southern Great Lakes region. This will maintain showers and widely scattered thunderstorms in the forecast through most of the period, with coverage trailing off by Tuesday night, assuming that the upper low begins to shift away to the east as model guidance suggests. Given the proximity of the upper low to the Mid-Atlantic, any thunderstorms that develop will be capable of hail, possibly large hail if the storms reach severe intensity, and locally strong wind gusts will also be possible. And, while most of the rainfall will be beneficial to our region given the recent dryness, we continue to see signals in the model guidance of south-to-north bands of rain developing for periods of several hours across the mountains. Confidence is low as to where, or even if, these bands may develop, but this is sometimes an issue with stalled upper level lows, where localized flash flooding occurs due to training showers/storms, so it is worth mentioning. Otherwise, rainfall totals through early Tuesday will range from 0.5" to 1" for the mountains, with 1" to 1.5" possible for the Piedmont. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... As of 245 AM EDT Saturday... Key Message: 1) Wednesday is potentially the driest day, with showers and widely scattered thunderstorms in the forecast for Thursday and Friday. 2) The threat for severe weather during this period appears to be limited at this time. Looking to the second half of the coming workweek, Wednesday may be the driest given the development of weak induced upper ridging east of the Mississippi River Valley between the departing upper low, and another one developing across the central Plains. That stated, weather forecast models are hinting at a disturbance passing across the south-central states that may reach the Tennessee Valley and beyond. High uncertainty remains as to whether this system will impact the Mid-Atlantic on Wednesday, or remain further to the south and/or arrive later in the period. For the Thursday and Friday timeframe, showers and widely scattered thunderstorms seem more likely as a cold front approaches from the north, with drier conditions arriving Friday evening. Overall, the threat for severe weather appears low during the period, with any rainfall proving to be mainly beneficial. && .AVIATION /11Z SATURDAY THROUGH WEDNESDAY/... As of 700 AM EDT Saturday... Conditions were primarily VFR early this morning, with the exception of a few spots of IFR fog in the higher elevations of northwest North Carolina. Winds will be south-southwest at 5 to 10 mph this morning. Wind speeds increase this afternoon with gusts of 20 to 25 kts. Expecting showers and thunderstorms to develop between 18Z/2PM-21Z/5PM over the mountains and foothills and evolve into a more organized line of storms in the piedmont before 00Z/8PM. Clouds will also increase over the mountains and ceilings will lower but remain VFR as the front to the west gets closer to the region. There is the potential for thunderstorms that are capable of producing damaging wind and/or large hail. Any of the stronger storms may have MVFR ceilings, and MVFR visibility due to moderate to heavy rain. A second band of showers and thunderstorms will cross from west to east across the region tonight. There is a higher probability of MVFR to IFR ceilings as this precipitation goes through. Have ceilings lowering to MVFR at local TAF sites between 23Z/7PM and 04Z/midnight. Average confidence in ceiling, visibility, and wind. Average confidence in the timing of thunder storms at local TAF sites before 00Z/8PM. Lower timing confidence after 00Z/8PM. EXTENDED AVIATION OUTLOOK... Additional chances of precipitation are likely into Tuesday, bringing sub- VFR conditions to parts of the area, though forecast confidence decreases by Tuesday. This is low confidence pattern due to the stalled upper low over the Ohio Valley. Most of the area will remain dry, but afternoon showers and thunderstorms are possible each day. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS NEAR TERM...AS SHORT TERM...NF LONG TERM...NF AVIATION...AMS/AS