661 FXUS61 KRNK 240714 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 314 AM EDT Mon Jun 24 2019 .SYNOPSIS... A warm front will slowly lift north through our area today. A cold front will sweep across our area this evening with high pressure building in behind this system for Tuesday and Wednesday. && .NEAR TERM /Through Monday Night/... As of 315 AM EDT Sunday... A warm front across our region early this morning will lift north today allowing much higher dew points and a more summerlike airmass to overtake the region. Meanwhile in the upper levels of the atmosphere, an impressive upper level trof becomes negatively-titled and pushes through the great lakes by Tuesday morning. This will help drive a cold front through our region Monday evening. In advance of the cold front, the mean 00Z HREF forecast SBCAPES exceed 1500 J/KG this afternoon. With forecast soundings showing no capping in place, expect thunderstorm to fire late this morning/early this afternoon, especially in areas with differiental heating such as the Blue Ridge. With forecast soundings hinting at an inverted-v signal and DCAPE values forecast to exceed 400 J/KG, damaging winds are looking more likely today and added 'gusty wind' wording in grids for thunderstorms. The CAMs are in good agreement bringing a more organized line of thunderstorms into the western portion of our forecast area around or after 00Z (8 PM Monday). This timing is slightly slower than earlier forecasts, so kept chance for storms in the east until around 06Z. With 0-6km bulk shear values 25-35 knots, this line of storms should continue well into our forecast area before gradually fading with loss of heating. Damaging winds and locally heavy rains are also expected with this line. With a nice surge in 850mb temps and winds becoming southwest in the wake of a warm front, leaned toward the warmer guidance for temps today and pushed highs up a degree or two. In the wake of the cold front tonight, gusty west to northwest winds are expected, so wind speeds were adjusted slightly upward tonight with lows staying toward the warmer end of guidance. && .SHORT TERM /Tuesday through Thursday night/... As of 230 AM EDT Monday... The cold front will be passing offshore by Tuesday morning. Model soundings show a 30-40 kt jet at 850 mb with the NAM showing a stronger jet than the GFS. Thus, the winds and wind gusts have been bumped upward due to the expected mixing from the boundary layer into that low-level jet during sunrise and through the remainder of the day. This jet will weaken by the afternoon, and winds should eventually subside toward evening as high pressure builds overhead. Although confidence is high that nothing should reach wind advisory criteria, there may be gusts over 30 kt in the highest elevations. Temperatures will warm up considerably across the Piedmont due to downsloping winds from the west-northwest. With drier air being depicted in the models for Tuesday night into Wednesday morning, dewpoints and low temperatures were nudged a few degrees downward. Wednesday and Thursday should start as pleasant with plentiful sunshine. The upper air pattern during those days will flatten as a broad upper level ridge takes hold from east of the Rocky Mountains all the way to the East Coast. This ridge combined with surface high pressure across the Mid Atlantic should place a good cap overhead that will limit any organized convective development. PoPs were decreased for Wednesday as the cap appears to be the strongest on this day, so it will be difficult for even an isolated shower or thunderstorm to pop up along the northwest North Carolina mountains. Confidence is a little better that some convection may fire on Thursday afternoon as the heat and humidity continue to increase, so chance PoPs were included along the southern Blue Ridge in North Carolina and Virginia. This activity should dissipate by early Thursday night. Elsewhere, it will likely stay dry. && .LONG TERM /Friday through Sunday/... As of 300 PM EDT Sunday... During most of this portion of the forecast, an upper level ridge will be centered over the Central Plains States, with its eastern edge over our region. Closer to the surface, high pressure will start this period over our region, and trend eastward through Saturday. The result will an airmass across our region that will average about five degrees above normal, and become progressively more moist throughout the depth of the column as low level winds trend more southerly. With limited, if any, upper level dynamics to help initiate vertical motion, any precipitation will be confined to diurnal/differential heating based showers and storms, with their focus near the higher peaks and ridges of the mountains, and, or, southern sections of the area where dew points will be higher than those of northern sections. Heading into Sunday, we may see a backdoor cold front head south toward, or into, the area as the upper level low over southeast Canada shift farther south into New England and possibly parts of the mid-Atlantic region. It's impacts are expected to be more noticable on Monday in the form of cooler temperatures, a day past the valid seven-day time period of this afternoon's forecast package. Confidence in the above section of the forecast is moderate. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... As of 140 AM EDT Monday... At 0530Z (130 AM EDT), a warm front bisected our area with south/southwest winds generally west of I-77 ushering in higher dew points and thus lower clouds and vsbys with IFR and LIFR conditions in some spots. For our TAF sites, the most likely areas to experience MVFR to IFR cigs early this morning will be KLWB and KBCB. Any low clouds and fog will erode after 9 AM EDT. As the warm front lifts north of our area today, a surge in moisture will help trigger scattered thunderstorms across the region, but for now left VCTS in all taf sites after 17Z, with later times for KDAN and KLYH. The probability of thunderstorms increases with a cold front that will reach KBLF around 00Z (8 PM EDT), and sweep east exiting our region by 06Z (2 AM EDT/Tuesday). Any storms today will have the potential to bring gusty winds. Continued VCTS for this later period until a more precise time can be pinpointed. .Extended Aviation Discussion... The cold front will cross the Mid Atlantic region by Tuesday morning. High pressure tries to build into the area later Tuesday into Thursday. Other than some late night/early morning patchy fog, VFR conditions are expected for the bulk of this time period. Confidence in the above aviation forecast discussion is moderate. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...PH/PM NEAR TERM...AMS/PH SHORT TERM...PW LONG TERM...DS AVIATION...AMS/PH