Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 260635 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 235 AM EDT Wed Jun 26 2019 .SYNOPSIS... High pressure will cover our area through the reminder of the workweek bringing mostly dry weather. The next chance for showers and thunderstorms will be associated with a cold front that arrives later in the weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 230 AM EDT Wednesday... Other than some river valley fog early this morning, tranquil weather conditions are forecast through the near term period with building heights aloft and high pressure at the surface. This has lead to some usually dry conditions, with the 0.68 PWAT value from the 00Z/26 RNK sounding near the 10% minimum moving average. Very few changes were made to the forecast for today, other than to increase cloud cover across the area, especially across the southern portion of our region from a veil of cirrus to our south and west. These clouds may keep highs from reaching their full potential in the south today, but with 1000-850mb thickness surging upward, highs should be a few degrees warmer today compared to Tuesday, especially in the mountains. Confidence is low on how this canopy of high cloudiness will impact lows tonight, with most models pushing the high clouds into our NC. As a result, kept lows tonight on the warm side of guidance in and near this region, such as DAN, but went below guidance for many of the mountain sites closer to the sfc ridge axis. Areas of valley fog will again be possible late tonight. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... As of 230 AM EDT Wednesday... A broad upper level ridge will span the United States east of the Rocky Mountains for Thursday and Friday. While the ridge aloft and surface high pressure should keep the atmosphere mostly capped, the mesoscale models indicate that a couple showers and thunderstorms may fire along the southern Blue Ridge on Thursday. The chances of convection increase slightly by Friday as the heat and humidity gradually increase, and the areal coverage could expand to all locations along and west of the Blue Ridge. Meanwhile, it may remain dry east of the foothills during these two days. By Saturday, an upper level trough and an associated backdoor cold front will dip southward over the Northeast. As it approaches, this extra dynamical support combined with the heat and humidity could allow the cap to more notably weaken. While some model differences still exist on how much that could increase the extent and intensity of any developing convection, confidence is modest enough to paint slight chance to chance PoPs across the region. Following the same pattern that is depicted in prior days, the best chance for thunderstorms should be along and west of the Blue Ridge. Overall, high temperatures will run around five degrees above normal for this time of year. Lower 80s to lower 90s should persist throughout this period. Low temperatures should hover near normal during Thursday night and Friday night with upper 50s to upper 60s expected. However, these lows will gradually increase toward above normal territory as dewpoints increase into the weekend. Most locations will likely not drop below 60 degrees by Saturday night. && .LONG TERM /SUNDAY THROUGH TUESDAY/... As of 345 PM EDT Tuesday... Expect upper level ridging across the central United States toward the end of the week, resulting in northwest windflow aloft across the mid-Atlantic. Given strong heating on Sunday, will have to keep an eye on any disturbances approaching from the Great Lakes region, which could trigger a line of strong thunderstorms. Confidence on timing, track and even development of these storms is low that far into the future. Chances for thunderstorm activity do increase Sunday night however as a cold front is expected to approach from the north, with the front possibly entering and stalling across our area on Monday. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... As of 135 AM EDT Wednesday... At 130 AM EDT, VFR conditions were reported at all TAF sites and this should continue through the entire TAF period with the exception of KLWB where IFR fog and ceilings are forecast to develop after 08Z (4 AM EDT). These restrictions should rapidly improve after sunrise. The combination of a weak surface ridge and zonal flow aloft will allow for VFR continues to persist today and into this evening, with scattered cumulus clouds in the mountains and a canopy of high cirrus clouds overspreading the area later today. Winds under 15 knots are expected. .Extended Aviation Discussion... High pressure is expected to take up residency over the region into Friday. For the most part, VFR conditions are expected outside of late night/early morning fog. Also, as we approach the weekend showers and storms will be on the increase, and these too may bring some temporary reductions to visibility and ceilings. Late Friday into Saturday, the chances of sub-VFR conditions increase espcly across the mountains with heating of low level moisture aided by orographics. The arrival of a backdoor cold front late in the weekend should allow for an increase in coverage of showers and storms by Sunday afternoon. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...PH NEAR TERM...PH SHORT TERM...PW LONG TERM...NF AVIATION...PH is the U.S. government's official web portal to all federal, state and local government web resources and services.