Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 220139 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 939 PM EDT Wed Aug 21 2019 .SYNOPSIS... Weak high pressure will remain over the region tonight resulting in a continuation of the muggy weather. A cold front approaches by the end of the week bringing increasing chances of showers and thunderstorms Thursday and Friday. This front should finally work southeast through the area Saturday with less humid weather possible Sunday. && .NEAR TERM /THROUGH THURSDAY/... As of 930 PM EDT Wednesday... A few isolated showers linger across southside, otherwise rain threat has pretty much ended. Evening RNK sounding indicates dry air above 600 mb. This in addition to loss of daytime heating should limit any additional shower activity. The only area to watch for renewed activity will be along the windward slopes...west side of the Appalachians, where weak westerly winds overnight may provide enough convergence to initiate some isolated showers late tonight. Temperatures have been slow to fall where it did not rain Tuesday, but overall expecting lows in the 60s to around 70. A cold front will approach from the north Thursday. Scattered showers and thunderstorms will develop especially during the afternoon and evening hours. Better forcing remains to our north and west, though we should still have enough convergence and instability along the Blue Ridge and Alleghany Mountains for storms to start in the high terrain and then travel east into the Piedmont. There remains the potential for scattered pulse severe storms with the strong instability. The SPC Day 2 highlights the chance for severe thunderstorms with a marginal risk on Thursday. High temperatures on Thursday will vary from the upper 70s in the mountains to the lower 90s in the piedmont. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... As of 307 PM EDT Wednesday... A cold front is expected to stall across the southern Ohio River Valley Thursday night. A surface reflection will then track along this boundary, moving to central/northern Virginia on Friday. With the front close to the area, scattered mountains (isolated east of the Blue Ridge) showers are possible Thursday night into Friday morning. Friday afternoon, this surface reflection will move east of the area and with strong heating (highs in the upper 80s), there is a marginal risk for severe storms Friday afternoon and evening east of the Blue Ridge. Morning clouds and rain should keep the heating/instabilities low across the mountains. The primary threat will be gusty winds. Torrential downpours are also possible but the threat will mostly be localized/isolated. As convection exits the area Friday evening, the cold front will slide south into the Carolinas into the day Saturday. As the front was slow to enter the region, it will also be slow to exit. Light rain and thick clouds may linger along and south of the VA/NC border through the day Saturday. Drier air will work into the region from the north Saturday night. High temperatures Saturday will range in the 70s. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 300 PM EDT Wednesday... If the front sinks south into the Carolinas Saturday, cool northeast winds will keep the area dry into Monday (ECM). The latest GFS has an upper level trough moving northeastward across the Ohio Valley with overrunning warm moist air moving over a wedge of cooler air. We think the GFS is overdone on measurable precipitation, but think it has the right idea with increasing cloud cover. The wedge is expected to hang over the region into Tuesday morning then erode with the passing of a weak front. Temperatures will run 10F or cooler than normal Sunday and Monday. Temperature return to normal Wednesday. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... As of 930 PM EDT Wednesday... Predominantly VFR anticipated through the overnight and during the day Thursday. With light winds and low level moisture, SCT-BKN areas of low cloud and patchy fog may develop late tonight into early Thursday morning, but confidence low as to whether it will be widespread. KLWB has the best chance for IFR/LIFR fog overnight since it is near the river. KBCB may briefly drop to IFR, also due to a light west wind causing drift of fog off the New River and into the airport there. Otherwise not expecting anything less than TEMPO MVFR due to fog/stratus around daybreak Thursday which should dissipate with the morning heating. The hot and humid weather continues Thursday with scattered MVFR showers and thunderstorms...buildups by noon yielding SCT- BKN cumulus field with embedded deeper convection. .Extended Aviation Discussion... Weather pattern will continue to promote scattered showers and thunderstorms. A cold front will approach from the northwest late in the week, resulting in scattered to numerous thunderstorm with potential for organized clusters of thunderstorms to track across the Ohio Valley into the Mid- Atlantic region. Improving conditions with more in the way of VFR will be possible for the late weekend, pending just how far south of the Mid Atlantic area the front progresses. Some MVFR showers are possible in the southwest portion of the forecast area on Monday. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS/KK NEAR TERM...KK/PM SHORT TERM...RCS LONG TERM...RCS AVIATION...PM is the U.S. government's official web portal to all federal, state and local government web resources and services.