Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 050534 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 134 AM EDT Wed Aug 5 2020 .SYNOPSIS... A weak cold front will cross the central Appalachians from the northwest tonight, then stall and dissipate Wednesday. The remainder of the week will feature building high pressure aloft which will result in typical summertime weather favoring near seasonal temperatures and scattered afternoon and evening thunderstorms. && .NEAR TERM /THROUGH TODAY/... As of 120 AM EDT Wednesday... A few showers remain across southside Va/NC piedmont along theta-e ridge and low level convergence, though appears weakening trend will persist to a point that we should be dry after 4am. Fog will be around into the morning especially the mountains of WV/far SW VA. Some mid level clouds will increase into these areas to keep fog becoming widespread and dense. Previous discussion from Tuesday evening... Showers tracking to the east across the area are beginning to fade as the sun sets. By midnight, the area should also see clouds thinning which could lead to fog forming by sunrise tomorrow. The best bet for fog would be in mountain valleys, but could also see good coverage in the piedmont where ground remain wet from Isaias. As of 300 PM EDT Tuesday... Scattered showers and a few thunderstorms are expected this evening associated with a cold front that is crossing the mountains from the northwest. This front is expected to stall and then dissipate over the area Wednesday with renewed shower/storm activity during the afternoon as instability nourishes new convective cells. Convective allowing models indicate a modest plume of CAPE to reside over the mountains Wednesday afternoon, MLCAPE of 2000 j/kg with primary convergence over the mountains during the early/mid afternoon then translating downstream into the piedmont Wednesday evening. Depending on how the storms cluster as they come off the mountains may have to deal with a few strong to isolated severe cells during the peak heating of the late afternoon and evening. Temperatures tonight and Wednesday reflect the seasonal norm with lows dipping into the upper 50s to lower 60s west, to the mid/upper 60s east...and highs 70s west to the mid/upper 80s east. && .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/... As of 300 PM EDT Tuesday... A dome of high pressure will sit over the Ohio Valley for most of this period, and slowly spread so there is broad surface high pressure over much of the eastern CONUS by the weekend. A weak front in our area will drift slowly east through the end of the week, providing some forcing in addition to orography to spark scattered storms each afternoon. When an upper trough passes by on Friday it will help usher the front off the coast and make room for the aforementioned high pressure. Highs will be in the 80s each afternoon east of the Blue Ridge, high 70s west. Nights will be nice and cool thanks to the high pressure helping suppress cloud coverage and allowing radiative cooling after sunset. && .LONG TERM /SATURDAY THROUGH TUESDAY/... As of 300 PM EDT Tuesday... The large scale pattern over the CONUS won`t be pushing the envelope this period, as we sit in a pretty standard summer setup through at least Tuesday. A Bermuda high will be in place over the southern Atlantic, spreading weak high pressure over most of the East Coast. This humdrum pattern also means there are no significant atmospheric features around which storms could fire up consistently. Thus, this period will be characterized by hot summer afternoons pockmarked by scattered to isolated diurnal thunderstorms. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... As of 125 AM EDT Wednesday... Expect mainly VFR this morning with exception of the mountains where fog and stratus appears to be setting up. Although some mid deck may bring variability in this, where vsbys drop to a mile or less, but then rise back up to 4-6sm, so overall leaning toward pessimistic per latest sat trends with lower vsbys. Any fog and stratus lifts toward 12-14z, with scattered/broken cumulus forming late in the morning into the afternoon with storms expected along a frontal boundary. Some of the storms will bring heavy downpours but overall coverage will be scattered. For now have VCTS at all sites except LWB where drier air will move in behind the front to limit coverage, though confidence is average on this. Storms could linger east of the mountains through the end of the taf period but overall will leave out VCTS past 00z. Extended Aviation Discussion... Typical summertime weather pattern expected through the weekend with scattered afternoon and evening thunderstorms and patchy late night fog. Any flight restrictions are expected to be temporary. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...PM NEAR TERM...PM/RCS/WP SHORT TERM...VFJ LONG TERM...VFJ AVIATION...RCS/WP

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