Area Forecast Discussion
Issued by NWS Blacksburg, VA

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525 FXUS61 KRNK 241931 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 331 PM EDT Sun Jul 24 2016 .SYNOPSIS... Strong high pressure aloft will continue to bring increasing heat and humidity through Monday. A series of weak surface cold fronts approaching from the northwest should gradually bring an increasing threat for showers and storms by the middle of next week. && .NEAR TERM /THROUGH MONDAY/... As of 211 PM EDT Sunday... A piece of the main upper level ridge over the southwestern US has broken off and is centered over the southern Appalachains today. This upper level ridge over the region is expected to sink south over the next couple of days. Heights over the area will be at its highest through Monday, therefore the warmest days for the week looks to be today and tomorrow. Temperatures across the mountains will peak into the upper 80s to lower 90s with ridges being a tad cooler. East of the Blue Ridge and into the piedmont, temperatures will warm into the mid to upper 90s. Dew points across the south-central piedmont of Virginia will likely remain in the 70s, producing heat indices values near 105F. A heat advisory has been issued for this area for Monday. Otherwise expecting mainly sunny skies with convection quite limited given little support aloft and warm mid level temps. Still appears some weak low level convergence across the western ridges could combine with heating/instability to pop isolated to scattered slow moving storms across the mountain by mid afternoon. Guidance suggesting any evening storms to fade by midnight if not sooner with the ridge hanging on while more organized convection stays to the north/west. This should again allow for mainly clear skies outside of debris clouds overnight, with patchy fog valleys and muggy lows, mid/upper 60s west to 70-75 east. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 310 PM EDT Sunday... Slight drop in 500 mb heights is forecast by the models on Wednesday. No significant change in air mass this time frame either. 850MB temperatures do not go any lower than +18 through Wednesday night. There will be some increased low level convergence along the tail of a weak front that crosses from the northwest into the forecast area on Tuesday. While the front may stall to the north there will still be some troffing on the lee side of the Appalachians on Tuesday and across North Carolina on Wednesday. Enough daytime mixing on Tuesday and Wednesday to lower surface dew points in the afternoon. This will keep heat index values in the piedmont just below heat advisory criteria. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As of 315 PM EDT Sunday... Amount of troffing in the eastern United States for the end of the week is questionable. GFS was the more amplified while the ECMWF was slightly flatter. Friday looks to be the next day with any potential for decent upper support. Will have the higher probability of precipitation on Friday and Saturday afternoon and evening. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... As of 128 PM EDT Sunday... LWB observation have returned as of 17Z Sunday. Outside of a very isolated diurnal thunderstorm, overall VFR conditions expected to continue for most of the period with high pressure aloft in place. Will again see some patchy fog in the valleys early Monday morning under thin high clouds. Extended aviation discussion... Strong high pressure aloft looks to remain in place on Monday with continued VFR outside of developing convection Monday afternoon/evening. However coverage of storms on Monday again looks rather isolated until late and mainly confined to mostly the western mountains at this point. Ridge will finally weaken through mid week as an initial cold front sinks toward the area from the northwest. This should bring about an increase in daily convective coverage Tuesday into Thursday with periodic MVFR/IFR possible. Late night and early morning fog will likely occur at the usual valley locations, and those chances increase across the entire region if any rain occurs during the afternoon or evening at any site. && .CLIMATE... Record high temperatures for today (7/24) Roanoke.....100 in 1933 Lynchburg...100 in 2010 Danville....101 in 2010 Blacksburg...92 in 1991 Bluefield....91 in 1987 Record high temperatures for Monday (7/25) Roanoke.....100 in 1934 Lynchburg...102 in 1934 Danville....102 in 2010 Blacksburg...92 in 1987 Bluefield....90 in 1987 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...Heat Advisory from noon to 8 PM EDT Monday for VAZ046-047-058- 059. NC...None. WV...None. && $$ SYNOPSIS...RCS NEAR TERM...RCS SHORT TERM...AMS LONG TERM...AMS AVIATION...RCS CLIMATE...JH

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