Area Forecast Discussion
Issued by NWS Blacksburg, VA
Issued by NWS Blacksburg, VA
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348 FXUS61 KRNK 051745 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 145 PM EDT Fri Jul 5 2024 .SYNOPSIS... High pressure offshore will continue to keep muggy conditions around through tonight, with heat indices exceeding 100 degrees in the Piedmont. A front is going to reach Ohio/TN Valleys this afternoon and several impulse will lead to scattered to numerous thunderstorms. This front will pass across the Mid-Atlantic by Saturday night into early Sunday. Spotty showers and thunderstorms will remain in the forecast for early next week as an upper level trough develops over the central United States. && .NEAR TERM /THROUGH SATURDAY/... As of 125 PM EDT Friday... Key Messages: 1) Heat Advisory remains in effect this afternoon/evening for our foothill and piedmont including Roanoke/Lexington, VA. 2) Strong to severe storms possible this afternoon and evening with the main threat being damaging winds. Greater chances in the mountains. Expect an unstable/humid airmass this afternoon. With plenty of sunshine this morning, SBCAPEs are forecast to reach 2000-3000 J/kg by mid afternoon across southern VA into NC. There is a convective system moving across central KY into Mid TN this morning with an associated MCV. This piece of energy should reach our mountains by mid afternoon and push into the piedmont by later in the afternoon. Enough instability and high pwats to bring a damaging wind threat for any storms that form or move in this afternoon. Majority of convective allowing models have storms arriving in our mountains between noon-2pm, then better chances will be in the 3pm-9pm time frame. Better coverage still looks across our mountains of SW VA/southern WV into NC, with less in the piedmont. High-res models are favoring storms remaining scattered into late evening over the mountains. The heat advisory remains with values already hitting 105 or higher in Brookneal VA and getting close elsewhere east of the Blue Ridge. Front expected to push into the Piedmont by late tonight and end any showers though could see lingering showers in the mountains into Sat morning. At the same time, winds weaken allow for fog formation, some of it becoming dense, but given potential cloud cover and if/where it rains will be patchy dense. Trends in the models showing a further east/south push to the deeper moisture but still enough low level moisture and upper shortwave energy to produce scattered showers/storms Saturday afternoon southeast of I-81. After today`s heat/humidity, some reprieve at least across the mountains/foothills for Saturday as dewpoints drop into the 60s. Muggy tonight with lows in the upper 60s to mid 70s, then another very warm to hot day Saturday but again dewpoints to take some bite out of the heat, with 80s in the mountains, to lower to mid 90s east. Heat indices could be around 100 or so southeast of a Buckingham to Danville to Greensboro line. Confidence in the near term is moderate on storm coverage through Saturday and severe threat, but higher on temps/sky/winds. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... As of 1215 PM EDT Friday... Key Messages: 1. A cold front will bring slightly drier air, limiting showers and thunderstorms to areas mainly south of Highway 460. 2. Slightly cooler temperatures expected for this weekend, though these will still be near to slightly above normal. Looking to Saturday night, weather forecast models are in decent agreement that a cold front will make slow progress eastward across central Virginia, where it will gradually stall as it loses its push of cooler drier air from the northwest. Difficult at this point to determine where the front will eventually stall. Regardless, it is expected to remain both close enough and shallow enough to support lingering showers and thunderstorms through Sunday night, mainly for areas to the south of Highway 460. Because of light steering winds, whatever activity that does develop has the potential to produce a few heavy/prolonged downpours that may result in localized flooding issues. Enough dry air will be present north of Highway 460 to limit any coverage of rainfall to isolated pockets at best. By Monday however, the front will begin to lose its characteristics and fade/wash out as low pressure passes across the Great Lakes, dragging another cold front across the lower Ohio River Valley. Southerly wind flow will increase in response to the area of low pressure, carrying deeper moisture from the Gulf of Mexico northward. This will allow for coverage of spotty showers and storms to expand further northward to include southeast West Virginia through the southern Shenandoah Valley. Temperatures will remain near to slightly above normal through the period. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 1230 PM EDT Friday... Key Messages: 1. Warmer than normal temperatures with daily storms next week. Spotty showers and thunderstorms will develop each afternoon through the middle of the next workweek as a cold front approaches from the west on Tuesday and eventually stalls somewhere across the Mid- Atlantic. Coverage of showers and thunderstorms looks highest for Tuesday as an upper level disturbance passes across the central Appalachians. Precipitable water values will remain abnormally high through the period, ranging from 1.7 inches to as high as 2.2 inches for much of the area, which would support the potential for heavy downpours, especially from the slower-moving cells. Warmer than normal temperatures are expected Tuesday and Wednesday. Near normal temperatures are possible for Thursday. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... As of 130 PM EDT Friday... Mainly VFR through this afternoon, except when any storms move over a TAF site. Best chance of TSRA 18z-00z especially from LWB-ROA-DAN and southwest of this line. Tonight, SHRA/TSRA will continue to affect mainly BLF and LWB as a front nears. Expect another night where fog develops where it rained, with higher confidence of sub-VFR, possibly LIFR at LWB/BCB/BLF, but even with moisture rich environment have fog at ROA/LYH/DAN as well. Fog lifts after 12z Saturday with VFR expected. Any shower/storms will be in the afternoon and generally southeast of a line from FVX-MTV. Average confidence in the above forecast. AVIATION OUTLOOK... Some lingering showers and sub-VFR possible Saturday evening in the DAN area. Fog possible through the period in the early mornings. The pattern stays unsettled such that daily chances for storms exists. Thinking mainly VFR but sub-VFR when it storms and any late night fog. Confidence is moderate for the extended aviation outlook. && .CLIMATE... As of 300 AM EDT Friday... Record highs and warmest lows temperatures for July 5th. Friday 07/05/2024 Site MaxT Year HiMin Year KBLF 93 1948 71 1969 KDAN 103 1919 76 1926 KLYH 98 2012 75 1900 KROA 100 1999 76 2012 KRNK 94 1930 78 1949 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...Heat Advisory until 8 PM EDT this evening for VAZ022>024- 032>035-043>047-058-059. NC...Heat Advisory until 8 PM EDT this evening for NCZ003>006-020. WV...None. && $$ SYNOPSIS...SH/WP NEAR TERM...WP SHORT TERM...NF LONG TERM...NF AVIATION...SH/WP CLIMATE...RCS/SH