![National Oceanic and Atmospheric Administration](/build/images/header/noaa.d87e0251.png)
![National Weather Service](/build/images/header/nws.4e6585d8.png)
![United States Department of Commerce](/build/images/header/doc.b38ba91a.png)
Area Forecast Discussion
Issued by NWS Blacksburg, VA
Issued by NWS Blacksburg, VA
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
412 FXUS61 KRNK 170030 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 830 PM EDT Fri Aug 16 2024 .SYNOPSIS... Unsettled weather expected through the weekend with clouds and an opportunity for showers and thunderstorms. Drier and cooler weather will follow after Monday. && .NEAR TERM /THROUGH SATURDAY/... As of 810 PM EDT Friday... Key Messages: 1) Showers and thunderstorms continue through midnight 2) Added fog for overnight 3) Low confidence with respect to showers/storms coverage Saturday Western band of showers and thunderstorms on National Weather Service radars will continue to track east for the rest of the evening. Convective allowing models had the storms weakening and the remnants east of the piedmont by midnight. Have adjusted the probability of precipitation for these trends. Also added fog across southern Virginia, in northern North Carolina and in the valleys west of the Blue Ridge. Dew points were still in the mid 60s to lower 70s, so enough low level moisture to support fog overnight, especially where it rained Friday afternoon and evening. Previous Discussion As of 300 PM EDT Friday... On the weather map, we have high pressure centered along the Mid-Atlantic Coast. A warm front stretches from the Ohio Valley into the central Mid-Atlantic with a cold front from the western Great Lakes to the southern Plains. Warm frontal showers and storms are advancing across the OH/TN Valleys and will become more numerous across our CWA this evening, favoring areas west of the Blue Ridge for the greatest QPF. The forecast remains a blend of models as they all seem to be in good agreement in bringing showers/few storms across the mountains this evening as the warm front advances to the northeast. The upper flow is diffluent, so activity may persist through the night. Warm sector airmass is moist with dewpoints in the upper 60s to lower 70s so expecting a muggy night as dewpoints to remain elevated. PWATs are forecast near 1.80 tonight so showers/storms will be rain efficient and may contain torrential downpours. Can`t rule out some localized flooding but antecedent conditions overall are dry enough to forgo any headlines. As for severe storms, majority of models are keeping higher instability along/west of the Appalachians, so although a strong storm or two may occur, think severe threat is low...at least for tonight. By Saturday, the warm front will have moved northeast of the area with a cold front advancing across the Ohio Valley. The entire CWA should be in the warm sector, so expecting a seasonally hot humid day with temperatures near the seasonal norm for mid-August. Convective allowing models suggest afternoon deep convection will develop lee of the mountains across the piedmont, and along the cold front advancing across the Ohio Valley. Much of our CWA may initially fall between these two convergent zones, so we may squeak out a mostly rain free day before activity gets going later in the afternoon. Attm think the piedmont, along and east of highway 29 will be an area to watch for storms...the activity developing early to mid afternoon and moving east. Storms which develop in advance of the approaching cold front will move into our far western areas later in the afternoon and during the evening. In general, expecting a marginal risk for severe weather, wind being the primary threat. Secondary threat is excessive rainfall, but wind fields are increasing ahead of the cold front so storm motion should limit residence time. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... As of 200 PM EDT Friday... Key Messages: 1: Showers and storms through the weekend 2: Temps mostly around normal Latest model runs have slowed down an approaching front coming out of the Great Lakes, through the OH Valley. Frontal passage through our region will likely be later Saturday evening and into the overnight period. Accordingly, the period with heaviest and most coverage for showers has shifted into the Saturday night time frame. There is a marginal risk of severe thunderstorms for Saturday, so despite the front potentially missing peak heating on Saturday afternoon, the front is fairly dynamic and progressive as far as summertime fronts go. As usual with these events, mountains will be most likely to see storm formation, and in the post frontal environment on Sunday, downsloping will provide some suppression for storms into the Piedmont and Southside. A remaining trough will continue to encourage precipitation on Sunday, despite a drier post frontal environment. Monday will see stronger winds, leading to some upslope shower formation. Temperatures will remain stagnant and around normal due to the showers and cloud cover holding things steady. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 230 PM EDT Friday... Key Messages: 1: Waning precip chances next week By Tuesday, surface high pressure will take over the synoptic pattern. It will be centered near the lower peninsula of Michigan, and as the week moves on, it will drift east, continuing to shield us and block any precip formation. The next opportunity for rain could be as late as next weekend, as some guidance indicates an upper wave over the southeast CONUS. That is a low confidence opportunity, however, and we could go longer without rain. Temperatures will be below normal with highs held in the mid to upper 70s most of the week. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... As of 820 PM EDT Friday... Western band of showers and thunderstorms on National Weather Service radars will continue to track east for the rest of the evening. Convective allowing models had the storms weakening and the remnants east of the piedmont by midnight. MVFR ceilings and visibility with these showers and storms may impact KDAN, KBCB, and KBLF before 04Z/midnight. Ceilings will lower into the IFR to MVFR range overnight and patchy MVFR fog will develop. Ridges will be in the clouds. KLWB and KBCB may lower to LIFR in dense fog, but that will depend on the amount of cloud cover. VFR conditions return to all local TAF sites around 14Z/10AM Saturday. The coverage of showers and thunderstorms will be scattered on Saturday afternoon. Above average confidence on wind. Average confidence on ceiling and visibility. .EXTENDED AVIATION OUTLOOK... High probability of precipitation arrives late Saturday. Showers and thunderstorms with MVFR conditions will continue into Monday morning with the passage of a cold front. MVFR clouds and upslope showers are expected to remain over the mountains through Monday. Ceilings should be VFR east of the Blue Ridge. Confidence is higher for dry and VFR conditions Tuesday and Wednesday as high pressure builds in. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...PM NEAR TERM...AMS/PM SHORT TERM...VFJ LONG TERM...VFJ AVIATION...AMS/EB