Area Forecast Discussion
Issued by NWS Blacksburg, VA

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011 FXUS61 KRNK 090119 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 919 PM EDT Tue Jul 8 2025 .SYNOPSIS... Our area will remain in a humid airmass with daily chances for thunderstorms through this weekend. && .NEAR TERM /THROUGH WEDNESDAY/...
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As of 900 PM EDT Tuesday... Key Messages: 1) Scattered storms this evening...waning with time. Outflow from storms which moved south into the forecast area is aligned w-e along highway 460. Even though models indicate weakening activity with time, there is still quite a bit of available CAPE across southside VA where dewpoints are still in the mid 70s. Plan to maintain chance for lingering showers/storms in this area for the overnight, just because the ingredients are there. Outside of any lingering deep convection, clearing plus high low level moisture and calm winds will promote fog. Expect best coverage over the mountains and in the river valley. Will have to monitor for potential dense fog advisory but should overall be the typical morning fog, that warrants travel caution. Wednesday could be more active as models show a stronger wave moving across the central Appalachians into the mid-Atlantic in the afternoon. Excessive rainfall and strong/severe storms possible. Ensembles and models painting more coverage especially along the Blue Ridge and west, then have potential for 2 areas of concentrated storms, one forming along the Blue Ridge and pushing east in the afternoon, and another forming in WV pushing east to the Blue Ridge. With potential for more organized storms Wed afternoon and higher pwats, plus lower flash flood guidance, will hoist a flood watch for Wed afternoon/evening for portions of the VA/NC piedmont, mainly along/east of a line from Lynchburg to Danville to Rockingham County NC. With convective development potential and more clouds Wednesday heat indices may be tempered so no heat advisory for Wednesday at this point, with highs close to 90 east to 80s west.
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&& .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... As of 1200 PM EDT Tuesday... Key Points: 1. Daily chances of showers/storms. 2. Localized heavy rain/flooding possible, especially over eastern and southeastern sections. 3. Slightly above normal temperatures. A look at the 8 Jul 00Z NCEP Ensemble Mean 500mb Geopotential Heights shows for Wednesday night a shortwave trough centered over the Lower Ohio Valley, moving east. A broad area of high pressure will be centered from southern CA into the Four Corners region, and extend eastward into the SE US. A shortwave trough will be over the Pacific Northwest. For Thursday/Thursday night, the shortwave trough to our west will still be approaching the region, but the ensemble averaging depicts a broader feature, extending from central Quebec into the Tennessee Valley. The ridge across the SW US becomes shunted slightly south as the Pacific Northwest shortwave trough makes progress eastward towards the Northern High Plains. For Friday/Friday night, the axis of the shortwave trough approaching our region is expected to cross the region, and by the evening hours be centered from ME to Long Island. The shortwave trough over the NW US moves to over/near the Upper Mississippi River Valley. A general region of a ridge axis remains positioned over the far SW US to the SE US. At the surface, for Wednesday night, a general region of troughiness is expected to be over the Ohio Valley. By Thursday/Thursday night, this feature becomes a bit more defined, with a closed surface low over far southern Quebec, with a cold front trailing into the mid- Mississippi Valley, and a warm front southeast into New England. By Friday/Friday night, the surface low loses is definition thanks to ensemble averaging, leaving a another general region of troughiness across much of the eastern US. A look at the 8 Jul 00Z NAEFS Ensemble Situational Awareness data shows 850mb temperatures around +18C for both Thursday and Friday. The above weather patterns offers the following forecast. With the region remaining within a warm/hot and humid airmass, and the presences of a front/trough near or over the region, daily chances of showers/storms looks promising each day. Additionally, with the potential for repeated rounds of precipitation, all the higher the potential for localized flooding will be. During this time period, the NAEFS offers the eastern and southeastern portion of the forecast area with the highest values of Mean Integrated Water Vapor Transport. This factor may suggest greater weight given to this region for the potential for flooding, especially given recent rains across parts of this area as a result of the remnants of Chantal. Temperatures are expected to average a few degree above normal for this time of year. Confidence in the above weather scenario is moderate to high. && .LONG TERM /SATURDAY THROUGH TUESDAY/... As of 1200 PM EDT Tuesday... Key Points: 1. Daily chances of showers/storms continues. 2. Temperatures around five to eight degrees above normal. A look a the 8 Jul 00Z NCEP Ensemble Mean 500mb Geopotential Heights shows for Saturday/Saturday night that the ridge over the SE US is expected to expand northward to over our region. A shortwave trough is expected to be over the Upper Mississippi River Valley, approaching the western Great Lakes region. For Sunday/Sunday night, little change is expected in the overall synoptic pattern. The shortwave trough is expected to make a bit more headway east into the Great Lakes. For Monday/Monday night, ensemble averaging washes out the particulars of a shortwave trough over the Great Lakes and offers a solution of a broader longer wave trough over much of central Canada extending into most of the northern quarter of CONUS. Ridging is depicted as broadening northward across roughly the remaining three-quarters of CONUS. For Tuesday, little to no change is depicted in the synoptic pattern over CONUS as compared to Monday. At the surface, for Saturday/Saturday night, a general area of weak troughiness will exist across the mid-Atlatnic into the SE US, all the while a more well defined trough exists from the Upper Mississippi Valley into the Great Lake region. For Sunday/Sunday night, not a lot changes are expected as compared to Saturday. Weak troughiness continues from the mid-Atlantic into the SE US, while a more robust trough will be over the Great Lakes. For Monday/Monday night, weak low pressure is still depicted over portions of the mid- Atlantic into the SE US. The trough over the Great Lakes region is not depicted as pronounced. A ridge of high pressure is noted from FL to the Lower Mississippi River Valley. For Tuesday, a weak trough is still depicted from the mid-Atlantic to the SE US with a ridge of high pressure from FL to the Lower Mississippi Valley and north into the Lower Ohio Valley. A look at the 8 Jul 12Z NAEFS Ensemble Situational Awareness data shows 850mb temperatures increase on Saturday to around +20C. Similar values are expected Sunday. For Monday, only a small decrease to +19C to +20C is forecast. On Tuesday, similar values are expected as compared to Monday. The top end of the range of temperatures on Monday and Tuesday touch the 90 to 97.5 percentile of the 30-year CFSR climatology. The above weather patterns offers the following forecast. Our weather pattern will remain stagnant through the weekend and into the early part of next week. With a general area of troughiness over or near the region, our forecast of daily chances of showers/storms will continue. With those daily chances will also come daily chances of localized heavier rains, which in turn could mean locally higher potential for flooding. Temperatures will trend hotter over the weekend as compared to late this work week, and remain at those elevated levels into the start of the next work week. Confidence in the above weather scenario is moderate to high. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
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As of 900 PM EDT Tuesday... Debris cloud from afternoon and evening storms is still floating around. An east-west outflow boundary stretches from FVX-LYH-ROA-BLF. Scattered showers and storms likely to persist along this boundary through at least midnight and possibly longer. There is a pool of CAPE and surface dewpoints in the mid 70s between LYH-DAN that may cause storms to linger across the piedmont even after midnight. Aside from this shower activity, expecting areas of fog for the late night. Fog may become dense at LWB/BCB resulting in LIFR between 06-12Z. MVFR vsbys are possible at ROA-LYH-DAN where wet ground from todays showers will promote light fog there too. A period of low level stratus is also possible at daybreak but will leave out of the TAFs attm except for the mountain valleys which are expected to fog- in. Any fog/low stratus will erode by 12-14z Wed. After that expect to replay thunderstorm cycle again Wednesday with cloud build- ups by 17Z, followed by scattered to numerous storms during the afternoon and evening. .EXTENDED AVIATION OUTLOOK... The forecast continues in a typical summertime weather pattern with daily chance of showers/storms during the peak heating hours each day through Saturday. Morning fog will also be possible each day, especially at LWB and BCB.
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&& .RNK WATCHES/WARNINGS/ADVISORIES...
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VA...Flood Watch from Wednesday afternoon through late Wednesday night for VAZ044>047-058-059. NC...Flood Watch from Wednesday afternoon through late Wednesday night for NCZ005-006. WV...None.
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&& $$ SYNOPSIS...WP NEAR TERM...PM/WP SHORT TERM...DS LONG TERM...DS AVIATION...PM