Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 181418 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 1018 AM EDT Tue Sep 18 2018 .SYNOPSIS... The remnants of Florence will exit to the northeast of the area today. High pressure builds in midweek with another front working in from the north toward the weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 1010 AM EDT Tuesday... Still seeing clouds as well as a few shower bands spilling into the area from the northwest with the wrap around moisture with the remnants of Florence as well as a passing upper trough. Short term models continue to show a decrease in showers/clouds into the afternoon as better drying aloft arrives and downslope increases per strengthening low level northwest flow. However morning soundings show that the moisture remains quite deep so may take longer to erode espcly until the embedded shortwave exits toward mid afternoon. Other concern with added showers forming across the extreme northeast counties where far enough removed from downslope drying to support development along a weak trough axis. Since most solutions including the latest HRRR and new Nam still clip sections out around Lynchburg, kept in some low pops including isolated thunder mention despite only weak forecast instability given low level drying. Otherwise clouds early, then becoming partly sunny with highs ranging from the 70s west to low/mid 80s east pending some afternoon sunshine to aid downsloping. Previous discussion as of 310 AM EDT Tuesday... Low pressure (Florence)was elongated over central-northeast PA this morning caught up in the upper level westerlies/trough which will work overhead this morning, then offshore this evening. As such increasing west-northwest flow allows for scattered to numerous showers this morning into the mountains. As we head into the afternoon, heating should allow for some deep convection formation along the trough axis, so may see some thunderstorms mainly east of a Highway 29 line, though severe threat is low, as airmass aloft dries out. Expect little change in airmass and with a return to sunshine temps will max out in the mid to upper 70s mountains, to lower to mid 80s east. W-NW winds are going to pick up some by midday, so will put somewhat a relief on the humid airmass. Tonight, any lingering showers across the piedmont head east/erode with high pressure arriving from TN/KY. Expect some fog tonight as winds die off and skies clear. Could be dense in the mountains. Low temps still running about 10 degrees above normal, from the lower to mid 60s most areas. Forecast confidence medium to high. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... As of 310 AM EDT Tuesday... Weak surface front edges southward into the area Wednesday but limited moisture and subsidence aloft, no precip expected. Temps continue to stay above normal as 5h heights rise. High pressure at the surface/aloft stay in control of our weather into Thu night as all areas continue to dry out. High forecast confidence this period. && .LONG TERM /FRIDAY THROUGH MONDAY/... As of 1225 PM EDT Monday... Friday and Friday night, a cold front heads southeast into the Ohio River Valley and the upper high shifts southeast into the far western Atlantic. The result will the development of isolated to scattered showers across southeast West Virginia Friday afternoon. These will continue into Friday night across the same general region. During the weekend, the cold front will continue its push south and become stalled, and centered over our region along a west-east orientation. Showers will increase in coverage during this portion of the forecast. By Monday, the cold front is expected to only make small progress south. Temperatures during this part of the forecast will average ten to fifteen degrees above normal through Sunday morning, then drop to slightly above normal Monday morning. High temperatures will average five degrees above normal through Saturday, then a few degrees below normal Saturday and Sunday. Forecast confidence in the above portion of the forecast is moderate. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... As of 712 AM EDT Tuesday... Low clouds and showers across the mountains with IFR to LIFR ceilings will improve to VFR by this afternoon with winds picking up from the northwest at 8-10kts with gusts to 15-20kts. A few showers and MVFR ceilings possible across ROA to the piedmont airport later this morning as well. We could see some thunderstorms fire up east of LYH/DAN this afternoon but not expecting them to impact those two locations. Confidence is medium to high in improving conditions today. Confidence medium again tonight as potential fog impacts the mountains with low confidence in the east. Will go with IFR vsbys at BLF/LWB/BCB late tonight and may see dense fog at least at LWB but for now will hold them at 1SM OVC001. Extended Discussion... VFR conditions are expected for Wednesday through Friday with high pressure over the area. Scattered MVFR showers will develop on Saturday. May see residual low level moisture fog Wed morning in the mountains. Confidence above average by Tuesday night into the end of this week. && .HYDROLOGY... As of 135 AM Tuesday... Only hydro issues now are river flood warnings along the New at Radford, the Dan from Wentworth to South Boston and Roanoke at Randolph. Forecasts reflect moderate flooding at all but Randolph where minor flooding is forecast, though as of midnight the New at Radford just dropped below moderate flood stage. Still some road closures here and there according to Dept of Highways, mostly close to rivers/streams, but receding waters are expected through the morning in the smaller tributaries. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...JH/WP NEAR TERM...JH/WP SHORT TERM...WP LONG TERM...DS AVIATION...JH/KK/WP HYDROLOGY...WP

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