Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 191807 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 207 PM EDT Thu Oct 19 2017 .SYNOPSIS... A large area of high pressure will remain over the eastern part of the country this week before slowly sliding off the coast on Saturday. This will keep skies mostly sunny and allow temperatures to warm to above normal levels. Early next week, a strong cold front and deep upper trough will approach from the Midwest bringing widespread rain showers followed by much cooler temperatures. && .NEAR TERM /THROUGH TONIGHT/... As of 944 AM EDT Thursday... Valley fog will continue to burn off this morning, leaving us with another fine fall day for this afternoon. Full sun and dry conditions will allow for another day with wide diurnal temperature variation on the order of 40 degrees at some locations. Highs today a couple degrees warmer than readings yesterday. Previous discussion... Surface high pressure will remain firmly entrenched across the area today allowing for another bright, blue, sunny day. A weak and dry upper-level trough was passing over the area this morning with the only notable associated weather some passing high clouds. This weak upper trough will continue to move east of the area today as ridging aloft develops just upstream of the area. 850mb temperatures will continue to hover in the +10C to +12C range today, yielding temperatures on par with what we saw Wednesday. However, with the center of the large surface high shifting toward the eastern part of the CWA, winds will come around to the southwest by afternoon for areas west of the Blue Ridge. This should allow temperatures to creep up a few degrees in comparison to what we saw yesterday. With the center of the cool high across eastern areas, they should be the coolest overall today. Maximum temperatures will be 5-10 degrees above normal and mostly in the 70s, except 60s higher elevations. Minimum temperatures Friday morning will continue to warm a few degrees compared to the previous day and all locations should remain at or above 37F, mainly in the 40s across the forecast area. Thus, no frost was included in the grids at this time. Patchy fog may develop in river and mountain valleys mainly west of the Blue Ridge. && .SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/... As of 300 AM EDT Thursday... An awesome weekend is shaping up weatherwise as a strong ridge of high pressure is forecast to linger through Sunday. This feature will maintain the fair dry weather, with temperatures 5 to 10 degrees above normal. Enjoy the weekend because next week will be unsettled. Clouds will begin to increase late Sunday, an indication of changes on the horizon. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... As of 300 AM EDT Thursday... An active upper air pattern is forecast for next week as full latitude long wave trough gets carved out over the east central Continental U.S. (CONUS). Models indicate an abundance of short wave energy flowing into the western CONUS this weekend with some of the energy becoming isolated on the west side of subtropical ridge of high pressure over the Southeast U.S., and developing into a cutoff low in the vicinity of the Lower MS valley. This cutoff low is forecast to eject northeast across the Mid-Atlantic Monday into Tuesday in an almost winterlike fashion as this energy phases with an ever increasing energetic northern stream trough along the U.S. Canadian border. The net result will be a highly amplified full latitude long wave trough by mid-week which will feature a significant change in temperature for much of the eastern U.S. Model consensus is for rain to develop from southwest to northeast across the region Sunday night into Monday, with the highest probability for measurable rainfall occurring Monday night into Tuesday as the southern stream Low ejects northeast across the region. Stability indices suggest slight potential for thunder Tue. With the upper trough becoming established over the eastern CONUS for mid week, temperatures will take a tumble. Arrival of cooler air Tuesday night into Wednesday may result in some p-type transition (wet snowflakes?) for the highest elevations of WV/NC and far western VA, followed by brisk/breezy conditions. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/...
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As of 205 PM EDT Thursday... High pressure will remain in control of our weather this TAF period with VFR flight conditions and light winds expected, with the exception of IFR conditions in nocturnal fog/stratus developing in the valleys. Expect KBCB and KLWB are most likely sites for IFR conditions in fog/stratus, and with increasing dew points coverage/duration look to be a bit greater than last night. Will forego tempo groups and go with prevailing IFR/LIFR these sites for a couple of hours around daybreak. Extended Aviation Discussion... High pressure will remain over the region through Sunday with generally VFR conditions expected, outside the usual late night/early morning patchy river and mountain valley fog. A deep upper trough and associated strong cold front will move into the region from the west by Monday promising a period of sub-VFR conditions in rain/showers along with increasing wind. Colder, blustery, unsettled weather with perhaps largely MVFR conditions across the mountains will linger through the later half of next week as an upper trough cuts off across the central Appalachians.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...RAB NEAR TERM...MBS/RAB SHORT TERM...PM LONG TERM...PM/WP AVIATION...MBS/RAB

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