Area Forecast Discussion
Issued by NWS Blacksburg, VA

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502 FXUS61 KRNK 091922 CCA AFDRNK Area Forecast Discussion...CORRECTED National Weather Service Blacksburg VA 322 PM EDT Thu May 9 2024 .SYNOPSIS...
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A low pressure system and cold front crossing through the Ohio Valley and Mid Atlantic region will bring scattered showers and isolated thunderstorms this evening. A second push of cooler air and gusty winds will bring clouds and showers to the mountains Friday through Sunday. Dry high pressure is expected on Monday, followed by a widespread probability of precipitation Tuesday and Wednesday.
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&& .NEAR TERM /THROUGH FRIDAY/... As of 135 PM EDT Thursday... Key messages: - Scattered showers and isolated thunderstorms - Breezy tonight and Friday Satellite images indicated much of the fog and low clouds from earlier this morning have eroded, as well as the presence of a thin layer of cirrus. Enough sunshine getting through to bring surface based CAPE to 500-1000 J/kg. Best coverage of precipitation will be along and north of I-64 west of Lexington and north of Route 460 between Roanoke and Lynchburg. As the cold front passes through tonight surface and low-level winds turn from the southwest to west, then with a second short wave, winds become northwest Friday afternoon. GFS and 3km NAM were both showing to 50 to 60 knot low level jet develops overnight and into Friday morning. The jet combined with cold air advection as 850 mb temperatures drop from around +12 into the +4 to +8 range on Friday, will result in wind gusts in the 30 to 40 mph tonight at higher elevations. Once mixing begins on Friday morning, much of the area will have a gusty wind. Due this good upslope, will have clouds in along the western slopes of the central Appalachians tonight and through the day Friday. Will keep the chance of showers on Friday. Cannot rule out isolated thunderstorms on Friday as cold air aloft will provide favorable lapse rates and some enhanced instability. Combination of MAV/MET guidance for lows tonight and highs on Friday look reasonable. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... As of 1245 PM EDT Thursday... Key Messages: 1) Confidence is high for cooler conditions this weekend. 2) Mountain rain showers will be possible during Saturday afternoon into Sunday morning. A cold front will exit offshore on Friday night, while a broad upper level trough enters the Mid Atlantic. After the recent stretch of warm and moist conditions, temperatures will turn noticeably cooler. Morning lows throughout this weekend should fall into the 40s for most locations with some upper 30s likely in the sheltered mountain valleys. The wind will become breezy from the west to northwest with gusts of 20 to 30 mph possible in the higher elevations during the daytime hours of Saturday and Sunday. Rotating around the periphery of the broad upper level trough will be a shortwave trough that should dive southeastward from the Great Lakes on Saturday. As it reaches the Appalachian Mountains by Saturday afternoon, rain showers will spread along and west of the Blue Ridge. The upslope northwest flow should keep the showers lingering through Saturday night before fading by Sunday morning. High pressure will build eastward by late Sunday to provide dry weather throughout the Mid Atlantic. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... As of 1245 PM EDT Thursday... Key Messages: 1) Confidence is high for warmer conditions by next week. 2) Daily chances of showers and thunderstorms will return with the highest odds possible by Tuesday. Monday should start dry with high pressure across the Mid Atlantic. The high should head offshore later in the day to provide warm air advection and moisture advection from southwest flow. However, this increase in warmth and moisture will combine with an approaching low pressure system in the central Mississippi River Valley to spark shower and thunderstorm chances over the next couple days. Isolated convection may reach the southern Blue Ridge and far southwest Virginia by Monday night, but the greatest odds for showers and thunderstorms appears to be Tuesday. Moisture will linger through Wednesday, but the abundant cloud cover might somewhat limit the thunder chances. Weak high pressure could bring a brief reprieve during Thursday morning, but another low pressure system may approach from the west by late Thursday. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... As of 200 PM EDT Thursday... Satellite images indicated much of the LIFR fog and MVFR clouds from earlier this morning have eroded, as well as the presence of a thin layer of cirrus. Enough sunshine getting through to bring surface based CAPE to 500-1000 J/kg. Best coverage of precipitation will be along and north of I-64 west of Lexington and north of Route 460 between Roanoke and Lynchburg. For now have VCSH at KLWB and VCTS at KLYH. As the cold front passes through tonight surface and low-level winds turn from the southwest to west, then with a second short wave, winds become northwest Friday afternoon. GFS and 3km NAM were both showing to 50 to 60 knot low level jet develops overnight and into Friday morning. The jet combined with cold air advection, will result in wind gusts up to 45 kts tonight at higher elevations. Once mixing begins on Friday morning, much of the area will have a gusty wind in the to 20 to 30 knot range. Due this good upslope, will have clouds in along the western slopes of the central Appalachians tonight and through the day Friday. Will keep the chance of showers on Friday. Cannot rule out isolated thunderstorms on Friday as cold air aloft will provide favorable lapse rates and some enhanced instability. Average confidence for ceiling, visibility, and wind. Extended Aviation Outlook... Expecting MVFR showers, mainly in the mountains on Saturday. Some upslope mountain showers may occur Saturday night. VFR conditions are expected Sunday and Monday under dry, high pressure. The probability of precipitation and sub-VFR ceilings and visibilities increases on Tuesday ahead of a low pressure system in the central United States. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS NEAR TERM...AMS SHORT TERM...PW LONG TERM...PW AVIATION...AMS