357 FXUS61 KRNK 302012 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 312 PM EST Sat Nov 30 2019 .SYNOPSIS... A major low pressure area and associated frontal system will move eastward from the central U.S. overnight with rainfall continuing into Sunday. A warm front will lift north of the area tomorrow quickly followed by the passage of a cold front Sunday afternoon. && .NEAR TERM /THROUGH SUNDAY/... As of 245 PM EST Saturday... Complex surface and upper level system centered across the mid-Mississippi Valley will continue to work eastward overnight with overrunning rainfall pattern persisting. A warm front will remain to our south until morning and then lift northward across the CWA during the day and a trailing cold front begins to approach from the west. Additional rainfall of 0.50 to 1.00 inch is possible overnight and early tomorrow, which comes on top of the 0.25 to 1.00+ inch that has fallen up to the current time. The highest observed amounts so far have been across the Tennessee River basin (mainly Smyth, Tazewell counties) where a few automated gages are showing up to 1.25 inches. A few small streams and rivers may approach or exceed bankfull across this watershed by tomorrow. Experimental guidance from the National Water Model (NWM) shows the North Fork Holston basin in Smyth County and the Reed Creek basin in Wythe County as the most likely to reach or exceed bankfull based on previous rainfall and HRRR/GFS QPF. Temperatures overnight will remain almost steady, mainly holding in the 40s. Temps tomorrow a bit trickier as the wedge breaks down ahead of the cold front. Low to mid-50s seemed to be a reasonable compromise among various model solutions. Precipitation winds down after the front with the winds picking up but upslope precipitation develops beyond this forecast period. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... As of 230 PM EST Saturday... Deep closed low drifts across the northern Ohio Valley Sunday evening, into the mid-Atlantic region Monday afternoon. Expect cold air to lag a bit behind the front Sunday evening, so snow will be mainly confined to the higher terrain of southwest VA and NC late Sunday evening as the colder air aloft actually arrives there first. We will see blustery and showery conditions Monday as the upper low moves overhead. Models are showing decent lapse rates with cold advection and 8h temps in the -3 to -6C range to allow for snow showers across the mountains during the day, with a mix to the east. Flurries will likely be seen even into the piedmont early in the day changing rain showers/sprinkles at best in the afternoon. Could see flurries into the evening Monday east, while main upslope will continue in the west. Several inches of snow will likely occur across the mountains of WV into NC from late Sunday night-Tuesday morning. Light accumulations (a dusting) could occur as far east as the Blue Ridge. Too early for headlines at this point. The other issue will be winds, as models ramp up the speeds briefly behind the front Sunday evening, but mainly elevations above 4000ft. Models have stronger low level jet Monday afternoon/evening. No wind headlines yet, but may be needing a wind advisory for at least Monday-Monday evening. Expect the snow showers to subside Tuesday as the northwest flow relaxes and low level moisture shrinks. Looking dry Tuesday afternoon-Tuesday night. Lows will be close to normal with highs about 5 degrees below normal in the piedmont to 10 to 15 degrees below normal in the west. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 1220 PM EST Saturday... Fairly progressive upper flow following the departure of the deep trough/low over the northeast will keep our weather fairly dry and cooler than normal from Wednesday-Saturday. A weak southern stream system may allow for a few rain or snow showers Friday. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... As of 1235 PM EST Saturday... Poor aviation conditions expected through the valid TAF period with IFR or occasionally MVFR predominating, for both CIGS and VSBYs. Rainfall may not be continuous but will have high probability through 18Z tomorrow. Cold front approaches late in the TAF period in the west with rainfall becoming more showery and winds picking up from the southwest at the western TAF sites and just beyond that time further east. Some possibility exists for a line of heavier rain showers scouring out the wedge, then followed by strong and gusty winds behind the front, continuing into Monday. Cigs/vsbys will improve to VFR east of the Blue Ridge and mostly MVFR west of the Blue Ridge by Monday, if not at times late in the day on Sunday. .Extended Aviation Discussion... A prolonged period of upslope snow possible Sunday night into Monday night across southeast West Virginia and from the Alleghany Highlands south into southwest VA and northwest NC. Upslope precipitation will be ending in the mountains by Tuesday. VFR conditions expected Tuesday afternoon through Wednesday. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...PC NEAR TERM...PC SHORT TERM...WP LONG TERM...WP AVIATION...PC/RAB