878 FXUS61 KRNK 151745 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 1245 PM EST Tue Jan 15 2019 .SYNOPSIS... High pressure will build across the area from the southwest resulting in drier and slightly warmer weather for today and Wednesday. An upper level disturbance will move into the central U.S. Wednesday, with low pressure developing over the mid part of the country. This Low will then track northeast into the Ohio Valley Thursday, with a cold front trailing south into the Tennesse valley. Moisture from this system will enter our region late Thursday and Thursday night. Following this relatively weak weather system, a much stronger storm system is expected to impact the region over the weekend with a dramatic change in temperature early next week. && .NEAR TERM /THROUGH TONIGHT/... As of 855 AM EST Tuesday... Made some minor adjustments to temperatures for this morning utilizing the latest surface obs, trends and blended in the GLAMP to capture slightly cooler temperatures this morning with slowly rise this afternoon. Adjusted the Cloud cover for this morning using satellite images and their trends, then sunshine returns this afternoon. High pressure will slowly build into our region resulting in clearing and subsidence working its way to surface. More changes later this morning. As of 400 AM EST Tuesday... Forecast for today: Clearing. Seasonal temperatures. High pressure is centered over the lower Mississippi valley. This feature has been slow to build across our region, but think today is the day for clearing as the subsidence finally works its way to the surface. Once the sun reappears, then a more bonafide chance for melting of this past weekends wintry mix will occur as temperatures climb above freezing. MOS suggests the warmest conditions this afternoon should be across southside VA and the piedmont of NC where readings are expected to reach the mid 40s. Coolest readings will be in the mountains with highs in the 30s... overall a near normal day with respect to temperature. Tonight will feature mainly clear skies with a quick cool down after sunset, radiational cooling at a premium. Temperatures across the entire CWA should slip below freezing, but nothing extreme... lows favoring the seasonal norm. There is a disturbance that will be moving across the Great Lakes. Warm air advection aloft ahead of this feature will likely result in some late night cloudiness along and north of I-64. The moisture appears shallow, so if there is any precip it would mainly be confined to the higher elevations of WV...north of Lewisburg...and in the form of freezing drizzle. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/... As of 400 AM EST Tuesday... On Wednesday, a shortwave trough is expected to head eastward from the Great Lakes region into New England. The southern extent of its trough axis will head across our region by Wednesday morning. Northwest flow behind this feature will yield upslope cloud cover across parts of southeast West Virginia and neighboring counties of southwest Virginia. The feature will be very limited in moisture to a narrow saturated strip just below 850mb. Guidance continues to offer a temperature within this saturated layer no colder than about -7 or -8 deg C, far from optimal for dendritic growth. Our forecast will offer mainly drizzle or freezing drizzle across this portion of the forecast area on Wednesday. By Wednesday evening, the depth of the already shallow layer of moisture is expected to shrink even more. Although, it may trend slightly colder to about -9 to -10 C. Also, mid to high level clouds will start overspread this very shallow layer of moisture, yielding some seeder-feeder potential. The two in concert point to the potential for some very light snow mixed among the already very light freezing drizzle Wednesday evening. The remainder of the forecast area during the Wednesday and Wednesday night time period is expected to be dry. Cloud cover will be very limited on Wednesday, but Wednesday night mid to high level clouds will spread across the area from west to east. By late Wednesday night into early Thursday, the very light precipitation over southeast West Virginia will end thanks to low level winds backing southwest, thus ending the upslope component, and dryer air finally removes the very shallow low level moisture. The next weather system to potentially impact the entire forecast area will head eastward from the mid-Mississippi Valley during the day Thursday, and cross our region thursday night. Low level temperature profile are suggested that the vast majority of the area will experience light rain from this system. However, enough colder air is expected to be in place for some measurable light snow mainly at the higher elevations Thursday afternoon and thursday night in areas along and north of the Interstate-64 corridor. On Friday, the region will be on the backside of the system with gusty northwest winds providing additional scattered rain/snow showers across portions of southeast West Virginia, south into the Northern Mountains of North Carolina. These will continue into Friday night, but are expected to decrease in coverage from south to north. The remainder of the forecast area will experience decreasing cloud cover Friday afternoon into the first half of Friday night. By late Friday night, low level winds will again back southwest in advance of another, yet more potent, weather system developing across the central U.S. Mid to high level cloud cover will increase by late Friday night across the entire region in advance of this system. Temperatures during this portion of the forecast will be above average and trend milder each day. By Friday, temperatures will average around ten degrees above normal. Confidence in the above portion of the forecast is moderate. && .LONG TERM /SATURDAY THROUGH MONDAY/... As of 300 PM EST Monday... Guidance is still in good agreement in developing a deep trof over the eastern US this weekend that will drive a strong surface low through the region with significant precipitation Saturday/Saturday night. However, there are more subtle differences in the track of the surface low that are causing significant differences in potential precipitation type. If the low tracks to our south and east we will remain on the cool side of the system with the potential for more wintry precipitation. If the low tracks to our west and north we will be on the warm side with much less potential for wintry precipitation. Current ensemble guidance indicates that, after some initial mix of snow/sleet/freezing rain mainly north of route 460, this system will be more of a rain producer for the Appalachians and central mid Atlantic, with an important qualifier. Once the low passes the region it will pull down arctic air and this may catch the backside of the heavy rainfall, changing ptype to snow for a quick accumulation and possibly a flash freeze as the rain departs. It will then remain quite windy with upslope snow showers west of the Blue Ridge through Sunday before precipitation tapers off on Monday. Will be tracking the evolution of this system closely over the next several days for developing threats of winter weather, flooding, and wind. Temperatures will warm considerably ahead of the approaching low later in the week with readings on Friday well above normal. However, readings will plummet behind the front as arctic air surges in for Sunday night and Monday with very cold wind chill values. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... As of 1245 PM EST Tuesday... SCT to BKN MVFR/IFR clouds will linger in the mountains this afternoon into tonight. SCT to BKN MVFR clouds are expected in the east. Mostly clear skies will develop east of the mountains this evening, while partly to mostly cloudy condition anticipated for the west. A weak upper air disturbance passing to our north may generate some patchy freezing drizzle in the West Virginia mountains Wednesday morning. Winds will remain light and variable tonight into Wednesday. Medium confidence in ceilings,visibilities and winds during the taf period. Extended Aviation Discussion... High pressure to our south will favor mainly VFR Wednesday afternoon into Wednesday night. A disturbance moving across the Great Lakes into New England will favor sub-VFR conditions for the WV mountains north of KLWB. A more bonafide opportunity for sub- VFR is expected across the region Thursday into Friday, associated with a developing area of low pressure that will move from the central U.S. Wednesday to the Ohio Valley Thursday, the associated front crossing the Mid-Atlantic Region Thursday night. Unsettled pattern will feature more storminess over the weekend. After a brief respite Friday afternoon/night with an opportunity for VFR, conditions are forecast to deteriorate Saturday ahead of a much stronger storm system that will cross the region Sunday. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...PM NEAR TERM...KK/PM SHORT TERM...DS LONG TERM...MBS AVIATION...KK/PM