Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 191444 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 944 AM EST Fri Jan 19 2018 .SYNOPSIS... High pressure over the Lower Mississippi Valley will move east across the Gulf Coast states today and tonight. Low pressure will develop in the Central Plains on Sunday then track into the Great Lakes by Tuesday. This system will push a cold front through the area on Monday night and Tuesday. && .NEAR TERM /THROUGH TONIGHT/... As of 940 AM EST Friday... No major changes are planned for the forecast update this morning. The one small adjustment will be in the introduction of some cirrus across the northern and eastern sections of the region based upon the latest satellite trends. Have also tweaked the hourly temperature, dew points, and winds based upon the latest observations and expected trends heading into the early afternoon. As of 330 AM EST Friday... Clear sky and dry air mass expected over southwest Virginia, southeast West Virginia and northwest North Carolina today and tonight. Surface high pressure will pass to the south of the region tonight. A 30 to 40 knot west low level jet will result in gusty winds today. Enough mixing tonight to prohibit excessive temperature drop. Stayed a little warmer than guidance for lows tonight on the higher ridges. Went slightly below guidance over the snow cover in the south. && .SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/... As of 340 AM EST Friday... The upper pattern will feature an eastern ridge/western trof through the weekend, establishing a trend to breezy conditions and temperatures well above normal. Saturday looks like a fair weather day, but by Saturday night moisture and isentropic lift associated with a warm front extending from a low developing over the Rockies will bring a chance of showers to locations west of the Blue Ridge. Some wet snowflakes may mix in at the higher elevations before the chance for showers gradually decreases from south to north on Sunday as the warm front pushes through. The first part of Monday looks to be mostly dry but the chance for showers will be increasing in the mountains later in the day as a strong cold front approaches from the west. The cold front has a good deal of dynamic support, being driven by low pressure moving through the Great Lakes and a vigorous closed low moving through the Ohio valley. The front is expected to be accompanied by widespread rainfall though lapse rates are not impressive and surface based instability is largely absent so chances for thunder look quite low. However, the low level wind field amplifies considerably and there is a good amount of shear with the front so this could become a QLCS scenario where embedded convective elements can mix down strong wind gusts without thunderstorms. QPF does not appear excessive but downpours may cause local hydro issues. Will be watching this situation closely to see how it evolves in later model runs. && .LONG TERM /TUESDAY THROUGH THURSDAY/... As of 130 PM EST Thursday... Temperatures will decrease behind the front on Tuesday, though readings will still remain above normal for this time of year heading through the middle part of the week. Our next chance for precipitation will be a small one Wednesday night into Thursday as a weak disturbance passes through FL/GA/SC. Otherwise, dry weather is expected as another area of high pressure builds into the region. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... As of 605 AM EST Thursday... VFR to prevail under a clear sky through the TAF forecast period. Models and NAM/RAP Bufkit soundings showed a 30 to 40 knot low level jet today and tonight. These stronger winds above the surface inversion may result in low level wind shear in spots for a few hours until mixing begins this morning and again after sunset when surface winds diminish. Wind gusts this afternoon will be from 20 to 30 knots, especially at higher elevations. Extended Discussion... High pressure will cover the region Saturday through Sunday. VFR conditions are expected as well as warming temperatures. Moisture will return to the west Sunday night into Monday night with sub- VFR conditions possible in low clouds and rain showers ahead of another cold front. VFR conditions return during Tuesday as weak high pressure follows the front in from the west. && .EQUIPMENT... As of 245 PM EST Thursday... NOAA Weather Radio, WXL60 (Roanoke Transmitter) which broadcasts at 162.475 MHz remains off the air. The phone company continues to investigate and no estimated time has been given for restoring this. We apologize for the outage. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...Winter Weather Advisory until noon EST today for NCZ001>006- 018>020. WV...None. && $$ SYNOPSIS...AMS NEAR TERM...AMS/DS SHORT TERM...MBS LONG TERM...DS AVIATION...AMS/JH EQUIPMENT...WP

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