Area Forecast Discussion
Issued by NWS Blacksburg, VA

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358 FXUS61 KRNK 191047 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 547 AM EST Sun Feb 19 2017 .SYNOPSIS... An upper low will cross the region this morning before exiting to the southeast this afternoon. High pressure builds in from the north behind this system tonight and remains into Monday night. A weak frontal system will approach from the west by midweek. && .NEAR TERM /THROUGH TONIGHT/... As of 215 AM EST Sunday... Upper low will continue to pivot across the region early this morning before exiting to the southeast by afternoon. Trailing deformation band currently producing a band of showers across the far northwest should also gradually shift east while slowly stretching/dampening out after daybreak as the associated upper support pulls away. However decent northwest flow in the wake of the upper system likely to keep low clouds trapped over much of the west to start with some showers northwest, and perhaps spotty light rain/drizzle elsewhere along the far western ridges early on. Subsidence to gradually increase this afternoon as ridging to the west starts to shift east and ongoing cool advection weakens. This should help to erode the low cloud canopy over the mountains with guidance profiles showing moisture pulling back to the west allowing for mainly sunny skies east and decreasing clouds west. Just how fast this occurs the key to high temps as MOS has trended cooler western sections while keeping things quite mild east per downslope under more insolation. Therefore edged highs from the Blue Ridge west down a little with some spots likely staying in the 50s espcly if clouds hold longer under a gusty northwest breeze. Strong upper ridging to build in overnight as surface high pressure bridges in from the north by daybreak. Models depict very strong warming aloft as the next round of warm advection to the west shifts east. Expect better subsidence to keep skies mainly clear although some potential for low clouds to again get trapped over the far west beneath the inversion aloft as warming comes in above. Otherwise appears a bigger range in low temps from 30s valleys to perhaps mid 40s at elevation likely with good radiational cooling outside of warming aloft. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... As of 208 AM EST Sunday... An upper level ridge and lots of sunshine will allow Monday`s temperatures to reach into the upper 60s to lower 70s. These temperatures are 20F-25F warmer than normal. Records could be broken at Bluefield and Blacksburg Monday. A light east wind will keep Roanoke, Lynchburg and Danville from reaching their records. The upper level ridge will slowly exit the region Tuesday. This ridge is stubborn and has, by model standards, been slowing the arrival of our next chance for rain, now set for Tuesday night. Dew points recover quickly into the 40s Tuesday night, however, dry prefrontal environment and the lack of lift will limit rainfall to under a quarter of an inch. The front that will bring the rain is weak and will likely washout over North Carolina Wednesday. A reinforcing shot of cool easterly flow and increasing cloud cover will keep temperatures in the low to mid 60s Tuesday. Despite Tuesday being cooler than Monday, temperatures will still be 15F warmer than normal. Temperatures will rebound Wednesday as the washed out front gives way to warm southerly flow. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... As of 230 AM EST Sunday... Residual moisture with the weak front across the region looks to dry up Wednesday night into Thursday as ridging re- establishes over the southeast states. This leads to a more amplified 500 mb pattern for the end of the week with a deepening trough moving across the central United States and more spread showing up in the models by that time frame. Increasing southwest winds Thursday into Friday will increase moisture and keep temperatures way above normal ahead of the front with 60s to near 70 likely west and well into the 70s east. Timing of the frontal passage across the Appalachians looks to be on Saturday morning with precipitation along and ahead of the boundary at this point. Colder air comes in behind the front for the end of the weekend but again not overly impressive and likely limited in duration per latest warmer 19/00z ECMWF. However the combination of a modest low level jet and strong cold air advection will result in strong gusty winds behind the front into late Saturday with a brief return to more normal temps to start the weekend. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... As of 545 AM EST Sunday... Axis of lower cigs remains along and west of the Blue Ridge early this morning with overall MVFR from KLWB to KBCB and IFR around KBLF where patchy MVFR vsby in fog persists. Otherwise VFR to start from KROA eastward including mainly clear skies at KLYH/KDAN early on. As a weak upper level disturbance passes to the southeast this morning, expecting some decrease/lifting of sub-VFR cigs over the mountains although may take until mid afternoon for KBLF to return to VFR and that remains uncertain. Elsewhere appears that will see mainly VFR this afternoon with little cloudiness across the east and slowly fading strato-cu over the mountain locations. Northwest winds will also remain gusty through much of the day behind the departing upper system with gusts to 25 kts possible along the Blue Ridge including KROA. High pressure builds in overnight while some low level upslope moisture may get trapped under warming aloft resulting in periods of sub-VFR cigs espcly around KBLF overnight. May also see some late night patchy fog develop with MVFR or briefly worse at KLWB/KBCB and perhaps KBLF late. Otherwise expecting clear skies under light winds making for overall VFR elsewhere. Extended Aviation Discussion... High pressure should bring VFR Monday into Tuesday. MVFR rain showers are possible Tuesday night into Wednesday with the next weak cool front entering the region midweek. High pressure should strengthen by Thursday with a return to widespread VFR expected toward the end of the week. && .CLIMATE... As of 307 PM EST Saturday... Record High Temperatures and Year of Occurrence Feb 19 Blacksburg, VA..65 in 1994 Bluefield, WV...66 in 1994 Danville, VA....73 in 1981 Lynchburg, VA...76 in 1939 Roanoke, VA.....77 in 1939 Feb 20 Blacksburg, VA..68 in 1984 Bluefield, WV...67 in 1986 Danville, VA....74 in 1971 Lynchburg, VA...76 in 1930 Roanoke, VA.....75 in 1939 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...JH NEAR TERM...JH SHORT TERM...RCS LONG TERM...JH/AMS AVIATION...JH CLIMATE...AL

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