Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 280147 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 847 PM EST Mon Feb 27 2017 .SYNOPSIS...
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High pressure will continue to drift east and offshore overnight. A warm front is expected to lift northeast into the region Tuesday, before passing to the north Tuesday night, in advance of a strong cold front that will arrive late Wednesday. Cold high pressure will follow the front for the end of the week.
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As of 840 PM EST Monday... Weak upper disturbance currently crossing the region per vapor loop will exit overnight leaving a warm advection pattern aloft in place around high pressure offshore. This feature may act to produce a few sprinkles over the north and west early on before better mid level drying seen to the west edges east. Some low level moisture will also gradually start to work in across the far south/west later tonight as southwest flow deepens, but appears too shallow with limited focus for much added shower coverage. In addition, evening soundings remain very dry below 700 mb which supports little rainfall overnight excluding current sprinkles. Therefore basically removing pops similar to latest short term solutions as appears the Nam remains overdone, with added showers over the southeast where will be to the north of ongoing convection attm. Clouds remain a bit more tricky with guidance showing enough drying for some clearing espcly mountains overnight in the wake of the exiting impulse. This while maintaining more canopy over the east where weak return moisture advection is expected late. However latest satellite trends would support some breaks all sections after midnight as brief subsidence increases. Thus have adjusted sky cover down enough for becoming partly cloudy most sections overnight. Low temps quite dependent upon sky cover given lingering dry dewpoints as more breaks could allow for 30s valleys with 40s most other locations. Since this scenario looks on track, only making small adjusts to going forecast low temps overnight at this point. Previous discussion as of 330 PM EST Monday... High pressure will continue to drift to the east this evening, as a weak upper-level disturbance overspreads mid to upper level clouds into the region. Weak radar echo returns show up periodically, resulting in little to no ground-truthing precipitation. This is made possible by a rather deep SFC to 700mb dry layer, featured well on the KROA/KGSO 12z sounding. The cloud cover did serve a purpose though, limiting temperature potential, especially along and west of the Blue Ridge Mountains. Minor tweaks to the forecast made here, accounting for cooler temperatures in the west, with warmer conditions in the Piedmont Counties of VA/NC where the sun made a longer appearance. Expect winds to continue responding to the slipping high pressure center, shifting to more southerly flow Monday evening. 5 to 10 mph winds with a few periodic gusts may be possible, but things should settle down quickly after sunset. Expect the cloud shield to hold strong most of the overnight hours, with the exception of portions of Southeast West Virginia who may see a shot of drier air in the mid-levels aiding in their ability to clear out between midnight and sunrise. Early Tuesday, a warm front draped across northern GA into northern SC will begin to inch its way North. Patches of light rain is expected to spread northward along/southeast of the Blue Ridge by mid day. Through this portion of the forecast period, QPF will generally be just a few hundredths of an inch at best and generally confined to areas south-east of the Blue Ridge. Higher amounts will be possible later on Tuesday as convergence and isentropic lift combine along the western ridges. A few rumbles of thunder aren`t out of the question in these areas, but conditions won`t be ideal for large scale development this far east. Convection bleeding over from the Ohio Valley would be the best bet for late February storm lovers. For now, have left thunder out of the forecast, with just isolated/scattered showers and highest accumulations west of the Blue Ridge. Persistent cloud cover and warm conditions will remain the top weather story in the afternoon.
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&& .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... As of 330 PM EST Monday... Expect warm front lifting north across us late Tuesday night. Showers will be situated mainly over the mountains in the evening and as the warm front continues north look for drying a bit into the piedmont. Wednesday still looking a bit active with cold front moving from the Mississippi River Wed morning to the Blue Ridge by evening. Strong wind fields with this system will lead to threat of showers and thunderstorms with gusty to damaging winds. SPC still has our area in a slight risk. Timing is still looking like afternoon/evening starting by noon-2pm WV to 7-9pm piedmont. Once the line moves across moisture dissipates quickly so limited snow shower threat in WV Thursday morning. Best pressure rises post frontal will be Wednesday evening and again Thursday. At the moment seems winds should stay just below advisory levels, but could see some stronger gusts along the Blue Ridge Thursday. Some increase in clouds late in the northwest ahead of a southeast moving front with limited moisture late Thursday night. Will see lows near normal. && .LONG TERM /FRIDAY THROUGH MONDAY/... As of 330 PM EST Monday... Secondary shot of cooler air arrives with a mainly dry front from the northwest Friday. Appears best lift/moisture stays north across the Shenandoah Valley, so it will be mainly low chance pops of snow showers across the mountains of Southeast WV into the Alleghanys. Winds should speed up behind this system Friday afternoon but 8h wind stay under 50kts, and pressure rises are marginal, so most gusts will be under advisory levels. Expect high pressure overhead Saturday to provide close to normal highs for early March ranging from the lower to mid 50s over the area, with some 40s in the mountains. Keeping it dry Sunday with milder temperatures as high pressure moves southeast off the Southeast coast. A front enters the northern tier of the U.S. the slides southeast to the Ohio Valley by Monday. Will see warmer temperatures Sunday-Monday with shower chances increasing Monday. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... As of 630 PM EST Monday... A weak upper-level disturbance producing a rather stubborn mid to upper level cloud deck will continue to push east of the area overnight. This will allow for a brief period of drying in the mid levels of the atmosphere, providing relief for ceilings prior to the arrival of a slow moving warm front approaching our from the Carolinas. A transition from a 5K foot BKN/OVC deck to SCT/FEW layers is expected during the overnight hours Monday into Tuesday, especially for the northern/western airport locations. These dry conditions should also limit any fog development, thus allowing the continuation of VFR conditions through at least the early morning hours Tuesday. A warm front arrives on our southern doorstep overnight, allowing for resaturation of the lower atmospheric levels. This will act to once ago lower ceilings during the day on Tuesday. Early indications have sub VFR conditions impacting KDAN/KLYH as early as mid afternoon, with other sites following suit rapidly. Precipitation chances also increase late in the TAF period, but uncertainty remains on aerial coverage and intensity. For now, have introduced VCSH, but reduction of visibilities may be needed in future TAF forecast runs. Winds shouldn`t be much of a factor this period, remaining sustained below 10KTs, with only localized gusting. Overall, medium to high confidence of VFR+ conditions through sunrise, with uncertainty increasing with ceilings + vsbys as the day continues on Tuesday. Extended Aviation Discussion... A warm front across the southeast states will lift northeast Tuesday before passing to the north of the area on Wednesday. An increase in low-level moisture will likely result in MVFR cigs Tuesday evening, especially along and near the Blue Ridge with moist southeast flow. A few light rain showers may also accompany the front. A cold front pushes east into the area Wednesday into Wednesday night with potential for more widespread MVFR/IFR in showers and thunderstorms. A west to east moving squall line with strong to possibly severe thunderstorms, perhaps a QLCS type convective configuration, will be possible late Wednesday into Wednesday evening in advance of the front. Strong northwest winds along with mountain sub-VFR in upslope low clouds and light precip will likely follow the front for much of Thursday. Expect downslope drying to return VFR to eastern locations by Thursday afternoon with this trend lingering across eastern sections through the end of the week. However another weak clipper area of low pressure looks to track just north of the region by Friday with possible mountain MVFR in at least upslope cloudiness, and possible light precipitation western ridges later Thursday night into Friday. && .CLIMATE... As of 330 AM EST Monday... Record warm Mins for March 1 Roanoke.....52 in 1918 Lynchburg...57 in 1910 Danville....51 in 2012 Blacksburg..45 in 1997 Bluefield...56 in 1997 Record highs for March 1 Roanoke.....76 in 1972 Lynchburg...78 in 1918 Danville....80 in 1972 Blacksburg..72 in 1976 Bluefield...78 in 1997 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...JH/JM NEAR TERM...JH/JM/RAB SHORT TERM...WP LONG TERM...WP AVIATION...JM/RAB CLIMATE...AMS is the U.S. government's official web portal to all federal, state and local government web resources and services.