Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 140435 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 1135 PM EST Mon Feb 13 2017 .SYNOPSIS... Weak high pressure will build across the region tonight into Tuesday allowing for continued dry weather under diminishing winds. The high exits offshore Tuesday evening, ahead of another cold front arriving from the northwest, and low pressure passing to the south into Wednesday. These features may combine to bring some light rain or snow by midweek followed by blustery and cold weather under high pressure by Wednesday night and Thursday. && .NEAR TERM /THROUGH TUESDAY/... As of 950 PM EST Monday... High pressure will slide through the region tonight and bring us quiet weather through Tuesday. Temperatures will be a bit tricky tonight as it looks like we will see very good radiational cooling conditions early tonight, but mid/upper level moisture will be increasing as a warm air advection pattern develops. Temperatures will level off once more high clouds arrive with the higher elevations starting to warm late. Will go with an early low around 30 east of the Blue Ridge with low/mid 20s in the colder locations west, with some gradual warming late. A strung out frontal boundary will then move into the region tomorrow as one area of low pressure moves through the Great Lakes region and another low moves through the southern Mississippi Valley along the Gulf coast. Low level moisture will remain limited so aside from increasing clouds, there will only be a slight chance for a late day shower/sprinkle for the Mountain Empire of Va and the mountains of NC. Highs Tuesday will be a bit above normal with middle 50s east of the Blue Ridge and upper 40s/lower 50s to the west. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... As of 230 PM EST Monday... Moisture will quickly increase from the west Tuesday night as energy shears east ahead of the residual upper low heading east out of the southwest states. This just in advance of a sharply digging northern stream trough/cold front that will attempt to link with the opening southern wave by early Wednesday within the split flow regime. Models remain rather consistent in tracking the southern surface low from Louisiana Tuesday evening to across South Carolina by late Wednesday before getting absorbed into the frontal boundary offshore Wednesday night. Still appears that much of the precip at least initially will tend to outrun the cold advection behind the front, with most seeing ptype start out as rain over the western third Wednesday evening before spreading east overnight. However soundings do show more isothermal nature espcly across the higher elevations after midnight, with the snow levels lowering by daybreak Wednesday. This as the front arrives and prior to drier air aloft winning out from northwest to southeast during the day. Also with guidance shifting a bit more QPF farther north to start, have boosted snowfall amounts a little mainly above 3000 feet with a couple inches possible from far southwest VA into the NC mountains. Could also see some of the higher peaks farther east see some light accumulation as well as upslope areas across the west with northwest flow behind the front. Otherwise slowed pops down a little Wednesday evening given low level dryness, then spread chance to likelys across much of the region similar to the latest European solution. Expect most precip to finally shunt off to the southeast by early afternoon Wednesday as the front catches up, so only low chances by Wednesday afternoon far south and across the northwest slopes for now. Lows mostly 30s to around 40 Tuesday night with some 20s on the ridges. Then quite chilly Wednesday under increasing northwest winds and deepening cold advection which should hold much of the west in the 30s/lower 40s and 45-50 east. Blustery and cold conditions continue behind the front on gusty northwest winds in the wake of the strengthening low exiting New England and high pressure well to the southwest. May again be close to wind advisory levels along the southern Blue Ridge espcly with guidance showing stronger upper troffiness and more of a pressure gradient during the overnight. However with the jet not overly impressive and subsidence weaker, local guidance suggests just below criteria at this point. Also with an even stronger shot now of cold advection than this last event, expect lows in the 20s with a few teens possible and highs 30s mountains to mid 40s east despite sunshine. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... As of 145 PM EST Monday... Last of the ongoing cold advection in the wake of the exiting cold front from midweek will gradually fade Thursday night as the upper trough lifts out and weak high pressure builds in from the south. This will make for a cold night Thursday night with lows mainly in the 20s before building heights and developing ridging takes hold for late week into the weekend per latest model consensus. Only concerns may be with a weak wave undercutting the eastern ridging along the southeast coast by Saturday night, followed by a passing northern stream shortwave trough associated with a backdoor front on Sunday. Could see a few showers with the southern wave Saturday night, otherwise running dry and very mild from Saturday into early next week with a transitional warmer day on Friday. Given decent warming aloft and westerly flow, going with highs mostly 50s Friday and overall 60s Saturday-Monday and perhaps around 70 piedmont by Sunday. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/...
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As of 1135 PM EST Monday... VFR conditions this TAF period with increasing mid and high clouds over southern Virginia and northern North Carolina Tuesday. As low pressure tracks across the Gulf Coast region, ceilings will lower and rain will spread into the Virginia and the Carolinas. Medium confidence on the arrival time of the rain. Best chance will be across southern Virginia and north North Carolina be after 00Z/7PM Tuesday. A cold front will approach the area Wednesday morning with enough cold air behind it to change the precipitation to snow at KLWB. High confidence that this will not occur until after the end of 06Z TAF forecast period. Low confidence concerning the extent of MVFR or lower ceilings. Mist likely period of these lower ceilings will be after 06Z/1AM Wednesday. Extended Aviation Discussion... The cold front will move in from the west on Wednesday and may bring sub VFR conditions west of the Blue Ridge. Passage of the front and coastal low will bring another round of stronger winds and colder temperatures for Wednesday night and Thursday. The northwest flow will continue to promote some MVFR cigs in the mountains through Thursday. Friday and Saturday will be milder and dry with VFR conditions.
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&& .FIRE WEATHER... As of 300 PM EST Monday... Very dry conditions remain in place this afternoon with humidity levels below 30 percent in most spots and in the teens along and east of the Blue Ridge. Gusty northwest winds also persist with lowering fuel moisture levels under the strong mixing. However expect ongoing gusty west/northwest winds to diminish by early this evening as high pressure shifts toward the region. This should allow a gradual recovery in humidity overnight but still likely below 50 percent in spots until after midnight when better radiational cooling develops. Very dry conditions will persist again on Tuesday although winds will be much lighter and generally westerly at 10-15 mph except still likely breezy along the higher ridges where gusts to 25 mph could occur. This should allow for added drying of fuels during the day, and again especially east of the mountains where winds will maintain a downsloping component. The next chance for any wetting precip will come Tuesday night into midday Wednesday as a storm system passes to the south of the region. Some light rain or snow looks likely especially across southern and western sections where up to one quarter of an inch of liquid could occur. Expecting a sharp gradient farther north with less than a tenth of an inch elsewhere. Another passing cold front by Wednesday afternoon will usher in the next round of increasing northwest winds into Thursday with stronger gusts and lowering humidity likely. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS/JH NEAR TERM...MBS SHORT TERM...JH LONG TERM...JH AVIATION...AMS/MBS FIRE WEATHER...JH/PM

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