Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 232316 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 716 PM EDT Tue Aug 23 2016 .SYNOPSIS... High pressure over the mid Atlantic shifts further east into midweek allowing a return of more humid weather by the 2nd half of the week. Outside of some mountain thunderstorms, it will be mainly dry with the upper ridge overhead through Friday. && .NEAR TERM /THROUGH WEDNESDAY/... As of 324 PM EDT Tuesday... High pressure is situated over the mid Atlantic but mesoanalysis loop suggesting that moisture is already back on the increase across the Tennessee Valley into the Southern Appalachians. Still influence of drier air aloft per WV will keep it dry over us tonight. Seems the main issue will be if this current sc/cu field dissipates this evening or stratifies as weak subsidence inversion sets up. Will lean toward partly cloudy near and east of the Blue Ridge overnight with mostly clear elsewhere. Fog will be limited to river valleys if at all. Wednesday shows increasing flow from the southwest at 8h with wedge eroding. Models are starting to fire up some convection toward the Southern Appalachians north into WV by the afternoon. Forecast sounding showing some moisture but shallow so will only included slight chance in the west tomorrow. Warmer tonight than this morning but still cooler than several days ago, and actually close to normal for Aug 24th. Lows will range from around 60 in the mountains to lower to mid 60s east. Should see more cumulus develop in the mountains Wednesday with more sunshine east. Highs will be warmer ranging from the upper 70s to lower 80s mountains to mid 80s east. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... As of 330 pm EDT Tuesday... High pressure aloft will start to center over our area Thursday while main belt of westerlies stays across the upper midwest into the Northeast. Showers and storms will be mainly orographically and diurnally driven with coverage scattered in the mountains to little or no coverage east. Friday looks even drier as the center of the high is directly overhead capping much of the region. A few stray showers or storms may fire across the ridges. Temps and dewpoints begin returning to what we had a week ago with highs Thursday in the lower to mid 80s mountains, to upper 80s piedmont, running higher Friday from the mid to upper 80s mountains to mid 90s piedmont. Lows will return back into the mid 60s west to upper 60s to around 70 east. && .LONG TERM /SATURDAY THROUGH TUESDAY/... As of 130 PM EDT Tuesday... During this portion of the forecast, surface high pressure will remain centered over the Carolinas. The prevailing synoptic flow will trend zonal to slightly northwest. The location of the high places southerly flow across the region, especially across western sections. Also, a number of weak disturbances are forecast to progress into or through the region within the northwest flow aloft. The result will be a pattern that will favor daily chances of showers and storms, especially across the western portions of the area. Most of these will be isolated to scattered in coverage. However, on days when the heating of the day coincides with the passage of one of the weak shortwaves, a brief period of enhance coverage is possible. The coverage will also have a greater potential to progress east of the crest of the Blue Ridge. Low temperatures will be around five to ten degrees above normal during this time frame, with highs around 5 degree above normal. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
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As of 645 PM EDT Tuesday... Cumulus field continuing to slowly fade this evening and should dissipate to little more than scattered coverage after sunset. However upstream axis of cloudiness associated with a weak wave aloft and residual surface trough likely to arrive across the west later tonight. This could bring another round of at least mid clouds but appears given dry air that will remain VFR overnight as high pressure drifts slowly east across the region. The only exception likely to be early morning fog mainly at western TAF sites, especially KLWB and possibly KBCB where MVFR/IFR will be possible around daybreak pending late night clouds. Surface high slips east to the Mid-Atlantic coast on Wednesday with weak southerly flow helping moisture increase in advance of a cold front well to the west. This should allow for a more widespread bkn cumulus/strato-cumulus layer by Wednesday afternoon with some lingering mid deck cigs above. Better low level moisture may also lead to widely scattered showers across the far western mountains but likely too isolated near any western taf site to include mention at this point. Otherwise still appears bases, after patchy early morning fog/stratus, should remain VFR on Wednesday with a possible period of MVFR at KBLF/KLWB later Wednesday. Any showers should fade with loss of heating Wednesday evening given lack of much support, making for mostly VFR again overnight outside of late night fog/stratus in the valleys. Extended aviation discussion... Thursday even more moisture will work its way north into western parts of the area on the west side of a departing high pressure. Isolated showers and storms will be possible across the mountains, but for the most part, VFR conditions will still prevail. On Friday, there is a greater chance of showers, and possibly some storms, with the approach of our next cold front. Pockets of MVFR conditions will again occur briefly under the stronger showers or storms. The front lingers in the area during the weekend keeping enough moisture for diurnal mountain showers and storms when periods of MVFR could occur.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...WP NEAR TERM...WP SHORT TERM...WP LONG TERM...DS AVIATION...JH/RCS/WP

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