Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 301426 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 1026 AM EDT Tue May 30 2017 .SYNOPSIS... Series of fronts will cross the Mid Atlantic region today through Wednesday. Wednesday night the strongest front will push into the region followed by cooler and drier air. Showers and thunderstorms return to the area Saturday and Sunday ahead of a developing low pressure system in the Ohio Valley. && .NEAR TERM /THROUGH TONIGHT/... As of 1018 AM EDT Tuesday... There is a weak front over the west side of the Appalachains this morning, with yesterday`s boundary situated from the Tidewater of VA southwest to Northern Georgia. Satellite showing thinning cirrus, with Cumulus forming underneath along the Alleghanys. High-res models showing little development of showers through midday west of the Blue Ridge, but show a little more coverage over the piedmont of NC into portions of southside VA by 18z. Should see some development starting around 2pm over the WV mountains, then weakening as it moves east with main emphasis further southeast with the deeper moisture toward the Tidewater to eastern NC. Still some instability with modified sounding suggesting SBCAPEs of 1000-1500 J/KG in the piedmont, though shear is limited, so any stronger storms will be isolated in nature. No change to the Storm Prediction Center`s marginal risk from Buckingham to Halifax and points east this afternoon. Previous discussion from early morning... Little change in the southeast synoptic flow and location of the large upper low over the northeast United States today or tonight. Highest probability of precipitation will be from North Carolina into eastern Virginia where surface dew points will remain in 60s and there is potential for higher CAPEs with any heating today. Axis of precipitation from west South Carolina to southeast Virginia this morning was along a weak front. Models show bulk of lift and deeper moisture east of Danville after 15Z/11AM. Trof/weak front will drift toward the region from the northwest today. Wind shift may cross the Mid Atlantic states today but not real change in air mass across this boundary. Cluster of showers and thunderstorms over western Kentucky may reach the central Appalachians this afternoon. Hi-Resnmm, Hi-Resarw and NAMnest showed this solution. Given the slow southeast progress of the front, this precipitation may not reach the region until after 21Z/5PM. Guidance has been running too warm for maximum temperatures the past few days. Starting out with abundant cloud cover this morning so have trimmed maximum temperatures for this afternoon. With no change in air mass, lows will be similar to past few nights. Bias corrected guidance accounts for this trends. Kept lows tonight generally in the mid 50s to mid 60s. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... As of 250 AM EDT Tuesday... A broad upper level low pressure system covers the majority of the area east of the Rockies Wednesday. Meanwhile, a Bermuda high resides in the western Atlantic. Both the low and the high will slowly move east during the day Wednesday. The upper low will eventually send a cold front over the region during the late afternoon, clearing the piedmont in the evening. Along with lift from the front, modest instabilities will bring showers and thunderstorms to the region. The higher instabilities for the area will be east of the Blue Ridge where less clouds and maximum heating will occur for the day. High temperatures will range from the mid to upper 70s across the mountains to the low to mid 80s east. The piedmont maybe flirting with highs in the upper 80s by the time convection rolls through. The low level jet is not overly strong, however winds will back to the southwest to help the potential for some strong storms to develop along the Blue Ridge and into the foothills during the afternoon. Diffluence aloft is best over the piedmont which should help promote isolated severe storms between 4p- 7p for areas along and east of hwy 29. The surface front will move to the Mid Atlantic coast by midnight then the dew point front will follow about 6 hours later. Since the dew point front lags behind, we kept clouds in a little longer overnight. High pressure and sunny skies expected Thursday with highs in the 70s west of the Blue Ridge to the lower 80s east. Dry conditions will continue into Friday morning as high pressure skirts over the region. Southerly flow returns Friday afternoon along with the chance for afternoon and evening thunderstorms. Highs Friday will range from the upper 70s west to mid 80s east. Dew points Friday will also creep back into the 60s. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... As of 100 PM EDT Monday... Forecast area then becomes embedded in a zonal, confluent mid-level flow for a large part of late week into the weekend. This is modulated by two primary 500 mb features: a persistent mid/upper- level low and cyclonic flow over the Northeast/Great Lakes, and increasing troughing over the Four Corners leading to greater southwest flow and warmer/more humid conditions from the Plains into the Tennessee Valley. Warmer and increasing humidity levels can be expected through the upcoming weekend, along with a return to a wet weather pattern in a general sense. Timing weak shortwave troughs/vorticity maxima in the confluent flow is difficult; and as such, I`ve kept chances for PoPs lingering through the upcoming weekend into early next week. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... As of 720 AM EDT Tuesday... Stationary front extended from a southeast Virginia to northern Alabama. After a isolated light showers around KDAN through 14Z/10AM, there be little to no precipitation in southeast West Virginia, southwest Virginia and northwest North Carolina through early afternoon, with VFR ceilings and visibilities. A weak front expected by this afternoon will bring a chance of showers and thunderstorms to the mountains, mainly after 21Z/5PM with medium confidence on that timing. Extended Aviation Discussion... A stronger front comes through on Wednesday night with showers and thunderstorms and the associated MVFR to IFR conditions. Then VFR expected for Thursday and Friday before showers and storms increase into Saturday. Exceptions will be any late night river fog, or shower/wet ground induced fog. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS NEAR TERM...AMS/WP SHORT TERM...RCS LONG TERM...AL AVIATION...AMS/JH

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