Area Forecast Discussion
Issued by NWS Blacksburg, VA
Issued by NWS Blacksburg, VA
622 FXUS61 KRNK 142352 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 752 PM EDT Fri Jun 14 2024 .SYNOPSIS... A front will move across our area this evening reaching the southeast U.S. and Gulf Coast states Saturday night. High pressure works in across New England by Sunday keeping us dry. An upper ridge sets up next week with building heat and humidity. && .NEAR TERM /THROUGH SATURDAY/... As of 745 PM EDT Friday... Not much activity this evening, with storms still well north of the area. Still a potential of a few isolated storms over the next few hours, but confidence of anything forming is rather low. Other than that, not much else overnight with maybe just some valley fog forming in the early morning hours. As of 125 PM EDT Friday... Key message: - Marginal risk of thunderstorms with damaging wind this afternoon and evening, but only isolated coverage. Already heated up into the upper 80s around Roanoke late this morning and should expect lower 90s. Caveat is an area of clouds moving across the mountains, which could keep temperatures somewhat lower. High-res guidance highlighting isolated cells developing between noon-2pm across the Blue Ridge and then heading southeast to the foothills/piedmont with lower coverage over WV until late. At the moment leaned this direction. Still coverage looks sparse but with SBCAPEs increasing to 1500 J/kg and elevated DCAPE, any storm that can take off would be capable of producing gusty/damaging winds, hence the marginal risk mainly along/west of the Blue Ridge. Storms should fade this evening but cannot rule out a few pockets of showers through midnight when the front moves across. Humidity levels drop by Saturday but temperatures tonight to stay slightly above normal in the 60s for most, with some 50s across southeast WV and the Alleghanys. Look for mostly sunny skies Saturday and a less humid/seasonable day. Scattered cumulus across the mountains should evolve during the afternoon. A few models suggest isolated showers across the southern Appalachians but looks meager so kept our area dry. Highs will be in the 80s, but dewpoints will be in the 40s and 50s. Forecast confidence is average on pops this afternoon/evening but above average on temps/winds and sky through Saturday. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... As of 1230 PM EDT Friday... Key Points: 1. Well above normal temperatures Monday. 2. At best isolated late afternoon showers/storms over the mountains. 3. Vast majority of the region will receive no rain. A look at the 14 June 00Z NCEP Ensemble Mean 500 mb Geopotential heights shows an upper level ridge over the Midwest advancing towards our region Saturday night. By Sunday, this ridge is expected to be centered over our region and stall all while strengthening through Monday and Monday night. At the surface, on Saturday night, high pressure is expected to be over Quebec/NY with a ridge axis extending southeast into the eastern Mid-Atlantic region. As we progress into Sunday and Monday, this high shifts east into the western Atlantic where it takes on more of an elongated ridge axis pattern that extends southwest back into portions of the Mid- Atlantic and Southeast US region. Output from the 14 June 00Z Ensemble Situational Awareness Table shows 850mb temperatures in the +14C to +16C range Saturday night. For Sunday into Monday values trend warmer each day with Monday seeing a range of +18C to +20C across the region. The high end of this range is expected to be across the western sections of the area. Portions of Southeast West Virginia, these numbers are expected to represent values in the 97.5 to 99 percentile of the 30- year climatology. Values within the 92 to 97.5 percentile are as far east as roughly the crest of the Blue Ridge. While 850 mb temperatures will well on the warm side of normal, so too, will be the 700 mb temperatures. During this portion of the forecast values of +6C to +8C Saturday night. These will be the lowest values for the remainder of the period. For Sunday and Monday values close to +9C to +11C or +12C are expected across the area. These values are no lower than the 90 percentile of the 30-year climatology. Many sections will have values with the 97.5 to 99 percentile of climatology with a few spots within the 99 to 99.5 percentile range. These high positive anomalies are at the highest and most expansive on Monday. A building ridge at the surface, up through the mid-levels of the troposphere, will provide for well above normal temperatures across the area by Monday. Additionally with no substantial mechanisms of lift and substantial capping inversion aloft, precipitation chances will be very low. About the only chance of precipitation will be over the mountains. By Sunday/Monday, with the position of the ridge axis where forecast, there will be a weak onshore flow from the Atlantic heading weakly upslope across the mountains. This potential weak upslope moisture flux, combined with peak heating of the day could allow for very isolated showers/storms, assuming an updraft finds a weak spot in the strong cap aloft. Confidence in the well above normal temperatures is high. Confidence in the occurrence of showers/storms is low/moderate. Confidence is specific location of any showers/storms is low. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 1230 PM EDT Friday... Key Points: 1. Well above normal temperatures continue. 2. Still, at best isolated late afternoon showers/storms over the mountains. 3. Vast majority of the region will receive no rain. A look at the 14 June 00Z NCEP Ensemble Mean 500 mb Geopotential heights shows an upper ridge over our region strengthening to an average of a 5940m closed high over much of the mid-Atlantic and New England region by Tuesday and Wednesday. By Friday, the average 5940m height remains, but is smaller in area, centered over PA. At the surface, A west-east oriented high pressure ridge remains over portions of the Mid-Atlantic region on Tuesday, but there are hints that by Friday this axis will have shifted slightly farther north. Output from the 14 June 00Z Ensemble Situational Awareness Table shows 850mb temperatures very comparable to, or even slightly higher than, those anticipated on Monday. Temperatures are expected to range from roughly +19C to +21C, with the Southeast West Virginia being the central of positive heat anomaly with values there with the 97.5 to 99 percentile of the 30-year climatology. Values within the 92 to 97.5 percentile extend east into portions of the NC and VA Piedmont regions. At 700mb, while not as significant as the first half of the week, forecast temperatures around +9C to +10C will place the region. This range falls within the 90 to 97.5 percentile of the 30-year climatology. So, the region will continue with temperatures well above normal. The same type of weather scenario expected the first half of the week is expected to continue the second half for the same regions. Temperatures will be well above normal, and any precipitation will be late afternoon isolated showers/storms across the mountains. Confidence in the well above normal temperatures is high. Confidence in the occurrence of showers/storms is low/moderate. Confidence is specific location of any showers/storms is low. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... As of 745 PM EDT Friday... Could have some fog late tonight near LWB, but confidence is not very high. Winds will be less than 10 knots out of the southwest to west ahead of the front this evening, then northwest to north behind the front tonight with winds remaining northerly through tomorrow. Other than patchy valley fog overnight, VFR expected through the 24HR TAF period. Average confidence for ceiling, visibility, and wind. EXTENDED AVIATION OUTLOOK... High pressure will build back over the region for the weekend and into early next week. Aside for some morning river fog in the mountain valleys, conditions are expected to be primarily VFR. The chance of showers and thunderstorms will be limited for much of next week. && .HYDROLOGY... As of 1230 PM EDT Friday... With a prolonged period of well above normal temperatures, and very little, if any, precipitation, our drought conditions are expected to either remain the same or worsen heading into next week. The next official drought monitor intensity analysis will be issued on Thursday, June 20, 2024. The national drought monitor intensity analysis can be found at droughtmonitor.unl.edu. One can examine the monitor at the state level and read discussions about the current intensities on the map by selecting options from the various pull down menus at the top of the page. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...WP NEAR TERM...BMG/WP SHORT TERM...DS LONG TERM...DS AVIATION...BMG/WP HYDROLOGY...DS