Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
130 FXUS61 KLWX 280145 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 845 PM EST Thu Nov 27 2025 .SYNOPSIS... Low pressure lingers over southeastern Canada while high pressure builds across the Midwest and Tennessee Valley through Friday. High pressure moves overhead Saturday, then pushes offshore Sunday into early next week. Several weather systems could bring wintry precipitation to parts of the region Sunday into early next week. && .NEAR TERM /THROUGH FRIDAY/... Stratocumulus clouds remain more widespread east of the mountains than most guidance has suggested. The area encompassed does seem to be fluid, but would expect some cloud cover to continue to spill across the divide through the night given Froude numbers over 1. Some flurries can`t be ruled out, especially west of I-81, although substantial surface dew point depressions and downslope subsidence will likely limit what reaches the ground. It is going to be even colder tonight as temps fall to the 20s, with teens in parts of the Alleghenies. Winds remain elevated through the night so wind chills in the teens will be widespread, and in the single digits for the mountains. Upslope mountain snow showers increase in coverage and intensity tonight as the main upper trough digs into the central Appalachains. Around 2 to 4 inches of snow is expected in western Grant and western Pendleton counties, where a Winter Weather Advisory has been issued. Elsewhere, 1 to 2 inches are possible along and west of the Allegheny Front. Would not be surprised by some isolated 3 inch totals in Garrett County given proximity to deeper moisture to the north, although this is not reflected in most models QPF. Cold temperatures, sufficient lift through the DGZ, and high SLRs (currently forecast at 20:1 but given the fluffy nature of this snow, could end up being higher) make conditions favorable for snow to accumulate. Some limiting factors will be limited moisture due to not directly feeding from the Great Lakes. Also, strong winds (gusting 30-40 mph) will also limit snow totals in some areas. Still, the 12Z HREF and most of the high res guidance point toward several inches of snow for those favored upslope areas along and west of the Allegheny Front tonight. The gusty winds and cold surface temperatures may also result in difficult travel despite the relatively light amounts. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... The main upper trough moves through the region Friday morning into the afternoon as cold air continues to advect into our area. Highs Friday struggle to reach the low 40s east of the Blue Ridge, and will be in the mid to upper 30s for the I-81 corridor. The mountains remain below freezing. Mountain snow showers continue through Friday afternoon, then come to an end by Friday evening. Most of the snow accumulation is expected to finish by Friday morning, so additional snowfall will be mostly light. However, there is going to be a period of time during the afternoon when upper dynamics are favorable for snow squalls. While overall coverage and location are still uncertain, any areas that do see heavier bursts of snow will have to deal with slick travel conditions and low visibility. This is going to be an issue for corridors along/west of the continental divide, so thinking of I-68, US-219, US-50, US-48, and US-33 that from Garrett, Grant, and Pendleton counties westward. Those who intend on traveling Friday afternoon in these areas should be mindful for rapidly changing conditions if snow squalls move through. High pressure builds in quickly behind the departing trough Friday night, then the high slides overhead on Saturday. Mountain snow showers come to an end Friday night, with dry conditions for Saturday. The coldest temps during this stretch are most likely Friday night with mid teens to low 20s across the area. A cold and mostly sunny Saturday as highs reach the mid 30s to low 40s. High level clouds filter through the day as the next, potent shortwave trough approaches from the OH Valley. Precipitation could begin as snow or a wintry mix in the mountains late Saturday night. However, there remains a lot of uncertainty regarding when precipitation begins, and how quickly the wet bulb effect can eat away at the dry air at the surface. Additionally some wintry precip is possible in parts of the Shenandoah Valley and maybe east of the Blue Ridge (though will have to overcome that dry air before temps rise after sunrise). Those traveling Sunday are advised to keep an eye on the forecast as confidence increases toward a particular solution. && .LONG TERM /SUNDAY THROUGH THURSDAY/... A more active weather pattern is likely to build over region late this weekend and continue to the early parts of next week bringing multiple chances for wintry precipitation. The first chance in the long term period for wintry precipitation will occur Sunday into early Monday morning as a strong sfc low passes to the north with it`s attending front moving through our region on Sunday. As precipitation associated with the front moves into the region, cold air in place ahead of the boundary may allow for some front end wintry precipitation. Additional wintry precipitation will be possible on the back end side of the front as cold air rushes into the region. Model guidance continues to have considerable spread on precipitation types with freezing rain and snow possible. Based recent trends,the best chance for impactful wintry precipitation at this time will likely be in areas along and west of the I-81 corridor. A brief lull in precipitation is likely on Monday, but a strong coastal low passing to the south of the region will bring another round of precipitation to the region Tuesday into Wednesday. Weather models have a range of solutions for the Tuesday event with some solutions having a combination heavy rain and some wintry precipitation and other solutions indicating the chance for a decent accumulating snow event. National Blend of Model plume graphics really shows the uncertainty with snow solutions ranging from 0 inches to near 15 inches of snow. At this time, we continue to have low confidence in the wintry threat early next week, but it`s a period of note worth keeping an eye on for planning purposes. && .AVIATION /01Z FRIDAY THROUGH TUESDAY/... VFR conditions are forecast to persist through Saturday. The main aviation impact is going to be from strong wind gusts through Friday. While winds may be relatively lighter tonight, some gusts of 20-25 kt could occur at times. Winds pick up more dramatically after sunrise, with peak gusts around 30-35 knots expected Friday late morning to afternoon. Winds decrease Friday evening into Friday night. Light winds expected for Saturday. Aviation restrictions are possible Sunday into early Monday due to a frontal passage with another chance for restrictions towards the middle parts of next week. && .MARINE... Hazardous marine conditions are expected to persist over the waters through the end of this week as cold west to northwest winds continue. Small Craft Advisories are now in effect through Friday night for all the waters. A period of near gale force gusts will be possible Friday morning to mid afternoon for the Chesapeake Bay north of the Bay Bridge, and the upper tidal Potomac River. These ares will see gusts in the lower 30 kt range. The rest of the waters will see gusts between 25-30 knots. Winds slowly diminish Friday night, and should fall below SCA levels by sunrise Saturday. Small Craft Advisories will likely be needed Sunday through early next week with gale conditions possible. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...Small Craft Advisory until 4 AM EST Saturday for MDZ008. VA...None. WV...Winter Weather Advisory until 9 AM EST Friday for WVZ501-505. MARINE...Small Craft Advisory until 4 AM EST Saturday for ANZ530>543. && $$ SYNOPSIS...KRR NEAR TERM...ADS/KRR SHORT TERM...KRR LONG TERM...JMG AVIATION...ADS/JMG/KRR MARINE...ADS/JMG/KRR