... Low pressure tracks south of the area tonight, bringing rain quickly changing to snow to the area. Cold high pressure Friday. Next system mid-late weekend into early next week.
NEAR TERM /THROUGH TONIGHT/... As of 1025 AM Wednesday...
Minor update to tweak temps and increase sky cover for the rest of today as low overcast should prevail except for some breaks possibly in the Greenbrier Valley. Expect freezing drizzle to wane or just turn over to some flurries in the mountains by noon.
As of 742 AM Wednesday...
Investigated the weak radar returns north of CRW and found webcams showing evidence of drizzle making it to the surface. Webcams at Snowshoe appear to show it drizzling at times there with some personal weather stations showing temps in the low 20s. NAM time/heights show clouds remaining warm enough for drizzle before perhaps cooling enough for some flurries later this morning into the mountains. So, forecast was updated to include some patchy drizzle and areas of freezing drizzle in the mountains, with some light glazing possible for the next couple of hours there. Will highlight this light glaze with short duration SPS.
As of 515 AM Wednesday...
The majority of the day is expected to remain dry, but mostly cloudy, as an upper level shortwave trough approaches. Temperatures are expected to remain on the chilly side today, generally remaining within the 30s in the lowlands and 20s to 30s in the mountains. Precipitation chances will increase from south to north late this evening into tonight as the surface low associated with this shortwave passes by to the south. Precip will gradually come to an end west to east late tonight as the system pulls away, though upslope snow will likely continue over the mountains.
Precipitation may start out as a rain or a rain/snow mix over the southern portion of the CWA this evening, but will transition to all snow during the night. Snow amounts are expected to be greatest to the southwest with forecast totals generally between 2 and 3 inches and up to 4 inches possible in some locations. Amounts steadily decrease to the northwest where minimal snow amounts are expected. A Winter Weather Advisory has been issued for the southern/southeastern counties of the CWA from 6PM today through 7AM Thursday.
SHORT TERM /THURSDAY THROUGH SATURDAY/... As of 510 AM Wednesday...
The southern stream snowstorm exits quickly first thing Thursday morning, however, upslope flow in its wake only gradually wanes, as high pressure only slowly approaches from the west. Low level moisture, and temperatures in the shallow cloud layer right in the wheelhouse of the favored dendritic growth zone, spell snow showers or at least flurries just about anywhere the cloud layer is at least 2 kft thick, in and near the mountains.
Upslope snow flurries may actually tick back up for a time overnight Thursday night, as a northern stream upper level low digs southeastward through New England, enhancing and deepening the northwest flow, while holding the high at bay to the west. Upslope flow clouds in and near the mountains should break up and mix through by midday Friday, allowing for abundant but ineffective sunshine area wide Friday afternoon.
The high will finally settle into the area Friday night, with clear, calm conditions. However, high and even mid cloud ahead of the next system will arrive late, and then increase, lower and thicken on Saturday. Precipitation associated with that system should hold off through much of the area Saturday, but may be fast approaching the Tug Fork area by evening, where is should have warmed sufficiently for rain there by then.
Central guidance temperatures generally accepted, except to lower lows a bit Thursday and Friday nights, which will compete for the coldest based on air mass Thursday night, and then radiative cooling Friday night, depending upon interference from high and mid cloud late. Lows will generally be in the teens on these two nights, with highs struggling to reach freezing across the lowlands Thursday and even Friday. Highs Saturday do get a little closer to normal, with milder air arriving ahead of the next system.
LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... As of 510 AM Wednesday...
Yet another in a parade of southern stream systems Miller Bs through the area Saturday night through Tuesday. There may be snow, mainly to the north and east, as the precipitation overspreads the area Saturday night, but milder air should result in rain throughout much of the area by sometime Sunday morning, as surface low pressure pulls into the lower Ohio Valley. Sunday will be a rainy day as low pressure moves up the middle Ohio valley. However, snow or mixed wintry precipitation may persist or only slowly change to rain in the mountains from south to north, depending upon how long the cold air holds on there, as a cold air damming wedge sets up between the primary low center, and a secondary center or warm wave forming off the Virginia coast.
The air mass cools back down Sunday night and Monday, as the primary center fills over the middle Ohio Valley, in favor of the secondary taking over off the middle Atlantic seaboard. The precipitation mixes with or changes to snow overnight Sunday night, which then continues Monday. However, the precipitation also diminishes to lighter showers. Lower temperatures and greater shower coverage in the mountains, as the filling primary low center allows upslope flow to develop Monday, could lead to accumulating snow there. Have highlighted this potential in the HWO there, together with the snow or mixed precipitation possibility on the front end of the system Saturday night into Sunday.
Upslope flow, lake effect and upper level low driven showers, mainly snow, continue Monday night into Tuesday, before only gradually diminishing thereafter, with additional accumulations possible in and near the mountains, as the system only slowly pushes east. Models are actually fairly well converged on this slow timing for a system at these forecast projections.
Central guidance temperatures reflect a quick sneak peak to near normal Saturday night through Sunday night, and then back below normal, and cold enough to support mainly snow throughout the area, during the early portion of the next work week.