|Wind||12.66mph from the WNW|
... Surface high pressure centered over the lower Mississippi Valley will build into the southeastern Appalachians later tonight and Thursday. Gusty northwest winds will relax and any lingering show showers will taper off tonight. Temperatures will moderate on Thursday and especially Friday and Saturday. A strong cold front will approach on Saturday and move through the area Sunday.
NEAR TERM /THROUGH THURSDAY/... As of 1025 PM EST Wednesday...
- No big changes this update
- Wind speeds diminish overnight
- Tranquil weather for Thursday
Satellite images showed coverage of stratocumulus over the mountains was shrinking. Have updates cloud cover to reflect these trends. No other changes at this time.
As of 630 PM EST Wednesday...
Still have a decent amount of upslope clouds persisting across the mountains and these will continue into the overnight. A few flurries will continue to be possible along and west I-81, along with continued light snow showers for Western Greenbrier. Snow will taper off tonight.
Upslope clouds decrease around sunrise Thursday and mostly sunny skies can be expected.
As of 325 PM EST Wednesday...
A vigorous upper trough is moving off the mid-Atlantic coast this afternoon with a northwest flow aloft enveloping the region. The strong northwest winds aloft will relax a bit as a short wave ridge axis moves into the TN and MS Valley on Thursday. The latest surface analysis shows a 1030mb surface high centered across the mid- Mississippi River Valley that extends into the OH and TN Valleys. A strong surface low was moving east into the western Atlantic. The strongest pressure gradient between these features was shifting east toward the coastal regions.
Recent visible satellite imagery shows a good deal of stratus and stratocumulus persisting across the higher terrain, especially in the upslope areas. The Winter Weather Advisory for the NC/VA mountains was cancelled early as accumulating snow has ended and conditions were improving. Will keep the advisory up in the Greenbrier area where lingering snow showers are possible into the evening as upstream energy dives into WV. This may result in a few spots with some minor additional accumulations. Mainly clear skies are noted east of the Blue Ridge in the Foothills and Piedmont. Gusty northwesterly winds have already begun trending down and this will continue into the evening. With cold advection, surface temperatures have nudged upward a bit over the past few hours but temperatures are struggling to get above freezing at the highest elevations, the 30s in the mountains and the 40s in the Foothills and Piedmont.
A deep layer northwest flow is expected overnight with the low and mid level flow becoming more west to southwesterly on Thursday. Surface high pressure will build east tonight and into Thursday with the high center located across AL/GA/SC during the daytime Thursday. Lingering snow showers across the upslope areas in WV will diminish this evening but areas of strato cumulus will persist for much of the overnight in the higher elevations. East of the mountains, downslope flow and a drying airmass will result in mainly clear skies. Lows tonight will vary with clear skies and very light winds in the Piedmont and Foothills allowing temperatures to fall into the mid to upper 20s. Across the higher elevations the combination of stubborn clouds and a little bit more wind will keep lows up a bit with lows ranging in the 20s.
Fair weather is expected for Thursday with skies becoming mainly clear and winds backing around to southwesterly. Highs will range in the upper 30s to lower 40s in the mountains to the upper 40s to lower 50s across the Foothills and Piedmont.
Confidence in the near term forecast is moderate to high.
SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... As of 1130 AM EST Wednesday...
1. Mainly dry through early Saturday, but increasing moisture. 2. Temperatures trend above normal.
Upper level ridging will develop over the eastern US in response to an upper trough developing in the west. This trough will push eastward through the second half of the week, reaching the central Plains by Saturday. As it approaches the east, southwesterly flow aloft will increase over the Mid Atlantic, tapping into plenty of moisture from the Gulf and advecting it into the region. This will lead to increasing dew points by the end of the week and beginning of the weekend. Surface high pressure will be situated overhead and help keep the area precipitation free Thursday, Friday and most of Saturday. The surface high will slide eastward into the Atlantic through the period, leading to a warming trend in temperatures, eventually reaching above normal values for this time of year. The cold front associated with the upper trough doesn't look to reach the area until Saturday night, but could see some prefrontal showers develop Saturday evening.
High temperatures will be in the upper 50s to low 60s Friday and Saturday in advance of the cold front. Lows initially be in the mid 30s Thursday night, warming to the mid 40s by Saturday night.
Forecast confidence is moderate to high.
LONG TERM /SATURDAY THROUGH WEDNESDAY/... As of 1150 AM EST Wednesday...
1. Widespread rain Sunday, higher amounts likely along and west of the Blue Ridge. 2. Dry weather to start the work week.
The strong 500mb trough will cross the area through Sunday, and be to the east of the area by Monday. The frontal system associated with the trough will reach the far western part of the area Sunday morning, and then quickly move eastward, as the main surface low tracks northeast from the Great Lakes into southeastern Canada Sunday into Monday. Prefrontal showers could begin in the southeast WV and northwest NC by Saturday night, but the majority of the precipitation will come Sunday. With southwesterly flow ahead of the front and abundant ambient moisture, confidence is increasing that this event will bring widespread rainfall to the region, with highest amounts along and west of the Blue Ridge. The risk of excessive rainfall is marginal at this time, but the ongoing drought will help to mitigate the risk of flash flooding. With increased dewpoints and stronger southwesterly flow, there is a slight chance of thunderstorms for Sunday afternoon, as models are also indicating the development of some surface based CAPE and bulk shear in the east. However, cloud cover through the day will reduce daytime heating and thus diurnal instability. That all being said, confidence at this time is low in the development of any convection, but it cannot be ruled out. Behind the frontal passage, strong cold air advection and steep pressure rises will bring gusty winds and a quick drop in temperatures. Depending when the cold air reaches the area, some snow showers could mix in with the rain west of the mountains Sunday night. For the beginning of the work week, high pressure returns to the area, which will keep the area dry through Wednesday.
Temperatures will drop following the passage of the front on Sunday, so the week will start off with highs in the 40s and 50s, then moderating.
Forecast confidence is moderate to high on the overall synoptic pattern, but low on convective potential Sunday.