Issued: 8pm on Sunday, January 8th 2023
Technical Forecast Discussion
Short Term
A moderate shortwave is currently propagating eastward as a 500 mb vorticity maximum revolves to the east side of the trough. As this feature moves out of the forecast area, the attendant low-pressure system located in the left exit region of the jet will also traverse eastward across the Appalachians. Weak temperature advection, corresponding with weak isentropic ascent is keeping precipitation isolated and light in nature. Nevertheless, with the 546 dm line currently over West Virginia and temperatures just below 32 F a few hundred meters above a 36 F surface temperature, any precipitation that does move over the area will likely consist of both rain and wet snow. No accumulation is expected with these, but roadways may become slick during any shower of precipitation.
The exiting low-pressure system will advect in cooler air and clouds along the backside for a short period tonight and Monday morning. Expect only short periods of sunshine with temperatures rising to the mid 40s Monday during the day with colder temperatures at night around 25 F.
Long Term
A large-scale ridge pattern will build in the wake of the shortwave exiting. Another shortwave is expected to move through the area on Tuesday, but with its origin coming down from the northern Plains states, and a weak mass response, moisture return from the southern states will be weak and precipitation will likely not occur. However, the weak low-pressure system attending this trough will bring more clouds to the area. The longwave ridging pattern, however, will allow temperatures to warm through Friday, increasing about 5 F per day. Tuesday is looking at highs around 47 F, Wednesday around 51 F, and Thursday around 54 F. With warm air advection maximizing Wednesday night into Thursday morning, a modest low-pressure system is expected to develop and move across the region bringing the chance for rain throughout the day Thursday. Some models hint at the chance for a thunderstorm or two to occur with this passage. The system will be accompanied by a deep mid- and upper-level trough which will once again bring cold air back to the region after the precipitation has passed.
