... A weak cold front crosses overnight tonight. High pressure returns for the weekend. Strong storm system to bring a variety of weather conditions early next work week.
NEAR TERM /THROUGH SATURDAY/... As of 930 PM Friday...
Forecast remains on track this evening.
As of 1235 PM Friday...
Stratocu continues to erode from the west-southwest, as low level drier air filters in from that direction, below the inversion. A weak cold front crossing tonight will reintroduce the stratocu, which will persist into Saturday morning, before scattering out from the west as high pressure builds in from that direction.
Not much precipitation is expected with the front, perhaps a light shower or sprinkle in areas in and near the mountains overnight into early Saturday morning.
After clouds and mixing preclude fog and keep temperatures above normal tonight, highs Saturday will be close to normal in the wake of the weak front, in an air mass of primarily Pacific origin.
SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/... As of 115 PM Friday...
High pressure sitting over the Lower Ohio Valley Saturday night will yield a clear and cold morning Sunday. Increasing south- southwesterly flow ahead of an approaching southern stream disturbance should yield fairly mild highs Sunday afternoon, mid to upper 50s for a bulk of the Lowlands with dry conditions expected to hold through Sunday evening.
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... As of 115 PM Friday...
As mentioned in the short term discussion, a southern stream wave emerging off the Southern Rockies will approach the region Sunday night. Concurrently, a weaker northern stream wind max will begin to carve out a mid-level trough across the Upper Great Lakes. Will begin to see some positive phasing of this feature by Sunday night with rain spreading across the region with a bulk of the forecast area on the warm side of the system. This should produce between three quarters to a inch of rain by midday Monday. The resultant surface low tracks up toward the Lower Great Lakes Monday night switching our near surface winds around to the northwest, allowing infiltration of much colder temperatures as well as eventual moisture advection off the Upper Great Lakes. Initially, this should present as a break in steadier precipitation Monday afternoon which could allow for a window of relatively dry conditions which may allow for enough drying of roads for effective pre-treatment with ice melt.
With adequately cold temperatures for ice nucleation and ample moisture fetch off the Upper Great Lakes, would expect to see lake enhanced snow bands during the overnight Monday heading into Tuesday. Could see some additional surface based instability developing with a modicum of filtered sunshine heading into the afternoon hours Tuesday, but moisture trajectories may already be turning more westerly by this point. Still too early to talk specific snowfall amounts, especially with potential for lake enhanced snow, but would expect most of the lower elevations to see their first measurable snow of the year. Outside of the snowfall, will also be quite brisk Tuesday with high temperatures only in the mid to upper 30s across the lower elevations and mid 20s in the mountains with winds across the lower elevations gusting 20 to 25 mph with gusts 30 to 35 mph in the mountains.
High pressure building in Tuesday night into Wednesday puts an end to any lingering snow showers with temperatures slowly recovering to near normal values for this time of the year by Thursday.