... High pressure will provide dry and chilly weather tonight. Approaching low pressure will bring rain by Saturday afternoon and evening, with snowflakes mixing in during the night and into Sunday morning. Another high then follows, with dry weather into early next week.
NEAR TERM /THROUGH TONIGHT/... Precipitation has ended across the CWA as low-level moisture has decreased behind the cold front. NW flow stratocumulus linger across the area, but due to the lack of moisture, no precipitation is expected outside of a stray sprinkle or flurry.
With surface high pressure and mid-level ridging arriving tonight, clouds will be on the decrease. They will linger a bit longer north of Pittsburgh thanks to the NW flow off of Lake Erie. Temperatures will drop into the mid and upper 20s thanks to the clearing sky and diminishing wind.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... The departing high will help to keep the region dry Saturday morning, although clouds will be on the increase as flow turns southwest aloft. This will occur in advance of the next shortwave trough, which will transition from a positive to a neutral tilt as it approaches Saturday and crosses Saturday night, along with surface low pressure. PWATs will increase to around 0.75 inch once again, with the surface/upper systems and isentropic upglide providing support for lift. The result will be another round of precipitation for the region from Saturday afternoon into Sunday morning, with precipitation tapering off Sunday. Total liquid QPF through the event will generally range between 0.25 and 0.50 inch.
All rain is expected at the onset on Saturday, with most locations reaching the mid 40s for high temperatures. Cold air wrapping in behind the departing low will allow some snow to mix in Saturday night, with most locations seeing at least some flakes. However, due to the initially warm ground and with the dendritic growth zone far above the ground, accumulations will be limited to under a half inch in most cases. With the deeper moisture departing later Saturday night, the presence of ice crystals in the clouds will become a bit more questionable, which could lead to some patches of freezing rain/freezing drizzle. Expect any impact from this to be minor and limited in areal coverage at this time, but the possibility of a light glaze in a few areas will need to be monitored.
A few rain/snow showers may linger in post-system NW flow Sunday morning, but developing low-level ridging should help to mostly clear these out by mid to late afternoon on Sunday. Although stratocumulus will be on the increase Sunday night, mid and upper clouds will arrive once again in developing southwest flow aloft.
LONG TERM /MONDAY THROUGH THURSDAY/... High pressure will keep dry weather in the area Monday and through most of Tuesday, with temperatures rising to above climatology in ongoing southwest flow.
The models continue to struggle with the system which will impact the region in the Tuesday night-Wednesday period. The general consensus rips a low pressure center across the Great Lakes Tuesday night, with a cold frontal passage in our area on Wednesday, but a wide variety of system tracks and strengths are evident on ensemble plots. The vast majority of precipitation will likely be liquid in any case as a significant cold push is not expected behind the system. High pressure should provide dry weather for Thanksgiving and Friday, along with seasonably chilly temperatures.