Lake City, PA Weather

What Has Changed

There are no changes to the forecast at this time.

Key Messages

1) Dry and seasonable weather will continue early this week before a warming trend mid to late week and eventually chances for rain next weekend.

Discussion

KEY MESSAGE 1... The impressive stretch of dry weather and near normal temperatures continues today and will last for the early part of the work week as the Omega Block gradually breaks down. A northern stream mid/upper shortwave trough, currently over the northern Great Lakes, will slide through Ontario, Quebec, and the eastern Great Lakes Monday but will quickly deamplify due to strengthening quasi-zonal flow across the CONUS. This will allow the large surface high to retreat southwest from its position along the East Coast this afternoon into the Tennessee Valley Monday, which will allow a weak cold front on the western edge of the shortwave to drop in from the north Monday afternoon. This front will wash out over the CWA due to the mid/upper flow rapidly turning quasi-zonal, but strong Canadian high pressure at the surface building in behind it across the Great Lakes Monday night and Tuesday will advect noticeably cooler air into the region, especially near the lakeshore given gusty NE winds. Expect highs Tuesday to fall into the upper 50s/low 60s near the lakeshore, with mid/upper 60s further south, which will be cooler compared to Monday.

The developing quasi-zonal flow pattern mentioned above will be in full force by Wednesday and will continue into next weekend as a subtropical Pacific jet extension, a response to the powerful El Nino, pumps extensive shortwave energy into the West Coast. This will eventually carve out a mid/upper trough and associated large closed low along the West Coast next weekend, helping to build a broad mid/upper ridge over the eastern CONUS. As this all occurs, the Canadian surface high over the Great Lakes Tuesday will retreat off the New England coast the second half of the week, supporting deepening southerly return flow. The end result will be a warming trend Wednesday into next weekend, with temperatures 10 degrees above normal at times. This will also allow the dry weather to continue until a potential cold front late Saturday into Sunday, however, there could be a few showers Thursday night in far NE Ohio and NW PA as a northern stream shortwave and weak cold front try to brush the region. Any QPF would be very light until a more widespread chance for rain late Saturday into Sunday depending on phasing between northern and southern stream energy.

Marine

Quiet marine conditions will continue on Lake Erie for one more day as weak pressure gradients support continued light winds. High pressure drifting into the Tennessee Valley tonight and an approaching cold front will turn winds SW at 5-10 knots until turning N at 5-10 knots by Monday afternoon and evening behind the front. Strong Canadian high pressure building over the central and eastern Great Lakes Monday night and Tuesday will bring a period of stronger 15-20 knot winds, and these could build waves to around 3.5 or 4 feet in the western and central basins. We are continuing to monitor for a potential Small Craft headline Monday night into Tuesday. Winds will turn light again Tuesday night and Wednesday before SW winds increase to 10-15 knots Wednesday night and Thursday, with W to SW winds then continuing through the end of the week.