... Cooler and dry conditions continue with northerly flow. A crossing cold front on Tuesday could develop isolated showers in the afternoon, primarily east and south of Pittsburgh. Generally dry weather will continue through much of the week.
NEAR TERM /THROUGH TUESDAY/... Dry conditions continue through tonight with sfc high pressure in place. Latest runs of the RAP/HRRR smoke models indicate smoke will continue to blanket the region into Tuesday.
Light wind and mostly clear overnight sky (despite smoke, which does not inhibit outgoing longwave radiation) should support radiational cooling. Low temperatures will be near seasonal average.
Upper low pressure, currently east of Cape Cod, will shift towards Newfoundland on Tuesday. Moisture starved shortwave troughs will rotate around the west side of this low toward the region, but little more than some cu coverage is anticipated for much of the area. A small exception can be made for the eastern forecast area where the ridges may provide some lift for a few showers/thunderstorms Tuesday afternoon.
SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... Wednesday is likely to remain dry areawide. Overall, significant precipitation is not expected, our current 15 day dry spell will continue at KPIT.
Afternoon RHs will dip into the mid/upper 20s areawide on Wednesday afternoon. Coupled with breezy conditions, there is elevated concern over fire danger. See the Fire Weather section below for more details.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... The upper low will meander across the Maine/New Brunswick/Nova Scotia area through Saturday before ejecting east. Additional shortwave troughs are expected to rotate across our area Thursday and Friday. This will boost PoPs into the S Chc/Chc range primarily north and east of Pittsburgh.
Global Ensembles continue to indicate another trough dropping into the Great Lakes in the Sunday to Monday timeframe. This should finally return widespread rain to the area by the end of the period. Have kept close with National Blend, which keeps chance PoPs areawide Sunday evening.