353 FXUS61 KPBZ 310701 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 301 AM EDT Sat Jul 31 2021 .SYNOPSIS... High pressure will provide dry weather today. Shower and thunderstorm chances return Sunday with a crossing cold front. && .NEAR TERM /THROUGH TODAY/... Building sfc high pressure under NW flow aloft should maintain dry weather today. Dew points should range from 50-55, with high temperatures around 5 degrees below average. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... Dry weather should continue tonight as the sfc high moves east across the region. A shortwave trough, and its associated sfc cold front, is expected to move SE across the Lower Great Lakes region early Sunday, reaching the Upper Ohio Valley region Sunday afternoon/eve. Scattered showers and thunderstorms are expected along and ahead of the front, with coverage being more numerous for areas N of PIT where more favorable upper support is progged. Shear is expected to increase, though available instability and relatively low equilibrium levels could be a limiting factor in thunderstorm intensity. The shortwave and sfc cold front should complete their passage Sunday evening, with shower and thunderstorm chances quickly ending. Dry and cooler than average weather is then expected through Monday night as sfc high pressure builds across the Lower Great Lakes and Upper Ohio Valley region. && .LONG TERM /TUESDAY THROUGH FRIDAY/... A longwave trough is expected to persist across much of the Eastern CONUS through the week. Daily diurnal instability and weak disturbances moving through the trough should result in occasional, mainly afternoon and evening, isolated/scattered showers and thunderstorms-though much of the time is expected to be dry. A gradual warming trend is also expected through the period. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... Sfc high pres undr nw flow alft wl maintain VFR save for lcl peri- dawn fog. .Outlook... Restrictions are likely with a Sunday cold front. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$