... A stationary front will remain near the Chesapeake Bay through Monday before pushing offshore. High pressure will then build across the area for much of the work week, with a cold front approaching by the end of the week.
NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Scattered showers, and even a few thunderstorms remain ongoing this evening. Instability is unimpressive across the area (MLCAPE 500-1000 J/kg), and should only decrease over the next few hours with loss of daytime heating. As a result, expect that the ongoing showers and storms should gradually weaken over the next few hours. Conditions should stay mostly dry overnight, but can't rule out an isolated shower while the main mid-upper level trough axis swings through. Winds will become light to even calm in some places, so if skies clear out, some patchy fog may develop. Locations to the west of the Blue Ridge that saw appreciable rainfall this afternoon/evening will have the greatest chance to see fog develop. Lows overnight will range from the upper 50s to near 60 in the mountains, to the mid 70s in downtown DC and Baltimore.
SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... By around midday tomorrow, the main trough axis will be situated off to our south and east. Meanwhile an upper level low will be located well off to our north-northwest over the Great Lakes. This should place our area in a zone of subsidence in the wake of the mid-upper level trough axis. As a result, expect that most of the area will remain dry, with skies gradually clearing throughout the day. Can't rule out a rogue shower or two, especially across far northern or far southern portions of the forecast area, but again, most locations should stay dry. Highs tomorrow will range from the mid 80s to near 90.
With the trough axis past, the remainder of the short term period looks dry and fairly quiet. Still seasonably hot, with lows mainly in the 60s and highs Tuesday in the upper 80s to near 90.
LONG TERM /WEDNESDAY THROUGH SUNDAY/... Upper level ridging over the Ohio Valley will continue to shift eastward Wednesday, resulting in surface high pressure dominating the region. This will induce a warming trend throughout much of the long term, resulting in hot/humid conditions persisting. With a upper level westerly flow, but southerly flow at the surface, cannot rule out a stray shower or storm over the mountains due to orographic lifting. However the ridging should suppress most activity.
Hot and humid conditions are expected to continue through the weekend as the jet stream becomes displaced well to our north; with upper level ridging amplifying over the southern CONUS. While conditions are expected to remain mostly dry, cannot rule out chances for pop-up showers/thunderstorms in the afternoon via convective heating. Also given the synoptic pattern, subtle shortwaves will have to be monitored which could aid in the development of potentially stronger storms.