Barry Farms, DC Weather

What Has Changed

A small but persistent area of stratocumulus is lingering near and just west of I-95 in northern Virginia, and may expand a bit through daybreak. Otherwise, the forecast is on track.

Key Messages

- 1) Below normal low temperatures give way to a warming trend early this week.

- 2) Above normal temperatures and dry conditions continue through the end of the week.

Discussion

KEY MESSAGE 1...Below normal low temperatures give way to a warming trend early this week.

High pressure will drift southwest through Monday. As a result, expect a continuation of frost and freeze conditions during the overnight periods with seasonable temperatures during the daylight hours.

After a chilly start, temperatures will rebound well into the 60s for much of the area this afternoon. Some stratocumulus are possible at times, but may ultimately be thin and transient.

High pressure will gradually drift southwest toward the central Appalachians tonight into Monday morning. Low-level flow will turn westerly allowing for less of a marine influence. This should set us up for one more good radiational cooling night before temperatures warm under return flow early in the workweek. Tonight will be more of a ridge-valley split type of night with cooler conditions in the valleys/cold pockets/locations along and east of I-95 compared to the ridge tops given the sharp surface inversion/decoupling.

Only minor changes have been made to the previous min temperature forecasts, which are near or below the coldest guidance which performs best in radiational cooling (MOS, NBM 10th percentile and Canadian Regional).

Expect temperatures to rise above normal (upper 60s to lower 70s) by Monday afternoon as the warming airmass mixes to the surface. Minimal cloud cover and light winds will remain persistent.

Aviation

Some ground fog could develop early this morning near IAD, MRB, and CHO. Otherwise, expect VFR with some stratocu possible. NAM and related guidance continues to show more widespread low CIGS and fog late tonight into early Monday morning, with at least some hint of this in other guidance and forecast soundings.

Winds will be light out of the NE this morning shifting to SE this afternoon, then W overnight. W/NW winds AOB 10 kts Monday.

P6SM SKC with light and variable winds as high pressure dominates. A dry cold front will cross the area late Monday night with winds shifting to NW Tuesday.