Bloomingdale, DC Weather

What Has Changed

A Coastal Flood Advisory has been issued for Annapolis. Otherwise, there have been no significant changes to the forecast thinking for the next seven days.

Key Messages

- 1) Frost or freezing temperatures are possible in many areas tonight and Sunday night.

- 2) Dry weather continues through next week along with generally seasonable temperatures.

Discussion

KEY MESSAGE 1...Frost or freezing temperatures are possible in many areas tonight and Sunday night.

With a large area of Canadian high pressure building overhead through the weekend, conditions will likely become favorable for radiational cooling (light to calm winds, mainly clear skies and a cool background airmass). At the moment, it is unclear which night will be the coldest, although tonight (Saturday night) will have a slight advantage given the position of the high overhead.

The growing season for 2026 has ended along and west of the Blue Ridge and Catoctin Mountains, but continues east of there. Any headlines for frost/freeze conditions will only be issued where the growing season remains active.

For tonight, more widespread cold (possible frost/freeze) conditions are possible as high pressure settles more directly overhead. This would bring the frost/freeze threat for most areas outside the major urban centers (downtown DC/Baltimore) and immediate shore of the Chesapeake Bay. If the colder guidance verifies, then the growing season may end for more areas west of I-95 come early Sunday morning. The high will remain overhead through Monday morning, and the low-level airmass doesn't change appreciably, so frost/freeze conditions will be possible again Sunday night.

Did not make appreciable changes to the previous min temperature forecasts, which are near or below the coldest guidance which performs best in radiational cooling (MOS, NBM 10 percentile and Canadian Regional).

KEY MESSAGE 2...Dry weather continues through next week along with generally seasonable temperatures.

Aviation

VFR conditions are expected to prevail through early next week. There are some hints that a slight uptick in low-level moisture could lead to some patchy fog during the early morning hours through the weekend, though confidence in timing and extent of sub-VFR is low at this time. The NAM and related guidance is by far the most aggressive with this outcome, but is an outlier.

E to SE flow is expected today, with light to calm winds again tonight. Wind direction may be a bit variable, ranging from SE to NE as high pressure passes directly overhead Sunday.

P6SM SKC as high pressure dominates early next week. A dry cold front will cross the area late Monday night with winds shifting to N/NW Tuesday.