Oxon Hill-Glassmanor, MD Weather

What Has Changed

Increased cloud cover a bit this evening as some guidance indicates a period of standing wave cirrus along the Allegheny Front. The next rain potential early next week remains uncertain. Otherwise little has changed to the forecast this week.

Key Messages

- 1) Dry through the end of October.

- 2) Precipitation chances return in early November.

Discussion

KEY MESSAGE 1...Dry through the end of October.

Large scale ridging persists aloft through the end of the week. This results in dry weather and above normal temperatures through the end of October. These mild conditions will prevent any further frost/freeze threats through the end of the week.

At the surface, high pressure settles over the Tennessee Valley tonight while a weakening front approaches from the north, tied to low pressure over the Canadian Maritimes. Without much forcing or moisture, no precipitation is expected, only an increase in high clouds and a wind shift to the north and northeast. The front will stall and further weaken over the area Tuesday, so there won't be much of a drop in temperatures compared to today. Wednesday may be a few degrees cooler with extra cloud cover from a combination of warm advection aloft and onshore flow at the surface.

Strong surface high pressure will build southward along the Mid Atlantic coast in the wake of the weak front. As winds turn southerly Thursday and skies clear, temperatures will rise notably above normal. That trend will likely continue Friday when highs in the mid to upper 70s are possible.

KEY MESSAGE 2...Precipitation chances return in early November.

Upper-level ridging overhead breaks down into zonal flow beginning Friday and into Saturday. Conditions likely start to become cloudier throughout the day Saturday as troughing develops over the Ohio River Valley before heading east Sunday into Monday. This likely brings the first chances for precipitation over the Mid- Atlantic in over a week, although overall breadth and total rainfall from this system remain uncertain at this time.

Aviation

VFR conditions are expected to prevail through Tuesday. Wind direction has been highly variable today but should settle on a west-northwest direction before shifting northerly late tonight as a dry front pushes through. Fog looks to be less likely tonight due to milder temperatures and some mixing along the front.

Winds will become onshore Tuesday night through Wednesday night. While there isn't a clear signal yet, some low clouds or fog are possible, especially at CHO and MRB. Light southerly winds and VFR conditions are expected Thursday as high pressure builds along the coast.

Prevailing VFR conditions are anticipated Friday through Saturday. The next chance for rain showers occurs Sunday with an incoming cold front, but uncertainty remains high at this time. Westerly winds Friday shift easterly Saturday.