Area Forecast Discussion

WHAT HAS CHANGED

Seasonable temperatures and dry conditions for Halloween. No hazardous weather expected through Tuesday with precipitation chances returning by the middle and end of next week.

KEY MESSAGES

- 1) Seasonable temperatures and dry conditions continue through Tuesday. Precipitation chances return late next week.

DISCUSSION

KEY MESSAGE 1...Seasonable temperatures and dry conditions continue through Tuesday. Precipitation chances return late next week.

1033-1035 mb surface high pressure will build in from the north today before meandering over the Chesapeake Bay/Delmarva Sunday into Monday. As a result, expect light surface winds out of the north and northwest today switching to the south Sunday. Temperatures will remain seasonable throughout the weekend with highs in the 60s (50s mountains) and lows in the 40s (30s valleys).

High pressure will gradually move offshore Tuesday into Wednesday as a deep upper level trough approaches from the Tennessee/lower Ohio River Valleys. Guidance continues to show numerous pieces of shortwave energy expected to traverse the base of this trough during this period. Additionally, there is indication that a cutoff low will develop over the southeastern CONUS ahead of this trough pattern. The interaction of these systems is likely to be complex, with it being hard to tell exactly where all of the pieces line up at this stage.The GFS has at least two cutoff lows along the trough itself while the Canadian and Euro have a low along the trough and off the coastal Carolinas. As for timing, the GFS and Canadian are slower compared to the Euro counterpart. With that said, expect dry conditions to continue through Wednesday as high pressure retreats further offshore allowing the ridge to flatten/mid-level dry air to erode. This will allow precipitation chances to increase from the southwest late Wednesday with widespread rainfall Thursday into Friday. High pressure will quickly return behind the system Friday into the upcoming weekend before a more potent trough/push of cold air follows beyond the period.

Monday through Thursday: High temperatures will be in the upper 60s to low 70s east of the Blue Ridge with those along and west in the upper 50s to 60s. Overnight low temperatures will be in the 50s each night.

AVIATION /06Z SATURDAY THROUGH WEDNESDAY/

Prevailing VFR conditions are expected through at least Tuesday. High pressure will build from the north today before meandering over the area Sunday into Monday and pushing offshore by the middle of next week. Winds will be light and variable out of the north today before switching to the south Sunday and southeast Monday at less than 10 kts. Some patchy fog or frost is possible in the river valleys over the next few mornings with ground fog at the local corridor terminals prior to daybreak each morning. Confidence in this is low given ample dry air in place across the region. However, some low chances of sub-VFR ceilings exist late Monday night into Tuesday depending on how the weather pattern evolves.

Sub-VFR conditions may return as early as Wednesday as rain chances return to the forecast. More widespread sub-VFR conditions are expected THursday into Friday as a wave of low pressure crosses the area.

MARINE

SCA conditions (north/northwest gusts 20-25 kts) are expected through early this morning, especially over the open waters. This is largely due in part to northerly channeling. Winds diminish below below sub-SCA levels this afternoon. Sub-SCA conditions look to continue Sunday into Monday with wedging high pressure meandering nearby. Winds will change to the south and southeast as high pressure sits north and east of the area. Speeds will generally be between 5-10 kts.

Winds turn out of the east Tuesday into Wednesday ahead of an approaching low pressure system, but should remain short of SCA criteria until at least Wednesday evening. Thereafter, winds do pick up slightly and could reach criteria Wednesday night.

LWX WATCHES / WARNINGS / ADVISORIES

DC...None. MD...Small Craft Advisory until 9 AM EDT this morning for MDZ008. VA...None. WV...None. MARINE...Small Craft Advisory until 9 AM EDT this morning for ANZ530>543.