Marine Weather and Tide Forecast for King George, VA

KEY MESSAGES
- 1) Another frontal system will bring strong southerly winds on Friday.

- 2) Another strong cold front will arrive early next week, bringing strong winds and the potential for severe thunderstorms.

DISCUSSION

KEY MESSAGE 1...Another frontal system will bring strong southerly winds on Friday.

Another low pressure system will be moving through the Great Lakes Friday. The increased pressure gradient will result in gusty southwesterly winds developing. The strongest winds are likely in the higher elevations, where a Wind Advisory remains in effect. Several zones across the Potomac Highlands were added during the daytime hours as there is a consistent signal in the guidance for the strong southwesterly winds to downslope in these areas. There is actually some concern some of the higher peaks in the Alleghenies could have gusts around 60 mph at times. Given the warm advection pattern (which is less conducive to downward transport of winds), confidence was not high enough for an upgrade to a warning at this time. There could be a light shower or sprinkle across northern areas Friday as the warm frontal lift passes, but overall this will be a dry system.

The cold front will push through Friday night with high pressure building in from the west Saturday. Overall there will be minimal impacts on temperatures. In fact, temperatures will likely remain slightly above average through Saturday. Westerly winds may be a bit gusty Saturday across northern areas, but not as strong as Friday. See section below for fire weather concerns this could present.

KEY MESSAGE 2...Another strong cold front will arrive early next week, bringing strong winds and the potential for severe thunderstorms.

A warm front will lift toward the area Sunday ahead of a low pressure system moving into the Great Lakes. Most of the day should remain dry, but showers will likely move into the area Sunday night. Increasing southeast to south winds will keep temperatures above normal.

A strong cold front associated with a powerful low pressure across the western Great Lks will cross the area Monday. Better moisture recovery is expected ahead of this front compared to the one Friday night to result in numerous showers and scattered thunderstorms.
Model trends during the past 24 hrs have shown lower pressure values locally across the area, stronger wind speeds aloft, and better destabilization resulting in an increasing threat for severe weather. The storm mode looks mostly linear this time as opposed to supercells, but the magnitude of the 850-500 mb winds is 20-30 kt stronger than it was yesterday (Wednesday). While the kinematics look a lot stronger with this next system, there is still a high degree of uncertainty with the thermodynamic environment and the exact timing of the frontal passage with recent trends showing an earlier frontal passage prior to peak diurnal heating. Regardless of severe weather, strong winds will accompany this front both in the pre-frontal and post-frontal environment.

Afterwards, longwave trough pattern will establish across the East with strong sfc high pressure settling in keeping a much colder than normal pattern for the middle and second half of next week.

AVIATION /00Z FRIDAY THROUGH TUESDAY/
As of 00Z, VFR returned to the TAF sites and winds were becoming lighter. A wind shift to the S/SW is expected after midnight.

Expect VFR conditions Friday into Saturday. The bigger story will be the gusty southwesterly winds on Friday ahead of another strong cold front. Gusts around 25 to 35 knots are expected before winds shift to west-northwesterly Friday night into Saturday. Some gusts to around 20 kt will likely continue through Saturday afternoon.

Expect sub-VFR ceilings and rain showers by Sunday night as a warm front lifts through the area. Strong cdfnt forecast to cross the area Monday with showers and thunderstorms and strong winds in both the pre-frontal and post- frontal environment.

MARINE
Winds will decrease fairly quickly this evening as high pressure builds to the south.

Ahead of the next cold front, southwesterly winds will increase Friday. SCAs are likely. While gusts could approach gale force, think the wind direction and relatively cooler waters will prevent the stronger winds from reaching the surface due to low level stability. The cold front will push through late Friday night. Advisory conditions in westerly flow may persist through Saturday afternoon, especially across the northern waters.

Southeasterly winds will begin increasing Sunday as a warm front lifts toward the area. Advisories will likely be needed. SCA condtions likely continue through the middle of next week ahead and behind potent cold front fcst to cross the area Monday.
Gales are possible Monday afternoon and night in both the pre- frontal and post-frontal environment. Special Marine Warnings may also be required Monday.

FIRE WEATHER
Friday and Saturday look somewhat concerning in regards to fire weather, although fuel moisture will be a limiting factor.
Except for some isolated areas in the Shenandoah Valley and Potomac Highlands, most of the area will have received a quarter inch of precipitation over the past couple of days.

With that said, a dry frontal system will be approaching the region Friday before moving through Friday night. Ahead of that, very strong southerly winds pick up. The air mass will be extremely dry, and could be locally enhanced in downslope flow west of the Blue Ridge. Current forecast has low to mid 20s RHs in the typical drier valleys.

Saturday may actually be the driest day, behind the frontal passage from Friday night. RH values could drop into the teens to 20s across much of the area. Winds will be on the decline, but will remain somewhat elevated, especially along/north of the interstate 66 corridor, where 15-25 mph wind gusts can be expected.

Gusty winds but increasing RHs are forecast Sunday ahead of another front, which looks to bring wetting rains Sunday evening/night. There is less of a threat Sunday, but any ongoing fires could feel the impacts of some gusty southeasterly flow (20-30 mph gusts).

LWX WATCHES/WARNINGS/ADVISORIES
DC...None.
MD...Small Craft Advisory until 11 PM EDT this evening for MDZ008.
Small Craft Advisory from 10 AM Friday to 4 AM EDT Saturday for MDZ008.
Wind Advisory from 11 AM Friday to 2 AM EDT Saturday for MDZ501-509-510.
Wind Advisory from 11 AM to 8 PM EDT Friday for MDZ502.
VA...Wind Advisory from 11 AM Friday to 2 AM EDT Saturday for VAZ503.
Wind Advisory from 11 AM to 11 PM EDT Friday for VAZ507-508.
WV...Wind Advisory from 11 AM Friday to 2 AM EDT Saturday for WVZ501-503-505.
Wind Advisory from 11 AM to 8 PM EDT Friday for WVZ050-055-502- 504-506.
MARINE...Small Craft Advisory until 11 PM EDT this evening for ANZ530>543.
Small Craft Advisory from 10 AM Friday to 4 AM EDT Saturday for ANZ530>543.