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ANZ535 Tidal Potomac From Key Bridge To Indian Head- 1234 Am Est Mon Dec 11 2023
.gale warning in effect through this afternoon...
Overnight..NW winds 15 to 20 kt with gusts to 30 kt. Waves 1 to 2 ft. Rain. Vsby 1 to 3 nm.
Mon..NW winds 15 to 20 kt with gusts to 25 kt. Waves 1 ft. Rain likely. Vsby 1 to 3 nm.
Mon night..W winds 10 to 15 kt. Waves 1 ft.
Tue..SW winds 5 to 10 kt. Waves 1 ft.
Tue night..SW winds 5 kt. Waves less than 1 ft.
Wed..NW winds 5 to 10 kt. Gusts up to 20 kt in the afternoon. Waves 1 ft.
Wed night..NW winds 5 to 10 kt. Waves 1 ft.
Thu..NW winds 5 to 10 kt. Waves 1 ft.
Fri..W winds 5 to 10 kt. Waves 1 ft.

ANZ500 1234 Am Est Mon Dec 11 2023
Synopsis for the tidal potomac and md portion of the chesapeake bay..
a strong frontal system will continue to push south and east of the waters overnight. High pressure will build in Tuesday while a weak cold front tracks through Wednesday morning. High pressure returns during for Thursday into Friday. Small craft advisories will likely be needed Monday evening through early Tuesday morning.

FXUS61 KLWX 110207 AAA AFDLWX

Area Forecast Discussion...UPDATED National Weather Service Baltimore MD/Washington DC 907 PM EST Sun Dec 10 2023

SYNOPSIS
A cold front will push east of the area Monday morning with high pressure set to return Monday afternoon and Monday night.
Dry weather and moderating temperatures are expected Tuesday through Saturday as high pressure sits nearby.

NEAR TERM /THROUGH MONDAY/

Cold front has cleared all of the area except southern MD where temperatures remain in the 60s. Cold air has worked into the Appalachians where snow is now falling based on traffic cameras and sfc obs. However, even there temperatures have not dropped as fast as models had indicated. The forecast overall doesn't seem to have verified well so far with lack of heavy rain and most rainfall totals well under 2 inches. However, light to moderate rain will continue through tonight as deep trough pivots through the area and takes on a negative tilt overnight through 12Z Monday. Based on latest global and hi-res model data, the highest precip totals tonight will be east of I-81. Snow accumulations are likely to approach warning criteria in the Blue Ridge Mountains assuming freezing levels drop fast enough. In the Appalachian region, however, QPF does not appear high enough to meet warning criteria and a substantial amount of QPF will likely melt on contact before accumulating on surfaces.
Overnight, colder air will gradually work its way eastward and I'm expecting a little snow (measureable) accumulation all the way to Route 15 before the precipitation ends around daybreak Monday. East of Route 15, any snow would be very brief with just trace amounts.

SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/
The cold front will continue to push offshore Monday morning with brisk and blustery northwest flow kicking in. Upslope snow showers will continue to fly over the Allegheny Front with perhaps a bit of spillover to the Blue Ridge and Catoctins given high FROUDE numbers and even the potential for a few squalls over northern portions of the Allegheny Mountains. Further east, any residual anafrontal mixed precipitation will come to an end by mid-morning as dry air rushes in. Winter weather headlines remain in place through early Monday afternoon for the Allegheny Mountain locales.

Falling temperatures and gusty northwest winds will be the primary concerns for the short term period. A very tight pressure gradient will set up overhead as low pressure phases to the northeast over New England and high pressure builds from the southwest over the Tennessee River Valley. Expect consistent gusts between 30-45 mph out of the northwest throughout Monday morning into Monday afternoon. Wind Advisory criteria may be met for a period of time over the mountains Monday morning into Monday afternoon where gusts could exceed 50 mph along the western facing slopes. Gale conditions are expected across the waters. Winds will gradually decrease Monday night into Tuesday as high pressure builds over the region.

With the gusty northwest winds in place, expect wind chills in the 20s and 30s (teens in the mountains) Monday afternoon and evening. Actual air temperatures Monday will struggle to get out of the low to mid 40s, with 20s and 30s over the mountains. The cold air continues into Monday night as high pressure builds overhead. Winds will lighten a bit allowing lows to fall into the teens and low to mid 20s.

High pressure takes full control Tuesday with less wind and dry conditions. Highs Tuesday will push back into the mid to upper 40s, with lows in the mid to upper 20s and low 30s.

LONG TERM /WEDNESDAY THROUGH SUNDAY/
Overall, looking at a fairly zonal flow heading into midweek.
Surface high pressure will build in from the south with a weak upper-level trough/front passing through late Wednesday. No precipitation is expected with this system due to ample dry air in place. Some extra clouds may be noted late Wednesday afternoon into Wednesday evening along with a reinforcing shot of chilly air. Highs Wednesday will range from the 30s over the mountains to low 40s over northern and central MD/northern VA.
Slightly warmer conditions are expected south of I-66/US-50.

Dry weather and moderating temperatures will continue for Thursday and Friday due to strong surface high pressure nearby. The models have remained consistent with the overall pattern throughout the workweek, but that consistency breaks down on Saturday as guidance struggles to discern southern stream low pressure developing along the Gulf Coast states.

Some of the latest deterministic/ensemble solutions keep this low pressure south of the region while others lift it northeast toward the coast. With very low confidence in place, have decided to introduce low end precipitation chances late Saturday night into Sunday.

Temperatures will remain at or slightly below average through Thursday before warming into the upper 40s and low to mid 50s Friday through the weekend.

AVIATION /02Z MONDAY THROUGH FRIDAY/

IFR conditions overnight in light to moderate rain. Rain will change to snow at MRB and mixed with snow before ending at rest of the terminals with just a trace of accumulation. NW winds will be biggest impact gusting 30-35 kt overnight through 18Z Monday before diminishing Monday afternoon.

MARINE

Gusty northwest winds are expected behind the cold front overnight through Monday. A Gale Warning is in effect for the waters. Winds will gradually diminish Monday night, but an SCA will likely be needed. High pressure will be nearby for Tuesday and Tuesday night.

Winds over the waters Wednesday increase out of the W/NW with a passing dry cold front and may hover around SCA criteria most of the day. As of now, the best chance for SCAs looks to be in the late afternoon through the overnight in our southern waters, but marginal SCA conditions may warrant issuance earlier in the day. Winds diminish and shift out of the W/SW Thursday afternoon.

LWX WATCHES/WARNINGS/ADVISORIES
DC...None.
MD...Winter Weather Advisory until noon EST Monday for MDZ001.
VA...Winter Weather Advisory until noon EST Monday for VAZ503.
Winter Weather Advisory until 6 AM EST Monday for VAZ025>027- 029-504.
Winter Storm Warning until 6 AM EST Monday for VAZ507-508.
WV...Winter Weather Advisory until 6 AM EST Monday for WVZ055-506.
Winter Storm Warning until noon EST Monday for WVZ501-505.
MARINE...Gale Warning until 1 PM EST Monday for ANZ530>543.

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