Marine Weather and Tide Forecast for Fredericksburg, VA

KEY MESSAGES
- 1) Southerly flow brings quiet and mild conditions through Wednesday morning ahead of a cold front.

- 2) A strong cold front will bring some light rain and accumulating mountain snow Wednesday afternoon through early Thursday morning, followed by much colder and blustery conditions through Friday.

- 3) A low pressure system may bring snow to the Allegheny Mountains Friday through Saturday night.

- 4) The weather will turn colder Sunday into early next week with weak weather disturbances possible.

DISCUSSION
KEY MESSAGE 1...Southerly flow brings mild conditions ahead of a cold front Wednesday night.

Clouds will continue to thicken overnight, but conditions are expected to remain dry for most. A light rain shower is possible prior to daybreak west of the Allegheny Front.
Overnight low temperatures are forecast to be in the upper 30s and lower 40s. High temperatures Wednesday will push back into the upper 40s and low to mid 50s (upper 30s mountains). Winds will remain light out of the south and southwest at 5-15 mph.

KEY MESSAGE 2...A strong cold front will bring some light rain and accumulating mountain snow Wednesday afternoon through early Thursday morning, followed by much colder and blustery conditions through Friday.

Troughing will dig across the Ohio Valley and gradually move eastward through the day. This will result in SW flow aloft with the FA in the left exit region of a potent jet streak. Guidance continues to hint at a period of steadier rain across potentially the northern half of the FA, with showers areawide.
Aside from the rain, skies will be cloudy, with mild conditions and temps in the upper 40s to low 50s (30s in the mountains).

Through the day, low pressure will develop across PA and move into New England. This will result in a trailing cold front that moves across the area starting Wednesday afternoon in the Alleghenies and eastward Wednesday night. Temperatures will crash below freezing during the evening, with snow continuing on and off through much of the night. A flash freeze is expected during the evening hours as the front moves through. In the Alleghenies, around 1-3 inches of snow is expected, with a few 4" reports possible on the highest peaks. Highest totals are most likely at elevations above 3000 feet in western Grant/western Pendleton Counties.

Biggest uncertainty remains the snowfall forecast in the Alleghenies. Thermal profiles during the day tomorrow are marginal at best, but do support a heavy wet snow above 3500 ft. Below that, snow is still possible, but may struggle to accumulate during the day. Winter Weather Advisories have been issued for western Grant and western Pendleton counties from 7pm Wednesday through 10am Thursday. These areas have the highest confidence for advisory threshold snow, especially at elevations above 3000 feet.

East of the mountains, the cold air will take longer to spill over and will be chasing moisture as it heads eastward. This is always a hard set up to achieve accumulating snow, but cannot rule out a few flurries east of the mountains or a worst case scenario of a coating (especially on some of the hilltops across the north).

Cold and windy conditions are forecast for Thursday. 850 hPa temperatures will crash to around -15 C, which will yield daytime highs around freezing at lower elevations (teens in the mountains).
Northwesterly winds gusting to around 30 mph will make it feel considerably colder, with wind chills holding in the teens through much of the day at lower elevations, and below zero in the mountains. Winds will start to decrease a bit Thursday night, but it will remain cold. Overnight lows are forecast to be in the teens for most, with single digits in the mountains.

KEY MESSAGE 3...A low pressure system may bring snow to the Allegheny Mountains Friday through Saturday night.

One, possibly two low pressure centers will meander through the Great Lakes Friday into Saturday as a series of shortwave troughs result in amplifying long wave troughing into the eastern US. There may be some light snow showers along the Allegheny Mountains on Friday, but the higher chances will arrive Friday night through Saturday night as the main trough approaches. Temperatures may attempt to rise above freezing Saturday in some of the valleys before the cold front pushes through, but profiles will be cold enough for all snow for most locations along and west of the Allegheny Front. Accumulations resulting in travel disruptions are possible. To the east of the Alleghenies, there are mixed signals whether any precipitation falls, but it will be related to the push of warm advection Saturday morning and/or the cold frontal passage Saturday afternoon/evening. Some snow or a mix could occur depending on the timing of any precipitation, but at the moment, impacts appear limited at the lower elevations. For temperatures, Saturday is expected to be the warmest day of the weekend before the cold front pushes through.

KEY MESSAGE 4...The weather will turn colder Sunday into early next week with weak weather disturbances possible.

Temperatures push farther below normal Sunday through Tuesday as troughing remains entrenched over the eastern US. High temperatures will be in the 30s with lows in the teens (teens/20s highs and single digit lows in the higher elevations). Gusty winds could bring wind chill values in the higher elevations below zero. There are low precipitation chances Sunday as a trough axis pushes through as well as some point Monday into Tuesday as the next clipper-type front swings through. As usual, the highest precipitation chances will be in the Allegheny Mountains, with much greater uncertainty to the east. However, thermal profiles would be cold enough to support snow should any precipitation fall.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
VFR conditions are expected to continue through Wednesday morning.
Expect increased high level cloud cover overnight with some showers over the western Alleghenies Wednesday morning into Wednesday afternoon. This light to moderate shower activity eventually spreads east late Wednesday afternoon and evening sometime after 18z/1pm EST. Beyond 18z/1pm EST Wednesday through 6z/1am EST Thursday looks to be the greatest opportunity for temporary sub- VFR reductions. This will be from -RA and perhaps -RASN on the back end of the front as it pushes through. Did PROB30s -RASN at KIAD late Wednesday evening into Wednesday night to encompass the threat. No snow accumulation is expected at this time with temperatures at or above freezing.

Light south/southwest winds continue Wednesday with speeds between 5 to 10 kt. Expect southwest winds to increase Wednesday night before turning to the northwest early Thursday morning. Gusts of 25 to 35 kts are expected along the immediate front and behind it for much of Thursday.

VFR conditions should largely prevail Friday through Sunday.
However, there are low chances of some rain or snow showers Saturday as a cold front moves through. South to southwest winds could gust up to 20 kt Friday into Saturday before turning westerly Sunday with gusts of 20 to 25 kts expected.

MARINE
SCA level southerly channeling looks to continue tonight across the main channel of the Chesapeake Bay, with more intermittent gusts elsewhere this evening. Gusts may linger over wider parts of the Chesapeake Bay into Wednesday morning.

Sub-SCA level winds are expected for the remainder of Wednesday. SCA level winds return with a strong cold front late Wednesday night into Thursday. Winds will switch from the southwest to northwest as the front passes. Along the front itself, the trend has been slightly faster, and the potential for gale-force gusts has increased due to the sudden onset nature. Solid SCA gusts appear likely in northwesterly flow Wednesday night through Thursday night, with a few low-end Gale gusts possible immediately in the wake of the front; this may be handled with SMWs or perhaps a short-fused GLW depending on sudden onset/duration.

SCAs are possible in southerly flow Friday into Saturday. A cold front will move through late Saturday, and additional advisories may be needed in westerly flow through Sunday.

LWX WATCHES/WARNINGS/ADVISORIES
DC...None.
MD...None.
VA...None.
WV...Winter Weather Advisory from 7 PM Wednesday to 10 AM EST Thursday for WVZ501-505.
MARINE...Small Craft Advisory until 7 AM EST Wednesday for ANZ530>533- 536-539>542.
Small Craft Advisory until 10 AM EST Wednesday for ANZ534-537- 543.
Small Craft Advisory until midnight EST tonight for ANZ535-538.