textproduct: Wakefield

WHAT HAS CHANGED

Temperatures lowered slightly for tonight. Snowfall forecast for Sunday added, though uncertainty remains high.

KEY MESSAGES

1) Wind chill values in the teens are forecast late tonight. Colder but mainly dry through Friday. There is a low-end chance for some light precipitation on Saturday, mainly across the VA piedmont.

2) There is the potential for wintry precip across portions of the area on Sunday. Uncertainty remains very high regarding specific impacts.

3) Another surge of Arctic air arrives for early next week, with below normal temperatures to continue through the first half of next week.

DISCUSSION

As of 235 PM EST Thursday...

KEY MESSAGE 1...Wind chill values in the teens are forecast late tonight. Colder but mainly dry through Friday. There is a low-end chance for some light precipitation on Saturday, mainly across the VA piedmont.

Diminishing winds, clear skies, and a cold/dry airmass in place will allow for frigid overnight temperatures tonight. Had to undercut the NBM temperatures for tonight to account for this and leaned closer to the statistical guidance, which was in pretty good agreement. This yielded overnight lows in the mid to upper teens W of I-95, around 20 in the inland east, and mid 20s right along the coast where winds will be higher. Not quite cold enough for a Cold Weather Advisory, but will see wind chills in the low to mid teens around sunrise tomorrow. High pressure slides by to the south tomorrow, turning winds back to the SW. The pressure gradient between the high and low pressure near MI will be enough to support breezy conditions with gusts up to 20mph. Temps will still be below average tomorrow, but not quite as cool as today with highs in the low to mid 40s.

A large UL trough over the central CONUS pivots/translates toward the eastern US Saturday. At the sfc, low pressure progresses towards New England and a cold front is dragged toward the local area. This may result in light precip, particularly over the NW. This could start out as snow across the NW border before sunrise, then transitioning to rain. It seems the vast majority of the moisture gets hung up on the other side of the mountains, though, so not expecting any sort of accumulation. Highs on Sat in the upper 40s across the N and in the 50s elsewhere.

KEY MESSAGE 2... There is the potential for wintry precip across portions of the area on Sunday. Uncertainty remains very high regarding specific impacts.

The late weekend period is still fraught with uncertainty. A deep UL trough digs into the Southeast CONUS and sfc low pressure looks to form somewhere near the southeast coast before lifting NE. Still seeing a variety of solutions from the 12z/15 suite. Both the deterministic GFS and ECMWF develop a weaker/broader low further from the local coast. Despite the similarity, the GFS is still more aggressive with throwing moisture N. Meanwhile, the Canadian and NAM12 are a bit stronger with the low and closer to the coast (albeit with timing differences). Will note that something that is consistent between the models is the southward trend of the high pressure originating out of Canada. All of the global models more or less take the high down to Texas, which would make it difficult to lock in the cold air needed for snow accumulation. Did not stray too far from the NBM given the range of solutions here. This brings precip up from the S starting early Sunday with highest PoPs (60- 70%) along the SE coast during the afternoon/evening period, tapering to ~30% heading toward the NW. Precip then pushes offshore Sunday night. Wx type starts out as a rain/snow mix for the bulk of the area excluding Hampton Roads and NE NC, then transitioning to all snow by Sunday afternoon/evening. There is certainly the possibility of Hampton Roads and NE NC staying all rain until after sunset if the cold air doesn't get that far southeast.

Hard to key in on an accumulation forecast at this point, so will focus on ensemble probabilities for now. Similar to its deterministic counterpart, the GEFS is more aggressive than the Euro Ens for the 1" probs. It shows 40-50% probs in the far south and 30- 40% up to Richmond and the Maryland Eastern Shore. The ECMWF ens is still a lot more suppressed and keeps most of the area in less than 30% for 1", 30-40% in the far south. Will also note that there is a 10-20% for 3" across most of the area in the GEFS and in the far SE in the Euro ens. The first cut of a storm total snowfall forecast has less than an inch for most with an area of 1-1.5" near the Northern Neck and upper Eastern Shore. Do note that this does not include anything that would fall after 00z Mon.

KEY MESSAGE 3...Another surge of Arctic air arrives for early next week, with below normal temperatures to continue through the first half of next week.

Arctic air is likely on the way behind Sunday's system. Frigid temperatures are expected for at least the first half of next week. Overnight lows in the teens are expected Sun night-Tues night. Cold Weather Advisories are possible Mon night given forecast wind chills in the single digits across the N and W. While day-time temps will be rather chilly each day, Tues looks to be the coldest day with highs struggling to make it above freezing.

AVIATION /00Z FRIDAY THROUGH TUESDAY/

As of 645 PM EST Thursday...

VFR conditions are expected to prevail through the 00z TAF period. WNW winds around 10 kt with gusts up to 20 kt become W and gradually diminish to 5-10 kt overnight. Winds become SW/SSW and increase to around 10 kt with gusts up to 15-20 kt Fri. Otherwise, mostly clear skies continue through tonight with high clouds increasing in coverage mainly across the Piedmont on Fri. Clouds increase Fri night along with SW LLWS.

Outlook: VFR conditions are expected Fri night with some potential for MVFR CIGs on Sat. Cannot rule out a few rain or snow showers Sat morning, mainly across the Piedmont. Another system approaches the region Saturday night and potentially impacts the region on Sunday with snow or a rain/snow mix and flight restrictions possible.

MARINE

As of 230 PM EST Thursday...

Key Messages:

- Gale Warnings and Small Craft Advisories are in effect through Friday morning as strong west winds continue.

- Elevated SW winds and likely SCA conditions return Friday night into Saturday morning.

- Low water conditions remain possible in the lower Chesapeake Bay, York/James Rivers, and along the coast of the Atlantic waters during low tide Friday night into Saturday.

This morning's cold front is now well offshore with NW winds currently averaging 15-20 kt with gusts 20-25 kt. Stronger cold advection arrives tonight and very efficient mixing will likely lead to a period of frequent ~35 kt gusts on the northern coastal waters. Elsewhere, wind gusts should stay closer to 30 kt, but cannot rule out occasional 35 kt gusts (best chance for this would be in the Chesapeake Bay N of Windmill Pt but probabilities there for gale conditions remain aob 20%). Small Craft Advisories remain in effect for all waters through Friday morning, with Gale Warnings now in effect from 00z-12z Fri (7 PM today-7 AM Fri) for the ocean N of Parramore Island. The lull in the winds looks brief Friday as high pressure quickly offshore and a low pressure system moves through the Great Lakes. This will allow for winds to shift back to the SW by Friday afternoon and another round of SCA conditions are likely Friday evening and overnight as a belt of stronger winds aloft overspread the area. Winds remain elevated into Saturday morning before subsiding to sub-SCA levels by the afternoon hours. There is decent confidence in a wind shift to the N-NW Saturday night as a cold front drops through, but uncertainty quickly increases by Sunday-Monday as low pressure may develop and ride along the remnant frontal boundary. A closer/stronger low would lead to higher winds while a weaker/suppressed system would have weaker winds. Consensus of the 12z guidance has trended toward a weaker low, farther offshore, resulting in decreasing potential for SCA conditions Sunday night and early Monday.

Seas remain in the 3-5 ft range (highest well offshore) through Friday morning with some potential for 6 ft seas out 20 nm on the ocean tonight. Seas then briefly subside to 2-3 ft Friday before increasing again to 3-5 ft Friday night and Saturday morning with the SW wind increase.

Low water conditions are still possible Friday night into Saturday in the lower Chesapeake Bay, James/York Rivers, and near the coast of the Atlantic waters. While guidance continues to trended a bit higher with the water levels, there is still potential for -1 to - 1.5 ft MLLW readings and resultant Low Water Advisories.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 7 AM EST Friday for ANZ630>634-638- 654-656-658. Small Craft Advisory until 4 AM EST Friday for ANZ635>637. Small Craft Advisory until 7 PM EST this evening for ANZ650- 652. Gale Warning until 7 AM EST Friday for ANZ650-652.