textproduct: Wakefield

WHAT HAS CHANGED

Winter Storm Warnings continue for the majority of the region tonight through Sunday night for coastal areas and Monday evening for inland areas, excluding far northeast North Carolina. Winter Weather Advisories continue for far northeastern North Carolina tonight into Sunday afternoon. Confidence is high in a strong winter storm for a large portion of the area.

KEY MESSAGES

1) A strong, damaging winter storm for a large portion of the area will impact the region through Sunday night with snow, sleet, freezing rain, and rain expected.

2) A prolonged period of very cold temperatures is expected through the majority of the week with potential for temperatures to remain below freezing for several days. Impacts from the winter storm are likely to last well into next week due to the very cold temperatures.

DISCUSSION

As of 930 PM EST Saturday...

KEY MESSAGE 1...A strong, damaging winter storm for a large portion of the area will impact the region through Sunday night with snow, sleet, freezing rain, and rain expected.

Winter Storm Warnings and Advisories continue unchanged with this forecast cycle.

Snow has begun across the Piedmont in addition to central/southeast VA this evening as the initial round of lift/overrunning moisture has arrived. The Arctic airmass remains in place with strong 1042 mb high pressure over the eastern Great Lakes with a classic CAD setup over VA and the Carolinas. Temperatures are in the mid teens-mid 20s and snow has accumulated on all surfaces quickly given the very cold temps (though totals are likely no higher than a half inch so far). Snow will overspread almost the entire area by 10-11 PM (except NE NC where precip may start as sleet).

Secondary low pressure forms off the Carolina coast tonight and lifts NE on Sunday. Ahead of the surface low (and as 850-700mb winds increase from the SE-SW), warm air aloft will quickly move in, changing the precip to sleet overnight (though it may remain snow across the far north through sunrise). Regional radar mosaic already shows the snow/sleet line pushing close to the VA-NC border. Feel that the snow/sleet changeover will be an hour or two faster than models indicate, so precip should change to sleet along the I-64 Corridor and RIC Metro around 2-3 AM. All headlines remain unchanged. The majority of the snow and sleet accumulations will occur overnight with the highest snow/sleet totals still expected across the north and northwest portions of the area. Snow/sleet totals drop off quickly with southeastward extent. Snow/sleet totals north and west of the I- 64 corridor will range from 4-8" with south of I-64 receiving 1-4". The warm nose will strengthen by sunrise with freezing rain spreading northward into the piedmont. Precip will transition to mostly freezing rain near and west of I-95 with some sleet possibly lingering across the far NW (Fluvanna/Louisa vicinity). 12z guidance has trended slightly downward in QPF totals as precip moves offshore faster. Most areas will now see 1.25-1.75" in storm total liquid equivalent (highest in the Piedmont and lowest across NE NC). Ice accumulations have decreased (very) slightly from previous forecasts with the somewhat lower QPF and a bit more cold air tonight. Although the QPF is slightly lower, freezing drizzle is now a concern Sunday night, which could result in better icing rates than a heavier freezing rain, which ultimates keeps the ice accumulations similar to previous forecasts. Still expecting a large ice impact footprint with many areas west of the bay seeing 0.25- 0.5" of ice accrual with the highest accrual for ice totals focused along and near the I-85 and I-95 corridor from near Richmond south to the Tri- Cities and Emporia. Significant ice accrual will lead to damaging impacts and widespread power outages and tree damage. Very cold temperatures and windy conditions into early next week will lead to long lasting impacts. Winds pick up on Monday as the system departs, continuing the threat of additional tree damage and power outages.

Latest guidance shows a faster transition to plain rain for NE NC and SE VA Sunday morning. There remains some uncertainty as to how far inland this warmer air will spread but it appears to set up near or just east of the I-95 corridor by Sunday afternoon. This divide may creep back to the east after sunset but the eastern third of the area will likely stay above freezing until coastal low pressure pulls away from the region and colder air moves back in.

KEY MESSAGE 2...A prolonged period of very cold temperatures is expected through the majority of the week with potential for temperatures to remain below freezing for several days. Impacts from the winter storm are likely to last well into next week due to the very cold temperatures.

Behind the winter storm, strong high pressure (1030+ mb) from the Canadian plains will shift over the SE CONUS with potent upper level troughing. The combination of these features will keep very cold temperatures over the area through much of next week. This, along with any snowpack/ice, will likely keep high temperatures below freezing for an extended period of time over much of the area. Model trends now show Monday night/Tuesday morning with the coldest lows rather than Tuesday night/Wednesday morning, but only by a few degrees. Low temperatures Monday night/Tuesday morning will likely be the coldest we have seen in some time, with readings ranging from around 0 across the NW Piedmont, to single digits for much of the inland forecast area, and teens closer to the coast/SE. Tuesday night/Wednesday morning will rival those temperatures with similar lows.

These temperatures do not take in account for the winds, which will likely be slightly more breezy Tuesday night/Wednesday morning, as there's a tighter pressure gradient, with W winds around 5 mph and gusts to 10 mph inland and gusts to 20 mph near the coast. With this, wind chill values will be could be as low as -10F in the NW piedmont to +10F in SE VA/NE NC. Extreme Cold Headlines will likely be needed for portions of the area with Cold Weather Advisories elsewhere. Overnight lows in the single digits and teens (maybe low 20s near the coast) will be common for the remainder of the week. Long term model guidance continues to show the potential for another Arctic blast by midweek, potentially sending our high temperatures back into the 20s by Thursday and Friday with overnight lows into the mid to lower single digits.

This prolonged period of very cold temperatures behind the winter storm could be quite dangerous for those without power. It is important that all take precautions in event that power is unable to be restored in a timely manner.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

As of 100 AM EST Sunday...

Snow already starting to change to IP across southern VA and NE NC, and this will progress northward through 12Z. IFR-LIFR conditions in VSBYs with MVFR CIGs dropping to IFR over the next few hrs. The IP is expected to mix with FZRA over southern VA/NE NC from 08-11Z, with plain rain then expected at ORF/ECG after 11Z (and at PHF after 12-13Z). However, impacts will be significant at RIC with SN changing to IP (possibly heavy at times) then FZRA as temps likely don't get above 32F throughout the day. FZRA will continue at RIC through 03-06z Monday before finally diminishing. At SBY, a period of SN prevails through 12Z, briefly mixed with IP/FZRA, followed by plain rain after ~14Z. VSBYs of 1/2-1 1/2SM are likely in snow (locally 1/4SM or less), with 1-3SM VSBYs in sleet and rain. CIGs will remain IFR- LIFR all places through this aftn/evening. Winds will diminish a bit overnight, with NE winds around 10 kt expected. Gusts to ~20 kts will return tomorrow morning near the coast. Some LLWS is likely in SE VA/NE NC later today and tonight and this remains indicated in the TAFs at PHF/ORF/ECG.

Outlook: VFR/dry conditions return on Monday with breezy NW winds. VFR conditions continue through the middle of the week. There is a low-end chance of light snow Wed night-Thu AM.

MARINE

As of 330 PM EST Saturday...

Key Messages:

- Strong winds continue Sunday (NE to E) as developing coastal low pressure slowly lifts NE offshore of the Mid-Atlantic coast. Gale Warning are in effect for the Ocean north of Cape Charles. - Another period of Gale Warnings are likely to be needed for much of the area late Monday afternoon through early Tuesday with NW winds.

- Yet another period of high-end Small Craft Advisory to gale conditions is possible Thursday night into early Friday.

- Periods of freezing spray are likely Monday night through much of the week as an arctic airmass overspreads the region.

Strong 1040mb high pressure is centered over the Eastern Great Lakes this aftn and is ridging S along the Mid-Atlantic coast. The pressure gradient has relaxed to some extent and a N to NNE wind ranges from 10-15kt with occasional gusts to 20kt N, to 15-20kt with gusts to ~25kt S. Seas range from 3-4ft N to 6-8ft S, with waves in the Ches. Bay approximately 2-3ft N to 3-4ft S. The high remains in place this evening, before retreating to the NE later tonight as low pressure begins to develop off the Southeast coast. By later tonight, a NE wind will increase to 15-20kt with gusts to ~25kt across the Ches. Bay, lower James, and Currituck Sound, and 20-25kt with gusts to ~30kt for the coastal waters. Low pressure deepens as it lifts NE along the Outer Banks Sunday morning and then off the Mid-Atlantic coast Sunday aftn. Strong pressure falls on the order of -10mb/3hr 15-18z Sunday combined with an ENE LLJ ~40kt are expected to bring gale conditions to the coastal waters N of Cape Charles for a 3-6hr period Sunday morning to early aftn. Elsewhere, SCA conditions are expected, with the exception of the upper rivers where cooler more stable air should result in less wind. Seas build to 6-9ft Sunday, with 3-4ft waves in the Ches. Bay and 4-6ft in the lower Bay to the mouth of the Bay. The wind should diminish and shift to westerly as the low pulls to the NE later Sunday aftn into Sunday night. Seas remain 4-7ft Monday into Monday night.

A cold front crosses the coast early Monday. However, stronger CAA waits until later Monday aftn into Monday night. Gale force gust probs are 60-95% offshore for the coastal waters N of the VA/NC border, and this will likely be a situation where the wind will overperform for 3-6hr Monday evening across the eastern side of the Ches. Bay. Have opted to wait on Gale Watches per coordination with neighboring offices. Seas remain elevated, generally 5-7ft, with 3- 5ft waves in the Ches. Bay.

A period of low-end SCA conditions is possible later Tuesday aftn and evening. Otherwise, the next period of attention is Thursday night into early Friday due to CAA behind another strong cold front. Periods of freezing spray are likely Monday night through much of the week as an arctic airmass overspreads the region, followed by another push of arctic air later in the week behind the aforementioned cold front.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...Winter Storm Warning until 7 PM EST Monday for MDZ021. Winter Storm Warning until 7 PM EST this evening for MDZ022>025. NC...Winter Storm Warning until 7 PM EST Monday for NCZ012>014. Winter Weather Advisory until 1 PM EST this afternoon for NCZ015>017-030>032-102. VA...Winter Storm Warning until 7 PM EST Monday for VAZ048-060>062- 064>069-075>090-092-093-096-509>524. Winter Storm Warning until 7 PM EST this evening for VAZ095- 097>100-525. MARINE...Small Craft Advisory until 4 PM EST this afternoon for ANZ630>632-634. Small Craft Advisory until 10 AM EST this morning for ANZ633. Small Craft Advisory until 1 PM EST this afternoon for ANZ638. Gale Warning from 7 AM this morning to 4 PM EST this afternoon for ANZ650-652. Small Craft Advisory until 7 AM EST this morning for ANZ652- 654. Gale Warning from 7 AM this morning to 1 PM EST this afternoon for ANZ654. Small Craft Advisory until 1 PM EST Monday for ANZ656-658.