textproduct: Wakefield

WHAT HAS CHANGED

Some snowfall remains possible Sunday, but the higher probability for accumulating snowfall has shifted northeast, with mainly rain expected for southeast Virginia and northeast North Carolina with a few wet snowflakes possible as precipitation ends. Otherwise, no significant changes.

KEY MESSAGES

1) Milder temperatures Saturday, especially southeast Virginia and northeast North Carolina. There remains a chance for light rain showers or a rain/snow mix early Saturday in the Piedmont.

2) Snow or a mix of rain and snow remains possible Sunday, with mainly rain expected for southeast Virginia and northeast North Carolina where a few wet snowflakes could mix in as precipitation ends late Sunday afternoon and early Sunday evening. The best chance for any (light) snowfall accumulation has shifted northeast to the Northern Neck and lower Maryland Eastern Shore.

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

DISCUSSION

As of 240 PM EST Friday...

KEY MESSAGE 1...Surface high pressure is centered immediately off the Southeast coast this afternoon beneath zonal flow aloft. Temperatures remain below average (mid 30s to lower 40s) with a WSW wind occasionally gusting to 15-20 mph. Temperatures should fall quickly through the 30s this evening as the sky remains mostly clear. Temperatures become steady overnight with increasing clouds as a shortwave trough lifts NE through the upper Ohio Valley. This system quickly lifts NE Saturday as a vigorous upper trough digs into the Midwest and Great Lakes. A few light showers are possible Saturday morning through midday, mainly from the Piedmont N and NW of the RIC metro through the MD Eastern Shore, and a brief rain/snow mix is possible early Saturday morning across the Piedmont NW of the RIC metro early Saturday morning. Any precip will be very light due to a dry sub-cloud layer and no accumulation or impacts are expected from any falling snow. Temperatures will hold in the upper 40s to around 50F from the Piedmont to the MD Eastern Shore (near to slightly above seasonal averages) while rising into the upper 50s and even lower 60s in far SE VA/NE NC.

KEY MESSAGE 2...The upper trough pushes E Saturday night into Sunday with low pressure developing off the Carolina coast and tracking NE Sunday. Overall there is still a potential for snow from the Piedmont across central VA to the Eastern Shore. The latest trends are slightly warmer and wetter across far SE VA and NE NC where only a few inconsequential wet snowflakes may mix in at the end. Overall, this is not expected to be a large or impactful snow event. The highest probs for >1" of snow (based on a 10:1 ratio) have shifted NE and are primarily across the Northern Neck and lower MD Eastern Shore. >1" snow probs from the 16/12z EPS/GEFS are generally 30-50% for these locations and 10-30% (or less than 10%) elsewhere. >3" probs are largely negligible, with the exception of 10-20% over the Eastern Shore, and the GEFS does have a small 20-30% contour over the lower MD Eastern Shore. Surface temperatures will be marginal (near to slightly above 32F) when snow is falling, and vertical ascent in the DGZ is weak, which points to lighter/less impactful snow with difficulty accumulating on anything other the grass or un- paved surfaces. The current official forecast is for 1.0-1.5" of snow over the Eastern Shore, with a few tenths to less than 1" for the Piedmont and central VA, and no accumulation expected for far SE VA and NE NC. A reasonable worst case scenario would be 2-3" for the MD Eastern Shore, and 1-2" back through the Northern Neck and central VA. Colder and drier air arrives from NW-SE later Sunday afternoon and evening bringing a rapid end to and snow or rain/snow mix.

KEY MESSAGE 3...Another surge of Arctic air arrives for early next week behind a secondary dry cold front, with below averages temperatures to continue through the first half of next week.

Arctic air arrives Monday night behind the secondary cold front. Frigid temperatures are expected for at least the first half of next week, with the coldest air occurring Monday night, Tuesday, and into early Wednesday morning. EPS/GEFS show 2m temperature anomalies 15F to nearly 20F degrees below average. Overnight lows in the upper teens to mid 20s are expected Sunday night, and primarily teens Monday/Tuesday 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 Monday through Wednesday, Tuesday is forecast to be the coldest day with highs struggling to make it above freezing.

Temperatures may attempt to moderate a bit by the middle and end of the week as the upper flow turns more zonal.

AVIATION /19Z FRIDAY THROUGH WEDNESDAY/

As of 1240 PM EST Friday...

VFR flying weather is expected to prevail through the 18z TAF period. Satellite shows few if any clouds near the main terminals but some mid level stratus is noted over the northern Piedmont. Winds are gradually swinging around from W to SW this afternoon, mainly 8-12 kt with gust 15-20 kt. SW winds continue tonight but decrease to 5-10 kt. A low level jet is still progged to form over the region tonight into early Saturday with LLWS indicated at all terminals except ECG. Rain or a rain/snow mix is also possible early Saturday in the Piedmont, but should remain NW of all terminals.

Outlook: Marginal MVFR CIGs are possible Saturday afternoon as a cold front approaches. More widespread flight restrictions are anticipated by Sunday as rain, and likely some snow as well, overspread the region.

MARINE

As of 205 PM EST Friday...

Key Messages:

- Small Craft Advisories have been issued for the Chesapeake Bay, lower James River, and northern coastal waters from this evening into Saturday morning.

Afternoon analysis shows occluded low pressure near Lake Superior with a cold front extending well south into the Ohio Valley and Mid- South. Surface high pressure near the Southeast coast is translating offshore this afternoon. Winds have become SW and decreased to 10-15 kt today. Waves and seas have followed suit and are mainly 1-2 ft and 2-3 ft, respectively. The pressure gradient tightens again early this evening and overnight as the front moves closer to the area. SCA headlines have been raised for the bay, lower James, and the coastal waters N of Cape Charles Light. SW winds increase to 15-20 kt with gusts 25-30 kt this evening. Guidance is somewhat lower for the lower James but given the favorable SW wind direction, opted to include this zone as well. Waves build to 2-3 ft in the bay with seas increasing to 3-5 ft (locally ~6 ft possible out at 20 nm off the MD Eastern Shore). The gradient slackens toward sunrise but have maintained the SCA headlines into mid morning for the coastal waters N of Parramore Island to account for lingering 4-5 ft seas. Sub-SCA conditions are expected to persist through Sunday and the daylight hours of Monday before another cold front crosses the waters and brings the potential for SCA conditions back to the area.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 7 AM EST Saturday for ANZ630>632- 634. Small Craft Advisory from 7 PM this evening to 4 AM EST Saturday for ANZ638. Small Craft Advisory from 7 PM this evening to 10 AM EST Saturday for ANZ650-652. Small Craft Advisory from 7 PM this evening to 7 AM EST Saturday for ANZ654.