textproduct: Wakefield

WHAT HAS CHANGED

Winter Storm Watches have been issued from late Friday night/early Saturday into Sunday for all but the far northern zones.

KEY MESSAGES

1) Winter Storm Watches have been issued for a majority of the FA for the weekend storm, with northern areas left out. Strong winds and a significant snowfall are expected within the Watch, with highest confidence across southern/SE VA and NE NC. In addition, very strong winds are expected late Saturday and Sunday along the coast, with potentially damaging wind gusts possible.

2) Well below normal temperatures remain through early next week, keeping localized impacts (i.e icy roads) in place through the winter WX this weekend. A Cold Weather Advisory is in effect for the entire area early this morning and temperatures Friday through Sunday will be even colder and additional headlines will likely be necessary.

DISCUSSION

As of 335 AM EST Thursday...

KEY MESSAGE 1...While significant disagreement remains amongst the deterministic and ensemble guidance, confidence is high enough to warrant the issuance of a Winter Storm Watch for most of the CWA from late Friday night/early Saturday through Sunday afternoon. The main mode of disagreement continues to be the battle zone between drier air from the N/NW associated with a very strong area of high pressure (~1045 mb) over the Plains, and an intense low pressure system developing off the SE coast late Fri night/Sat. The GFS/GEFS is the NW outlier, wrapping significant amounts of moisture and QPF all the way into central VA, while the ECMWF/GEM are farther south and somewhat more suppressed with this moisture. The 00Z NAM is the opposite solution: almost completely dry other than in far southern VA and NE NC. One trend that continues in most of the models is a "piece" of the sfc high over the Plains ridging SE into the local area Friday into early Saturday, with low pressure across the eastern Gulf coast showing an inverted sfc trough extending north into the southern Appalachians. This has trended to an initial overrunning precip event (all snow) that could begin as early as Friday (but is more probably late Friday night through Saturday morning). For the piedmont, this portion of the storm may account for a majority of the snowfall. SLR values will be very high, 15:1 to 18:1 so even a relatively low amount of QPF could lead to a significant accumulation (which will be efficient on area roads given temperatures well below freezing). Still think the GFS is too far north with this feature (and keeps it maintained into Sat night even after the coastal low rapidly intensifies), so forecasted snow totals are well below what the GFS depicts over the NW 1/2 of the CWA.

Part 2 of the storm gets amped up later Saturday, and is expected to peak Saturday night into early Sunday. The models (even the GFS) are all in pretty good agreement that the digging upper trough becomes cutoff as it drops SE from the TN Valley (at 12Z/Sat), to the GA-SC coastal plain by Sat evening (00Z/Sun). The resulting sfc low is forecast to deepen by as much as 15 mb/6 hr Sat evening as it drifts NE off the coast. Therefore, in addition to heavy snowfall, which is of highest confidence across SE VA and NE NC, very strong winds are likely to develop for coastal areas, with winds rather strong even for inland zones. Strong winds and a significant snowfall are expected within the Watch, with highest confidence across southern/SE VA and NE NC. Decided against a Blizzard Watch for the coast, but as timing confidence improves, a Blizzard Warning is certainly plausible for portions of Hampton Roads and coastal NE NC Saturday night/Sunday morning where the winds may be potentially damaging. Our latest snow forecast blends all of this and leads to 1-2" over the far N/NW, with 12"+ in portions of NE NC into VA Beach.

As mentioned above, impacts will vary across the region, but the synoptic setup supports the potential for a high-impact winter storm. Additional messaging and headlines will need adjustments over the next few forecast cycles. Please continue to follow the latest forecast.

KEY MESSAGE 2...A Cold Weather Advisory is in effect for the entire area early this morning, though as has been prevalent the past 3 days, the NBM temperatures have been terrible, verifying nearly 10 degrees too cold in some areas, which is leading to a Cold WX Advsy that has been very marginal with only spotty values down in the single digits. Will maintain the Advisory for now and re-assess over the next few hrs. Otherwise, today will continue to be well below normal with highs struggling to get out of the 20s across the north, with lower 30s south. Wind chills will struggle to rise above the mid teens to mid 20s during the day (coldest on the eastern shore). Tonight will again be very cold, though winds are expected to be light as the sfc ridge of high pressure extends into the area, keeping wind chills near ambient temps that will mostly be in the teens, with some single digit values N and NW. Friday is even colder with highs only in the 20s for most, along with a chc for light snow mainly along and W of I-95.

AVIATION /07Z THURSDAY THROUGH MONDAY/

As of 100 AM EST Thursday...

Mainly VFR conditions in place across area terminals will persist through the 06z/29 TAF period, the exception being a brief period with MVFR CIGs possible at ORF due to cold air over the Bay and elevated N winds. Otherwise, skies are mostly clear with NNW winds of 5-10 kt or less inland and. Locations closer to the coast, including ORF and ECG, will see gusts of 20-25 kt through ~11Z before diminishing.

Outlook: Dry/VFR conditions persist through Friday across the area. Continue to watch a developing coastal low, which is forecast to strengthen Saturday/Saturday night. This system will likely create another round of winter weather for the terminals, especially later Saturday afternoon through Sunday morning. Exact impacts and locations aren't clear yet, but widespread flight restrictions are likely during this timeframe. Strong winds are likely to develop at least for coastal terminals with this storm, particularly Saturday night and early Sunday with gusts of 40 kt+. Elevated winds are expected farther inland, gusting to 20-30 kt. Slowly improving conditions are expected later Sunday into Monday as winds diminish and VFR returns from W to E.

MARINE

As of 155 AM EST Thursday...

Key Messages:

- Small Craft Advisories in effect for all local waters this morning.

- Storm Watches issued for the Ches. Bay, Lower James, all coastal waters, and the Currituck Sound starting Sat afternoon. Gale Watches issued for the upper tidal rivers.

- A Freezing Spray Advisory has been issued for the Chesapeake Bay, coastal waters north of Cape Charles Light, and the upper rivers from tonight into Thu. Additional freezing spray is likely this weekend.

Another push of CAA behind a cold front has triggered another surge of northerly winds, primarily over the Chesapeake Bay. Latest obs indicate winds of 15-25kt with a few of the higher sites showing gusts up to 30kt. Similar conditions are present over the rivers and Currituck Sound, but with gusts only 20-25kt. So far, winds are under-performing over the coastal waters with latest obs showing 10- 15kt. SCAs are in effect for all of the marine zones. Despite the under-performance, will leave the SCAs in place for now over the coastal waters in case there's a sunrise surge as there often is in these scenarios. Otherwise, expecting gradually diminishing NW winds through the day and into tomorrow, though remaining breezy. Seas will be 3-4ft today, then 2-3ft tomorrow. Waves in the bay 2-3ft today and 1-2ft tomorrow.

Attention then turns to the increasingly likely significant coastal storm over the weekend. There is high confidence in a strong surface low forming along and traveling up the coast early Saturday through Sunday. The models still have some variation in exact track of the low, but do consistently depict a very tight pressure gradient and drastic pressure changes over a short time period. Still sticking with blended guidance at this point since the high res models are still mostly out of range. this morning's forecast package has not changed much since yesterday afternoon's forecast, but am feeling more confident in it. NNE look to gradually increase through the day Saturday, reaching gale force gusts across most waters Saturday afternoon. Winds continue to increase Sat night, then peak Sunday morning. This peak would be 35-45kt over the bay, Currituck Sound, and coastal waters with gusts 50-60kt. The upper rivers would be a bit lower, but still well within Gale range. This forecast is supported by local wind probs, which have 80-85% for 48kt+ wind gusts for the southern coastal waters and 50-70% in the bay and northern coastal waters. Did go ahead and put up Storm Watches for the Bay, lower James, coastal waters, and Currituck Sound starting Saturday afternoon and going into Sunday night. Went with Gale Watches for the upper rivers starting Sat evening. Seas during this period will be 8-12ft. Waves in the bay climb to 7-8ft.

Lastly, periods of light freezing spray are expected through the end of the week due to cold water/air temperatures and gusty winds. Moderate freezing spray over the weekend will likely require Freezing Spray Advisories.

Tides/Coastal Flooding...

Given the strength of the low coinciding with higher astronomical tides, widespread coastal flooding is increasingly likely this weekend. Early indications are for moderate to locally major coastal flooding across the Mouth of the Bay and the Virginia Beach and Currituck Outer Banks coastline, with minor to moderate coastal flooding possible elsewhere. With a strong northerly wind, locations in the upper bay could actually see low water during this period. The worst coastal flooding conditions look to be Sat night into Sun.

CLIMATE

Record Low Max Temperatures for Sat Jan 31:

- RIC: 23 (1948) - ORF: 25 (1936) - SBY: 24 (2019) - ECG: 29 (1965)

Daily Record Snowfall for Sat Jan 31 and Sun Feb 1:

- Date: Sat Jan 31 Sun Feb 1

- RIC: 7.0" (1948) 3.1" (1948) - ORF: 4.0" (1980) 4.0" (1910) - SBY: 4.0" (2010) 4.0" (1962) - ECG: 5.0" (1980) 7.0" (1948)

AKQ WATCHES/WARNINGS/ADVISORIES

MD...Cold Weather Advisory until 10 AM EST this morning for MDZ021>025. Winter Storm Watch from Saturday morning through Sunday afternoon for MDZ023>025. NC...Cold Weather Advisory until 10 AM EST this morning for NCZ012>017-030>032-102. Winter Storm Watch from late Friday night through Sunday afternoon for NCZ012>017-030>032-102. VA...Cold Weather Advisory until 10 AM EST this morning for VAZ048- 060>062-064>069-075>090-092-093-095>100-509>525. Winter Storm Watch from Saturday morning through Sunday afternoon for VAZ099. Winter Storm Watch from late Friday night through Sunday afternoon for VAZ092-093-095>098-100-524-525. Winter Storm Watch from Friday evening through Sunday afternoon for VAZ060-061-065>069-079-087. Winter Storm Watch from late Friday night through Sunday afternoon for VAZ076>078-080>086-088>090-512>520-522-523. MARINE...Small Craft Advisory until 4 AM EST Friday for ANZ630. Freezing Spray Advisory until 4 PM EST this afternoon for ANZ630>632-634. Storm Watch from Saturday evening through Sunday evening for ANZ630-631-650-652-654. Small Craft Advisory until 1 PM EST this afternoon for ANZ631- 632-634-656-658. Storm Watch from Saturday afternoon through Sunday evening for ANZ632>634-638-656-658. Small Craft Advisory until 10 AM EST this morning for ANZ633. Small Craft Advisory until 7 AM EST this morning for ANZ635>638. Freezing Spray Advisory until 1 PM EST this afternoon for ANZ635>638. Gale Watch from Saturday evening through Sunday evening for ANZ635>637. Small Craft Advisory until 6 PM EST this evening for ANZ650- 652-654. Freezing Spray Advisory until 6 PM EST this evening for ANZ650- 652-654.