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Do they not know how to math? Where does the other 10% fall? They only have 90% accounted for?

Yep. The other was the 18Z. It looked like the 18Z Euro hadn't been used in it. Must have been 12Z in it. Ensembles are used in the NBM as well.

Saturday and possibly Sunday could see high temperatures below 20° across much of the New York City area. Such frigid highs have been very infrequent since 2020.

Pumping heights out ahead vs 18z. Good sign if anyone still fears suppression

Not necessarily

Yeah not entirely surprising, don't really see a change in ice accumulation though which I would have expected to increase with the 18z Euro.

I didn’t realize he had passed. I’ve been lurking since 2010 so this is sad to hear. What happened?

Deep winter about to slap us! 13F currently.

So now what do we do? I feel lost.

I took the Acela every week for nearly 4 years. It's not Japan-esque but it sure as hell beats driving up/down 95. New ones are pretty slick too.

859 FXUS61 KLWX 210229 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 929 PM EST Tue Jan 20 2026 .WHAT HAS CHANGED... Increasing confidence for a significant/impactful winter storm with several inches of snow late Saturday into Sunday. Additionally, increased snow totals over portions of the Alleghenies late Wednesday afternoon into Thursday morning as a series of fronts pass through. && .KEY MESSAGES... - 1) Increasing confidence of a significant winter storm across the region on Saturday into Sunday. - 2) Frigid temperatures are looking likely this weekend into early next week. - 3) Accumulating snow over portions of the Alleghenies late Wednesday afternoon through Thursday morning. && .DISCUSSION... KEY MESSAGE 1...Increasing confidence of a significant winter storm across the region on Saturday into Sunday. Ingredients are slowly coming together to produce a potentially significant winter storm across the region this weekend. Based on the latest guidance, wintry precipitation arrives by Saturday evening and continues throughout Sunday, while possibly continuing into Sunday night. While deterministic guidance continue to show the run-to-run variability expected in such solutions, the overall trend has been bringing the higher amounts toward central Virginia. In a multi-day sense, global ensemble probabilities are very high in seeing 6 inches or greater, particularly south of I-70. This comes with the presumed snow-to-liquid ratio of 10:1 which this system will not be given the Arctic nature of the air mass. Ratios will be considerably higher yielding a fluffier snow. With the parent features still across the more barren high latitudes, models may take another day or two to resolve such features with better precision. On the synoptic pattern side of things, many ingredients are in place to produce the mentioned winter storm. On Saturday, Arctic high pressure (1045-1050 mb) across the Midwest eventually reaches New England by the evening as a still robust 1040 mb anticyclone. This yields the familiar cold air damming wedge setup which stretches down into the southeastern U.S. Looking aloft, a split jet structure is evident with deep cyclonic flow in the northern stream and a progressive feature ejecting out of the Four Corners. The downstream confluent flow will aid in ample forcing across vast portions of the central/eastern U.S. While the main surface low sweeps across the Gulf Coast states, a broad area of isentropically driven precipitation spreads over the frigid air mass to the north. Precipitation type issues appear minimal through the event, although far southern Maryland could see some changeover to freezing rain or sleet at some point on Sunday. An energy transfer eventually unfolds Sunday afternoon/evening which focuses to deepening low pressure off the Outer Banks coast. Eventually this features pulls away from the coast late Sunday which gradually brings the brunt of the snow fall to an end. With the system not arriving until Saturday evening sometime, now is the time to prepare for this winter storm. Check back at the office website (weather.gov/lwx) as well as the winter page as the system moves into the Day 1-3 period (weather.gov/lwx/winter). KEY MESSAGE 2...Frigid temperatures are looking likely this weekend into early next week. As mentioned in the winter storm section, Arctic high pressure takes charge over the weekend which yields frigid temperatures across the area. On Saturday, forecast 850-mb temperatures range from -15 to - 20C which even dry adiabatic mixing would keep surface temperatures below freezing. However, given the time of year and the fact 1000- 850 mb winds are northerly, mixing largely tops out around 900-mb. With that said, Saturday`s high temperatures should struggle to escape the teens in most spots, with a few low 20s possible across far southern Maryland. Along the Allegheny Front, single digits are likely all that can be mustered. As snow comes in Saturday night, this will fall amidst temperatures in the single digits to lower teens. While a small increase in temperatures is expected on Sunday, it will likely not be noticeable with area-wide highs in the mid-teens to low/mid 20s. As snowfall comes to an end on Sunday night, the forecast calls for overnight lows in the single digits to lower teens. Looking ahead into the next work week, frigid conditions should persist. Depending on the degree of snowpack, the forecast may even be too optimistic in terms of "warmth". While daily highs next week are to push into the 20s, all could see low temperatures in the low/mid single digits on certain nights. Given elevated winds overnight, some locations along the Allegheny Front could see wind chills fall into the negative teens. - 3) Accumulating snow over portions of the Alleghenies late Wednesday afternoon through Thursday morning. A warm front will lift into the area Wednesday into Thursday with a cold front to follow Thursday night. This series of fronts will deliver a period of accumulating upslope snow shower/squalls across the Alleghenies late Wednesday afternoon into early Thursday morning. Elsewhere, dry conditions are expected with moderating temperatures and breezy conditions. Highs Wednesday will push back into the mid 30s and low 40s after starting in the upper single digits and low to mid teens. Temperatures warm even more Thursday with widespread highs in the mid 40s and low 50s east of the Alleghenies under increased south/southwest flow. As for snow in the Alleghenies, totals have come up slightly even with marginal temperatures profiles. 18z/00z hi-res CAM guidance suggest a dusting -3" of snow along the western facing slopes of the Alleghenies between 18z/1pm Wednesday through 12z/7am Thursday. Precip should mix with rain below 2500 feet at the onset with all snow expected during the overnight period Wednesday into Thursday morning. Snow to liquid ratios look to remain at 9:1/10:1 increasing to 13:1 during the peak of the event. The bulk of the snow looks to fall during the warm frontal passage with upslope snow showers & perhaps a few squalls lingering into Thursday morning as a weak cold front swings through. Some instability has also been noted in the DGZ leading to the potential for near advisory level snow in far western portions of Garrett Co. (west of the Eastern Continental Divide) and down into portions of western Grant Co. These locations could see 2-4" of snow with localized amounts up to 5" along western favored slopes above 2800 feet (i.e Keysers Ridge, Piney Mountain, Hoyes Crest/Backbone Mountain). Confidence is medium for an advisory at this time and will likeLy be further evaluated on the overnight shift. Expect slick travel and delays along I-68/US-40 west of Frostburg, MD and US-219 from the MD/PA line to WV line late Wednesday evening through Thursday morning. Further east downsloping will eat away at any precipitation chances outside of a rogue snow shower pushing toward the Catoctins/northeast MD as the front lifts through Wednesday evening. No accumulation is expected at this time as plenty of dry air will be hard to overcome east of the mountains. With the series of fronts pushing through expect wind gusts around 25-35 mph with gusts up to 40 mph along the ridges. Winds will gradually decrease Thursday night into Friday. Next chance of wintry precipitation arrives Friday, especially in locations south of I-66/US-50. This is due largely in part to strong isentropic lift/warm air advection ahead of the southern stream upper level low. This could lead to overrunning precipitation in the form of light snow or even a light wintry mix (rain/snow/sleet) across the central VA Piedmont and northern neck. Confidence in this remains low at this time, given recent model trends. Even with that said, something to watch given the dynamical setup in place before the main event this weekend. Highs Friday range from the teens over the mountains to mid 30s and low 40s east. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... VFR conditions will continue through Friday morning as surface high pressure shifts offshore and a series of moisture starved fronts push through. The biggest concern for aviators will be the wind, especially heading into the midweek period. Expect southerly winds Wednesday gusts 20 to 30 kts outside the mountains as a warm front lifts through. These winds will slacken a bit Wednesday night before increasing again Thursday ahead of an approaching Arctic cold frontal boundary. Expect 15 to 25 kt gusts Thursday out of the west and southwest. LLWS also cannot be ruled out Wednesday into Wednesday night although confidence was too low to include in the corridor at this time. Winds will turn back to the northwest Thursday night into Friday with gusts less than 15 kts expected. A light rain/snow mix could impact terminals across central and southern VA Friday although confidence is low at this time.Skies begin overcast on Saturday morning, but any snow should not commence until around Saturday evening. As ceilings lower through the day, expect restrictions to kick in ahead of this swath of snowfall. At that point, expect a lengthy period of IFR caliber conditions Saturday evening/night and into all of Sunday. Given the degree of cold air in place, this should be an all snow event across the terminals. KCHO could get close to the line where freezing rain and sleet mix in on Sunday, but it remains rather uncertain. Initial winds will be out of the northwest on Saturday morning before shifting to the north to northeast through the day as Arctic high pressure builds across New England. For Sunday, winds largely remain northerly as low pressure eventually develops off the North Carolina coast later in the day. Gusts each day over the weekend should top out around 10 to 15 knots. && .MARINE... Sub-SCA level winds are expected through Wednesday morning with SCA conditions returning Wednesday afternoon and night under southerly channeling. Gusts of 20 to 25 kts are expected at this time. Highest gusts look to be over the open waters of the bay/tidal Potomac. Winds will fall back below SCA levels for most of the waters Thursday into Thursday night under westerly flow. This will continue into Thursday night into Friday. Additional SCAs will be needed Friday night. With Arctic high pressure pushing from the Midwest toward New England on Saturday, northerly winds will increase across the waters. Channeling effects look possible which may require Small Craft Advisories, especially across the wider waters on Saturday morning. After a brief lull as winds shift to northeasterly, gradients increase again on Saturday evening/night yielding additional 20 to 25 knot gust potential. These blustery winds continue into Sunday as winds turn northerly. Widespread snow impacts the waters Saturday evening through most of Sunday. There may even be a threat for some freezing spray given the frigid nature of the air mass and elevated wind fields. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None.

Yeah, NAM is def more interaction and further east vs 18z by a good bit

00z nam starting off with a major trend toward a early phase.

Some good information from the AFD:

I’d go to the upstairs bar portion, which is not all that classy. Nobody would turn you away. I wouldn’t come in covered in dirt but you’ll be fine.

In tinted lip gloss and jogging shorts?

THIS

Thank you! No surprise NBM went down in East TN after that Euro run

I'm thinking about a Shenandoah hike before meeting. How classy is the joint?

If we do have a fresh snowpack next Tuesday morning could be quite frigid

Going to inject some positivity around here.. couple things going for us. 1. EE rule.. 2. How many times have we seen the models around this time frame lax in density of cold air mass getting pumped down only to key back in on it, especially as NAM gets into range and we see the CAD potential? Sure even if there’s CAD we could still always be subjected to the sneaky warm layer. But in all reality we still have way more positives than negatives current time. I-40 north bare minimum is in a great spot. Let’s see if we can get the I-85 guys and gals back in as well!

LWX AFD is eye candy. Worth a read. Not really worried about mixing, >10:1 ratios…

Still useful. 12km not so much.

Might double that