GaWx

What NorthHills said. In addition, dewpoints are relatively high (mid 50s). So, even with clear skies, the high RH (70%+) isn’t conducive for strong radiational cooling as the water vapor acts as a blanket (kind of what you were speculating).

As posted earlier, MJO phase 3 is a plus based on it having been the coldest phase on avg in Feb during La Niña. However, the GEFS progged strong -PNA presents a challenge to getting a significant snow per daily PNAs since 1950. For the 19 DC 3”+ snowstorms during the 40 La Nina or cold neutral Febs since 1950, here were the daily PNAs: 2/11/25 +0.9 2/25-6/14 +0.5 2/13/14 -1.1 2/12/06 +1.7 2/8/97 +0.5 2/16/96 -0.4 2/2/96 +0.7 2/4/95 +1.6 2/24/86 +0.3 2/22/86 -0.4 2/4/75 -0.3 2/8/74 -0.2 2/19/72 -0.5 2/17/72 -0.7 2/2/72 -1.1 2/17/67 +0.3 2/7/67 +0.7 2/13/60 +0.2 2/7/51 +0.3 Median +0.3 Mean +0.2 Highest +1.7 Lowest -1.1 Feb 8th GEFS PNA for 2/22-3: ~-1.2 So, should the PNA verify close to this GEFS run and there be 3”+, this would be near the lowest PNA for a DC Feb 3”+ snowstorm during La Niña since 1950. Thus, for a better shot at 3”+, I’d rather the PNA trend less negative.

Nobody should ever have faith in any model. But Weathernext was pretty good for some storms this winter.

12Z AI Weathernext2 SV: DC 6” vs 8” on 6Z

Me. I’m always desiring BN temps any time of year. BN in late Mar and Apr with relatively low dewpoints is generally delightful and great for outdoor activities here. Today’s Euro Weeklies 2m anom for 3/23-29:

12Z Euro SV 10:1 is much different in many areas, including DC where it has 2” vs almost nothing on WB Kuchera. Opinions? Does it make sense that Kuchera would be much lighter there? Are temps that borderline?

I think many (like me) cut Euro AI clown map amounts way down from what it shows when way above consensus.

It is well-known that the Euro AIFS tends to show quite a bit too much snow and to thus not take it literally. Plus it shows as 10:1 instead of Kuchera on WB. Just look at it more for run to run trends is my recommendation. For amounts, I much prefer the regular Euro.

It will likely be awhile. Maybe after 2PM for Weathernext2.

The model consensus is still forecasting the MJO to be in or near phase 3 for Feb 22-23. Phase 3 has been the coldest MJO phase (based on Baltimore as a representative city) by a good margin when averaged out day by day during the 20 La Niña Februaries since 1975. It has averaged 4 F colder than the avg anomaly for all 566 Feb Niña days since 1975. Keep in mind that Feb Niña has averaged ~2 AN, which is intuitive. Regardless, the GEFS progged strong -PNA presents its own challenge.

Even if Weathernext2 is also off by one color, it would still be 6” at DC. I’d think 6” would be bordering on a “major” hit there considering that I saw a stat that only 0.7 5”+ snowstorms hit DC each year at this link meaning many years don’t even get a 5” storm: https://downloads.regulations.gov/FWS-R5-ES-2016-0030-0073/attachment_18.pdf#:~:text=For four days a year on average%2C,events that occur about twice a decade.

Is the SV color scale off on AI Weathernext2, too? How would we know?

Keep in mind that phase 3 has on average been the coldest phase during the 20 La Niña Februaries since 1975. Note that the upcoming snowstorm threat period of Feb 22-23 centered on the Mid Atlantic is forecasted to be in or very near phase 3 fwiw all the while fighting the making it a challenge progged strong -PNA.

6Z SV AI Weathernext2: 8” DC

You set up a good example of what I was referring to in my last post. If someone from Lincoln County, which has gone well over climo this winter with 11”, had moved to NYC for more snow this winter, he/she despite getting double that as of now (21.2” vs 11”) might end up mad if that were to be about it for the winter (that’s very doubtful though as this next storm could give them a lot but that’s beside my point). Why not be happy they got 10” more to enjoy as a result of moving? That’s why moving north often doesn’t work like one expected.

Today’s Euro Weeklies are cooler but only in the shorter term (week of 2/23-3/1), which covers the latter portion of the expected storm that’s being heavily discussed: Yesterday’s 2/23-3/1: Today’s 2/23-3/1 has a colder signal:

They seem to because they actually do as they have much snowier climo, of course, and thus get much more on average. Some there, just as seems to be the case in most subforums, are almost always mad. If they don’t reach climo they’re mad, which keeps them from enjoying what they do get. Thus in their own minds, they almost always “need” more. Some southerners move north for more snow. But then many of them feel the need to get much more in order to be as content. When despite getting more snow than in the S they don’t reach climo, they’re often no happier than they were in the south and sometimes madder! Why can’t they just enjoy the higher amounts vs what they got before? It might be better if they didn’t know climo.

Great point except that isn’t usually at least til Mar or April for even the strongest oncoming ones. And lots of times it isn’t till summer or even early fall, especially for the weak ones. In summary, it’s too early for a predominant -SOI even assuming El Niño is on the way in 2026. March is typically the very earliest. —— Edit: @LakeEffectOH is your avatar pic Mrs. Slocombe from “Are You Being Served?”

Interestingly, the MJO forecasts of the major models are centered on phase 3 for Feb 22-23, the period of this snow threat. Based on Baltimore’s daily temperatures, phase 3 has by a good margin been the coldest MJO phase there during the 20 La Niña Februaries with it on average being 4F colder than the overall Feb Nina avg. Second coldest is phase 8, which has averaged 2F colder than the overall Feb Niña avg. In Feb of 1996, Baltimore got 8.2” during phase 3. In addition, forecasts have both a -EPO and a -WPO for Feb 22-23, two other favorable indices for cold. OTOH, the models have a moderate to strong -PNA for then, a potential negative factor for cold. So, MJO phase 3, -EPO, and -WPO would be favorable. But would a -PNA hurt?

Thanks for posting that. Will it get the dip right this time? It busted with those runs having it very weak around 2/10-15. So far this month the weakest has been down only to 19 m/s.

AI Weathernext2 (from Google DeepMind), which has done pretty well overall this winter, gives DC ~10” per the 6Z on SV though this is likely overdone since it is 10:1:

Thanks Chuck. Based on this OHC anomaly chart already showing ~+0.9C, I think your idea of a fast transition is quite believable as of now. However, keep in mind that this isn’t adjusted downward for relative (as in the RONI idea) purposes:

This WB 6Z Euro AI op run based on 10:1 has 19” at DC! Of course the 10:1 is way overdone because it has temps 33-35 for the first half of the storm. And the WB Euro AIFS has issues as many of us know with too high snowfall in general. However, the WB 0Z CMC and 6Z GFS do have a big hit per Kuchera of 9”! That’s probably a more realistic scenario for the upside potential imho. If DC were to get 9”, it would be their biggest since the 10.3” of 1/12-14/2019!

Although today was AN mainly due to the low, it felt a good bit cooler, especially closer to the coast with a steady breeze off the cold ocean and most noticeably later in the afternoon. Looking forward to a chilly walk this evening.

The official record has the following for phase 8 in Dec and Feb this winter: Dec: 3-7, 15, 17-19. Was cold in E US overall. Feb: 1-7 (coldest phase 8 in Feb La Niña recorded MJO history (per Baltimore), which goes back to 1975) MJO phase each day: https://www.bom.gov.au/clim_data/IDCKGEM000/rmm.74toRealtime.txt Baltimore daily temperatures: https://www.weather.gov/wrh/Climate?wfo=lwx