Winter 20-21 Discussion

[raindancewx]

Increasingly looks like California's rain/snow deficits are going to be nearly destroyed or destroyed in the coming days with up to 100 inches of snow forecast in the mountains through Friday Night. A lot of Arizona is going to flip to positive precipitation departures for January after today and Monday. New Mexico already had some areas running above average this month, and the above average moisture should expand here as well.

[Weather Geek01]

Apparently IMD is coming up with 3 forecasting model to predict weather data better.

[raindancewx]

Meanwhile, in the cold, wet Southwest. Whoops dry warm I mean. It's a La Nina after all. Models still show up to 11 inches of liquid equivalent falling as snow in the mountains of California the next six days.

[raindancewx]

Blizzard warnings for California for up to six feet of snow by Friday, and 100 mph winds. Fingers crossed.

[raindancewx]

The CFS is trending February colder at the moment. My view is it is overdoing cold in California because of the snows right now. But it should be cold in the Midwest & interior West. That makes sense to me. Very similar to my analog blend for winter and February 2008. But I'd probably connect the two cold areas via WY/CO. I'd push the warmth centered over Roswell to about Dallas. That would warm up the south and allow the cold to extend into the interior SW. We'll see though. I'll post the final CFS & Canadian outlooks for February in a few days. CFS had a good forecast for January on 12/31.

[andyhb]

-PDO signature getting stronger over the last week per CDAS (cooling along the West Coast + warming over the north-central Pacific), as is the +TNI over the ENSO regions (Nino 4 substantially cooler than Nino 1.2).

[raindancewx]

Here are three objective blends for February 2021. Take your pick.

Nino 4 around 27.0C in January...AND a -NAO in January composite. By this method I'd probably go in between the two maps.

Top SOI Matches for Nov-Jan, using data from 1931-2019.

 

[CheeselandSkies]

6 hours ago, raindancewx said:

Here are three objective blends for February 2021. Take your pick.

Nino 4 around 27.0C in January...AND a -NAO in January composite. By this method I'd probably go in between the two maps.

Top SOI Matches for Nov-Jan, using data from 1931-2019.

 

Encouraging to see some active severe weather seasons on those analogs, although not necessarily stellar from a Plains chaser perspective (apart from 1999 and 2008). 2017 wasn't ideal but not the worst of the lackluster half-decade plus that we've been in (tie between 2018 and 2020 IMO).

[raindancewx]

More precipitation for the Southwest today means Arizona will see more more contraction of the dry January. Of the Southwest states, Arizona will end up the least dry in January after today. I'm expecting some decent contraction of the dryness over California when the map updates again tomorrow. 

[raindancewx]

My guess for February is the WPO/EPO/NAO are volatile/neutral(ish) overall, but the PNA/AO remain negative. Early February is supposed to see the WPO favoring SW cold and the EPO favoring eastern US cold, so that'll be interesting. 

[raindancewx]

The Canadian forecast for February finally has the Northern Plains getting cold. Interior West & Midwest cold too.

Here is how my winter analogs did for January 2021. As with December, the observations snapped closer to the analog blend with time. From the 21st to the 31st, Florida, southern Maine, southern Kansas, West Texas, eastern New Mexico, SE Colorado, southern Arizona, Las Vegas all corrected toward the blend. Green Bay, Des Moines and Kansas City were within 0-3 briefly, on 1/28, and then snapped back to 3-4 out. A lot of the West snapped closer at the end but was too far out at the start of the month.

[raindancewx]

My forecast was pretty good in the South in January and pretty good in the interior West in December, with NM/TX, most of the South and Northeast and eastern Midwest good both months. If the February pattern is cold in the NW/Northern Plains/Midwest, warm in the South as is forecast, should be a pretty good for highs nationally for the season even though I screwed up the progression to some extent. Big miss will be the Northern Plains.

My snow outlook for the Northeast is interesting. Philadelphia reported 6.1" total for 1/31-2/1. They'll probably get more 2/2, but not too much. NYC reported 16.8" for 1/31-2/1. Boston was supposed to be above average for the season, and Logan got 1.2" or something. Baltimore/DC are still running well below average seasonally at the three airports as I had them. I'd say I'm still fine in Boston, DC, and Philadelphia. For the moment, Central Park has 27.4" for the season, while Boston has 24.3" - that's unusual, especially since Philly is at 12.7".

This storm busted my snow outlook for NYC, ~23". They'll get a bit more 2/2 and then anything else later on. But it hasn't for Washington, Baltimore, or Boston. Philadelphia may bust with the next storm, but the pattern seems to be they get screwed with mixes. They reported 12-18 hours of freezing rain, and are now seeing above freezing light snow as I type this. So presumably if the next storm comes later in February or March, it won't add too much to their total. Not optimistic for DC/Baltimore either.

 

[raindancewx]

February has started off cold in the south, mixed in the Northeast and warm elsewhere. CPC is unusually confident in the major cold snap advertised on the models.

I've been running too cold all winter in the North-Central US, so this should drag the anomalies of 2020-21 a lot closer to my analog blend. I did have the North, and the East, outside the deep south fairly cold in February, so this is all fine by me.

[raindancewx]

On 12/24/2020 at 1:10 PM, raindancewx said:

This is what I have for correlations for all the major indexes for January. You can see for New Mexico, it's at least possible all five will be favorable at the same time for cold in January. I don't expect all five to be favorable the whole month though, but it seems like they'll align at times. Blues and purples are negative correlations, greens and yellows are positive. The SOI is probably going to warm the south pretty quickly by February - which mechanism that is by is anyone's guess.

Looks to me like the WPO was at record positive levels in January. AO/NAO were very negative with the EPO negative (which CPC considers the warm phase for the East as you can see in the correlation image). PNA neutral. Pacific wins.

https://psl.noaa.gov/data/correlation/wp.data

[StormchaserChuck!]

I don't like February Arctic blasts... too much southery flow at the surface underneath. We have till like Jan 31st imo. 

[StormchaserChuck!]

The only Winter's that are really going to compare to the AO we have this Winter are 2010, 1977, 1969, 1963

 

[raindancewx]

I was trying to remember if the early part of February 2019 started off warm in Bismarck and Billings before the bottom fell out for temperatures. They did have a few warm days up there that month. Not expecting Billings to finish 22 below average like that incredible month. But the cold coming is pretty severe. Just the past couple days of cold has already moved 2020-21 a lot closer to my analog blend, wiping out 10-30% of the distance between the highs my blend had and the actual highs in some spots in the North Central.

[raindancewx]

It's amazing how hard my maps are going to snap toward 2020-21 with the current/coming cold in the Plains. The warmth for this winter is going to get beaten back pretty hard. In the end, it looks like 2007-08 was a pretty decent analog to this year, despite a lot of timing issues. You can see that there was a major cold dump into the Plain in February 2008. Unlike that year, the core of it seems to be 2/7-2/20 or so, but we'll see how it goes. We're just now getting to the point where the Northern Plains are about to flip below average for February temperatures.

[raindancewx]

Philadelphia only got 0.7 inches of snow today. Less for DC/Baltimore. That's consistent with the pattern of marginal temperatures (never dropped below freezing in Philadelphia today - that seemed pretty likely given the warmth yesterday) that's been there and south of Philly all winter. The snow totals for much of the east are near average or below for the date, despite a small area from central New England to NYC and North Central PA doing pretty well. 

My big theory for this winter has been that the cycles are well established at about 45-days. So the big Nor'easter cycle is:

late Oct-->mid Dec-->2/1-->mid March. Not really expecting any huge snow dumps until then. We'll see though. Temperatures start to climb as you get later in February even as the oceans are still getting colder. There was a lot of small crap that never really materialized as big snowstorms for the NE between mid-Dec and 2/1. That's where we are now I think.

[LibertyBell]

On 1/22/2021 at 6:12 PM, raindancewx said:

Today is the 60th day in a row without hitting 60 degrees in Albuquerque. Hasn't actually topped 57 in that time frame either.

Places that have hit 60: Boston, New York, Philadelphia, Denver, Billings.

wait NYC hasn't hit 50 for a long time, this is the third longest streak of no 50 degree temps

[LibertyBell]

6 hours ago, raindancewx said:

Philadelphia only got 0.7 inches of snow today. Less for DC/Baltimore. That's consistent with the pattern of marginal temperatures (never dropped below freezing in Philadelphia today - that seemed pretty likely given the warmth yesterday) that's been there and south of Philly all winter. The snow totals for much of the east are near average or below for the date, despite a small area from central New England to NYC and North Central PA doing pretty well. 

My big theory for this winter has been that the cycles are well established at about 45-days. So the big Nor'easter cycle is:

late Oct-->mid Dec-->2/1-->mid March. Not really expecting any huge snow dumps until then. We'll see though. Temperatures start to climb as you get later in February even as the oceans are still getting colder. There was a lot of small crap that never really materialized as big snowstorms for the NE between mid-Dec and 2/1. That's where we are now I think.

JFK got 7" of snow and it looks like NYC and the tristate area is on for perhaps a historically snowy month

[raindancewx]

1 hour ago, LibertyBell said:

wait NYC hasn't hit 50 for a long time, this is the third longest streak of no 50 degree temps

I wrote that on 1/22. NYC hit 60F in late December and then 50F in early January.  It's nowhere near a top three streak for not hitting 50F in Central Park currently. Even as recently as 2015 NYC went over 60 days without hitting 50 degrees. There were also much longer streaks in 2004 and 2007.

Number of Consecutive Days Max Temperature < 50
for New York-Central Park Area, NY (ThreadEx)
Click column heading to sort ascending, click again to sort descending.

Rank	Run Length	Ending Date
1	77	1969-03-15
2	65	1977-02-10
3	63	2015-03-08
4	62	1941-03-02
5	59	1948-02-13
6	54	1971-02-11
7	50	1981-02-01
8	47	2004-02-20
11	46	1968-03-07
12	45	1945-02-15
13	44	2007-03-01
17	43	2001-01-29
18	42	2011-02-13
20	39	2010-03-05
21	38	1958-03-01
22	37	1986-03-04
23	36	1947-03-12
25	35	2021-02-06
-	44	1996-01-17
-	47	1985-02-18
-	44	1978-03-11
-	47	1970-01-28
-	44	1956-02-07
-	42	1936-02-24
-	36	1935-02-15

Albuquerque had a streak from 11/24-2/1, 70 days in a row - without hitting 60F. My point was a lot of much colder climates hit 60F in that time frame. New York may do well for snow this month. I'm skeptical that Philly and south are going to do well. I had thought NYC would be on the borderline of the good snow areas. Essentially, with the NAO staying negative into January that area shifted south of where I expected.

[andyhb]

Lol, all the climate models are like "what severe weather season". NMME, CANSIPS, Euro, you name it. Poleward retracted jet + torching southwest/south-central US + dry.

[CheeselandSkies]

2 hours ago, andyhb said:

Lol, all the climate models are like "what severe weather season". NMME, CANSIPS, Euro, you name it. Poleward retracted jet + torching southwest/south-central US + dry.

So much for La Niña +TNI, -PDO magic, lol. Of course, they could easily be wrong at this range, but if ALL of them are doing it it's kind of worrisome.

Guess this is why you haven't started the 2021 tornadoes/high risk thread yet.

[LibertyBell]

15 hours ago, raindancewx said:

I wrote that on 1/22. NYC hit 60F in late December and then 50F in early January.  It's nowhere near a top three streak for not hitting 50F in Central Park currently. Even as recently as 2015 NYC went over 60 days without hitting 50 degrees. There were also much longer streaks in 2004 and 2007.

Number of Consecutive Days Max Temperature < 50
for New York-Central Park Area, NY (ThreadEx)
Click column heading to sort ascending, click again to sort descending.

Rank	Run Length	Ending Date
1	77	1969-03-15
2	65	1977-02-10
3	63	2015-03-08
4	62	1941-03-02
5	59	1948-02-13
6	54	1971-02-11
7	50	1981-02-01
8	47	2004-02-20
11	46	1968-03-07
12	45	1945-02-15
13	44	2007-03-01
17	43	2001-01-29
18	42	2011-02-13
20	39	2010-03-05
21	38	1958-03-01
22	37	1986-03-04
23	36	1947-03-12
25	35	2021-02-06
-	44	1996-01-17
-	47	1985-02-18
-	44	1978-03-11
-	47	1970-01-28
-	44	1956-02-07
-	42	1936-02-24
-	36	1935-02-15

Albuquerque had a streak from 11/24-2/1, 70 days in a row - without hitting 60F. My point was a lot of much colder climates hit 60F in that time frame. New York may do well for snow this month. I'm skeptical that Philly and south are going to do well. I had thought NYC would be on the borderline of the good snow areas. Essentially, with the NAO staying negative into January that area shifted south of where I expected.

Thanks, it seems like the big AO/NAO block has been keeping us from hitting 50 and looks like that might continue for the rest of the month.  I read that Philly got 9 inches from the last storm?  Can you double check that?

 

[raindancewx]

https://www.scribd.com/document/494132283/Spring-2021-PDF

I got tired of waiting for the January 2021 CPC update for the Tropical Pacific. That is my Spring 2021 outlook.

Basic idea is a blend of Spring 1955, 2008, 2012 for the La Nina, but Spring 1979 is added for the unusual (near record) +NAO November to consistently -NAO Dec-Jan in a cold ENSO. That transition is very unusual.

I'm expecting several big tornado outbreaks, two Plains blizzards, and one final big Nor'easter in mid-March. There is a good signal for cold shots into the Southwest US mid-March and late-April. Those are my guesses for timing the big tornado outbreaks. I've laid out the justifications in the forecast. I won't rehash it all here. 

[andyhb]

Curious to see the exact periods of projected tornado events there. I have some disagreements with doing that, namely all of the things that could go wrong that can't be forecasted on the sub-seasonal/seasonal timescale. Are these periods just when "western trough/eastern ridge" is expected?

[raindancewx]

As a general rule, if Albuquerque gets snow in March or April, you tend to get tornadoes east of us, since the normal heat here (~60s-70s) is blown east but over sea-level places where it warms to the 80s. Cold rain is usually good enough too if we are in the mid 30s to low 40s in April or May. I'm mostly putting out the timing for when I expect the tornado outbreaks just to see if I get even close.

What I did in the forecast is include looks for when NM is cold, and then compare those looks to temperature profiles in tornado outbreaks in the analogs. The looks are similar. So the idea is if I can time when New Mexico is cold with a storm, it might work for identifying an outbreak.

[raindancewx]

Looks like a pretty historic cold outbreak and snow storm is coming for Texas and eastern New Mexico the coming days. Albuquerque probably won't drop below 0F, but we should get some snow. Weather.com has accumulating snow down to Houston.

Even with the cold coming deep into Texas, I'm not sure they'll end up cold for the month. El Paso has been hanging out around +10 to date in February. After the next week or so, much of the severe cold in the center of the US should get destroyed as Canada warm ups and the mechanisms that have brought the cold in relax. I had a cold February in the northern US, so the month is fairly close (if more severe) to what I had in mind. There is some fairly intense cold in the Northwest right now too, so the warmth in OR/WA is getting attacked. The temperature pattern of February has really snapped a lot of the US pretty quickly toward my analog blend. Places that were really far out like Billings, Rapid City, and Minneapolis are fairly close now, and will continue to improve for at least the next five days. The deeper you get into a season, the harder it is for individual days to meaningfully change the seasonal average. So it's been amazing seeing places snap 0.5F or more closer - for the season - each day in the North Central US.

[raindancewx]

The funny thing about this pattern is extremely far south snowfall has been a feature since September. It snowed down to Santa Fe (they had an inch) on 9/9/2020. Then you had this, and it got deeper toward Mexico on 10/28. So these big cold/snow outbreaks have been advertised. I'm pretty sure the WPO flipped back negative for the first time since October and that's part of why it is happening again (that and the strat warm stuff).