bluewave

Since I have a frame of reference back to the 70s, I consider a model bust a complete miss of the P-Type or storm track from the day before for a high impact event. January 2000 fits that description with the storm coming hundreds of miles west from the day before. There was no storm forecast for many sections that got warning level to historic snows. I would consider January 2015 a large model error with a 60 mile + shift in the track to the east from the day before. We still got warning level snows around NYC and Western LI, but the jackpot shifted out to our east. Had the storm shifted hundreds of miles east and dropped no snow in NYC, then I would call that a bust. This happened several times in the 70s and 80s. We haven’t seen a complete P-type bust from the day before for a major event in a while. The most memorable one for me was 1-20-78. The forecast from the day before was for rain heavy at times. The next morning we had 12-18” on the ground. But I guess the term bust can be highly subjective.

It will be interesting to see if we can end the pattern with a nice snowstorm like we had at the beginning of it on January 7th. Sometimes we get bookend snows at the beginning and end of new patterns. Since the start of November, it has been a steady 30 day pattern followed by a shift at the beginning of each new month.

The RGEM has really been improving in recent years with continued upgrades. Unfortunately, there have been no NAM upgrades since 2017 when they decided to move toward developing a FV3 based CAM. But we have seen several problems with the the FV3 GFS changes. So we are stuck with an older version of the NAM until a replacement is ready. If the FV3 issues with the GFS are any indication, it may take a while for a suitable NAM replacement. Meanwhile, models like the RGEM will continue to pull ahead. The HRRR is often hit or miss in these situations with too much of a cold bias. https://vlab.noaa.gov/web/environmental-modeling-center/fv3-convective-allowing-forecast-system NAM development was frozen after the March 2017 upgrade, and RAP/HRRR development with the WRF-ARW model will cease after the RAPv5/HRRRv4 upgrade in 2020. However, operational execution of these modeling and associated DA systems will continue until comparable FV3-based systems are able to give similar performance.

34° and light snow here in SW Suffolk.

The models have become much more accurate than they were in the past. But in those days, we didn’t have weather forums and twitter posting every long range model snowstorm forecast. Models never have done particularly well with East Coast storm tracks past 3-5 days. Every once in a while a model like the Euro would score a long range win. This happened in January 1996 and February 2013. But we often forget how many long range misses the models had between the few long range successes. In the 70s and 80s, we often didn’t even know the storm track or P types a day before the storm. The forecast a day before the Jan 78 snowstorm with 12-18” was for rain heavy at times. That was my first school snow day in the 1970s that I can remember. Numerous snowstorm forecasts like in 1980 from a day before went OTS during nowcast time. The January 1987 forecast was for snow changing to rain hours before the storm started. Instead we got a heavy wet 10” of snow in about 5-6 hours. Our last actual model bust from a day before was January 2000. We went from no snow to record snows in the Mid-Atlantic. Nothing like that has happened in over 20 years. So that represents a great improvement. Perhaps the eventual Euro and EPS upgrade to convection permitting 3-5 km resolution will extend the forecast range for East Coast snowstorms. But we may not know until they actually try it.

We got the colder Pacific Ridge pattern this month. But record Pacific Jet from December never fully relaxed. So it served to suppress the STJ too far to our south. Hopefully, we can get a larger snow event before the retrogression of the ridge back to the Aleutians and milder Western Trough returns in early February.

The historic +13.3 departure in December 2015 marked the shift to much warmer winters. This January is only the 5th winter month out of the last 20 with below normal temperatures. The coldest departure month was December 2017 at only -2.5. NYC Jan 22….-1.4 Dec 21….+4.7 Feb 21….-1.1 Jan 21….+2.2 Dec 20…+1.7 Feb 20…+4.8 Jan 20….+6.5 Dec 19….+0.8 Feb 19….+0.9 Jan 19….-0.1 Dec 18…+2.6 Feb 18…+6.7 Jan 18….-0.9 Dec 17…..-2.5 Feb 17…..+6.3 Jan 17….+5.4 Dec 16….+0.8 Feb 16….+2.4 Jan 16….+1.9 Dec 15….+13.3

The EPS is great for general 500 mb teleconnections days 5 to 15. But the OP and EPS doesn’t have great skill with coastal storm tracks beyond 3-5 days. It does seem to have a slightly better long range track record with cutters like we had on Monday. Maybe the future 3-5 KM convection allowing resolution upgrade on the OP and EPS will extend the range of coastal storm track prediction.

The rule this season has been needing more than one model showing the event. The GFS was the overamped model on January 3rd initially showing the heavy totals near ACY in our area. But the mesos showed the confluence over our area and us missing the storm. This event it was the Euros turn to show several overamped runs before it backed off and joined the other models. It would be great to have the old days back like February 2013 and January 1996 when amped up Euro run was all we needed for a KU without any other models on board. But these days we need multiple globals on board beyond 72 hrs and then have the mesos hone in on the finer details like banding locations.

My guess is there have been several factors contributing to the record snowfall since 02-03. Much stronger blocking patterns both in the North Atlantic and North Pacific. Warming winters allow the atmosphere to hold more water vapor. Record SSTs also provide more moisture for snowstorms. The last 20 years will stand against any historic 20 year period for snowfall. But the one caveat is that older eras before the 1980s measured snowfall differently. They measured after snowstorms which allowed the snows to compact. So those older totals would be higher if they used the modern methods. https://news.ucar.edu/14009/snowfall-measurement-flaky-history

We can get a KU without NYC reaching 10”. But the lowest rank of cat 1 usually requires widespread accumulations over 10” somewhere in the NE corridor. Most KUs also produce numerous 10” + totals in our area. Sometimes the 10”+ zones are east of NYC like Nemo in Feb 2013. With Stella in March 2017, the jackpot was NW of NYC. So the normal or better snowfall winters in NYC need storms that can reach these levels somewhere in our area.

The bar was lower for normal snowfall in the 1980s since the 1951-1980 30 year normal was around 24.7” in NYC. So NYC had around 5 seasons in the 1980s with close to normal snowfall. We had 1KU in February 83…1 KU in April 82…2 KUs a few days apart in January 87. The 2nd event did much better in Central NJ to Eastern Long Island. There was another KU in February 87 that favored Central NJ. Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Nov Dec Jan Feb Mar Apr Season 1980-1981 T 2.8 8.0 T 8.6 0.0 19.4 1981-1982 0.0 2.1 11.8 0.4 0.7 9.6 24.6 1982-1983 0.0 3.0 1.9 21.5 T 0.8 27.2 1983-1984 T 1.6 11.7 0.2 11.9 0.0 25.4 1984-1985 T 5.5 8.4 10.0 0.2 T 24.1 1985-1986 T 0.9 2.2 9.9 T T 13.0 1986-1987 T 0.6 13.6 7.0 1.9 0.0 23.1 1987-1988 1.1 2.6 13.9 1.5 T 0.0 19.1 1988-1989 0.0 0.3 5.0 0.3 2.5 0.0 8.1 1989-1990 4.7 1.4 1.8 1.8 3.1 0.6 13.4

I sure hope so. NYC is going to need at least 1 KU event before the season is over to reach normal snowfall. This is the first season with the new higher 29.8” normal seasonal snowfall in NYC. Every season since 09-10 needed at least 1 KU event in the region to make it to at least normal snowfall. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Ending Date Total Snowfall Oct 1 to Apr 30 KU Storms 2022-04-30 6.8 0 2021-04-30 38.6 2 2020-04-30 4.8 0 2019-04-30 20.5 0 2018-04-30 40.9 4 2017-04-30 30.2 2 2016-04-30 32.8 1 2015-04-30 50.3 2 2014-04-30 57.4 3 2013-04-30 26.1 2 2012-04-30 7.4 0 2011-04-30 61.9 3 2010-04-30 51.4 3

While it has gotten much colder than December, we still have the overpowering Pacific Jet. So we have had several events get suppressed. The cutter was our most intense storm but the lack of -AO and -NAO hurt us. We generally need the northern branch to back off when there are STJ disturbances. So places to our south like ACY already have reached their normal snowfall for the entire season. At least we are close to average for January so far which is a big win coming off December.

Models seem to lock in cutter tracks like yesterday earlier than coastal storm tracks. Especially like the OP runs did over the ensembles such as the GEFS which were way too suppressed and cold. My guess is that the complexity created by the thermal contrast between the Eastern US and Gulf Stream is just too hard for the longer range runs to resolve.So it’s no surprise that the mesos like the NAM often take the lead with coastals like we saw in January 2016. But they only go out 84 hrs so we need to be patient until the storm track gets within their better range under 36-48 hrs.

The GFS hasn’t been doing so great recently with storm tracks either like we saw with it being overamped on January 3rd.

I believe Nemo in February 2013 was the last high profile snowstorm that only the Euro showed to work out. But that was before the series of upgrades and the January 2015 and 2016 misses. So now we need more than just one model showing any given solution to have enough confidence in an event from more than 72 hrs out.

We really need enough spacing between this very crowded vort pattern to make something work for us.

I believe they stopped doing upgrades on the NAM back in 2017. They are working on some type of FV3 replacement. In the mean time, the Canadians are continuing to improve the RGEM which seems to be getting better. So maybe the RGEM will become the go to meso with 84 hrs once the NAM stops running. Not a big fan of having to learn all the new biases of a FV3 CAM model.

We definitely want something like that since the Euro is gong in the opposite direction from what we want to see at the start of February.

This will be the storm that tells us how effective the recent Euro upgrade was. Before the upgrades around 2015, the Euro would often be the first model to lock onto southern stream systems. The GFS and CMC were always too flat and slow to catch on. The next thing to watch will be the mesos. In the old days, we had something called the EE rule. The ETA which is now the NAM agreeing with the Euro was always a great sign.

4th highest January 24 hr temperature rise on record at Newark. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=169&network=NJ_ASOS&zstation=EWR&hours=24&month=jan&dir=warm&_r=t&dpi=100&_fmt=png

Coldest January so far for NYC in 4 years. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Ending Date Mean Avg Temperature Jan 1 to Jan 16 Missing Count 2022-01-16 32.3 0 2021-01-16 37.7 0 2020-01-16 42.6 0 2019-01-16 35.3 0 2018-01-16 26.5 0 2017-01-16 35.9 0 2016-01-16 35.9 0 2015-01-16 29.1 0 2014-01-16 32.0 0 2013-01-16 38.7 0 2012-01-16 36.3 0 2011-01-16 31.2 0 2010-01-16 29.7 0 Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Jan Click column heading to sort ascending, click again to sort descending. Year Mean Avg Temperature Missing Count 2022 32.3 15 2021 34.8 0 2020 39.1 0 2019 32.5 0 2018 31.7 0 2017 38.0 0 2016 34.5 0 2015 29.9 0 2014 28.6 0 2013 35.1 0 2012 37.3 0 2011 29.7 0 2010 32.5 0

Gusts close to 70mph on the Long Island South Shore.

Yeah, the NAM gets the 925mb jet near 75 KT while the strong squall line is crossing the area. The record for January at OKX is very close to those levels. But the balloon launch will probably miss it since the peak winds will be before 12z. So it’s no surprise that the NAM has wind gusts in the 60-70 mph range from near NYC South Shore across Long Island. Some spots especially further east could even see higher gusts than that.