bluewave

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.

The low of 6° at Newark is the coldest in 3 years. Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Ending Date Lowest Min Temperature Oct 1 to Apr 30 Missing Count 2022-04-30 6 105 2021-04-30 16 0 2020-04-30 12 0 2019-04-30 2 0 2018-04-30 4 0 2017-04-30 12 0 2016-04-30 0 0 2015-04-30 1 0 2014-04-30 3 0 2013-04-30 11 0 2012-04-30 12 0 2011-04-30 5 0 2010-04-30 14 0

It’s great that you start these storm threads. We need a dedicated thread for storms since the January thread can become unreadable when when too many topics are crammed into just one thread. We have an active storm discussion on which type of weather elements can be expected with each event. Once a model consensus begins to show a storm threat, it’s great to have a thread whether it’s snow, rain, mix, high winds,flooding, thunderstorms…etc.

This is going to be one of the most intense cutters that we have seen during the month of January as per the extreme LLJ wind speeds.

That’s it. A more north based -PNA with some ridging lingering near California is always preferable. It’s the deep trough digging toward the Baja that’s not what we ever want to see. Models seem to agree on the ridge pull back closer to the Aleutians. But the critical depth of the -PNA in early February will probably have to wait for later runs. As you mentioned, the AO is even less certain long range for the models. This could be related to the potential for wave breaks to pop up in the short term.

Sometimes a 15 day ensemble teleconnection forecast will do better than an operational run for a snowstorm from 5 days. But you need to check which 500 mb parameters the ensemble is showing compared to past snowstorms. It’s easier to nail a KU event from weeks out when we get a verified SSW event in progress that results in strong blocking near Greenland. We got this last winter ahead of the SSW in January and also in February 2018 for the epic March. The historic January KU pattern in 2016 became more obvious when the KB block built back across the pole early in the month.

While the long range 500 mb anomaly charts can identify patterns favorable for snow, it’s always better to wait until we get to within the 5 day window before getting overly invested in any individual snowfall opportunity.

Sure it was. But people that pointed it out in these threads were labeled as being anti snow or overly pessimistic. The PNA flip snowstorm potential was being discussed as far back as December. This matched past climo when long -PNA or Western Trough intervals relaxed. As for this last week, that ocean storm was reliably modeled OTS. The trailing storm system to impact the area on Monday was too amped up with no blocking to hold the high pressure in place. So the OP runs did a great job indicating the cutter track. The GEFS low resolution showing a more easterly track were never designed to handle situations like this. So its always a matter of choosing the right forecast tool for the situation.

The long range pattern discussions have been doing very well this winter so far. Models were indicating a very warm and snowless December from as early as late November. This month we got a 6-10” snowstorm as soon as the Pacific flipped. While the 500 mb height anomalies for this last week were indicating cold, they never had the big classic snowstorm look for us. The PNA ridge was centered too far to the east indicating suppression potential for the ocean storm. The Monday cutter emerged due to the lack of blocking to hold the Canadian high in place over New England.

That wasn’t the point that I was trying to make. Models have been consistent in showing the Western Ridge pulling back to the Aleutians in early February. The EPS weeklies have been showing this for a while. Now the GEFS is picking up on the retrogression. This would allow the trough to return to the West. If this trough is too deep, then it just pumps the SE Ridge. This scenario would be a less favorable -PNA. The more favorable -PNA patterns for us in February involve a shallower trough over Western Canada with a flatter ridge over the SW US. A north based -PNA if you like. But the recent models are showing more of a deeper trough returning to the Western US in early February. But even that type of pattern could still allow for a small snow event like we got in February 2018.

A deep trough in the West is never a good pattern for us during any month from December to March.

The low of 10° in NYC is colder than the last two winters that didn’t drop below 14°. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Ending Date Lowest Min Temperature Oct 1 to Apr 30 Missing Count 2022-04-30 10 105 2021-04-30 14 0 2020-04-30 14 0 2019-04-30 2 0 2018-04-30 5 0 2017-04-30 14 0 2016-04-30 -1 0 2015-04-30 2 0 2014-04-30 4 0 2013-04-30 11 0 2012-04-30 13 0 2011-04-30 6 0 2010-04-30 13 0

That’s why we discuss the 500 mb patterns where the actual height anomalies are located. Raw teleconnection indices by themselves don’t tell you very much. Models are good at identifying the long range long wave patterns. These 500 mb patterns give a good broad sketch of what type of weather is possible within a certain domain. Back in December, the deep Western Trough that the models forecast from mid to late November was the dominant feature. So the lack of snow then was no surprise given the type of 500 mb pattern being shown. As soon as the trough began to lift out of the West in early January, we got the 6-10” snow event. This has matched the past climatology for our area following Pacific pattern changes.

It’s all about where the 500 mb anomalies line up. A ridge pulling back to the Aleutians could allow the trough to dig into the Western US in February. That scenario generally isn’t favorable for us since it allows systems coming east to pump the SE Ridge. That’s why we would want to make the most of our +PNA and -EPO interval while it lasts.

Let’s hope we can cash in in this +PNA -EPO while we have it in late January. The latest ensembles moved to the EPS idea of a pattern reversal in early February. The big ridge pulls back to the Aleutians allowing a more neutral to eventually -PNA in early February.

I said some of the models were showing colder potential in late January than we’ll see this weekend. But they have been back and forth in recent days on the magnitude of the cold. Temperatures around 10° tomorrow in NYC would be the coldest in 3 years. I mentioned that less cold suppression could be good for our snowfall prospects. We already have one January 6”+ snowstorm. It would be great to get another before the month is over. The last time we pulled of an early and late January multiple 6”+ snowstorms was 2014. Since 2003, we have had an early January snowfall peak followed by a mid-January lull like this year so far. If we can score a major snowfall event near or after the 20th, then it would match recent snowfall climatology. Snowiest January days since 2003 1-4….9.8 1-7….12.6 1-12…6.6 1-15…6.2 1-18…6.6 1-21…19.5 1-22…9.2 1-23…32.6 1-26…18.9 1-27….18.0 1-28….12.0

The suppression is today with the 959 mb ocean storm and Arctic outbreak right behind it into the weekend. The PNA ridge axis was just a little too far to the east. The Monday phase matches other very active patterns in recent years. Last December featured the big snowstorm followed by the much warmer system on Christmas. We seldom get big follow up snowstorms so soon following 6-10” snowstorms like we got last week. That’s why a winter like 10-11 was so rare to produce 3 KU events in a little over a month. Most years we are lucky to just get 1 KU event.

The models have backed off a bit on the magnitude of the cold they were showing for late January a few days ago. I am hoping this means less of a chance for storm suppression. This more Nino-like pattern has already produced a record STJ in South Florida.