bluewave

Here you go. I just wanted to highlight the unusual storm motion and strength. The Pacific Jet continues to make headlines. DISCUSSION...Models remain in good agreement with the historically deep low moving onto the coast of Southern Oregon this afternoon. Models continue to show a very deep low pressure center around 973 mb when it hits the coast, this is lower than the 975 mb low of the historic Nov 9-10 storm in 1975. The low is expected to hit the coast near Brookings late this afternoon, moving over northern Klamath and Lake counties a little before sunrise Wednesday as it continues to weaken after moving inland. Discussion on each weather element is below; WIND...Low pressure will rapidly intensify today. The storm will undergo bombogenesis, with the pressure lowering to around 973 mb by 4 pm PST. This is a greater than 40 mb drop in just 24 hours. A "bomb cyclone" is defined as a 24 mb drop in 24 hours, so this one is almost double that and wind impacts will be felt across the entire area. What makes this storm unique is the trajectory that it will take as it deepens and moves inland. Rather than a deepening system moving from SW to NE inside 130W, which typically bring our strongest coastal and inland wind storms in SW Oregon and northern California (and onshore gradients ALL along the coast), this one will be moving in from NW to SE as it moves inland this evening. This will focus the core of the strongest winds (and onshore gradient) for the headlands/beaches from Cape Blanco southward. Winds in those places will likely gust in excess of 75 mph with gusts in excess of 100 mph possible at exposed areas and headlands. This is a dangerous storm and we don`t want to downplay the winds for areas farther north, but an easterly (offshore) gradient usually results in the winds getting blocked somewhat by the terrain. We are still expecting gusts of 45 to 55 mph at North Bend, but that`s the reason it should be somewhat lower there.

The Pacific Jet continues to exhibit extreme behavior. This low is unprecedented in its strength and track. It`s also historic because storms of this magnitude have not been observed on this track in the last 40 years or more! What makes this storm unique is the trajectory that it will take as it deepens and moves inland. Rather than a deepening system moving from SW to NE inside 130W, which typically bring our strongest coastal and inland wind storms in SW Oregon and northern California (and onshore gradients ALL along the coast), this one will be moving in from NW to SE as it moves onshore Tuesday evening. This will focus the core of the strongest winds (and onshore

One problem is that the models can’t really reliably resolve the MJO accurately enough beyond 6-10 days. Once the MJO starts to become active, models go into short term correction mode and the older runs become worthless. We saw this often last winter with the models constantly playing catch up.

Not much skill from the weeklies beyond day 8-10. That’s why they show something different every time they are run. It’s actually a good thing so people don’t have to waste their money on an expensive subscription.

We had our moderate winter -EPO blocking intervals from 15-16 to 18-19. But nothing rivaling the extreme -EPO blocking in 13-14 and 14-15. That was the last time we had cold winters here. Seems like our strongest -EPO episodes since then have come in November.

It goes to show how Important storm tracks are for seasonal snowfall in NYC. Average winter temperatures over 3 months can mask other factors. The last 2 winters had similar average temperatures with much different snowfall outcomes. Especially across Suffolk which had a 60” season in 2018. But a colder than average winter this decade was a guarantee for a 50”+ season in NYC. DJF average temperature 35.1 Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Season Mean Avg Temperature Seasonal Snow 2018-2019 36.3 20.5 2017-2018 36.2 40.9 2016-2017 39.3 30.2 2015-2016 41.0 30.8 2014-2015 31.4 50.3 2013-2014 32.9 57.4 2012-2013 36.8 26.1 2011-2012 40.5 7.4 2010-2011 32.8 61.9 2009-2010 33.8 51.4

Yeah, we have had much more success with major SSW’s later in the season.

Yeah, record cold temperatures now in the stratosphere above Finland.

Last winter was one virtual long range snowstorm after another.

These repeating weather patterns have become the new normal.

Haha. The 40N to 50N zone is acting like a gutter for those bowling balls. Always seems like models have an easier time getting storm tracks correct in that zone than the ones that track between 30N and 40N.

You know the Pacific Jet is on steroids when we get 3 bowling balls cross the country in 7-8 days.

Stormy pattern coming up. We are seeing a continuation of the supercharged Pacific Jet of recent years. First storm on Sunday followed by another on Wednesday. Strong winds may be an issue for the Thanksgiving parade balloons as the low stalls east of New England. 5+ SD Pacific jet max over Alaska Thursday

Even with the record +IOD, the forcing pattern this November was very similar to last. Notice the split forcing west of the dateline and over Africa. If this same forcing regime continues, then it would support a milder pattern after December 10th. It’s interesting how the same forcing can produce a cold November and mild December. But we’ll check back in early December to see if anything changes.

I wouldn’t rely too heavily on the CFS details. It usually flips around from run to run and day to day. I only pointed it out since matches the general EPO progression from last December.

My very rough guess right now is that we are following along the track of November 2018. Very cold Novembers with a -EPO pulse December 1-10. We saw a colder start to December in NYC during 2018. But last year featured a moderating temperature trend after December 10th. December 11-30 also coincided with the milder MJO phases. So we’ll have to reevaluate what the pattern and model forecasts look like once we get past the first week of December. This will be to see if the pattern is following the recent past or it goes in another direction. While the CFS isn’t the worlds greatest model, it does show this pattern progression.

It’s quite possible.

This could be the windiest period around Thanksgiving in years.

While the amplitude has increased in recent runs, the ridge axis remains stuck north of Hawaii and over the SE US.

The fly in the ointment this year has been the unusually strong low over the SW US. So the SE ridge corrects stronger the closer we get to the forecast period. https://ktar.com/story/2850504/hail-falls-across-the-phoenix-area-but-storms-are-heading-out-of-town/

The -NAO blocks this time of year have been fleeting. We had a big -NAO drop at the same time last year. Our best recent success with more sustained -NAO blocking has been later in the season. https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.nao.index.b500101.current.ascii 2018 11 19 -0.274 2018 11 20 -0.826 2018 11 21 -0.726 2018 11 22 -0.348 2018 11 23 -0.369 2018 11 24 -0.804 2018 11 25 -1.373 2018 11 26 -1.404 2018 11 27 -1.144 2018 11 28 -0.872 2018 11 29 -0.440 2018 11 30 -0.133

It’s not really worth looking at the models past 7 days.The Niña-like SE ridge keeps beating expectations from what is shown at day 10. So the main storm track in the fast Pacific split flow is through the Great Lakes. New day 7 forecast Old day 10 forecast Old day 11-15 forecast

Top 3 coldest first 20 days of November at several of our stations before the temperature moderation. Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Nov 1 to Nov 20 Missing Count 1 1933-11-20 38.7 0 2 1976-11-20 40.5 0 3 2019-11-20 42.4 0 Time Series Summary for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Nov 1 to Nov 20 Missing Count 1 1976-11-20 41.0 0 2 1967-11-20 41.2 0 3 2019-11-20 41.4 0 Time Series Summary for IGOR I SIKORSKY MEMORI AP, CT Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Nov 1 to Nov 20 Missing Count 1 1962-11-20 41.2 0 2 2019-11-20 42.0 0 3 1967-11-20 42.3 0

We need a strong -NAO event to counter the unfavorable Pacific like we had late in the last few seasons. Root for another -EPO pulse in early December to combine with the weak -NAO. That would be one way we could see some wintery weather. But that is too far out to speculate on now. Otherwise, we get the same default unfavorable Pacific pattern.

I am just weary of the Pacific defaulting back to its multi-year Niña-like base state. Notice how the EPS has the ridge north of Hawaii and SE ridge holding on with the weak -NAO near the end of the month. My guess is that the warm western Pacific and cold Niño 1+2 has a hand in this pattern of the last few years.