Absolute Vorticity

tpweather wrote: ↑Wed Sep 07, 2022 8:29 pm Les I love seeing these seasonal forecasts but I believe they are very similar in many respects to the long range maps that go out 15 days or so. To much of what is happening at the moment tends to be put into the models and this always seems to cause problems. One of these may be correct but going to wait until at least mid-Oct and see what the same models are showing.

Agreed Tim.... tons of time to go! As long as we avoid the -PNA in Dec, it can be a favorable month in Nina. Same with January. Then we lose it by Feb is typically how they go. However, every year when we try and figure it all out, something else drives the pattern and we bust. I'd be thrilled with a typical Nina progression.

An avg of all December temps from 2011-2021. Remember, 2010 was our last great December we've had. Yikes what a trend! Can we break out of the mold this year?

tron777 wrote: ↑Thu Sep 08, 2022 8:27 am An avg of all December temps from 2011-2021. Remember, 2010 was our last great December we've had. Yikes what a trend! Can we break out of the mold this year?


CrappyDecembers.png

That is wild Les and you could probably show the maps for May and see how much cooler than the previous 30 years and get a map with tons of blue. Later start to every season for the most part.

tpweather wrote: ↑Thu Sep 08, 2022 11:19 am

tron777 wrote: ↑Thu Sep 08, 2022 8:27 am An avg of all December temps from 2011-2021. Remember, 2010 was our last great December we've had. Yikes what a trend! Can we break out of the mold this year?


CrappyDecembers.png

That is wild Les and you could probably show the maps for May and see how much cooler than the previous 30 years and get a map with tons of blue. Later start to every season for the most part.

Absolutely. Later start to winters, later ending to winter. Delayed springs. That has been the trend for sure.

tron777 wrote: ↑Thu Sep 08, 2022 8:27 am An avg of all December temps from 2011-2021. Remember, 2010 was our last great December we've had. Yikes what a trend! Can we break out of the mold this year?

Great map! I figured we used to have colder Decembers on average than we have lately. 1989 comes to my mind - what a frigid December that was if anyone recalls I think the Ohio had thick ice on it if I am not mistaken.

cloudy72 wrote: ↑Thu Sep 08, 2022 1:37 pm

tron777 wrote: ↑Thu Sep 08, 2022 8:27 am An avg of all December temps from 2011-2021. Remember, 2010 was our last great December we've had. Yikes what a trend! Can we break out of the mold this year?

Great map! I figured we used to have colder Decembers on average than we have lately. 1989 comes to my mind - what a frigid December that was if anyone recalls I think the Ohio had thick ice on it if I am not mistaken.

Even to go further back Mike is the fall and winters in the 60's and 70's seem to come earlier for the most part but this also led to springs that really got going by late March and April. I wonder if the true 3 month coldest period in winter has moved even further back as for years that period was like Dec 5th- March 5th. That may be closer to the 10th of each month.

cloudy72 wrote: ↑Thu Sep 08, 2022 1:37 pm

tron777 wrote: ↑Thu Sep 08, 2022 8:27 am An avg of all December temps from 2011-2021. Remember, 2010 was our last great December we've had. Yikes what a trend! Can we break out of the mold this year?

Great map! I figured we used to have colder Decembers on average than we have lately. 1989 comes to my mind - what a frigid December that was if anyone recalls I think the Ohio had thick ice on it if I am not mistaken.

The Winter of 1989-1990 was a strong Nina. Dec 89 was the coldest on record at CVG! We broke 6 record lows two of which were -20+! We also had a nice 7" snow storm on the 15th! After that come Jan 1, 1990 the pattern broke down and never recovered. 50s and rain for the rest of winter.

Top Ten coldest and snowiest Decembers at CVG are below.

The summer ice melt season is about over. Snow starting to fall in the mountains of Siberia and BC Canada / Alaska. That will increase by months end and into October especially. IMHO, the cold air will build rapidly this Autumn. We just have to figure out where it's going to go. That's our job. You need cold for snow. We'll get the moisture, we usually do. Winters over the last decade have been wetter and snowier based on the new climate normals that were updated for the next decade last year. CVG is up to like 23 some inches now for the season instead of 21 something. The avg went up by 1-2" over the last 10 years. Just goes to show you timing is everything. No arctic outbreaks does not equal below normal snow but it can aide in the development of big storms and snow cover retention as well. Which for me is all part of it. Laying the snow down then keeping it.

After Merbok moves through the Bering there won't be much ice left to melt if any, but that should end the melt season and expect the new ice season to begin roughly close to when it normally would , maybe a touch late.


Latest JMA weeklies show an interesting late fall and early winter , should it be correct. I won't torture you with the awful illustrated maps, but it continues to show(500mb) a - NAO for Nov., and a strong -NAO in Dec. along with a SW ridge combo. I'll have to dig into my bookmarks to refresh my memory what this combo and strength could mean for us in Dec.

Siberian snow forecast for the short term looks exceptional. Both GFS/EU ensembles show a large build-up For eastern Russia starting shortly through the end of September

Bgoney wrote: ↑Wed Sep 21, 2022 6:53 am Siberian snow forecast for the short term looks exceptional. Both GFS/EU ensembles show a large build-up For eastern Russia starting shortly through the end of September

In the last week alone, the Siberian side is doing very nicely this early for snow cover. Not seeing much on our side of the globe yet thanks to the typhoon action and influx of warm air into the Arctic regions. But the trade off is we cool off this week so I'll take it! Wondering also how the N PAC SST's will respond down the road with the typhoon action? Bering Sea as you would expect is beginning to cool off some but currently the area of cooling is insignificant in size.

tron777 wrote: ↑Wed Sep 21, 2022 8:12 am

Bgoney wrote: ↑Wed Sep 21, 2022 6:53 am Siberian snow forecast for the short term looks exceptional. Both GFS/EU ensembles show a large build-up For eastern Russia starting shortly through the end of September

In the last week alone, the Siberian side is doing very nicely this early for snow cover. Not seeing much on our side of the globe yet thanks to the typhoon action and influx of warm air into the Arctic regions. But the trade off is we cool off this week so I'll take it! Wondering also how the N PAC SST's will respond down the road with the typhoon action? Bering Sea as you would expect is beginning to cool off some but currently the area of cooling is insignificant in size.

Great post and yes parts of Siberia are getting some snow and parts of northern Europe are seeing a really nice cold spell this early. Les I agree about Alaska and how the tropical system part milder air to that region but expecting Alaska to really get going in terms of colder weather over the next few weeks which is really their fall going into winter season

tpweather wrote: ↑Wed Sep 21, 2022 8:17 am

tron777 wrote: ↑Wed Sep 21, 2022 8:12 am

Bgoney wrote: ↑Wed Sep 21, 2022 6:53 am Siberian snow forecast for the short term looks exceptional. Both GFS/EU ensembles show a large build-up For eastern Russia starting shortly through the end of September

In the last week alone, the Siberian side is doing very nicely this early for snow cover. Not seeing much on our side of the globe yet thanks to the typhoon action and influx of warm air into the Arctic regions. But the trade off is we cool off this week so I'll take it! Wondering also how the N PAC SST's will respond down the road with the typhoon action? Bering Sea as you would expect is beginning to cool off some but currently the area of cooling is insignificant in size.

Great post and yes parts of Siberia are getting some snow and parts of northern Europe are seeing a really nice cold spell this early. Les I agree about Alaska and how the tropical system part milder air to that region but expecting Alaska to really get going in terms of colder weather over the next few weeks which is really their fall going into winter season

Agreed. Siberia typically does begin to fill in now. AK and N Canada more so in October.

The above shows temps during the last 4 Triple Dip Ninas for the Dec - Feb period. We've had only 4 since 1900. 2 were colder then avg and 2 were warmer. 1917-1918 was a brutal winter for cold and snow around here. 2000-2001 wasn't too shabby either with a very cold December. But anyway, 4 is a very small sample size. I will posted a larger version of the above image below.

I found an interesting article talking about the PV and its importance in winter. It is now developing as most of you know, and this article seems to indicate that the PV even in its beginning stages of development is already getting attacked.

https://www.severe-weather.eu/global-we ... europe-fa/

Relentless LaNina

Bgoney wrote: ↑Tue Sep 27, 2022 8:35 am Relentless LaNina


u.anom.30.5S-5N.gif

Looking like one more strengthening period is ahead as we've expected on here.

Good Afternoon and way to early to give a winter forecast. Saying that patterns do repeat and if the current pattern repeats in 2 or 3 months we would be in a cold but rather dry pattern but several bouts of snow squalls from the lakes. If the La Nina continues then a dry area north of the southern jet is seen quite often which is exactly what is happening at the moment. Relying on the northern jet usually means some colder weather but hard to get the big storms. The first 10 days or so of October look to be normal to below normal in temps and a really good chance of an early widespread frost. The early frost is nice and usually this can lead to a later Oct and November warming trend as the jet stream is trying to realign for the winter which would bring some troughs into the west during this period. As we know Oct and Nov gives us clues about the upcoming winter though those clues sometimes never play out which makes long term forecasting tough.

New Euro Seasonal is out and it isn't bad for Nov / Dec. -PNA but a nice blocking in the -AO / -NAO domains so we can make that work. Aleutian Ridge is very poleward as well. Jan - Mar looks torchy so won't bother posting it. Below are for Nov and Dec.

I don't like the November look at all there. That might work for the NE and upper midwest in November, but the OV , I don't think so

Bgoney wrote: ↑Thu Oct 06, 2022 8:11 am I don't like the November look at all there. That might work for the NE and upper midwest in November, but the OV , I don't think so

I have seen some guidance trending warmer for November, then cold for Dec and parts of Jan. Then it all goes to hell in typical Nina fashion for Feb. Lately though, the trends most winters have been for Nov to be warm or cold, doesn't really matter... very warm Dec, 50 / 50 Jan, nice Feb's then March and April's have gone both ways too, but have also trended colder overall. So we'll see. I like seeing the persistence of the +PNA pattern and -EPO at times as well as -NAO. Just hope it can continue into the winter. November should be telling. I do think Oct will be cooler then normal overall.

Watching the weather up north and Alaska is still very mild with storminess arriving while northern Canada is really getting cold and saw a temp of -16 this morning. That is one of reasons we are getting these earlier than normal cold shots as that air is headed this way but of course modified. This is one trend that may repeat in December imo and of course that would mean an early start to winter. Of course to much of a good thing could be cold and dry and when we get cold air I hate to spend it on cold and scattered snow showers.

We've been seeing some good gains in the SST's in the North Pacific. Gulf of AK and off the West Coast of North America. You want to see the warmest SST's concentrated there going into winter. Hope the current looks continues to develop. IMO if correct, and we see the +PNA continue, the outcome is going to be vastly different then your typical Nina. A +PDO is not expected, but would be welcome if it came. Over the summer, the PDO was in the -1 and -2 ranges (still is) so it'll be interesting this Fall if it rises or not.

Snow cover is coming along nicely, esp in Siberia where over 90% of the area has snow on the ground. I am impressed by this. Departure from normal, shows Siberia doing great and SE Canada also building up nicely, which would benefit Charles. We'd like it to build more to the West for the rest of the forum area... no doubt in time it will.

tron777 wrote: ↑Fri Oct 07, 2022 8:53 am We've been seeing some good gains in the SST's in the North Pacific. Gulf of AK and off the West Coast of North America. You want to see the warmest SST's concentrated there going into winter. Hope the current looks continues to develop. IMO if correct, and we see the +PNA continue, the outcome is going to be vastly different then your typical Nina. A +PDO is not expected, but would be welcome if it came. Over the summer, the PDO was in the -1 and -2 ranges (still is) so it'll be interesting this Fall if it rises or not.

Yea I don't think there is any chance the PDO goes positive during the winter months with that huge chunk of warm water in the NP east of Japan