so_whats_happening

NAM is to be replaced by FV3

Haha thats pretty funny. I actually went to school with him. Had horst as the lead forecaster when I was there.

That statement solely relies on the pacific pattern at the time and serves no other purpose other than to shift the storm track further south. I think a better statement would be it gives opportunity to have colder air to funnel with a -NAO versus a +NAO if the pacific pattern cooperates enough leading into the development of the NAO (whichever phase comes about). I feel we have been far too lucky with getting a -EPO/+PNA pattern within a -NAO regime that it gives us this sense cold will be there when we get a -NAO, hence a big reason many associate the -NAO with a cold pattern. Honestly with all this talk none of this was even remotely intended toward you, you just happen to think the statement was about what you had said, not entirely sure why you felt that way but hey to each their own. I wanna say raindance's comment of -NAO was in jest toward the lot of people saying it will be a December to remember as is usually the case pointed out almost every year and then on top of it posting GFS maps of warm anomalies as we are transitioning into a west based -NAO during that timeframe. GFS unfortunately is a bit wonked out of its mind right now 0 consistency run to run so it was in bad taste.

Yea 2010 was a bit of an oddball situation with a -PNA and -NAO and widespread cold. Not to say a -PNA/-NAO combo doesn't produce cold and at that coast to coast, it can and does happen just not very often. This year is different in that we did not have a -NAO leading up to that cold period like in 2010. We had a fairly weak -NAO if you want to call it that with similar ridging pattern in the Alaska region leading up to current time. So cold got to build up in the similar regions except now it is just being released along the west instead of across the country. Talk about anomalous -PNA though in 2010. Here are the 2 weeks leading up to the end of November you can see the similarities between the two years except for one fairly noticeable difference and that is the lack of -NAO leading up to December this year. If we had that -NAO present it would have been able to funnel in the cold much better. We also had a very weak MJO basically null that month so not much influence in that department versus this year we have a more pronounced wave making its presence known and throwing curveballs at us.

It definitely was implied just a few posts above. Right a -NAO just provides staying power into a pattern if the cold got released in any other instance, it simply doesn't mean a cold pattern.

Little bit of cringe going on here. It is well known -NAO does not bring cold temps into the US so im not sure where that is coming from. Didn't have a -NAO with the cold blast in November even with a neutral to negative PNA sticking around we reduced the heat anomalies easily by half. -NAO is all about storm track and slowing the forward speed of systems. I personally would rather take my chances with temps near or slightly above average as a whole than have a ton of cold pressing down east of the Mississippi. Suppression/depression with missed opportunities off the coast no thanks. Many areas need rain and would rather see the rain falling then see the constant bickering of no snow. Plus it is only December folks need to relax a bit.

DCA _ NYC _ BOS ___ ORD _ ATL _ IAH ____ DEN _ PHX _ SEA -1 -1.2 -1.5 -1.4 +1 +1.8 -1.4 +1.2 0 DCA _ NYC _ BOS ___ ORD _ DTW _ BUF ___ DEN _ SEA _ BTV 18 38 64 45 38 110 42 11 84 Little late but wanted to do more of the snowfall contest than anything

As always thanks Roger!

When the central portion of the storm crosses land. It should be making landfall soon if it hasn't already. Definitely took more of NW track recently so this may delay actual landfall a bit. ASOS readings indicate it should be over land.

I see this being very possible to start out December maybe not quite on those extremes but nonetheless a +NAO/-PNA pattern. This look will potentially be especially true if we do indeed come into phase 5 again toward the end of the month. I believe as we close out the month of December that would be our next opportunity to allow for cold and snow potential outside of around turkey day in the east and midwest. I mentioned on another forum this really is looking like a back and forth winter for us in the east. So how the rest of November plays out of course. Im also rather happy to see the west coast getting into some action. Can not believe what Arizona and New Mexico look like on the drought monitor havent seen it at those levels in a long long time.

Last week of November could feature warmth again as this cool down does look abrupt and cold but rather brief.

Im sure in the past those two instances had occurred unfortunately the amount of data we have only takes us so far. I wanna say it is probably harder to sustain a triple el nino phase though as it is considered such an anomaly versus triple dip ninas which are an exaggeration of the normal pattern.

I gotta agree there does seem to be some cyclical pattern to triple dip Ninas. The overall trend though still does show that temps in ocean basins continue to warm so impacts of these triple dips may be different with time than say what we experienced in the turn of the millennium or back in the mid 70s. Each triple dip Im sure has its own flavor too as differing atmospheric patterns occur during these time periods than say what we are in currently for example AMO/PDO, etc. If it is somewhat in that range of time 7-22 years we could see another decent cooldown of the tropical pacific waters come the end of the decade. ~22 years has been my go to for seeing triple dips.

Subsurface warming starting to dip in the normal location may be the end of the subsurface look for the Nina at least as we move into November. Im not sure we fully get out of cold neutral through most of the winter though, especially 3.4/4 as expected, have to see how this materializes.

Congrats RJay!

Looks like the CFS is pushing west with the higher anoms fits with the idea of the -EPO pattern. This opens up the door for another recurving hurricane as you mentioned with the potential of another FL east coast rider if one were to occur. The highs coming in the east are rather impressive coming up. At least for the foreseeable future west coast ridge east coast troughing should occur. We seem to be having another broad wind event across the Pac so this should help spread the Nina out a bit and allow a little relaxing period again toward early November where the 1+2 and 3 region warms up as the waters push back to 3.4 and 4. Subsurface still looks pretty intact though.

DCA +.7 NYC +.4 BOS 0 ORD +1.4 ATL -.5 IAH +.4 DEN +1.5 PHX +1.7 SEA +2.5

Guess not technically water vapor will have a net cooling effect in the stratosphere. https://www.severe-weather.eu/global-weather/cold-anomaly-stratosphere-polar-vortex-volcanic-cooling-winter-influence-fa/

One random thought with the Hunga Tonga Eruption. Releasing that much water vapor into the upper atmosphere would this not potentially induce a warming within the stratosphere with that large amount of water vapor being added? If we induce a warming in the stratosphere from the incoming solar radiation is it possible this then allows the tropospheric portion to cool or be cooler? I know SO2 is usually the main driver in inducing cooling hemispherically or globally, depending on location of the eruption, but wouldn't water vapor create a similar process but one that is thermodynamically driven. It surely will be up in those portions of the atmosphere for many many years to come and should be most likely a southern hemisphere thing but would love to know what that amount of water vapor could do to the system. We are technically starting to get within the time frame where large volcanic eruptions show up in some data, usually is about 6 months after the eruption.

DCA _ NYC _ BOS __ ORD _ ATL _ IAH ___ DEN _ PHX _ SEA +1.4 +1.5 +2.1 +1.7 +0.7 +0.6 +1.2 +0.7 +2.5

^^^ That would be a lovely pattern into winter, if only. We may get another round of easterlies coming up here.

Think this lead system is the sacrifice storm may get to a TS but will have to watch how the ULL interact in the Atlantic, GEM also has a weak system and another potential to watch in western Caribbean/ GOM area. Either way both look to take it to about the Antilles area by Day 10

Gotta admit it was a little later than I expected but yea this is about to get interesting. The system in the Gulf/ Caribbean comes from the Central American Gyre and then just sits along the coast for a few days. It only takes one...

This is a fair point they don't always need to correlate. PDO tends to produce a more -PNA regime but not always. I do remember seeing the record -PDO last year while I believe we had a -EPO/+PNA (went to neutral as we pushed into Decemeber) regime at the same time, was pretty impressive to see. Yea we definitely need a +PNA for our classic storms but we can manage pretty well with a -PNA sometimes usually our fun anafront situations. Nothing like going from 50's-60's to heavy wet snow in 24 hours.

I could agree with that intensity may not be the issue. It may be where forcing takes place. If we look at 2010-2011 season we went to strong La Nina status but the cold pool was so far west that it actually ended up being beneficial for us in the east. That with the situation of a -NAO pattern present from the solar minimum that was around at the time. The biggest difference between than and this time frame is the east coast waters. Back then waters were warm south of Greenland and rather chilly across much of the east coast. Right now waters are just wayyy too warm across much of the eastern sea board. This promotes a ridging like pattern (normally) which in turn would drive weather systems inland with pushing of the baroclinic zone on the coast or just inland, as you stated very +NAO like regime. That would be in conjunction of - PNA pattern bearing a -PDO sticks around too. 2016-17 was an interesting one had another scenario with the coldest waters in Nino 4 similar to this year (so far) and warming as you went east. The result was a pretty barren snow land of a winter in the mid atlantic, not entirely sure about the NE though ( I would think interior did well that year with how the 500mb pattern setup). The cooling couth of Greenland seemed to help re-enforce the idea of +NAO that season. I think the biggest concerns for the upcoming winter scenario could be how extensive those warm waters are in the east. Do they reach up to around Greenland and help promote a pseudo -NAO regime at times or do we get a cooling that occurs just south of Greenland giving it +NAO regime? Also how extensive the Pacific ridge would be do we see a scenario of ridging along the west coast or is it more confined to the Aleutians? We definitely do not want ridging along the coast and a +NAO that is just a death spell (11-12). I would gladly take a 10-11 scenario of -NAO and forcing rather far west where the ridge was near the Aleutians.