So now that we are closing in on mid November, where are headed for the second half of the month? If we look at the current 5 day h5 hgts anomalies from today to Friday. We can see on the map below we have our +pna pushing into the -epo domain then ridge bridge across the top over the pole into Scandinavia. All thise high latitude blocking displaces the cold anomalies that are normally at the pole and relocates it into the mid latitudes. We also have a nice Aleutian low which also teleconnects well to a +pna. All of this basically means there is going to be a nice trough in the east with potentially arctic intrusions with that big -epo, which we have gotten.
Here is the next 5 days from nov 15th-20th. We still have our Aleutian low, but it's starting to shift out of the Aleutians and build more towards Siberia and into Alaska. Our PNA ridge has shifted westward off the west coast due to the shuffling of the Aleutian low. The big ridge bridge across the top has broken down and we now have low hgts on the north American side of things but still a big Scand ridge. Without the big poleward -epo and properly placed pna ridge, arctic air into the US should be at a minimum. We should see some Pacific puke start entering the US, specifically the western US/canada into the plains as the ridge out west flattens out a bit in response to the lowering hgts in Alaska. The east will still be under nw flow to start the period but then more zonal to sw flow as the ridge out west retrogrades offshore pulling the trough in the means towards the plains/lakes. Even though there is below normal hgts in the east, the source region is right off the north pacific, so it's not a cold look, nor warm.
Next is the 10-15 day period so from nov 20 to nov 25th. We still have our big scand ridge that grows even stronger. This is also starting to push into Greenland for an east base -nao look. We lost the Aleutian low which has moved over Siberia/arctic circle area. The low hgts over this part of the area into Alaska will continue to promote some pacific flow into the US again. The ridge out west continues to be featured off shore mainly which promotes more of a trough into the plains/lakes so not ideal for noreaster developments or snow in this look. In this time period we will have to see how the nao domain starts to materialize as modelling is trying to build something is this timeframe.
MJO currently is coming into phase 6 and will be getting into phase 7 by end of this week, then phase 8 and 1 for next week into the start of Thanksgiving. Phase 6 of the MJO favors zonal flow across the US and phase 7 favors cold push into the plains with a se ridge look. This fits well as to what the eps are starting to show for this weekend and beyond. We start with some PAC flow then as the pna ridge retrogrades westward the main trough axis pulls west as we start getting some se ridge looks. Phase 8 favors cold in the northeast, while phase 1 favors a -pna look.
Looking at the Wave potential velocity maps, this wave should continue around again through phase 2 and so on. Phase 2 should occur by the end of November which is bias cold in the east but a transition phase.
Looking at the strat we are at the peak of our wave 2 hit that helped in bringing multiple Barneys to the area. The wave 2 hits to the strat look to subside over the next week and we start to get a big wave 1 displacement event of the PV.
The euro by day 10 is just starting to sniff out the wave 1 look while the GEFS are going full bore on this. this is day 10 on the gefs, you can still see the wave 2 look on the temperature anomalies but the Siberian ridging is starting to take control.
By day 15, we have a full on PV displacement off the pole by a significant wave 1 hit as the pv gets displaced to Europe
The temperature anomalies are getting close to SSW territory here as there is a robust warm signal over the pole.
Right now we have a strong PV but the wave 2 hits we are seeing followed up by a big wave 1 hit weakens the pv zonal winds big time as it's in a free fall. If we were to follow up this big wave 1 hit up with a good wave 2 hit in December it could be enough to shred the PV at some point in Dec.
So in conclusion, after the Barney shots of cold this week and then a secondary push this weekend we should moderate to around normal, some days a little below some a little above as we get the influence of PAC flow. As the ridge out west backs up offshore that should pull the trough a bit further west, so while it won't be a torch any stronger system will most likely cut to our west as we get a bit of se ridge in response to where the trough is. I think we may get another shot of colder air just prior to Thanksgiving or right around there in response to where the MJO goes. Strat induced effects to the weather I think will remain quite low and the pattern will be more controlled by the MJO. Any strat impacts I think will be more towards late Thanksgiving and start of December depending on how/if that wave 1 hit develops. One other wild card which may also be influenced by the strat would be in the nao domain. Have to start watching this once we get past Nov 20th as that big scand ridge may try and retrograde a bit into Greenland and also how the strat displacement evolves as well.