1000 EDT NOVEMBER 10
Why is it that whenever I start some sort of new venture ….all sorts of weird stuff seems to happen …both culturally and with me personally? …. Just one of those things I guess.
I will start out this morning by taking a look at some of the MJO forecast models and see how or what they are forecasting in the current MJO pulse over the next 2 weeks and what… if anything …they that can tell us about the evolving pattern. The Current MJO is of moderate intensity and located in phase 6. This corresponds to the map below where we can can see several important features. There is a large area of strong positive height anomalies over Scandinavia and over the north slope of Siberia… And a strong negative high anomaly over the gulf Alaska.
In the general sense this appears to be a fairly close match to what most of the medium range models of forecasting over the next several days with the strong negative anomaly developing in the gulf Alaska as a series of strong Lows crash into Western Canada the Alaskan panhandle and eventually down by Vancouver and Seattle day 8-9-10.
In fact the operational European and the GFS Models do show a pretry potent system traveling down the Alaskan panhandle and slamming into Vancouver and Seattle November 19 – 20. It does so because all the models are developing or expanding a Ridge over the Bering sea into Western Alaska. Right now the model data shows 850 MB temperatures clearly cold enough to support snow even in downtown Seattle and maybe even Portland…. which in mid November is pretty darn usual. The development of this Ridge at 500 MB allows for the first large cold arctic High of the season in Northwest Canada .
So whats happens with the current MJO impulse?
The first link here represents the NCEP GFS Ensemble mean which is forecasting the current impulse to reach phase 1 close to region 2 by November 24
The operational European MJO model shows the impulse collapsing by the time they reached the thanksgiving weekend…
And this trend is supported by the European MJO ensemble mean and spaghetti plots
Therefore if we assume that the current MJO impulse will make it to at least PHASE 1 and POSSiBLE Phase 2…. We end up with this sort of pattern. In PHASE 8 we can clearly see strong positive height anomalies at 500 MB increasing southeastern Canada… and over Northwest Russia into Scandinavia. In addition we can also see strong negative height anomalies over the Siberian side of the arctic circle— which is currently were the PV is
By phase 1 however we see a strong positive height anomalies developing over southeastern Canada into Greenland and extending into northwest Scandinavia. This would count as a -NAO. The very strong negative anomaly just to the west of the UK ould also be significant as would the intense Neagtive anomaly over eastern Siberia. http://raleighwx.americanwx.com/MJO/NovemberPhase1500mb.gif
The PNA and NAO plots from ERSL show a moderately negative –NAO but it extremely strong a persistent West Coast trough / -PNA. http://www.esrl.noaa.gov/psd/forecasts/teleconn/images/compare.pn.png
Even though the WPO changes phase sometime around the Middle of the month the EPO does not. It moves into a persistently strong positive phase which of course means more strong negative anomalies over Alaska and the Gulf Alaska and above Normal Heights over southeastern Canada. http://www.esrl.noaa.gov/psd/forecasts/teleconn/images/compare.we.png
This sort of solution matches all of the model data in the 11 to 15 day from the GFS and European ENSEMBLES . What we are left with then is pretty neat tidy package of strong model agreement that matches the MJO November pattern for Phase 8 1 and 2.
While the strong ridge over the eastern half of North America and especially over the CONUS is going to be very slow to move out with a +EPO and a strong – PNA … this pattern will allow for the significant buildup of arctic cold and rapidly increasing deep snow cover over the next two weeks for most of Canada. If you are bored looking at thisn pattern east of the Rockies you might want a look at the increasingly cold temperatures and deepening cold air mass across all of Canada rght up to the U.S. Border.
One last point is to focus on the connection between the strong Ridge over the dateline into the Bering sea and the strong Negative anomaly over the British Columbia region. I am sure it’s obvious to many but I thought I would emphasize the point that until the Ridge in the north Pacific over the dateline / Bering sea shifts or e altars position ….the -PNA is not going anywhere. On the other hand if you are in Seattle… over Portland… Boise Spoakne Redding Calif into the N Rockies your winter is going to start early