When you look back at the last 12 months, the US and North America as a whole has been stuck in a rut, a cold rut. The big drivers steering the global weather pattern has changed since this time last year but the US upper air pattern hasn’t really changed.
This year we have the onset of a weak to moderate El Nino, the QBO has shifted from strong west to east and the solar cycle is on a downward trend. Siberian snow cover is also dramatically greater than last year with the 3rd greatest October coverage in recorded history.
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There is however ONE constant that’s ultimately driving this prolonged cold pattern over the US and that is the warm pool in the northeast Pacific Ocean.
Check out the warm anomaly back last December.
That warmth remains but notice the cold developing to the SW.
Look at how anomalous the blocking is over Alaska.
Barrow on Alaska’s Arctic Coast is some 20-25F above normal while 850mb temps are reaching all-time record levels above Fairbanks.
2-metre temp anomalies
This is while all-time record cold affects the Lower 48 as a consequence of driving this abnormally warm air abnormally far north.
Credit: AccuWeather Pro
850 temps at 96 hrs
The air mass coming down within the next 5 days will break more all-time November records… this time further east.
Current snow cover
Model projection through 96 hours
Sure, we’ve seen a dramatic increase in Siberia/N Hemisphere snow coverage which has likely triggered the strat warming and that is probably fuelling the extremity of the current cold waves driving into the Lower 48 but we didn’t have these factors last winter. The warm NE Pacific was the driver.
What is going to be interesting to watch is just how cold this winter may become given that we’ve not just the warmth up the West Coast which should yet again boost heights into Alaska but other ‘cold drivers’ are in play.
Sustained negative SOI values show El Nino is coming on in a similar fashion to 2009.
QBO is well into an east QBO mode.
Credit: Michael Ventrice)
As stated, the warm water has sustained the ABOVE normal heights over Northwest Canada and thus made for one very cold 2014 over most of the Lower 48. Alaska has undoubtedly experienced one of it’s warmest years.
Continued warming at 50mb over the arctic shows the polar vortex struggling under the stress. A possible split and SSW is looking increasingly likely late November or early December.
This COULD trigger an avalanche of cold air surging south in December. Before then, expect a warm-up following a brutal upcoming 7 day period.
CFSv2 shows the frigid week 1 followed by a recovery week 2.
The golden question I have in my mind today is this… based on the STILL warm NE Pacific and the fact we have a favourable CENTRAL Pacific Nino developing, the easterly QBO, lower solar (coming off a max) and enormous early season snow cover (way ahead of last year and 3rd greatest on record), COULD THIS WINTER BE EVEN WORSE THAN LAST?
The pattern is likely showing us that that potential is very real, after all we’re already seeing the extremity of the pattern just now. There’s nothing to suggest that this setup will ease. Many a great US winter has started off with all of the above. Remember the late 70s, 80s and 90s? I think we have some of the coldest weather in the last 100 years ahead for the Lower 48 this year based on all the factors.
Upcoming 7 days off the GFS. Brrr
Warming Up Ahead Of Thanksgiving?
Following record balmy days in Alaska, it’s turning colder again up there.
Currently -2 in Fairbanks with snow back on the ground.
This you would think is a sure sign of troughiness returning and thus ridging for the Lower 48 beyond day 5-7?
Meteogram for North Dakota shows the warming trend towards the end of the upcoming 8 day period.
GFS 500mb height anomalies day 7-14 still shows an eastern trough.
Interesting times for sure. Stay tuned!
Will have a video later…
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