December 2020 Forecasts and Discussions

[AbbyJr]

Better to be realistic

Good point. January 2011 bust

[Weather101]

Good point. January 2011 bust

Hopefully not

[wetcoast91]

They are pretty unreliable anyway. I’d bet they have trended warmer in the short term but still look good for January. Those seasonal models lean heavily on ENSO, so they will look Nina like almost for sure.

Those Alaska vortex patterns can be tough to break but it could be good if we ever dislodge the cold once it gets stacked up to our north.

ECMWF weeklies are only right when they predict a depict AK vortex/ +PNA patterns.

I find any troughing that is depicted becomes zonal in closer range.

[Storm]

ECMWF weeklies are only right when they predict a depict AK vortex/ +PNA patterns.

I find any troughing that is depicted becomes zonal in closer range.

Absolutely right. Why they even run.

[Catnip]

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[PortKells]

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Zonal until day 35.

[Rubus_Leucodermis]

Zonal until day 35.

Oh, the weather outside is crappy,
And I didn’t want to disturb your nappy,
But here’s some egg nog to sip,
Let it drip, let it drip, let it drip.

[Bonovox]

12z Euro also showing a SSW event occurring over Siberia near day 10. Interesting times ahead.

[wetcoast91]

Mild zonal flow slowly progressing into a chilly zonal flow by early-mid Jan. Potential coast to coast blow torch for xmas.

Looks like bets are off for any cold until 2021. Prime threat of any arctic blast appears to be mid-late Jan based on that run.

[Typeing3]

Mild zonal flow slowly progressing into a chilly zonal flow by early-mid Jan. Potential coast to coast blow torch for xmas.

Looks like bets are off for any cold until 2021. Prime threat of any arctic blast appears to be mid-late Jan based on that run.

1999-2000.

[wetcoast91]

12z Euro also showing a SSW event occurring over Siberia near day 10. Interesting times ahead.

For Halifax.

[Rubus_Leucodermis]

[hawk2]

8

For Halifax.

[Bonovox]

12z GEM is trying.

[Rubus_Leucodermis]

From the most recent forecast discussion from NWS Seattle (emphasis added):

.LONG TERM /THURSDAY THROUGH SUNDAY/...We should expect temperatures to begin their return back to normal as towards the end of the week. This return will be largely due to a stronger frontal system moving through Thursday. This will bring rain to the lowlands and a few inches of snow at pass level on Thursday. This system will also bring more seasonable temperatures to the area. After the front moves through, there is the potential for some ridging to occur offshore. Moisture would be transported over the ridge crest and down through Western Washington. This moisture will could produce some heavier rain and mountain snow. Moreover, with the trough over the area, providing colder surface temperatures and snow levels dropping to less than 1000 feet in some locations (mostly near Bellingham), there is the potential for snow or rain snow/mix to occur towards the end of the week. This is still a ways out so confidence is low, but it is night three of both deterministic models and ensembles suggesting this.