Severe Cold Spell Possible

For those hardy residents of Alaska's interior who enjoy the occasional spell of intensely cold winter weather, and who have felt that the warmth of recent years has been over the top, the latest forecast indications may be welcome.  Others will feel less enthusiastic.  Recent forecasts have been coming into agreement with expectations for a period of very cold weather later this month, and there's a chance the cold may be extreme and prolonged.  Here are the 500mb height anomaly forecasts from 3 leading models for 7-10 days from now (click to enlarge): notice the extremely pronounced trough over Alaska and the good agreement between the models.

Here are the CPC's latest 6-10 and 8-14 day forecasts, emphasizing the likelihood of unusual cold over southwestern portions of the interior in particular:

And here are a few words from Rick Thoman (note this is personal opinion, not official NWS guidance):

"Models having been pointing this way for some days, and now we have increasing agreement on the potential for a period of prolonged deep cold Jan 15-21 or so. The basic forecast pattern has similarities to portions of the 1989 and 1999 cold events. The devil is in the details (of course), especially east of 150W, where there is potential for clouds and snow to wrap around from the GoA, and so keep surface temps higher (just as we saw in the 1999 event).

North of the Alaska Range there is a plausible potential for multiple days with 850mb temps lower than -35C and surface temps lower than -60F, which in the past has resulted in some of the commuter airlines (and Everett's) shutting down service to rural communities."

For reference, here's a chart of the mean 500mb height anomaly during January 20-30, 1989, when extraordinarily cold conditions affected the interior.  It's hard to imagine, but the temperature in Bettles dropped below -60°F on 9 out of the 11 days in this period, including -69°F on January 26.  Fairbanks reached "only" -51°F but had many days that stayed at or below -40°.