US December 2017 Outlook

November 2017 will be remembered as a chilly North, warm South with an impressive opening arctic outbreak which broke long standing records from Montana to the Mid Atlantic. It’s also going to be remembered as very snowy in the interior Northwest, perhaps a top 10 cold month over parts of the Northern Plains and will end exceptionally warm in the Southwest, chilly in the Southeast.

November temperature anomaly as of the 21st.

Credit: Michael Ventrice

The final days of November look like this below with 3 ridge cores 1 Bering Sea/N Pacific 2 southwest 3 Greenland promoting record warm in West, cold under the trough in the East.

Credit: Tropical Tidbits

Looks like the warmth spreads east as we depart November and begin December. HOWEVER, even the biased warm CFS is now showing a cold signal into mid month which may attempt to hold towards Christmas.

CFSv2 weeklies

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

So, one could say that November ends and December begins on the mild side even in the East. While the models didn’t see the typical -AO/NAO teleconnection over the US now, it appears it’s beginning to see it now for a couple of weeks from now.

December looks to open uneventful in terms of cold but I suspect once we get into the 2nd week, things shall turn.

Check out both GFS ensemble and EPS Control below for 360 hours which is December 7 and see the strong high latitude blocking and in the places which supports a cold pattern for the East.

Credit: Tropical Tidbits

Credit: WXBell

While the CFSv2 weeklies now show a colder East from about the end of week 1, I am certainly not see this below off the CFSv2 for December.

Credit: Tropical Tidbits

Credit: Tropical Tidbits

FEATURED IMAGE CREDIT: Bretton Woods @bretton_woods

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