Author: Bill McMillan- Founder and Owner of IndyWx.com

Date: Sunday, October 30th, 2016

2016-2017 IndyWx.com Winter Outlook

We’re bullish on a colder and snowier than normal winter across central IN (and a widespread portion of the Mid West and Ohio Valley, for that matter) for 2016-2017.  Furthermore, model data and analogs suggest the period Thanksgiving to Christmas could be quite wintry this year.  If you’re one of those that likes it cold with storms and rumors of storms through the holiday season, this could be your year.

The basis of the IndyWx.com 2016-2017 Winter Outlook

• Weak La Nina
• West-based QBO (read more about the Quasi-Biennial Oscillation here)
• PDO- does the negative trend continue?

The PDO (read more about the Pacific Decadal Oscillation here) is a bit of a wildcard moving forward.  The past (2) years has featured a positive PDO, but latest data shows that we’ve slipped into a slightly negative state (-1.06 in Sept).  Negative phases favor warmth, locally.  Interestingly, most model data suggests a positive look this winter.

The image below shows the differences in what a warm (left) and cool (right) PDO looks like.

(Image courtesy of JISAO)

Sea surface temperature model data centered on the upcoming winter

SST CA model

NMME model

JAMSTEC model

JMA model

We’ve done an “about face” in the equatorial Pacific.  Last year at this time featured one of the strongest El Ninos on record.  (Remember that ridiculously warm December last year)?!  This year, a snap shot of the SST anomalies (from 10.27.16) shows a vastly different look and the weak La Nina underway. We think a weak La Nina dominates the majority of the upcoming meteorological winter.

The International Research Institute for Climate and Society (IRI) plume shows the weak La Nina continuing through winter before rebounding over the spring.

Analogs:

We’re keying in on the following years to get an idea of what the future may hold for meteorological winter (December-February), based on the ENSO state and QBO west.

• 2013-2014 *snowiest winter on record (52.2″)
• 2008-2009
• 1995-1996 *6th snowiest winter on record (37.8″
• 1971-1972
• 1961-1962
• 1959-1960

We expect a southeast ridge to be a big player through the balance of the upcoming winter.  While that will likely keep our friends in the southeast region milder and drier when compared to normal, it’ll also serve as enough resistance to keep us on our toes with an active storm track through the Ohio Valley.  We’ve alluded to this since late summer and early fall, but the idea of a “big hitter” winter is very much on the table and could include a couple significant winter storms through our part of the country.  Additionally, a second storm track from northwest-flow clippers will have to be monitored- particularly mid and late winter.

Despite a warm fall, we expect the evolution of the pattern to undergo a significant shift mid-November and again want to reiterate the holiday stretch could be quite “fun” this year- in stark contrast to the 2015 Christmas season.

IndyWx.com 2016-2017 Winter Forecast

• Snowfall: 35″, including first flake this fall to last flake next spring (average snowfall at IND is 25.9″)
• Temperatures: 1 degree below average for meteorological winter (December through February)