Winter Forecast 2019-2020

Here we are again in a cool and seemingly snowy November in Maine. It’s time to start looking head to winter 2019-2020.  Here’s what we’re thinking for December through February.

  • Average Around Normal Temperatures in Maine. Start Warm in December And Transition Cold Late January Through February
  • Above Normal Precipitation And Snowfall in Maine
  • Higher Than Normal Probability Of No Snow On the Ground Christmas Morning Portland
  • January Thaw With Temperatures Rising Above 50 Degrees
  • Most Snow And Cold Late January Through February
  • Higher Than Normal Probability of Blizzard Conditions 2nd Half Of Winter

A great to place to start when forecasting winters in New England is the ocean temperature in the Pacific.  ENSO(El Nino Southern Oscillation) does not have a look of an EL Nino or La Nina, but more of a “Neutral Signal”.  Therefore, the Equatorial Pacific will probably not be the big driver of winter weather this year.

Modeling suggests sea surface temperature anomaly will be between 0.0° and +0.5°.

It’s worth mentioning though most “Neutral” and weak El Nino  winters feature above normal snowfall in Portland Maine. Thanks Josh Timlin.

The Northern Pacific however is showing some interesting clues in how warm the water temperatures are there.

The theory is the warm water in the Gulf of Alaska will manipulate the jet stream to pump a big ridge in the Western US, and develop a trough in the Great Lakes and Eastern United States. That’s a pattern for an active storm track and big temperature swings in the east.

I compared this fall to 10 others that showed some sort of warming in the north Pacific.

Some were given more weight that showed interesting similarities to this fall.  2014-2015 comes out on top for its SST anomaly, and very dry September to wet October. Here’s the data for Portland.

Here’s a look at how similar the ocean water temperature anomalies were October 2014 and October 2019.

If  you remember back to the winter of 2014/2015, we started winter slow and then all heck broke loose in late January and February.  Odds are we’ll never see a February like that one in our lifetime again, but the pattern could try to repeat.

These 10 analog winters looked like this for temperature.

Precip looked like this.

Since our closest comparison this fall is 2014, lets look at the 500 MB Height  composite mean. Note the ridge west and trough east. 🙂

500 MB height anomaly December – February 2014-2015

Temperature anomaly December – February 2014-2015

These analogs are mostly cold and snowy for the eastern half of the US. Now lets take a look at seasonal computer modeling.

The new European Model seasonal run which came out Tuesday shows little consistency from the previous October run. It keeps the same general pattern all winter now, and skips right over the slow start in December and early January.

I was happy to see ECMWF December through February precipitation anomaly looks in line with our forecast and also analog years.

Canadian Model is locked onto the ridge west and trough east. It suggests the slow start in December, but flips to big winter look in January.

 

Japanese Model December through February parks some cold in the eastern half of the United States.

Precipitation anomaly look reasonable to our thinking and analog years.

Here’s the breakdown of the Japanese Model December through January suggesting a slow start December and January.  My guess is the model is seeing February making up for a warmer start.

My forecast mirrors this evolution of winter. After a cool and snowy November, December and January have a good shot at averaging out warmer than normal in Maine.


The big question is can February and possibly March cold and snow make up for the warm start?

Analog winters and modeling were factored into some of the winter highlights listed at the beginning of this blog post.

  • 80% of the winters analyzed had a January thaw with temperatures 50 degrees or warmer Portland.
  • 70% of the winters analyzed  had normal or above normal snowfall in Portland.
  • 40% of winters analyzed averaged colder than normal, 20% warmer than normal, and 20% around normal Portland.
  • 70% of the winters analyzed had no snow on the ground in Portland Christmas morning.  Any given year Portland has a 53% chance of having at least one inch on the ground.

Winter may have a hard time letting go in March, but the pattern would favor an early start to summer.  Rapid melt can often result in river flooding. That’s something we’ll be watching if a big snow pack remains into spring.

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Charlie Lopresti

About Charlie Lopresti

Charlie makes up the "Weather Part" of CBS News 13s evening edition. A native New Englander, he grew up enjoying the area's exciting and sometimes wild weather.