FACT OR FICTION....

October 27, 2018

I've said it before and I'll say it again, all El Nino's are not created equal. This years forecast is for a Modoki El Nino. 

A Modoki El Nino occurs when the warmest waters in the tropical Pacific are centered near the Dateline as opposed the South America. You can compare the difference in sea surface temperatures below. You can also see winter years with traditional El Nino's vs those associated with Modoki events. Very clearly Modoki's are much colder across the eastern half of the U.S.

The strength of the El Nino also matters. Notice how much colder weak El Nino's are compared to strong ones.

One final factor that needs to be measured is sea surface temperatures over the rest of the Pacific. I present to you the "blob". Its an expansive area of above normal SST temperatures in the north Pacific centered over the Gulf of Alaska. Such anomalous warmth in that area would promote a winter ridge over western Canada. That in turn would argue for a downstream trough over the eastern U.S. opening the door for Arctic air masses to penetrate the eastern half of the nation.

I took the winter's with Modoki's (see above) and compared them to the sea surface temperatures in the Pacific this year. The closest match or analog is 2002. Check out the comparison to 2018.

So, I of course decided to see what the winter of 2002-03 was like. My expectation based on the Modoki El Nino and Pacific SST, was that it would be colder than normal and probably near to above normal on snowfall. However, what I found in Cedar Rapids was that the mean temperature was 22.4 degrees...exactly average. Snowfall was 22.4" (Dec-Feb.)...well below normal by 10-12".

 

There you have it, a statistically based forecast on where this winter might go in my area. Fact or fiction, this is certainly not the result a snow lover like me wanted to see. Roll weather...TS 

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© 2019 Terry Swails