Each year I like to look at comparisons of snow cover across the U.S., the ocean temperature anomalies, and the upper air flow to find good ways to correlate these three seemingly unrelated factors in our winter weather.
The best way to do this is to take a snapshot of all three conditions on the same date for separate years. That way you are comparing apples to apples.
This winter we have a developing strong La Nina…cold water across the equatorial Pacific…with a stripe of warmer water extending across the northern Pacific Ocean…pointing to the NW coast of the U.S.
Take a look at the ocean temperature anomalies, snow cover and upper air flow for this year:
Now, go back to 2016, which was a snowier winter. Here are the three maps for that winter, which was dominated by an El Nino…warmer than normal water in the equatorial Pacific:
If we go back yet another 5 years to 2011, another La Nina winter, you can see the three maps: