Wednesday, April 20, 2016

The BIG Winter 2015-16 Recap - Part 1

The winter is finally in the books. I delayed the publishing of the recap because of the snow earlier this month. Since I have so many images and analysis to show, this year's recap will be in two parts. So here we go...

So what did our Winter Outlook illustrate back in October?

Based on the developing El Nino (warmth more basin wide vs 1998 which ended being one of the strongest El Ninos in recent memory), the position of the warm and cool pools in the northern Pacific and Atlantic, our forecast was for a strong, southern jet stream (storm track) for the December-February time period.  Temperatures would be below average in the deep south with above normal temperatures centered in the midwest, upper Great Plains with slightly above normal temperatures for Ohio and the Ohio Valley.

During the early fall, 1997-98 became a stronger analog as the El Nino strengthened  Many used the El Nino split jet stream history formula (including myself) as a guide to this upcoming winter. Not all El Ninos are alike but we felt that this assumption was solid given past history.

Here are the December 1997 through January 1998 jet stream wind speeds anomalies (compared to average) on the left with the associated precipitation rates on the right side.  I labeled the parent lows and highs for guidance.  I circled the areas of heaviest precipitation ALONG THE WEST COAST AND SOUTHERN STATES/MID ATLANTIC

My December blend (issued back in September) was created using 1997-98 and other years showing the positions of the highs and lows at 500mB (steering current level).  The winter 2015-16 southern jet stream position was positioned further south than above.  I believed the southern jet would be a driver early on...

Our snowfall for northern Ohio took this "panhandle storm track" into consideration by calling for snowfall slightly below normal (65") but higher than the strong El Ninos of 1982-83 (38") and 1997-98 (56").  We figured it would take one or two bigger snows to bring this total to reality.

HOWEVER, the southern jet was nullified by the east coast ridge in December.  It stayed well south until January.  Even then, panhandle snow systems stayed close to the east coast and the mid Atlantic.

300mB Zonal Wind
The Pacific northwest received above normal rainfall in December from storm systems that rode over the northern Pacific high pressure cell north of Hawaii. Gulf moisture fed above normal precipitation in the cornbelt.

By January, the southern jet was established but was deflected south by the west coast ridge (high pressure). Above normal precipitation was confined to northern California, Mexico and the deep south. Notice the BELOW NORMAL precipitation over the Ohio Valley. February precipitation was not much better.  The one exception was the historic snow that hit the Mid-Atlantic in late January (see below).

We forget how close the heavy snow came to northern Ohio in Late January.

Snow Forecast for January 22-24
The storm track kept the snow south through Kentucky, West Virginia, Maryland and parts of New England.

As for the winter temperatures, temperatures were in-line with our forecast for the northern states. In the deep south, they were warmer than forecast.

A far cry from last winter (2014-15)...

...yet very similar to the winter of 2011-12 (MORE ON THIS COMPARISON FOR NORTHERN OHIO IN PART 2)

Much of the Great Lakes had well below normal snowfall. Portions of New England it was the opposite.

Seasonal Snowfall
How did this winter compare more specifically to last winter and 2011-12 (recently the most similar winter) in northern Ohio?  Head to PART II for the details >>>

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