Sunday, May 24, 2015

Winter 2014-15 Roundup

This is a quick review of the Winter 2014-15 Outlook.

the title "No Guts, No Glory" was indicative of my excitement heading into the season. Even though expected public school disruption goals were met, winter failed to deliver on my hype. 

 What went Right?

Our region finished colder than average despite a mild December: The cold came as advertised. For reasons discussed in the next section, we were not as cold as expected:

Cold persisted into March and became so severe in the US Northeast that ice still exists in the Great Lakes today.  Note how the same map run Jan 1 to March 30 depicts a deepening of the cold anomaly that delayed the onset of real spring in most of the East.

Therefore the idea of Eastern US Cold was numerically correct overall but the coldest anomalies further NE than expected.

What went Wrong

The short technical reason for what went wrong is the +NAO despite a cold North Atlantic Tripole.   In plain English:  A feature that normally correllates with warmer, drier winter conditions dominated.   In fact, regionally, the big driver of the cold was the mega-High that is fueling the drought in the far West.  Cold air was literally pushed SE by that feature leading to overwhelm of what could have been warm.

Snowfall results north of I-40  in the RDU area were above average. However, icy conditions were the bigher story because ideal snow conditions did not materialize.  It was frustrating to see how often warm air would overrun the cold and lead to storms not living up to expectations.

There is a oscillation of winds in the Stratosphere called the Quasi-Biennial Oscillation (QBO).  Ordinarily it would be considered a minor player.  This past season it reached record negative (weak warm signal).  Perhaps the record strength made the minor influence, a major player?   

How Did I Do?

Feedback has been mostly postive.   I rate myself a C+ because of wanting the technical details to have been as expected.  Even a few instances of North Atlantic blocking (-NAO) could have led to spectacular winter weather.   That being said ... all of us were beyond ready for Spring when April warmth began to take over.

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