Friday, November 15, 2013

Winter Outlook 2013-14

It is time again to ry to figure out how the upcoming winter is likely to unfold,  Those of you who follow me on Facebook or in person have a good idea of what is coming in the subsequent paragraphs.  Despite not having the best track record in the 2000's (about 50%) my confidence level is pretty high for the upcoming season despite a significant number of outlooks that are much different,

One hard lesson that  have learned in the 2000's (and look forward to improved accuracy as we progress through the 2010's) is how easy it is to twist logic into a cold winter.  I can tell you that there is one decent argument for a warmer, drier season that may not play out as many web outlooks seem to express.   I have identified a common feature of the most exciting Central NC/VA winters that is present right now and am choosing to go with it as the variable that will rule the heart of winter.

Analyzing Sea Surface Temperatures for clues about the upcoming weather pattern is where we begin.  The below map is courtesy of the Plymouth State University Weather Center:
1) Gulf of Alaska Warm Pool: This feature was missing last winter and seems to be a very relable indicator that more opportunities for snow or ice will affect the SE and Mid-Atlantic at the best possible time in the heart of winter.  The resultant trough position NE of Hawaii is known as the -EPO. It correlates very well with Eastern US Cold.

2) Slighty Warm W Tropical Pacific: Paired with cold water near N Austrailia, this yields a neutral-warm Nino 3.4 Zone which if holds through the winter will be a source of energy for the jet stream (but not too much ).   The cold air encourages higher surface pressure, and in my opinion leads to bouts of negative Southern Oscillation Index that provides pulses of energy that will provide the needed split flow that leads to the big eastern US storms when the branches phase,

?) Atlantic Ocean - The North Atlantic warmth is called the +AMO.  When that feature is strong, it is a winter killer.   Normally, one prefers subtropical ocean warmth and a bigger cold pool in the North Atlantic,  IF the area that is circled is truly warming then that signals a 2009-10 style next drainage of cold air aimed SE.   Those who are ignoring the Pacific in favor of the Atlantic are most likely keying on N Atlantic warmth and the unfavorable stratospheric winds for early WInter -NAO.    My conclusion is that early and mid-December is going to be warmer than average.   When the upper level winds begin to shift near Christmas <GULP!> there is likely to be a big change in the weather.

Other Factors

1) Solar Activity: Even though he current solar cycle is at the maximum, somebody needs to inform the sun!  Low solar activity mostly correlates with colder winters and more high latitude blocking.

2) Golden Sunsets: My personal indicator that Volcanoes have been busy.  Greater particulate matter in the high latitude stratosphere is another correlation to a colder winter.  

3) Siberian/Canadian Snowpack: The rapid expanse of Siberian snow in October is an indicator that the cold air supply will be loaded up for journeys over the pole and into North America.

The Outlook

Refer to the below map:

1) Rest of November:  Winter patterns like the one that I expect often feature a measurable snow or ice between now and early December.  We saw snow this week but there seems to be a better opportunity between the 24th and early December.

2) December:  Winter seemingly ends early and there could be a downright balmy period.  Around Christmas <GULP!> expect a reversal!

3) January: Could the warm Atlantic be really signalling that this is a big ice year for Central NC/VA?   Expect frequent bouts of cold, harsh at times, with ample opportunity for storm systems to take advantage.

4) February:  A good reason to celebrate Valentine's Day?  The end of "The Heart of Winter" means the end of winter.

Temperatures: The winter will likely be remembered as being colder than its average,   I think that the warm 3 weeks in December and last 1-2 week of February will probaly balance the heart of winter to make the total within 1-2 degrees of average,

Precipitation:  Totals close to average,  We could easily have a winter that damaging ice is the big story.  If that happens, snowfall totals will be low even though the frozen precip will be high.   It depends on how much warm influence the Atlantic can extert inland.

My overall expectation is for a disruptive winter that costs  7-10 snow days (incl. late arrival or early release).   I remember a season like this one that shut down my Church for a MONTH due to a frozen, unplowable parking lot!   The once-in-a-lifetime 20" snowstorm occured in 2001 (it snowed 2-3" the  previous November!).   In the first week of Dec 2003 there was a devastating ice storm, after a long break in the action Jan and Feburary were action-packed including 12" in 2 storms to fnish the season (Johnston and Harnett got their 15-20" snow that year). 

Am I being a bit too bold?   Perhaps ... but I like the setup for big events this winter...