Friday, October 14, 2016

What about Winter?

What About Winter? 

Part Two - October Indicators 



1) Arctic Sea ice: Slow to rebound from late September melt-off, and seasonal refreeze levels currently lagging behind levels seen before recent winters of 2014 and 2015. Researchers and bloggers alike have noted the unusual nature of this season's sea ice melt and rebound.


2) Snowcover in adjacent areas has rapidly expanded in western and central Siberia to northern & central Canada, relative to seasonal averages. Snowcover is clearly lagging in Alaska as compared to seasonal norms and observations from previous years at mid-October.

3) Polar temperatures: Seasonal readings above 80 North reported by the Danish Meteorological Institute are running several degrees above the seasonal range for this time of year. 

OUR EARLY ASSESSMENT OF WHAT IT MEANS: 
  • Early clues: Arctic/Polar conditions in October provide early indications of how climate factors may interact to influence the start of winter in the Northern Hemisphere, and North America,.
  • Strange days ahead: This season follows an above-normal temperature regime from last winter for the Arctic above 80 North. Now with sea ice lagging but snowcover rising in areas farther south than usual, these competing data point suggest a divergent and erratic start to winter.
  • Possible results:  This inconsistent alignment of ice & snow could lead to wildly fluctuating conditions in early winter. One option would be an early season sharp cold outbreak, then a rapid warm up, followed by equally strong cool downs and erratic snowfall events that briefly disrupt, then quickly disappear.


Part One - Clues from Summer


Finally, as the heat takes a break, we can get the winter forecast gears warmed up with this question: How many school closing curveballs and schedule shutouts could happen this winter? Science students and the FF team are on the case. 

The preliminary report begins below the bullet summary:

  • The above normal temperature pattern in East, connected to growing below normal pattern in West, may be early sign this winter could start like 2015-16: Mild first half, stormy and cold second half.
  • Seasonal melt-off of Arctic sea ice appears on level with readings of the past 3 years, not as low as the September 2012 record meltoff.
  • Rapid transition of El Nino to La Nina conditions sets stage for surprise ice events throughout the season ahead, especially in the Mid-Atlantic.
Orioles Opening Day in April 2003. Photo credit: The Baltimore Sun

ANALYZING SUMMER CLUES FOR THE PRE-WINTER PATTERN

Late summer in the Foot's Forecast team is the start of our seasonal process to identify how pre-winter indicators stand so as to detect developing trends. Large scale hemispheric trends known to influence how winter develops in the Mid-Atlantic include frequency and location of tropical systems, sea surface temperatures in the eastern Pacific and end-of-summer Arctic sea ice meltoff. 

In September 2016, this investigation will be conducted by science students at several high schools in the Baltimore metropolitan area, in collaboration with member of our team across the Mid-Atlantic. Initial findings released arround September 15, draft projections by October 1, full winter assessment by October 30.

Click below if ready for a sneak peek...



A GLANCE AT WINTER CLUES FROM SUMMER
 NOAA National Snow & Ice Data Center. 
(See below the chart for an overview) 


SOURCE OF THE DATA: The NOAA National Snow & Ice Data Center (NDISC) publishes a wide range of important data on hemispheric snow cover, sea ice levels and peer-reviewed research into state of Earth's Polar regions throughout the year. 

ABOUT THE CHART: Seasonal trends in Arctic sea ice summer meltoff is one indicator climate scientists and long range weather forecasters look to for assessing how the winter pattern may be influenced by ice levels. 

WHY IT MATTERS? A technique employed by our student researchers is to track the relative amount of sea ice remaining by end of the summer and compare those levels to previous years. The challenge is to: 1) identify those years where sea ice levels ended high in September and; 2) were followed by winters with significant storm events in the Mid-Atlantic and eastern U.S.

CLUES IN THE CHART:
  • As of 8/30/16, geographic extent of Arctic sea ice was 4.48 million sq. km.
  • At this same point in 2015, sea ice extent was 4.46 million sq. km.
  • Compare levels: Aug 2009- 5.45 mil sq. km; Aug 2012- 4.11 mil. sq. km.

WHAT THE CLUES TELL US?
  • Remember Winter 2009-10? Those in the Mid-Atlantic recall the high impact nature of that winter and the multiple historic snowstorms. Officially at BWI airport, the season snowfall total was 77.0 inches. (NWS Sterling) Sea ice levels started the season relatively higher than the preceding five winters.   
  • Compare to Winter 2012-13. Not so fondly recalled by our team, it was the season of busts. One of the lower snowfall totals on record for BWI airport... just 8.0 inches. Arctic sea ice levels in September 2012 was a paltry 4.11 million sq. kms, one of the lowest in the 30-year climate record. 

THE "HMMM" CONNECTION IS...
  • 1) Although just two data points on the same day across two different years is not strong enough evidence to say with certainty this represents a reliable trend...
  • 2) It is important to observe that how much sea ice remains at end of each summer can be an early clue on the type of winter to follow for North America, Europe and Asia. The final seasonal reading is usually taken around 9/23-24 and compared to previous years as well as the 30-year climate average.
  • 3) From this early look, sea ice levels appear similar to summer 2015 at this time. Consider how last winter played out: A slow start in the East, then BANG by January with a long slog into even April. That may turn out to be the clue nature is sending us for the winter ahead. (Links to work by others on this important topic)
Climate researchers investigate sea ice levels in the Arctic. For motivated students, there are even summer research internships in Alaska. Check out the 2016 posting

- Report prepared by members of the Foot's Forecast Long Range Team

Sources:



2 comments:

Patricia said...

Hey, what thoughts do you have about the upcoming fall/Winter. I thought something was going to be released on the 15th. Just curious.....

Patty

rockbd said...

Broncos vs Jaguars
Rams vs Patriots
Lions vs Saints
Bills vs Raiders
Redskins vs Cardinals
Giants vs Steelers