"A 50% reduction in Arctic sea-ice cover has increased open-water and winter evaporation to fuel more extreme snowfall further [sic] south across Europe.
"When analyzing the long-term trends from 1979 onwards [sic], researchers found that [sic] for every square meter of winter sea-ice lost from the Barents Sea, there was a corresponding 70 kg increase in the evaporation, moisture, and snow falling over Europe."
Science Daily ...
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| BOSOX Opening Day (14-APR-53) |
Climatology (Period-of-Record-Normal) followed by Consensus verified 1st and 2nd for the first time in the Contest's 20 year history.
Forecasters ranked descending by their Total Absolute Error (TAE)
RED ==> 4th Quartile
WHITE ==> Interquartile range
BLUE ==> 1st Quartile
The '%MPRV over PORN' metric indicates how well the forecast improved over climatology.
Skillful forecasts beat climatology.
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Forecasters' stations having the lowest absolute error
Season-total snowfall from all stations (895") came in 4% below the Period-Of-Record Normal (929").
Winter '20 / '21 ranks 11th among the 17 Contest years since winter '04 / '05 ... the season when BGR and BGM were added to the station list.
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Teleconnections
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| VT - Stowe (Marion Post Wolcott - 1940) |
Green ==> 4th quartile
"... "rime splintering" isn't nearly the whole story.
"The new results from the Arctic show ... larger supercooled water droplets, classified as drizzle, play a much more important role in producing secondary ice particles than commonly thought.
" "When an ice particle hits one of those drizzle drops, it triggers freezing, which first forms a solid ice shell around the drop," explained Fan Yang, a co-author on the paper. "Then, as the freezing moves inward, the pressure starts to build because water expands as it freezes. That pressure causes the drizzle drop to shatter, generating more ice particles."
"... drizzle freezing fragmentation can enhance ice particle concentrations in clouds by 10 to 100 times -- and even 1,000 on occasion!"
More ...
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| BWI St. Paul St.looking N from Read St. (MAR-42) |
Green ==> 4th quartile
White ==> Inter-quartile range
Red ==> 1st quartile
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FEB Forecast Station Highlights
16 stations at or above normal monthly snowfall
ABE
29.7" (400%) above FEB normal
BDR
21.7" (341%) above FEB normal
EWR
21.5" (336%) above FEB normal
NYC
17.1" (292%) above FEB normal
MDT
10.4" (212%) above FEB normal
Biggest Losers
ORF ... RDU (4% and 2% of FEB P-O-R-N)
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Season-Total-to-Date
FEB P-O-R-N contributes 262" (28%) toward the season-total snowfall (D-J-F-M) of 929"
FEB-21 observed snowfall: 429" (64% above P-O-R-N; 46% of season-total snowfall)
Image courtesy NOHRSC @ http://www.nohrsc.noaa.gov/nsa/
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Teleconnections
After FOUR contest-worthy snow storms ... under the ‘two-thirds’ rule … forecasters who have entered at least THREE forecasts are included in Interim standings #2.
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| Lincoln Memorial Reflecting Pool and Washington Monument (c.1930) |
For each contest-worthy snow storm ... the forecasts are verified against the observations of storm-total snowfall.
Statistics are calculated to determine how well each forecast captured the magnitude and distribution of the storm's snowfall.
Individual forecaster statistics for the first four snowstorms here.
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Statistics include:
The average normalized ‘SUMSQ error’ is the Contest/s primary measure of forecaster performance.
This metric measures how well the forecaster/s expected snowfall 'distribution and magnitude' for _all_ forecast stations captured the 'distribution and magnitude' of _all_ observed snowfall amounts.
A forecaster with a lower average SUMSQ Z Score has made more skillful forecasts than a forecaster with higher average SUMSQ Z Score.
Complete forecaster verification table and the FINAL Results / Storm Summary available at NEWxSFC/s home page.
"This article describes where and when thundersnow happens, the ingredients needed to make thundersnow, and new efforts at understanding and forecasting the occurrence of thundersnow."
http://www.newx-forecasts.com/reference/An%20overview%20of%20thundersnow.PDF
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| Accumulation-weighted SN:H20 (SLR) |
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