Tuesday, March 23, 2021

Explosive origins of 'secondary' ice and snow

"... "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 ...

 

Thursday, March 4, 2021

Winter '20 / '21 - 'Season-total' Snowfall Forecast Contest: FEB Totals

BWI
St. Paul St.looking N from Read St. (MAR-42)

FEB-21 snowfall summary by forecast station.
Rank-ordered descending by percent of monthly period-of-record-normal (%FEB).

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

AO / NAO / PNA data
https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/daily.index.ascii

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DEC totals
https://newxsfc.blogspot.com/2021/01/winter-20-21-season-total-snowfall.html
JAN totals
https://newxsfc.blogspot.com/2021/02/winter-20-21-season-total-snowfall.html