Winter '22 / '23 - Eurasia Snow Cover: SEP

Eurasia/s areal snow cover for SEP-22: ~2,520,000 SQ-KM

- Almost 60% above normal (1,620,000 SQ-KM)
- Ranks 6th during period-of-record (1967 - 2022).
- Highest since 1998 (25 years ago).

The extent of Eurasia/s OCT snow cover has been positively correlated with cold and snowy winter weather in the eastern CONUS so we/re off to a good start.

Data courtesy Rutgers University Global Snow Lab

Winter '21 / '22 - Eurasia Snow Cover: OCT-21

Observed:  10,671,792 km^2
Average:  10,310,000 km^2
Median:  10,130,000 km^2

3.5% (5.3%) above normal (median)
Rank:  19 (n = 54)

Above average snow cover observed in 10 of the past 10 OCTs.
At least 1 standard deviation above normal snow cover in 5 of the last 10 OCTs.

Top Analog Winters (weight) / ENSO state / QBO state
1 - 2009/10 (2x) / W / E
2 - 2001/02 (2x) / nada- / W
3 - 2020/21 (1x) / C / W
4 - 2019/20 (1x) / nada+ / E
5 - 2015/16 (1x) / W+ / W

These analog winters have questionable predictive value b/c a moderate La Nina (C) and QBO-E are expected to prevail during Winter '21 / '22.

Blue markers located between the inner and outer circle have a weak yet statistically significant (p <= 0.05) positive correlation between Eurasia/s OCT areal snow cover and a forecast station/s season-total snowfall.  Strongest correlations found in New England where correlations range between 0.269 (BTV) and 0.376 (ORH).

A paultry ~16% of the variability (R2 = 0.158) in combined season-total snowfall from all forecast stations is explained by Eurasia/s OCT areal snow cover. 

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Period-of-Record:  1967 - 2021 (1969:  no data)
Data courtesy Rutgers Global Snow Lab

Previous posts about Eurasia's OCT areal snow cover here. 

Winter '20 / '21 - Season-total Snowfall Anomalies During La Nina Winters

 Taken at face value M-A snow crows suffer the most ...

The NOAA analysis of Rutgers' Global Snow Lab data does not account for the different categories of La Nina episodes (weak ... moderate ... strong) and it has an end date of 12 years ago.  Since then ... there have been three La Nina winters - '10 / '11 ... '11 / '12 ... and '17 / '18.

Relative to season-total snowfall at 28 NEWxSFC stations ...
'10 / '11 - well above average (moderate La Nina)
'11 / '12 - well  below average (weak La Nina)
'17 / '18 - above average (weak La Nina)

 Image courtesy NOAA Climate

Winter '20 / '21 - Eurasia Snow Cover: OCT

~ 11,000,000 SQ-KM

 

Under-performing all year ... 

6% above P-O-RN (~10,320,000 SQ-KM)
9% above median (~10,080,000 SQ-KM)
Period-of-Record:  53 years
Rank: 19th

2nd lowest past 10 years
16 of past 20 years above P-O-R-N

OCT-19:  ~12,700,000 SQ-KM
OCT-20:  14% less than last year

Eurasia snow analog years offer little if any guidance given this winter should have cool ENSO / PDO and QBO-W.

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P-O-RN ==> period-of-record normal

Data courtesy Rutgers University Global Snow Lab
http://climate.rutgers.edu/snowcover/index.php

Winter '19 / '20 - Eurasia Snow Cover: OCT

Eurasia/s areal snow cover for OCT-19: ~ 12,800,000 SQ-KM
24% above 52-year P-O-R-N (~10,300,000 SQ-KM)
27% above 52-year median (~10,100,000 SQ-KM)

Rank: 7th
3rd highest past 10 years
4 of past 20 years below median ('05 ... '07 ... '08 ... '11)
OCT-18:  ~10,400,000 SQ-KM
OCT-19: 23% greater than OCT-18

Ranked analog years 500 mb anomaly height composite for Winter '19 / '20
('15 / '16 ... '16 / '17 ... '09 / '10 ... '01 / '02 ... '14 / '15)

- High 500 mb geopotential heights at hi-latitude ==> NAO & AO < 0
- EPO > 0 ==> fast zonal flow over CONUS & mild PAC air masses
-weak evidence of trof over coastal M-A & NE CONUS

CORRECTION:  '15 / '16 & '09 / '10 ENSO should be 'W+'

Key
ENSO:  nada- (-0.5 < Region 3.4 SSTa <  0); C- (weak La Nina); W- (weak El Niño)
NAO:  sign of D-J-F average
AO:  sign of D-J-F average
PDO:  sign of O-N-D-J-F-M average
QBO:  + ==> west; - ==> east

Read more »

Winter '19 / '20 - Eurasia Snow Cover: SEP

Eurasia/s areal snow cover for SEP-19: ~1,570,000 SQ-KM

3% below 48-year P-O-R-N (~1,629,000 SQ-KM)
1% below 48-year Median (~1,588,000 SQ-KM)

Rank: 26th
4th lowest past 10 years
11 of past 20 years below median
SEP-18:  ~1,300,000 SQ-KM
SEP-19 21% greater than SEP-18

KEY
ENSO:  nada+ (0 < SSTa <  0.5); C- (weak La Nina); W- (weak El Niño); W (moderate El Niño); W+ (strong El Niño)
NAO:  sign of D-J-F average
PDO:  sign of O-N-D-J-F-M average
QBO:  + ==> west; - ==> east

Read more »

Winter '18 / '19 - Eurasia Snow Cover: OCT

Eurasia/s areal snow cover for OCT-18:  ~10,391,000 km2

Last year:  ~12,052,000 km2

1% above 53-year P-O-R-N (~10,260,000 km2)
Rank: 22nd

Lowest in eight years

Seven of the last ten years above normal

Analog years for winter '18 / '19
Rank Winter ENSO
1 82-83 W+
2 00-01 C-
3 69-70 W-
4 01-02 nada-
5 84-85 C

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Data courtesy Rutgers University Global Snow Lab
http://climate.rutgers.edu/snowcover/index.php

Winter '17 / '18 - Eurasia Snow Cover - OCT

12,052,000 km2
18% above 52-year P-O-R-N (10,225,000 km2)

Rank: 11th
Lowest in five years

Eight of the last nine October above period-of-record-normal
Analog years for winter '17 / '18

Rank Winter ENSO
1 06-07 W-
2 69-70 W-
3 77-78 W-
4 00-01 C-
5 98-99 C+

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Data courtesy Rutgers University Global Snow Lab
http://climate.rutgers.edu/snowcover/index.php

Winter '17 / '18 - Eurasia Snow Cover - OCT Preview

Cohen projecting above normal Eurasia snow cover for OCT ahead of an expected weak La Nina winter (D-J-F).

Nine previous weak La Nina winters ... including the famed 1995 - 1996 season ... have been observed during the Eurasia snow cover period of record (1967 - 2016). Only two NEWxSFC forecast stations -- BGM and ALB -- have a statistically significant correlation between season-total snowfall and above normal Eurasia snow cover.


Related:
Winter '17 / '18 - Correlation of Eurasia's OCT Snow Cover and Season-total Snowfall in NE and M-A Regions 

Winter '16 / '17 - Eurasia Snow Cover

Winter '14 / 15 - Arctic Oscillation Analysis and Forecasts

New blog devoted to the Arctic Oscillation (AO) ... Siberian snow cover ... and more authored by Atmospheric and Environmental Research's (AER) Judah Cohen and Jason Furtado.

Cohen ... et al ... discovered the strong correlation between the areal coverage ... advancement rate of Eurasia/s OCT snow cover and the character of northern hemisphere's winter as modulated by the AO.

Snow Advancement Index (SAI)

The chart reports a correlation index (r) of 0.810 indicating the AO and SAI often move in tandem. 

Squaring the correlation index gives the 'coefficient of determination'; a measure of how much of the variability of one (DJFM AO) is explained by the other (SAI). The SAI 'explains' 66% of DJFM/s AO variability.

 

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Cohen/s 2013 interview with the WAPO

Cohen/s 2014 interview with the WAPO

Snow cover data from Rutgers Global Snow Lab

 

 

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AER offers a 'notify new post' form requiring personal contact information.

Or use the free Change Detection web page monitoring service.

Winter '13 / '14 - White Christmas

Area Covered By Snow: 41.7%

Winter '13 / '14 - Eurasia Snowcover: September

Rutgers' Global Snow Lab reports a dramatic increase in September/s areal snow cover over Eurasia.

2,362,682 km^2
7th highest overall
49% above the period-of-record (1967 - 2013) normal of 1,587,905 km^2.
120% above 2012.
Largest areal coverage since 2001.

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Top chart:
BLUE - areal snow cover in millions of km^2
ORANGE - mean areal snow cover
YELLOW - +/- 1 standard deviations
RED - 9-point binomial filter

Bottom chart:
BLUE - period-of-record (1967 - 2013) median areal snow cover in millions of km^2
RED - observed areal snow cover (2013)

Rutgers data here.

Winter '12 / '13 - Eurasia Snow Cover - October

Period of record median:  9,599,610 km²
October-12:  11,106,205 km²

October-12 Eurasia snow cover...as reported by Rutgers Snow Lab...is 16% above normal.  This bodes well for a cold and snowy winter in the eastern US...according to the statistically significant correlation between these global two features discovered by AER's Dr. Judah Cohen.

...Eurasian snow cover during this year’s October has increased far more rapidly than...is normally the case (the corresponding index value exceeds two-standard deviations).

Given the large anomaly for the predictor variable, the following winter will be a good test for assessing if the approach is suitable for real-time seasonal forecasts.¹

Eurasia OCT snow cover : season-total snowfall (D-J-F-M) at NE and MA Contest stations in recent winters...
'09 / '10:  11,288,371 km² - 1,225" (observed*) v. 908" (normal*)
'10 / '11:  10,615,933 km² - 1,426" (observed) v. 921" (normal)
'11 / '12:  9,293,740 km² - 393" (observed) v. 934" (normal)

* SBY removed for lack of station snowfall data.



Blue dotted - observed snow cover
Red - 9-point binomial filter
Orange - period of record median snow cover
Yellow dashed - one standard deviation

The 9-point binomial fiter shows the long-term trend by removing noise from the signal.



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Reading room...
- A new index for more accurate winter predictions (pdf)
GEOPHYSICAL RESEARCH LETTERS, VOL. 38, L21701

- Eurasian Snow Cover Variability and Links with Stratosphere-Troposphere

Coupling and Their Potential Use in Seasonal to Decadal Climate Predictions (pdf)

Climate Test Bed Joint Seminar Series

NCEP, Camp Springs, Maryland, 22 June 2011

Winter '11 / '12 - Eurasia Snow Cover - December

The latest monthly data from the Rutgers Snow Lab shows the observed areal snow cover over Eurasia was -- yawn -- average during December after being at or quite close to one standard deviation above the mean the past two years.

The month's ~26,642,000 km² coverage ranked 26th in the 46-year period of record (1966 - 2011) which is slightly less than the median December coverage of ~26,786,000 km².

Solid ORANGE line:  period of record's AVERAGE areal snow cover.
Dashed YELLOW lines:  + / - one standard deviation about the mean
RED line:  nine-point binomial filter

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Snowfall data courtesy Rutgers Snow Lab.
Earlier post about Novembers' Eurasia snow cover here.

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BONUS chart...
Monthly Eurasian snow cover for 2011 (RED line; BLUE markers) and the 'period of record' median.

Winter '11 / '12 - Eurasia Snow Cover - November

The latest monthly data from the Rutgers Snow Lab shows the observed areal snow cover over Eurasia was more than one standard deviation above normal during November for the 2nd time in three years.  It was the 5th highest coverage during the period of record (1966 - 2011).

Other Novembers where the snow cover was more than one standard devaition above the long term mean occured in 2009...1993...1973...1972...1970...and 1968.

Note the cluster of above normal Novembers between 1968 and 1973.  What the 3 out of 4 years had in common were negative PDO...negative QBO...and negative NAO.

Areal snowfall data courtesy Rutgers Snow Lab.
Earlier post about Octobers' Eurasia snow cover here.

Winter '11 / '12 - Eurasia Snow Cover - October

The latest monthly data from the Rutgers Snow Lab shows the observed areal snow cover over Eurasia was normal during October.

The chart's orange line marks the month of October's long-term average snow cover.  The dashed yellow lines are one standard deviation above or below the average.

From a statistical process control (SPC) perspective...little variation above or below the mean has occurred in the region since the early '90s.  The early '90s marked the end of a 'warm' convergence resulting from predominantly +ENSO and +PDO conditions in the tropical and extra-tropical Pacific ocean that began in the mid '80s.

Long range seasonal forecasting schemes based on autumnal Eurasia snow cover have received a fair amount of attention in recent years.  The working hypothesis centers around the idea that 'above normal' snow cover in this region during the early fall is a strong leading indicator of colder than normal winter surface air temperatures over the eastern CONUS.

These colder surface air temperatures are thought to be a consequence of upward propagating Rossby waves -- initiated by above normal Eurasia snow cover -- entering the stratosphere which...in turn...weakens or reverses the polar vortex (PV).  A weaken PV is a favorable condition for negative index values of the northern annular oscillations (AO; NAO) which generally lead to below normal temperatures and increased storminess over the eastern CONUS.

The current state of Eurasia's autumnal snow cover does not suggest the eastern CONUS will experience below normal surface air temperatures and/or increased storminess during the upcoming winter. 

Areal snowfall data courtesy Rutgers Snow Lab.

Winter '10 / '11 - December Snow Cover

From NCDC...

"The Northern Hemisphere snow cover extent during December 2010 was much above-average, marking the fourth largest December snow cover extent on record — behind December 2009, 1985, and 1970."

"During December 2010, the North American snow cover extent was above average, ranking as the seventh largest on record. This marks the fourth consecutive December with above-average snow cover extent for the continent."

Global Snow Report here.
National Snow and Ice Report here.

Winter '10 / '11 - The United States of Snow

Image courtesy NOHRSC

Winter '09 / '10 - Snow in Spain

"Snow fell in parts of Spain for the first time in half a century Monday as a wave of Arctic cold that has killed scores of people and caused billions of euros in damage to Europe's economy swept southwards.

 

"The southern Spanish city of Seville, which normally enjoys temperatures in January of around 15 degrees Celsius (59 degrees Fahrenheit), shivered under its first snowfall in half a century."

 

Elsewhere...

"Prague has had its heaviest snowfalls in 17 years and hundreds of homes across the Czech Republic were without electricity.

"Meanwhile Albania has been contending with a different type of extreme weather, as disastrous floods engulfed more than 10,000 hectares of farmland."
More...

Turning out to be a memorable winter after a long series of miserable seasons.