CONTEST STATUS - Updated: SAT ... 17-APR-21 @ 5 PM EDT

Winter '20 / '21 - Snowfall Forecast Contests
22nd Annual 'Snow Storm' Snowfall Forecast Contest
FINAL results here

---
20th Annual 'Season-total' Snowfall Forecast Contest
FINAL results here

DEC snowfall totals here
JAN snowfall totals here
FEB snowfall totals here
MAR snowfall totals here

---
Winter '19 / '20 - Snowfall Forecast Contests
21st Annual 'Snow Storm' Snowfall Forecast Contest
Season ended as quickly as it started.
No winner this go'round ... too few storms (minimum of three required)

---
19th Annual 'Season-total' Snowfall Forecast Contest
FINAL Results here

Saturday, April 17, 2021

Winter '20 / '21 - 22nd Annual 'Regular Season' Snowfall Forecast Contest: FINAL Results

DC (30-JAN-66)

After FOUR snow storm forecasting contests ... under the ‘two-thirds’ rule … forecasters who entered at least THREE forecasts are included in this season's FINAL standings.

Full table with all other error statistics at the Contest/s web site here (direct link).
Individual forecaster's storm statistics here (direct link).

Best Forecasts by Storm (lowest SUMSQ Error Z-Scores)

Top 10 Forecasts (Error statistic:  SUMSQ Z)

 

SUMSQ Error Z is the primary measure of forecaster skill (lower the better).
Accounts for the magnitude and distribution of the storm-total snowfall for all stations.

Top 10 Forecasts (Error statistic:  Total Absolute Error Z - TAE)

 

TAE Error Z is the secondary measure of forecaster skill (lower the better).
Accounts for the magnitude of snowfall forecast errors at each station.

Top 10 Forecasts (Error statistic:  RSQ Z) 


RSQ is a measure of the how well the 'forecast' snowfall captured the variability of the 'observed' snowfall (higher the better).

---
28 unique forecasters submitted a total of 2,036 station forecasts.
14 forecasters entered all 4 contests.
5 forecasters entered 3 contests.
8 forecasters entered 1 contest.

---
Hope to see y'all again next winter!

Tuesday, April 13, 2021

Snow chaos in Europe caused by melting sea-ice in the Arctic

"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 ... 

Monday, April 12, 2021

Winter '20 / '21 - 20th Annual 'Season-total' Snowfall Forecast Contest: FINAL Results

BOSOX Opening Day
(14-APR-53)

Congratulations to MillVilleWx for issuing the top forecast among forecasters in the 'Season-total' Snowfall Forecast Contest.

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.

---
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.

---


Climo ... Observed ... Departure ... and Percent of Normal Snowfall
...
Forecaster verification table at the Contest web site (direct link)

http://www.newx-forecasts.com/
http://www.newx-forecasts.com/NEWxSFC_22/season-total/season_total_verification_2021.htm

 ---
Teleconnections


---
PRIZES
1st place prize (delivered post-paid right to MillVilleWx/s front door):
... pick of the litter from NEWxSFC/s library of meteorology and weather publications
... the august title 'Chief Season-total Snowfall Forecaster' for Winter '21 / '22
... a well-deserved place of honor with past Contest winners

2nd place prize (delivered post-paid right to kc2dux/s front door):
... second pick at NEWxSFC/s library of meteorology and weather publications

3rd place prize (delivered post-paid right to Shillelagh/s front door):
... third pick at NEWxSFC/s library of meteorology and weather publications

---
Prizes winners: please contact (newxsfc [at] comcast [dot] net) with a USPS address.

Sunday, April 11, 2021

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

VT - Stowe
(Marion Post Wolcott - 1940)

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

Green ==> 4th quartile
White ==> Inter-quartile range
Red ==> 1st quartile

---
MAR Forecast Station Highlights
Stations at or above normal monthly snowfall:  none

Biggest Losers
BDR .. MDT ...PHL ... ACY ...BWI ... DCA ... SBY ... RDU (not even a Trace)

---
Season-Total-to-Date
MAR P-O-R-N contributes 184" (20%) toward the season-total snowfall (D-J-F-M) of 929"
MAR-21 observed snowfall:  19" (90% below P-O-R-N; 2% of season-total snowfall)
Image courtesy NOHRSC @ http://www.nohrsc.noaa.gov/nsa/

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

---
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
FEB totals
https://newxsfc.blogspot.com/2021/03/winter-20-21-season-total-snowfall.html

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

---
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)

---
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/

---
Teleconnections

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

---
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

Wednesday, February 24, 2021

Winter '20 / '21 - Snow Storm Contest: Interim Standings #2

 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.


Complete interim statistics table and chart at the Contest/s web site HERE (direct link)
Forecaster statistics for Winter '20 / '21 contest-worthy snow storms HERE (direct link)

---
SUMSQ errors for each contest snow storm are normalized (i.e., standardized) with a 'Z-score' ... then averaged to compute the standings. If a forecaster has issued forecasts for more than two-thirds of all snow storm contests ... then Z-scores from their 'best two-thirds' forecasts are used to calculate the Interim and Final standings.  Similar idea as dropping the lowest test score before computing the final grade.

Tuesday, February 23, 2021

Winter '20 / '21 - Forecaster Statistics

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.

---
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.

Monday, February 22, 2021

Winter '20 / '21 - Snow Storm #4: FINAL Results and Storm Summary

Complete forecaster verification table and the FINAL Results / Storm Summary available at NEWxSFC/s home page.


SUMSQ:  sum of square error (")
SUMSQ Z:  Z-score
STP:  storm total precipitation error (")
TAE:  total absolute error (")
AAE:  average absolute error (")
(#):  category rank


Forecast by Observed Snowfall Scatterplots for Top Forecasts
Forecast/s dotted blue line below (above) the Observed snowfall/s solid red line ==> under (over) forecast error.


Station by Station Comparison of Top Forecasters

Sunday, February 21, 2021

An Overview of Thundersnow


"The purpose of this article is to summarize our current understanding about this unusual wintertime event.

"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


Winter '20 / '21 - Snow Storm #4: Preliminary STP Verification

Accumulation-weighted SN:H20 (SLR)
Preliminary verification of storm-total snowfalls for THU (18-FEB-21) through SAT (20-FEB-21) from CDUS41 (CLI) ... CXUS51 (CF6) ... METARs ... and PNS bulletins.  Spotty coverage and reporting.

HYA STP estimated from a vicinity report within 2.5 SM of the station carried by the BOXPNS bulletin.  H2O value derived from METAR precipitation groups 7nnnn (24 hour) ... 6nnnn (6 hour) ... and Pnnnn (1 hour).

SBY STP estimated based on METAR 6-hour precipitation report of '60006' and 10:1 SLR.

CON/s Daily Climate Bulletin on THU reported 0.01" liquid but no snowfall total.  Estimated snowfall of 0.1" by applying 10:1 SLR.

---
SLR not reported for some stations with measurable snowfall b/c significant liquid and / or freezing precipitation also occurred during the verification period.

---
Stations observing at least 0.1":  23 (85%)

Given a station had measurable snowfall; stations observing at least ...
4" - 12 (44%)
6" - 2 (7%)
MAX:  7.6"

MAX snow melt-water (minimum SLR 8:1)
ABE:  0.55"
BDR:  0.51"
HYA:  0.36"

MAX precipitation (frozen + freezing + liquid):
ORF:  1.50"
RDU:  1.20"
RIC:  0.91"

Thursday, February 18, 2021

Winter '20 / '21 - Snow Storm #4: The Forecasts!

Barton ... VT
Main train summit (1886)
Rookie      3
Intern      -
Journey      -
Senior      11
GOVT      1
PWSP      1
TOT      16

We welcome Rookie petenotpetrock who's issuing his first NEWxSFC forecast.

Forecasters rank-ordered by ascending storm-total precipitation (STP)
BLUE ==> 1st quartile
RED ==> 4th quartile
WHITE STP cells fall between the 1st and 4th quartiles

Heaviest snowfall (+5") consensus along and to the right of BDL - ORH - BOS - PVD - ISP - JFK - EWR - MDT - ABE - BDL.

Lollypop expected at ABE (7")

All three teleconnections were photographed getting onto a plane destined for Cancún ... Mexico.

Forecasters' station-by-station forecasts posted to the Contest/s web site ...
http://www.newx-forecasts.com/

Direct link to the table of forecasts ...
http://www.newx-forecasts.com/NEWxSFC_22/storms/storm4_forecasts_18FEB21.htm

Wednesday, February 17, 2021

Winter '20 / '21 - Snow Storm #4: RAW forecasts


Portland ... ME
28-JAN-1886

Entry No. 1785
Forecaster = petenotpetrock
Time = 2/17/2021 6:57:51 AM
CAR = 3
BGR = 4
PWM = 6
CON = 6
BTV = 5
BOS = 4
HYA = 3
ORH = 7
PVD = 4
BDR = 5
BDL = 6
ALB = 6
BGM = 7
ISP = 3
JFK = 3
ABE = 8
MDT = 8
PHL = 2
ACY = 2
EWR = 6
BWI = 2
IAD = 3
DCA = 1
SBY = 1
RIC = 2
ORF = 1
RDU = 0
Comments =
----End of Entry----

Tuesday, February 16, 2021

Winter '20 / '21 - Snow Storm #4: Call for Forecasts! - Take 2

Boston Public Garden
25-FEB-62

Too few stations stayed in play after Storm #4/s first Call for Forecasts on SUN.

This storm shows much more promise to have more than enough forecast stations in play to be contest-worthy.

One thing remains unchanged from - the parade of winter storms affecting the M-A and the NE with messy p-types.

Enter your forecast at the NEWxSFC/s home page at http://www.newx-forecasts.com/

Follow the top-of-page link from 'Enter Snow Storm Forecast'

---
Forecast element: each station/s storm-total snowfall

Deadline for entries: 10 PM EST ... WED ... 17-FEB-21
Verification begins: 12:01 AM EST ... THU ... 18-FEB-21
Verification ends: 11:59 PM EST the day when snow stops accumulating

Sunday, February 14, 2021

Winter '20 / '21 - Snow Storm #4: Call for Forecasts!

BWI
Columbia Ave.  (13-FEB-1899)

UPDATE 4:30 PM EST ... MON ...15-FEB-21

Not happenin' ...

UPDATE 10:45 AM EST ... MON ...15-FEB-21
Trend not being very friendly ... 

---
Original post (5:13 PM EST ... SUN ...14-FEB-21)

Contest-worthy snows expected along the NW edge of the precipitation shield as the next in a parade of winter storm slides east across the northern M-A then off the SNE coast.  Messy p-type forecasts downstate.

Enter your forecast at the NEWxSFC/s home page at http://www.newx-forecasts.com/

Follow the top-of-page link from 'Enter Snow Storm Forecast'

---
Forecast element: each station/s storm-total snowfall

Deadline for entries: 10 PM EST ... MON ... 15-FEB-21
Verification begins: 12:01 AM EST ... TUE ... 16-FEB-21
Verification ends: 11:59 PM EST ... TUE ... 16-FEB-21

You also get the chance to see how well your forecast stacks up against NWS Eastern Region Weather Forecast Offices. Turns out they/ve been fairly easy to beat!

Saturday, February 13, 2021

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


Mass General Hospital (06-FEB-61)

UPDATE 14-FEB-21 4 PM EST:  corrected JAN total for EWR ... NYC ... BDR and JAN Forecast Station Highlights section.

h/t Roger Smith

---
JAN-21 snowfall summary by forecast station.

Rank-ordered descending by percent of monthly period-of-record-normal
(%JAN)


Green ==> 4th quartile
White ==> Inter-quartile range
Red ==> 1st quartile

---
JAN Forecast Station Highlights
3 stations with above normal monthly snowfall

BTV
4.1" (21%) above JAN normal

ORF
0.2" (6%) above JAN normal

SBY
0.2" (6%) above JAN normal

Biggest Losers

PWM ... CON (less than 35% JAN P-O-R-N)

---
Season-Total-to-Date

JAN P-O-R-N contributes 279" (30%) toward the season-total snowfall (D-J-F-M) of 929".

JAN-21 observed snowfall:  212" (-44% below P-O-R-N; 17% of season-total snowfall)

Image courtesy NOHRSC @ http://www.nohrsc.noaa.gov/nsa/

---
Teleconnections

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

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

Thursday, February 11, 2021

Winter '20 / '21 - Snow Storm Contest: Interim Standings #1

After three snow storm forecasting contests ... under the ‘two-thirds’ rule … forecasters who have entered at least TWO forecasts are included in interim standings #1.


Complete interim statistics table and chart at the Contest/s web site HERE (direct link)
Forecaster statistics for Winter '20 / '21 contest snow storms HERE (direct link)

Don Sutherland has been identified incorrectly as the Chief 'Regular Season' forecaster for the '20 / '21 season when that honor belongs to Brad Yehl.  We regret the error and apologize to Brad for the oversight.

---
SUMSQ errors for each contest snow storm are normalized (i.e., standardized) with a 'Z-score' ... then averaged to compute the standings. If a forecaster has issued forecasts for more than two-thirds of all snow storm contests ... then Z-scores from their 'best two-thirds' forecasts are used to calculate the Interim and Final standings.  Similar idea as dropping the lowest test score before computing the final grade.

Tuesday, February 9, 2021

Winter '20 / '21 - Snow Storm #3: FINAL Results

Complete forecaster verification table and the FINAL Results / Storm Summary available at NEWxSFC/s home page.


SUMSQ:  sum of square error (")
SUMSQ Z:  Z-score
STP:  storm total precipitation error (")
TAE:  total absolute error (")
AAE:  average absolute error (")
(#):  category rank

Forecast by Observed Snowfall Scatterplots for Top Forecasts
Forecast/s dotted blue line below (above) the Observed snowfall/s solid red line ==> under (over) forecast error.

Station by Station Comparison of Top Forecasters

Monday, February 8, 2021

Winter '20 / '21 - Snow Storm #3: Preliminary STP Verification

Accumulation-weighted SN:H20 (SLR)

Preliminary verification of storm-total snowfalls for SUN and MON from CDUS41 (CLI) ... CXUS51 (CF6) ... METARs ... and PNS bulletins.  Excellent coverage and reporting.

HYA STP estimated by applying inverse distance weighting interpolation of three timely reports within 3.5 SM of the station carried by the PNS bulletin from BOX.

SBY STP estimated based on one report from the forecast station/s county (Wicomico) carried by AKQ/s PNS bulletin.

---
SLR not reported for some stations with measurable snowfall b/c significant liquid and / or freezing precipitation also occurred during the verification period.

Sunday, February 7, 2021

Winter '20 / '21 - Snow Storm #3: The Forecasts!

NYC
Summit Hotel on Lexington Ave
07-FEB-67
Forecasters
Rookie      2
Intern      -
Journey      -
Senior      18
GOVT      1
PWSP      1
TOT      22

---
Forecasters rank-ordered by ascending storm-total precipitation (STP)

BLUE ==> 1st quartile
RED ==> 4th quartile
WHITE STP cells fall between the 1st and 4th quartiles

Heaviest snowfall (+5") consensus along and to the right of ISP - BDR - ORH - BOS - HYA - ISP
Lollypop expected at PVD (5.8")

Two out of three teleconnections on vacay.

Forecasters' station-by-station forecasts posted to the Contest/s web site here.
http://www.newx-forecasts.com/

Direct link to the table of forecasts here.
http://www.newx-forecasts.com/NEWxSFC_22/storms/storm3_forecasts_07FEB21.htm

Winter '20 / '21 - Snow Storm #1: NESIS

The Northeast Snowfall Impact Scale (NESIS)


 

Friday, February 5, 2021

Winter '20 / '21 - Snow Storm #3: Call for Forecasts!

BOS
04-FEB-40
Took a while for this winter to get a'goin' but we're underway with the second contest-worthy snow storm in a week/s time.

The fast-moving Miller 'A' nor'easter on the menu progged to race from the Gulf of Mexico toward the VA Capes then up the northeast coast ducking just under the 40/70 Benchmark on its way out to sea.

Enter your forecast at the NEWxSFC/s home page at http://www.newx-forecasts.com/

Follow the top-of-page link from 'Enter Snow Storm Forecast'

---
Forecast element: each station/s storm-total snowfall
Deadline for entries: 10:00 PM EST ... SAT ... 06-FEB-21
Verification begins: 12:01 AM EST ... SUN ... 07-FEB-21
Verification ends: 11:59 PM EST on the day when flakes stop accumulating.

You also get the chance to see how well your forecast stacks up against NWS Eastern Region Weather Forecast Offices. Turns out they/ve been fairly easy to beat!

---
If you are issuing your first forecast this winter ... or you entered the 'season-total' forecast contest ... you/ll need to create an account -- user name / password / valid e-mail (if you want a copy of your forecast sent to your Inbox).

The forecasting contest for Snow Storm #3 may be cancelled prior to the deadline if at least 6-to-8 stations are unlikely to observe at least a 4" storm-total snowfall.

---
As always ... there/s no cost ... no fee ... no advertising ... or annoying requests for personal information to enter a forecast. It/s just a fun exercise for winter wx enthusiasts to see who can make the best synoptic-scale snowfall forecast.