Complete Results @

Follow the left-panel link from '22nd Annual Snow Storm Contest > Verified Forecasts > ‘18-FEB-21’ to see the complete forecasters’ verification table by station


In the table ...

Yellow cells indicate the best score in category. 

Forecast STP cells:  yellow if within +/- 5% of observed STP.


Blue (Red) cells indicate the 25% (75%) percentile.


SUMSQ:  sum of square errors (measure of forecast accuracy accounting for magnitude and distribution of snowfall)

STP:  storm total precipitation

TAE:  total absolute error
AAE:  average absolute error


Final Standings - all Forecasters



Station by Station Comparison of Best Forecasts


Perfect Forecasts (Batting Average - Forecast Stations with No Error)


Best Station Forecasts (Batting Average - Forecast Stations with Lowest Absolute Error)


Best Station Forecast Busts (Batting Average - Forecast Stations with Highest Absolute Error)


Consensus forecast best @ PWM … BGM …ISP

MAX forecast best @ CON … HYA

MAX forecast less than observed @ HYA

MIN forecasts best @ BTV … BDL … ALB … BWI … IAD … DCA

MIN forecasts more than observed @ ALB … BWI … IAD … DCA



Strong correlation (R = 0.949) between SUMSQ and TAE Z-scores



A dashed Forecast trend line above (below) solid red Observed snowfall line ==> over (under) forecast

R2 value indicates how well the forecast captured the observed snowfall’s variability … i.e., R2 = 0.874 ==> the forecast captured ~87% of the observed snowfall’s variability.



Storm-total snowfalls for THU (18-FEB-21) through SAT (20-FEB-21) from CDUS41 (CLI) ... CXUS51 (CF6) ... METARs ... and PNS bulletins.

Excellent 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"



New daily record(s)

THU ... 18-FEB-21

ABE - 4.4" (3.9"; 2000)

EWR - 4" (3.1"; 2000)

JFK - 4.3" (2.1"; 2000)

ISP - 3.9" (2"; 2014)



Approximate storm-total snowfall courtesy NOHRSC


SFC analysis:  18z ... 18-FEB-21

Image courtesy DOC / NOAA / NWS / NCEP / WPC


Teleconnection time-series data courtesy CPC



Upper air charts courtesy University of WY


Surface analysis courtesy DOC / NOAA / NWS / NCEP / WPC




Imagery courtesy George C. Marshall Space Flight Center Earth Science Branch



Radar imagery courtesy College of DuPage NEXLAB