NE.Wx Snowfall Forecast Contest

Complete Results @ http://www.newx-forecasts.com/

Follow the left-side link from '21^st Annual Snow Storm Contest > Verified Forecasts > ‘01-DEC-19’ 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 (forecast accuracy measure accounting for magnitude and distribution of errors)

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 - Percentage of Forecast Stations with No Error)

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

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

Consensus forecast best @ BGR … PWM … BOS …HYA … BDR … BGM … ISP … EWR

MAX forecast best @ ORH … PVD … ALB

MAX forecast less than observed

MIN forecasts best @ CON …BTV … JFK

MIN forecasts more than observed @ ABE

Strong correlation (R = 0.938) between SUMSQ and TAE Z-scores

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 ~87.4% of the observed snowfall’s variability.

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Storm-total snowfalls for SUN thru TUE from CDUS41 (CLI) ... CXUS51 (CF6) ... METARs ... and PNS bulletins.

Good coverage and reporting with an exception at CON.

Exceptions

CON

No daily snowfall reported in CF6 or CLI bulletins for 02-DEC-19.

PNSGYX carried 5.2" from ASOS

SUN-TUE CLI bulletins carried 3.5" ... MM ... 1.9" = 5.4" (0.69" liquid)

CON METARs did not report mixed-precipitation

PWM SLR 10:1 (no mixed precipitation)

ORH SLR 10.7 (0.02" freezing precipitation removed)

CON verification STP: 6.9" (estimated at 10:1 SLR for 0.69 liquid precipitation – value in line with PNS vicinity reports using inverse distance weighting technique)

STP may be amended if official data reported prior to posting of FINAL results.

HYA

STP estimated by applying 10:1 SLR to 0.12" liquid reported in METARs during period of frozen precipitation at the station.

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Average forecast area snow-to-liquid ratio (SN:H20) is quantity-weighted.

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

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Stations observing >= Trace: 20 (74%)

Given stations with measurable snowfall ... stations observing at least:

4" - 10 (63%)

8" - 6 (38%)

12" - 3 (19%)

18" - 1 (6%)

Max snow melt-water (minimum SLR 10:1)

ALB: 2.09"

BDL: 1.67"

ORH: 1.61"

Max precipitation (frozen + freezing + liquid):