Contest # 4 - Take Two

MR model solutions continue trending toward a possible contest storm later in the week. Heavy rain at coastal stations with good snows inland.


Click to animate.

Upper trof sharpens on Saturday as it approaches the EC then acquires a negative tilt with the surface LOW wraping up over Newfoundland and a broad polar HIGH settling over the M-A.

Coastal Teaser #6

MR has certainly had its way with NEWxSFC forecasters this year. A frustrating parade of one fantasy coastal teaser after another. The best storm has always been just a week away...so it comes as no surprise that the models are singing their siren song for our unrequited affections yet again.


ECMWF...GooFuS...and even the Canadians are currently trending toward a sharper EC trof scenario at the coming week/s end. The EC D+6 prog has a secondary coastal LOW around the 40°N / 70°W 'benchmark' and an arctic HIGH to its N and W...which could offer a late season opportunity for another snowfall forecast contest.

Interim Standings

After three contests comes the first opportunity to post interim standings. Forecasters must have entered at least two of the three contests held so far this season to be included. If a forecaster entered all three contests...scores from the two best forecasts are used to calculated an average normalized SUMSQ score.

First Place: Donsutherland1 with an average SUMSQ Z-Score of -0.925.
Second Place: Bubbler86 -0.882
Third Place: Herb@MAWS -0.751

A data table with the complete interim standing statistics...including Sum Squared Error (SUMSQ)...Storm Total Precipitation (STP)...Total Absolute Error (TAE)...Average Absolute Error (AAE)..and R-Squared (RSQ) at the web site.


Click on image to enlarge.

There appears to be a tie for 3rd but Herb@MAWS leads TQ by 0.00007.

The chart shows the distribution of forecaster SUMSQ Z-Scores (plum) and Total Absolute Error Z-Scores(cyan). Lower (higher) Z-Scores indicate better (worse) forecasts compared to all other forecasts made for each storm.

A Z-Score of 0 means the forecaster's error was equal to the average of all forecast errors. A Z-Score of -1 (+1) means the forecaster's error was 1 standard deviation below (above) the average of all forecast errors.

Contest # 4?

(Updated)

Not impressed by tonight/s 00z f-soundings from the Eta / NAM. This run doles out saturated columns to ACY and BWI for all of ~3 hours. Columns at the other stations under the clipper look too dry.

The combination of a short duration event and limited moisture doesn/t usually make for a good forecasting event.

Update
Turned out to be not much of an event afterall...especially given the advanced billing from private...public...amd hobby forecasters.

Station / SN / SN:H2O
MDT 2.0 - 12
ACY 1.8 - 15
IAD 1.4 - 18
PHL 1.4 - 16
ABE 1.2 - 11
EWR 1.0 - 10
DCA 1.0 - 9
JFK 0.8 - 16
BWI 0.8 - 10
BDR 0.7 - 14
ISP 0.5 - 10
BGM 0.2
BDL T

Some of the snowfall totals seem low considering the SN:H2O. 10:1
ratios from clipper-type snows are highly suspect.

Contest # 3 - Final Results

Full forecast verification and results summary at the web site.

Follow the links to 'Forecasts - Contest #3' and 'Results - Contest #3.'

Forecasters: 10
9 veterans
1 rookie

Station forecasts: 123
Average stations per forecaster: 12
Stations with observed snowfall: 11

Storm-total precipitation (STP), all stations
Forecast
Minimum: 27" (mitchel volk)
Consensus Median: 50.9"
Maximum: 94.75" (Donald Rosenfeld)

Observed: 32.35"
Max single station: 9.5" CAR
Shutout: HYA...BDR...ISP...JFK...ABE...MDT...PHL...ACY...EWR...BWI...IAD...DCA...SBY...RIC...
ORF...and RDU

***************************************************
Storm #3 - Results Summary

Congratulations to the Winners!

1st Place - bubbler86
SUMSQ Error: 17.3
SUMSQ - Z: -1.164
STP: 3.65 (1st)
TAE: 10.5" (1st)
AAE: 0.91" (1st)

2nd Place - Raven
SUMSQ Error: 33.1"
SUMSQ - Z: -1.009
STP: 4.65" (2nd)
TAE: 15.75" (2nd)
AAE: 1.58" (2nd)

3rd Place - TQ
SUMSQ Error: 75.3"
SUMSQ - Z: -0.825
STP: 15.7" (4th)
TAE: 19.7" (4th)
AAE: 1.79" (4th)

Honorable Mention - mitchel volk
SUMSQ Error: 69.3"
SUMSQ - Z: -0.653
STP: 5.35" (3rd)
TAE: 19.15" (3rd)
AAE: 3.19" (8th)

SUMSQ: sum of square errors
STP: storm total precipitation
TAE: total absolute error
AAE: average absolute error

One More?

Click image to animate.

The clipper poised to sweep across the M-A on Wednesday may produce enough snow to hold Contest #4. Time-height x-sects from the Eta / NAM / WRF-NMM / WTF suggest there could be 6...possibly 10 stations in play...although it remains to be seen just how many are likely to get more than nuisance amounts. Clippers are commonly good for a stripe of 2-4"...sometimes a bit more if it/s particularly vigorous.

Antecedent conditions look good with plenty-o-arctic air in place. Forecast temperatures aloft also appear favorable for the production of hi-fluff stellar dendrites in the crystal factory.


GooFuS forecast sounding for MDT.

Go / No GO decision coming tomorrow evening.

Contest # 3 - Verification

Preliminary storm-total snowfall based on final CDUS41 bulletins from Friday and Saturday.

Report any errors in 'Remarks' along with a link to the correct data. Final results and contest summary will be posted tomorrow evening.

1 CAR 9.50
2 BGR 6.60
5 PWM 2.50
3 CON 6.40
4 BTV 5.90
9 BOS 0.05
12 HYA 0.00
6 ORH 0.60
9 PVD 0.05
12 BDR 0.00
9 BDL 0.05
8 ALB 0.20
7 BGM 0.50
TOT 32.35

Contest # 3 - Teleconnections

Event starts out with AO and NAO near normal...then both indices increase to about 0.5 standard deviations above their mean. PNA has been below normal since Contest #2.

Contest # 3 - Day One Leader Board

Based on Friday/s preliminary CDUS41 reports.

bubbler86
Raven
mitchel volk
herb@maws
TQ
ilibov
donsutherland1
DAROONEY
MatthewRydzik
Donald Rosenfeld

Contest # 3 - The Forecasts

Forecasters: 10
Rookies: 1
Veterans: 9


Clearly a NNE event. The consensus +SN axis runs from BTV - CAR - PWM - CON - BTV with a max of 11" at BTV.

All individual forecasts have been posted to the NEWxSFC web site. Follow the link to 'Forecasts - Mar 2.' The forecasts are ranked from minimum to maximum storm total snowfall (STP) for all stations.

Minimum STP: 27" (mitchel volk)
Maximum STP: 94.75 (Donald Rosenfeld)
Average STP: 56.8"
Median STP: 50.9"
10th percentile: 35.1"
90th percentile: 81.9"

Verification snowfall reports will be posted Sunday morning. They are considered preliminary and subject to change / challenge for 24 hours. Final results will be posted late Monday evening.