Sunday, January 7, 2018

Winter '17 / '18 - Snow Storm #2: FINAL Results

Forecasters' station verifications and the storm summary at NEWxSFC/s home page.
http://www.newx-forecasts.com/

     
 1st - Brad Yehl   
 SUMSQ:107  
 SUMSQ Z:-1.566  
 STP:19.9 (3) 
 TAE:42.8 (1) 
 AAE:1.58 (1) 
     
 2nd - WeatherT   
 SUMSQ:156  
 SUMSQ Z:-1.220  
 STP:23.1 (4) 
 TAE:46.1 (2) 
 AAE:1.71 (2) 
     
 3rd - Shillelagh   
 SUMSQ:190  
 SUMSQ Z:-0.977  
 STP:23.2 (5) 
 TAE:56.6 (3) 
 AAE:2.10 (3) 
     
 HM - donsutherland1   
 SUMSQ:215  
 SUMSQ Z:-0.799  
 STP:42.9 (11) 
 TAE:56.7 (4) 
 AAE:2.10 (4) 
     

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


Forecast by Observed Snowfall Scatter Plots of Top Forecasters
Dotted blue line below (above) solid red line ==> under (over) forecast


Station Verification Comparison of Top Forecasters

Snowfall Distribution and Magnitude by Station (Power Map - Excel 2013)


Melt-water Distribution and Magnitude by Station (Power Map - Excel 2013)

4 comments:

Shillelagh said...

Thanks TQ! Interesting storm for sure. Had i thought more about verification start time i might have reduced ORF from 8" to 5". Maybe it would have been enough to avoid the Bronze Medal again. Prolly not though...cuz ISP...hats off to thise that saw (and forecasted) that banding.

TQ said...

Congrats on finishing high on the ladder and more than a few rungs above NWS. Great contest storm especially one where snow is not confined to the NW edge of the precip shield. Impossible to know where banding will set up shop. Just look at the huge melt-water diff (~1") btwn JFK and ISP.

Shillelagh said...

Thanks...beating NWS WFO's like a rented mule is always entertaining...;). Definately a "cold" storm given the ratios at most stations. Hard to believe ISP had 1" more liquid and a 10:1 ratio as compared to JFK, but I suppose when it's dumping like that, a lower ratio is feasible. I wonder if BLSN affected their melted value. Also, ORH, 41:1 ratio...clearly something was off though I believe their snowfall. Interestingly, their were banding signatures esp on the NAM and HiRes 3km NAM model IIRC.

Looking forward to this airmass exiting. It's bad when 13 degrees for a high temp feels mild...

End of week offers potential Contest #3 but would have to see NWP slide S&E from current progs to get enough stations involved. I may do well near SYR but even more iffy S&E of here. After that, we may wait a bit for another one it appears.

TQ said...

The SLRs were all over the place. No rhyme or reason. Could be tipping bucket / wind issues and the commitment of FAA observers to their snow boards.

Checked the sensitivity of your ORF forecast. Reduced the value from 8" to 5". Your rank stayed the same; however ... the Z-score improved from -0.944 to -0.994.

Had you nailed ISP like WeatherT ... you'd have moved into 2nd. Had you gone 5" @ ORF and nailed ISP you'd also have ended up in 2nd. The 8" under-forecast at ISP racked up 64 error points.

Medium range appears similar to the way DEC started with the storm track on the wrong side of the mountains.

BTW: -12°F this AM at NEWxSFC/s World HQ ... a stone's throw from AKQ.