CONTEST STATUS - Updated: TUE ... 01-SEP-20 @ 11 AM EDT

Winter '20 / '21 - Snowfall Forecast Contests
22nd Annual 'Snow Storm' Snowfall Forecast Contest
Season starts when flakes start a'flyin'
Watch this space

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20th Annual 'Season-total' Snowfall Forecast Contest
Window for entries opens on 01-NOV-20 @ 12:01 AM EDT and closes on 30-NOV-20 at 11:59 PM EST

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Winter '19 / '20 - Snowfall Forecast Contests
21th 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)

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

Wednesday, December 4, 2019

Winter '19 / '20 - Snow Storm #1: Preliminary STP Verification

AVG SN:H2O is quantity-weighted
UPDATE 2 (09-DEC-19 @ 6:50 PM EST):  For the Record - CON STP changed from 6.9" to 7.1" per CF6 bulletin.

Revised STP did not change rank ordering of forecasts; however ... the minor changes in Z-Scores will be applied to season-end calculations.

UPDATE (04-DEC-19 @ 9:50 PM EST):  corrected BOS STP

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Preliminary verification of storm-total snowfalls for SUN through TUE from CDUS41 (CLI) ... CXUS51 (CF6) ... METARs ... and PNS bulletins.  Good coverage and reporting with exceptions 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)
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

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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):
ALB:  2.09"
BDL:  1.67"
ORH:  1.61"

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New daily record(s)
01-DEC-19
ALB - 13.3" (3.7"; 1969)
ORH - 8.9" (4.2"; 1917)
BDL - 4.6" (1.9"; 1925)
BOS - 1.6" (1"; 1940)
PVD - 1.6" (0.5"; 1907)
BDR - 0.7" (T"; 2012)

02-DEC-19
BGM - 9.6" (4.6"; 2005)
BDL - 8.8" (6"; 1949)
ALB - 6.8" (6.2"; 1949)

03-DEC-19
BOS - 4.8" (4"; 1893)
PVD - 3.4" (3.3"; 1963)
JFK - 0.2" (T"; 1989)

Storm total snowfall
Image courtesy NOHRSC

SFC analysis:  00z ... 02-DEC-19
Image courtesy DOC / NOAA / NWS / NCEP / WPC

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Please report any errors in Comments along with a link to the correct data.
FINAL results expected NLT THU evening.

7 comments:

Anonymous said...

IAD had trace snow on 2nd and .01 liquid. -- RS

TQ said...

I saw that in the daily climate and F6 reports; however ... if you examine the METARS there's no report of frozen precipitation i.e., SN or PL.

Don said...

Boston's 3-day total snowfall was 7.1". December 1, when 1.2" fell from the warm air advection, was part of the forecasting period.

TQ said...

Appears I picked up the late afternoon value of 3.6" on the 3rd for BOS instead of the 4.8" final report.

Thanks for catching the error.

Don said...

You’re welcome. Have a great evening.

Unknown said...

Re IAD -- maybe somebody drove there from Albany and it fell off their car.

(LOL at my decision to under-forecast ALB and BGM for maybe the first time ever) -- RS

TQ said...

😲