NE.Wx Snowfall Forecast Contests

Friday, February 14, 2025

Winter '24 / '25 - Snow Storm #4: RAW Forecasts

by TQ @ 10:38 PM

Click on 'Read more >>' to see RAW forecasts.

NWS ER WFO forecasts to follow

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Winter '24 / '25 - Snow Storm #4: Call for Forecasts!

by TQ @ 6:44 PM

Beacon St.
Boston ... MA (FEB-1901)

Another in a series of mid-latitude cyclones predicted to deepen as it translates east from the lee of the Rockies toward and through the St. Lawrence River valley this weekend. Contest-worthy snows expected across northern stations of the forecast area.

- Enter your forecast from NEWxSFC/s home page at http://www.newx-forecasts.com/

- Follow the top-of-page link from 'Enter Snow Storm Forecast'

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Forecast element: each station/s storm-total snowfall

Deadline for entries: 10 PM ET FRI ... 14-FEB-25
Verification period BEGINS: 12:01 AM ET SAT ... 15-FEB-25
Verification period ENDS: 11:59 PM ET the day snow stops accumulating

The forecasting contest for Snow Storm #4 may be cancelled prior to the deadline if at least 6
to 8 stations are unlikely to observe at least 4" of storm-total snowfall.

By entering ... you also get the chance to see how well your forecast stacks up against NWS Eastern Region's Weather Forecast Offices. Turns out they/ve been easy to beat!

Winter '24 / '25 - 26th Annual 'Regular Season' Snowfall Forecast Contest: Interim Standings #1

by TQ @ 6:57 PM

DC
20-MAR-1924

After 3 contest-worthy snow storms ... under the ‘two-thirds’ rule … forecasters who have entered at least 2 forecasts are included in Interim Standings #1.

Complete interim statistics tables and a chart at the Contest/s web site (direct link)
Forecaster statistics for Winter '24 / '25 contest snow storms (direct link)

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SUMSQ errors for each Contest snow storm are normalized / standardized) by computing a 'Z-score' ... then averaged ... and ranked to compute the standings.

If a forecaster has issued forecasts for more than two-thirds of all snow storm contests ... then Z-scores from their 'best two-thirds' forecasts are used to calculate the Interim and Final standings.

Tuesday, February 11, 2025

Winter '24 / '25 - Snow Storm #3: FINAL Results and Storm Summary

by TQ @ 4:05 PM

14.3"
DC (07-FEB-36)

Complete forecaster verification table and the FINAL Results / Storm Summary available at NEWxSFC/s home page.

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

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Forecast by Observed Snowfall Scatterplots for Top 4 Forecasts

Forecast/s dotted BLUE line below (above) the Observed snowfall/s solid RED line ==> under (over) forecast error.

R^2: how well the forecast model 'explained' the variability of the observed snowfall (i.e., an R^2 of 0.710 means the forecast model explained 71% of the observed snowfall's variability).

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Comparison of Top 4 Forecasts and Observed Snowfall by Station

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Forecast Skill Score (measured against NWS ER WFOs)

- Positive (negative) SKILL values indicate the degree of a forecast/s improvement (degradation)
compared to NWS forecasts.
Bias: the arithmetic difference between the average Forecast snowfall and the average Observed snowfall (avgForecast - avgObserved).

Monday, February 10, 2025

Winter '24 / '25 - Snow Storm #3: Preliminary STP Verifications

by TQ @ 4:46 PM

Knickerbocker storm
DC (28-JAN-1922)

Preliminary verification of storm-total snowfalls for FRI and SAT based on reporting from CDUS41 (CLI) ...CXUS51 (CF6) ... METARs ... and PNS bulletins issued by NWS.

Good coverage and reporting.

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HYA
STP derived from inverse distance-weighting technique using vicinity STP reports from Barnstable county carried in the BOXPNS bulletin as inputs.

Summary SLR value is quantity-weighted.
Stations with SLR < 8 are not reported b/c of probable contamination from liquid and/or freezing precipitation.

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Stations observing >= Trace: 25 (93%)
Stations observing > Trace: 18 (67%)

Given a station had measurable snowfall; stations observing at least:
4" - 10 (37%)
6" - 1 (4%)
8" - 1 (4%)
10" - 1 (4%)

MAX snow melt-water (minimum SLR 8:1)
BDR - 0.58'
ORH - 0.51"
PVD - 0.46"

MAX precipitation (frozen + freezing + liquid)
JFK - 0.72"
JFK - 0.69"
EWR - 0.64"

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New daily snowfall record(s)
None

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Daily snowfall data table

ORANGE: new daily record
GREY: STP derived from PNS or METARs or inverse distance weighting

Trace amounts (displayed as 0.05") are not included in STP or SLR calculations.

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Areal distribution of storm-total snowfall

Image courtesy NOHRSC
https://www.nohrsc.noaa.gov/

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SFC analysis: 06z ... 09-FEB-25

Image courtesy DOC / NOAA / NWS / NCEP / WPC
https://www.wpc.ncep.noaa.gov/html/avnsfc.shtml

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Please report any errors in Comments along with a link to the correct data.
FINAL results expected NLT TUE evening on or about 9 PM ET.

Sunday, February 09, 2025

Winter '24 / '25 - Snow Storm #4: Call for Forecasts!

by TQ @ 7:45 PM

Dutch Reformed / Bay Ridge Church
2nd Ave Ridge Blvd 80th St
Brooklyn ... NYC (c.1900)

UPDATE: 1:30 PM ET MON ... 10-FEB-25

THIS 'CALL FOR FORECASTS' FOR SNOW STORM #4 HAS BEEN CANCELLED.

TOO FEW STATIONS IN PLAY FOR A CONTEST-WORTHY SNOW STORM.

Contest Status

by TQ @ 1:14 PM

PHL - Broad and Chestnut
early 1930s

Winter '24 / '25
NE.Wx Snowfall Forecast Contests

26th Annual 'Snow Storm' Snowfall Forecast Contest

UPDATE: 8:15 PM ET - TUE ... 18-FEB-25

Snow Storm #5
Synoptiscope in VCP32

Snow Storm #4: 15-FEB-25

FINAL Results and Storm Summary here

Snow Storm #3: 08-FEB-25

FINAL Results and Storm Summary here

Snow Storm #2: 19-JAN-25

FINAL Results and Storm Summary here

Snow Storm #1: 05-JAN-25
FINAL Results and Storm Summary here

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Deadline for entries: 10 PM ET. Typically ~24 hours before the leading edge of a contest-worthy snow storm is predicted to enter the forecast area.

Enter your forecast here.

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24th Annual 'Season-total' Snowfall Forecast Contest

UPDATE: 4:30 PM ET - FRI ... 14-MAR-25

Deadline for entries has passed.
Details and Forecasts here

Monthly snowfall totals

DEC here

JAN here
FEB here

MAR here

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Winter '23 / '24 - Snowfall Forecast Contests

25th Annual 'Snow Storm' Snowfall Forecast Contest

FINAL results here

23rd Annual 'Season-total' Snowfall Forecast Contest
FINAL results here

Saturday, February 08, 2025

Winter '24 / '25 - Snow Storm #3: The Forecasts!

by TQ @ 2:07 PM

4th Ave
NYC (c.1908)

Everyone/s station-by-station forecast on the Contest/s web site. NOTE: Some forecasts for 'Trace' (0.05) display as 0.1 but are recorded in the database as 0.05.

Direct link to the forecast table.

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Rookie      -
Intern         -
Journey      1
Senior      14
Chief           1
GOVT        1
PWSP         -
TOT         17

Forecaster table ranked ascending by the forecast storm-total precipitation (STP)

BLUE ==> 1st quartile
RED ==> 4th quartile
WHITE and GREY STP cells range between the 1st and 4th quartile

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Heaviest snowfall (+6") forecast consensus along and to the right of BOS - PVD - BDL - ALB - ORH - BOS. Lollypop expected at ORH.

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Teleconnections

Everyone/s station-by-station forecast at the Contest/s web site.
Direct link to the forecast table.

Winter '24 / '25 - Snow Storm #3: RAW Forecasts

by TQ @ 9:30 AM

Click on 'Read more >>' to see RAW forecasts.

Winter '24 / '25 - Snow Storm #3: Call for Forecasts!

by TQ @ 1:31 PM

Grand Army Plaza
Brooklyn ... NY (FEB-1929)

LOW pressure coming ashore over northern CA on THU predicted to re-organize in the lee of the Rockies on FRI then enter the forecast area as a contest-worthy storm SAT PM.

- Enter your forecast from NEWxSFC/s home page at http://www.newx-forecasts.com/

- Follow the top-of-page link from 'Enter Snow Storm Forecast'

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Forecast element: each station/s storm-total snowfall

Deadline for entries: 10 PM ET FRI ... 07-FEB-25
Verification period BEGINS: 12:01 AM ET SAT ... 08-FEB-25
Verification period ENDS: 11:59 PM ET the day snow stops accumulating

The forecasting contest for Snow Storm #3 may be cancelled prior to the deadline if at least 6
to 8 stations are unlikely to observe at least 4" of storm-total snowfall.

By entering ... you also get the chance to see how well your forecast stacks up against NWS Eastern Region's Weather Forecast Offices. Turns out they/ve been easy to beat!

Short History of NEWxSFC

99/00 - spawned on USENET/s ne.wx newsgroup to discover which poster(s) made skillful forecasts for synoptic-scale snowfalls in the NE and Mid-Atlantic. No formal entry process. Forecasts gleaned from newsgroup posts. Contest storms: 5

00/01 - Permanent station list created. (RDU - CAR). Rules and scoring formalized. First Contest 12/30. Contest storms: 10

01/02 - 'Season-total' forecasting contest launched. Twenty-five forecasters predicted each station/s 'total snowfall' for the winter. First Contest storm 12/9. Contest storms: 9

02/03 - First Contest storm 11/27. Contest storms: 10

03/04 - Web site launched. Developed online entry forms. Streamlined forecast reporting and verification processes. Added two forecast stations (BGR, BGM). First Contest storm 12/14. Contest storms: 10

04/05 - First Contest storm 12/20. Contest storms: 9

05 /06 - First Contest storm 12/5. Contest storms: 4

06/07 - Regular season starts late with first Contest storm 2/14. Contest storms: 5 (last one in April)

07/08 - Record number of forecasters (36) enter 'Season-total' Contest. Regular season starts 12/3.

08/09 - 10th anniversary!

18/19 - 20th anniversary!

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NEWxSFC appreciates greatly the on-going support from Senior Forecaster Donald Rosenfeld who began sponsoring the Contest/s web site in 2003 and enabled the development of our online entry forms.