Winter '24 / '25 - 'Season-total' Snowfall Forecast Contest: FEB Snowfall Totals

US-13 to Penny Hill
New Castle ... DE (1922)

FEB-25 snowfall summary by forecast station.

Rank ordered descending by percent of monthly period-of-record-normal (P-O-R-N)

Green ==> 4th quartile
White ==> less than 4th and greater than 1st quartile (inter-quartile range - IQR)
Red ==> 1st quartile

'Obs' reporting '0.05' denote 'Trace' amounts (observed but unmeasurable)

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Forecast Station Highlights - FEB
15 stations observed at least 100% of their monthly climo snowfall.
ORF and SBY led the way with over 400% and 300% ... respectively.
Even RDU got into the action with 113% of P-O-R-N.

Biggest Losers
6 northern M-A stations observed less than 80% of their P-O-R-N.

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Season-total-to-Date
FEB P-O-R-N contributes 266" (28%) toward the season-total (D-J-F-M) snowfall of 936".
FEB-25 observed snowfall:  308" (116% of monthly P-O-R-N; 33% of P-O-R-N season-total snowfall).

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Teleconnections

AO / NAO / PNA data

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DEC snowfall totals here
JAN snowfall totals here
FEB snowfall totals here
MAR snowfall totals here

Winter '24 / '25 - Snow Storm #4: FINAL Results and Storm Summary

BOS - Morrissey Boulevard
FEB-78

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 'explained' the variability of the observed snowfall (i.e., an R^2 of 0.710 means the forecast 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).

Winter '24 / '25 - Snow Storm #4: Preliminary STP Verifications

Presidents Day
19-FEB-79

UPDATED 18-FEB @ 10:30 AM ET to include snowfall for CAR ... BGR ... and BGM plus trace amounts for several other stations on 17-FEB.

h/t RS

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Preliminary verification of storm-total snowfalls 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 an inverse distanced-weighting technique using vicinity STP reports
from Barnstable county carried in the BOXPNS bulletin as inputs.

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

Read more »

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

Flatiron Building
NYC (c.1905)

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

Rookie      -  
Journey    1
Senior      9
Chief        1
GOVT      1
PWSP      -
TOT       12

 
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 CAR - BGR - CON - BTV - CAR. Lollypop expected at CAR.

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Teleconnections

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

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

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

NWS ER WFO forecasts to follow

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Read more »

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

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!

Read more »

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

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.

 

 

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

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).

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

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.

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

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.

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