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

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!

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

NYC
26-DEC-47

JAN-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 - JAN
Over-achievers of the month:  SBY @ 283% of monthly P-O-R-N and ORF @ 190%.
9 stations observed at least 100% of its monthly climo snowfall.

Biggest Losers
4 stations observed less than 50% of their monthly climo.

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Season-total-to-Date

JAN P-O-R-N contributes 278" (30%) toward the season-total (D-J-F-M) snowfall of 936".
JAN-25 observed snowfall:  221" (79% of monthly P-O-R-N; 24% 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 #2: FINAL Results and Storm Summary

BWI - Mount Vernon Place (1938)

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

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SUMSQ:  sum of square error (")
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.

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Comparison of Top 4 Forecasts and Observed Snowfall by Station

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Forecaster 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 #2: Preliminary STP Verifications

NYC - West Broadway at Spring Street
(1983)

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

Good coverage for station snowfalls but spotty/questionable reporting of melt water.

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Missing/questionable melt-water values precludes accurate SLR calculations for some stations

HYA
STP derived from inverse distanced-weighted scheme based on vicinity reports from PNSBOX.

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

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Winter '24 / '25 - Snow Storm #2: The Forecasts!

DC
N St ... NW (2007)

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

Rookie     -
Intern       -
Journey   -
Senior      14
Chief      1
GOVT    1
PWSP    1
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") consensus along and to the right of BGR - PWM - ORH - BDL - CON - BGR.  Lollypop expected at BGR.

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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 #2: RAW Forecasts

Click through on the 'Read more >>' link to see the forecasts.

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Winter '24 / '25 - Snow Storm #2: Call for Forecasts!

NYC
27-JAN-1937

On SUN ... surface LOW pressure predicted to undergo explosive development -- deepening ~25 mb in 24 hours -- as it moves early in the period from western NC toward the NE along the eastern seaboard then on to the CN maritime provinces by the wee hours of MON morning.

Contest-worthy storm-total snowfalls expected mainly over the northern two-thirds 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 SAT ... 18-JAN-25
Verification period BEGINS:  12:01 AM ET SUN ... 19-JAN-25
Verification period ENDS:  11:59 PM ET the day snow stops accumulating

The forecasting contest for Snow Storm #2 may be cancelled prior to the deadline if at least 6
to 8 stations are unlikely to observe 4" or more 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 - 'Season-total' Snowfall Forecast Contest: DEC Snowfall Totals

DC
Connecticut Ave and Chevy Chase Circle - 1942

DEC-24 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)
Red ==> 1st quartile

'Obs' reporting '0.05' denote 'Trace' amounts (observed but not measurable).

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DEC Forecast Station Highlights
1 station observed at least 100% of its monthly climo snowfall (BGM).

Biggest Losers
9 stations with less than 10%.
2 stations observed trace amounts (displayed as 0.05").
3 stations not a single flake ... ice pellet ... or hailstone observed.

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Season-total-to-Date
DEC P-O-R-N contributes 207" (22%) toward the season-total (D-J-F-M) snowfall of 936".
DEC-24 observed snowfall:  130" (63% of monthly P-O-R-N; 14% of P-O-R-N season-total snowfall).

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Teleconnections

AO / NAO / PNA data

Winter '24 / '25 - Snow Storm #1: FINAL Results and Storm Summary

NYC
26-DEC-47

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 bias.

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Comparison of Top 4 Forecasts and Observed Snowfall by Station

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Forecaster Skill Score (measured against NWS ER WFOs)

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

 

Winter '24 / '25 - Snow Storm #1: Preliminary STP Verification

Smithstonian - 1920s

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

Good coverage and reporting.

Exceptions
SBY
NWS Climatological Report (Daily - CLI) carried 'MM' for SAT snowfall-total and 0.53" liquid.

NWS WFO Monthly/Daily Climate Data (CF6) carried 8.5" and 'M' for liquid.

STP derived by an inverse distance weighting scheme with AKQ and PHI vicinity reports carried in their PNS bulletins for Sussex county ... DE and Worcester and Wicomico counties in MD came to 8.5".

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