Winter '20 / '21 - RAW Forecasts

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28-JAN-1922

 

Winter '20 / '21 - Snow Storm #2: Call for Forecasts!

Six long weeks after the start to NEWx/s 22nd Annual 'Snow Storm' Forecasting Contest ... Snow Storm #2 finally comes a'calling.

Amplifying mid-level flow ... shortening wavelength ... hi-latitude blocking ... Miller 'B' mid-latitude cyclogenesis ... Arctic wedge ... mixed-precipitation type issues ... and a long-duration nor'easter just like days of yore.

Even the Mid-Atlantic and a long stretch of the I-95 corridor are in play this go'round.

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Enter your forecast at the NEWxSFC/s home page at http://www.newx-forecasts.com/
Follow the top-of-page link from 'Enter Snow Storm Forecast'

Forecast element: each station/s storm-total snowfall
Deadline for entries: 10:00 PM EST ... SAT ... 30-JAN-21
Verification begins: 12:01 AM EST ... SUN ... 31-JAN-21
Verification ends: 11:59 PM EST on the day when flakes stop accumulating.

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

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If you are issuing your first forecast this winter ... or you entered the 'season-total' forecast contest ... you/ll need to create an account -- user name / password / valid e-mail (if you want a copy of your forecast sent to your Inbox).

The snowfall forecasting contest for Snow Storm #2 may be cancelled prior to the deadline if at least six-to-eight stations are unlikely to observe at least a 4" storm-total snowfall.

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As always ... there/s no cost ... no fee ... no advertising ... or annoying requests for personal information to enter a forecast. It/s just a fun exercise for winter wx enthusiasts to see who can make the best synoptic-scale snowfall forecast.

Winter '20 / '21 - Coastal Teaser #2

Long-duration and ginormous Miller 'B' storm complex beginning to loom large in the window as an otherwise disappointing JAN comes to a close.

Contest-worthy nor'easters have been in short supply of late so this is a welcome development.

Latest NWP guidance points toward snow beginning to accumulate over southern portions of the forecast area early SUN AM and continuing through the first few days of FEB over northern stations.

Should events unfold as advertised currently ...
Call for Forecasts:  FRI ... 29-JAN-21
Deadline for entries:  10 PM EST ... SAT ... 30-JAN-21
Verification beginning:  12:01 AM EST ... SUN 31-JAN-21
Verification ending: 11:59 PM EST the day when flakes stop accumulating 

Could be the start of an hyper-active period as heights progged to rise over the Pole and PNA region while AO remains below zero and the displaced PV drifts toward Greenland ...

Winter '20 / '21 - VCP 32: Another Month At Least

 

Winter '20 / '21 - 'Season-total' Snowfall Forecast Contest: DEC Totals

DEC-20 snowfall summary by forecast station.
Rank ordered descending by percent of monthly period-of-record-normal (P-O-R-N).

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Green ==> 75th - 100th percentile
White ==> less than 75th and greater than 25th percentile (inter-quartile range)
Red ==> 0 - 25th percentile

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DEC Forecast Station Highlights
15 stations above normal monthly snowfall
5 stations at least 200% of monthly normal

BGM
30" above normal
68% of its normal season-total snowfall

CON
53% of its normal season-total snowfall

ALB
47% of its normal season-total snowfall

Biggest Losers
RDU ... DCA ... ACY ... and ORF observed less than 10% of normal monthly snowfall

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Season-Total-to-Date

DEC P-O-R-N contributes 203.3" (22%) toward the season-total snowfall (D-J-F-M) of 929".
DEC-20 observed snowfall:  292" (44% above P-O-R-N; 31% of season-total snowfall)

Image courtesy NOHRSC @ http://www.nohrsc.noaa.gov/nsa/

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Teleconnections

AO / NAO / PNA data

Winter '20 / '21 - Coastal Teaser #1

UPDATE:  02-JAN-21 @ 9 AM EST
Not happenin' ...

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UPDATE:  01-JAN-21 @ 6:41 PM EST

Today/s 12z / 18z progs suggest too few stations in play for a contest-worthy snow storm.

Will evaluate 00z / 06z runs just in case ...

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Originally posted:  31-DEC-20 @ 6:41 PM EST

Cyclogenesis progged early this weekend in the Gulf of Mexico on the trailing end of a cold front attending FRI/s storm moving NE through the Mid-West ... Great Lakes ... and New England may turn into a long duration contest-worthy snow storm for the northern half of the forecast area come SUN.

Should the present trend in NWP output continue ...

Call for Forecasts:  FRI ... 01-JAN-21
Deadline for entries:  10 PM EST ... SAT ... 02-JAN-21
Verification period:  12:01 AM EST ... SUN ... 03-JAN-21 till flakes stop accumulating

Watch this space ...

Winter '20 / '21 - Snow Storm #1: FINAL Results

Forecaster verification table and the FINAL Results / Storm summary available at NEWxSFC/s home page.

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

Forecast by Observed Snowfall Scatterplots for Top Forecasts
Forecast/s dotted blue line below (above) the Observed snowfall/s solid red line ==> under (over) forecast bias.

Station by Station Comparison of Top Forecasters

Winter '20 / '21 - Snow Storm #1: Preliminary STP Verification

Accumulation-weighted SN:H2O

Preliminary verification of storm-total snowfalls for WED and THU from CDUS41 (CLI) ... CXUS51 (CF6) ... METARs ... and PNS bulletins.  Excellent coverage and reporting.

HYA STP estimated by applying inverse distance weighting interpolation of five timely reports within 3 SM of the station carried by the BOSPNS bulletin.

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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 >= 0.1"  20 (74%)

Given a station had measurable snowfall; stations observing at least ...
4" - 16 (76%)
8" - 11 (53%)
12" - 7 (33%)
18" - 3 (14%)
24" - 2 (10%)

MAX snow melt-water (minimum SLR 10:1)
BGM:  2.8"
ALB:  2.0"
BOS:  1.3"

MAX liquid precipitation (frozen + freezing + liquid):
BGM:  2.8"
ACY:  2.06"
ALB:  2.0"

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New daily record(s)
16-DEC-20
BDR - 6.5" (2"; 1970)
ISP - 5.7" (1.5"; 1995)
JFK - 3.8" (1.3"; 1981)

17-DEC-20
BGM - 26.4" (9.8"; 1973)
CON - 24.2" (8.6"; 1970)
ALB - 19.7" (11.1"; 1970)
BOS - 12.7" (6.4"; 2013)
ORH - 10.5" (9.9"; 1970)
BDL - 7.8" (6.5"; 2016)
PVD - 6.4" (4"; 1961)
EWR - 5.9" (3"; 2016)
JFK - 3.4" (3"; 2016)

Storm total snowfall
Image courtesy NOHRSC

SFC analysis:  09z ... 17-DEC-20
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 SAT evening.

Winter '20 / '21 - Snow Storm #1: The Forecasts!

MDT
07-FEB-67

Forecasters
Rookie     2
Intern       1
Journey    1
Senior      15
GOVT     1
PWSP      1
TOT        21

NEWxSFC welcomes Rookie Forecasters NJTom and Leigh Rosenthal along with our returning veterans.  Congratulations to Briannavaught for her promotion to Intern Forecaster and kc2dux to Journeyman Forecaster.

Don Sutherland retains his title as Chief Forecaster this winter b/c there was only one 'contest-worthy' snow storm last winter -- minimum three storms required -- to hold a valid contest and declare a winner.

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Forecasters ranked by ascending storm-total precipitation (STP)

BLUE ==> 25th percentile
RED ==> 75th percentile
WHITE STP cells range between the 25th and 75th percentile 

Read more »

Winter '20 / '21 - Snow Storm # 1: RAW Forecasts

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