Winter '20 / '21 - Snow Storm #3: Preliminary STP Verification

Accumulation-weighted SN:H20 (SLR)

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

HYA STP estimated by applying inverse distance weighting interpolation of three timely reports within 3.5 SM of the station carried by the PNS bulletin from BOX.

SBY STP estimated based on one report from the forecast station/s county (Wicomico) carried by AKQ/s PNS 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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Winter '20 / '21 - Snow Storm #3: The Forecasts!

NYC
Summit Hotel on Lexington Ave
07-FEB-67

Forecasters
Rookie      2
Intern      -
Journey      -
Senior      18
GOVT      1
PWSP      1
TOT      22

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Forecasters rank-ordered by ascending storm-total precipitation (STP)

BLUE ==> 1st quartile
RED ==> 4th quartile
WHITE STP cells fall between the 1st and 4th quartiles

Heaviest snowfall (+5") consensus along and to the right of ISP - BDR - ORH - BOS - HYA - ISP
Lollypop expected at PVD (5.8")

Two out of three teleconnections on vacay.

Forecasters' station-by-station forecasts posted to the Contest/s web site here.
http://www.newx-forecasts.com/

Direct link to the table of forecasts here.
http://www.newx-forecasts.com/NEWxSFC_22/storms/storm3_forecasts_07FEB21.htm

Winter '20 / '21 - Snow Storm #1: NESIS

The Northeast Snowfall Impact Scale (NESIS)

 

Winter '20 / '21 - Snow Storm #3: RAW Forecasts

ACY
1928

HERE

Winter '20 / '21 - Snow Storm #3: Call for Forecasts!

BOS
04-FEB-40

Took a while for this winter to get a'goin' but we're underway with the second contest-worthy snow storm in a week/s time.

The fast-moving Miller 'A' nor'easter on the menu progged to race from the Gulf of Mexico toward the VA Capes then up the northeast coast ducking just under the 40/70 Benchmark on its way out to sea.

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'

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Forecast element: each station/s storm-total snowfall
Deadline for entries: 10:00 PM EST ... SAT ... 06-FEB-21
Verification begins: 12:01 AM EST ... SUN ... 07-FEB-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 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 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 - Snow Storm #2: FINAL Results

Complete 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 error.

Station by Station Comparison of Top Forecasters

Winter '20 / '21 - Coastal Teaser #3

UPDATE:  05-FEB-21 @ 9:45 AM EST 

No consensus among the overnight NWP model runs whether enough stations are in play to warrant a contest-worthy snow storm.

Will continue to evaluate through the 00z run this evening.

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Originally posted 04-FEB-21 @ 6:49 PM EST

Hot on the heels of this week's heavy snowfall event looms a full-latitude ... mid-level trof poised to excite a Miller 'A' nor'easter and the threat of a contest-worthy snow storm over the forecast area.

Latest NWP guidance points toward accumulating snow beginning over southern portions of the forecast area early SUN AM and continuing into MON as the storm scrapes along the coast. Without a closed LOW at 5H this go'round ... a long duration event is not expected.

Should events unfold as advertised currently ...
Call for Forecasts:  FRI ... 05-FEB-21
Deadline for entries:  10 PM EST ... SAT ... 06-FEB-21
Verification beginning:  12:01 AM EST ... SUN ... 07-FEB-21
Verification ending: 11:59 PM EST the day when flakes stop accumulating

Snow Storm #3 comes about seven days after Snow Storm #2.  In its wake ... the progs rocket the AO toward neutral and give the PNA a pump.  Should the cycle continue ... what's in store for Presidents Day 2021? 🤔

Winter '20 / '21 - Snow Storm #2: Preliminary STP Verification

Accumulation-weighted SN:H2O

 UPDATE:  FRI ... 05-FEB-21
Additional measurable snowfall associated with Snow Storm #2 was observed on the 4th at CAR (1.7") ... CON (0.1") ... BTV (0.1") ... BOS (0.1").

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Originally posted THU ... 04-FEb-21 @6:49 PM EST

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

HYA STP based on METAR's present weather and hourly P-group data.

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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 at least 0.1":  25 (93%)

Given a station had measurable snowfall; stations observing at least ...
4" - 18 (67%)
8" - 12 (44%)
12" - 7 (26%)
18" - 2 (7%)
24" - 1 (4%)

MAX snow melt-water (minimum SLR 8:1)
ABE:  2"
EWR:  1.66"
JFK:  1.41"

MAX liquid precipitation (frozen + freezing + liquid):
ABE:  2"
EWR:  1.66"
ACY:  1.59"

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New daily record(s)
31-JAN-21
BWI - 3.8" (3.7"; 1985)

01-FEB-21
ABE - 22.4" (7.2"; 1957)
BDR - 15.2" (4.4"; 1957)
EWR - 15.1" (7.5"; 1957)
JFK - 11.9" (1.7"; 2011)
BDL - 11.7" (5.9"; 2011)
ISP - 10.3" (0.6"; 2011)
BGM - 4.8" (4.3"; 2011)
IAD - 2.5" (1.5"; 1966)

Storm total snowfall
Image courtesy NOHRSC

SFC analysis:  03z ... 02-FEB-21
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 FRI evening.

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

Forecasters
Rookie      4
Intern      -
Journey      -
Senior      15
GOVT      1
PWSP      1
TOT      21

NEWxSFC welcomes Rookie Forecasters Auntie ... Kmc134 ... and snowtoriousBIG.

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Forecasters rank ordered by ascending storm-total precipitation (STP)

BLUE ==> 1st quartile
RED ==> 4th quartile
WHITE STP cells fall between the 1st and 4th quartiles

  

Heaviest snowfall (+12") consensus along and to the right of MDT - ABE - ORH - BDR - JFK - EWR - PHL - MDT.
Lollypop expected at MDT (14.6")

Teleconnections more-or-less playing their 'expected' roles (CORR:  01-FEB-20 PNA)

Forecasters' station-by-station forecasts posted to the Contest/s web site here.
http://www.newx-forecasts.com/

Direct link to the table of forecasts here.
http://www.newx-forecasts.com/NEWxSFC_22/storms/storm2_forecasts_31JAN21.htm

Winter '20 / '21 - RAW Forecasts

 here

28-JAN-1922