Friday, February 05, 2021

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

Thursday, February 04, 2021

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.

Sunday, January 31, 2021

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

Saturday, January 30, 2021

Friday, January 29, 2021

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.

Thursday, January 28, 2021

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 ...

Sunday, January 10, 2021

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

Saturday, January 02, 2021

Winter '20 / '21 - Coastal Teaser #1

UPDATE02-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 ...