Winter '17 / '18 - Snow Storm #5: RAW FORECASTS

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Winter '17 / '18 - Snow Storm #5: Call for Forecasts

Apologies for the truncated notice.

Sad looking area of LOW pressure progged to ride the STJ into the forecast area on SAT and lay down a stripe of frozen precipitation along the NW edge of the precipitation shield as it deepens off the SNE coast near the 40/70 benchmark.

Synoptics seem all wrong for a contest-worthy snow storm but hate to be left at the alter this late in the season after seeing the broad brush of plowable snow forecast currently by ER WFOs.

Whatever happened to those blockbuster nor'easters around Presidents Day?

The forecast contest for Snow Storm #5 may be cancelled prior to the deadline if fewer than six stations are likely to observe at least a 4" snowfall.

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Forecast element:  each station's verification period snowfall
Deadline for entries:  10:30 PM EST ... FRI ... 16-FEB-18
Verification period begins:  12:01 AM EST ... SAT ... 17-FEB-18
Verification period ends:  11:59 PM EST ... SUN ... 18-FEB-18

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

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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.  See how well your forecast stacks up against NWS Eastern Region Weather Forecast Offices.

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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).

Winter '17 / '18 - Regular Season Interim Standings: 2

Under the ‘two-thirds’ rule … forecasters who have entered at least THREE forecasts are included in the interim standings.

Complete interim statistics table and charts at the Contest/s web site here (direct link)
Forecaster statistics for Winter '17 / '18 contest snow storms here (direct link)

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SUMSQ errors for each contest snow storm are normalized (standardized) with a 'Z-score' ... then averaged 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.

Same idea as dropping the lowest quiz score before computing the final grade.

Winter '17 / '18 - Snow Storm #4: FINAL Results

Forecasters' station verifications and the storm summary at NEWxSFC/s home page.
http://www.newx-forecasts.com/

	1st - Herb @MAWS
	SUMSQ:	26
	SUMSQ Z:	-0.729
	STP:	16.8	(4)
	TAE:	17.3	(1)
	AAE:	0.82	(1)
	2nd - donsutherland1
	SUMSQ:	29
	SUMSQ Z:	-0.682
	STP:	18.7	(5)
	TAE:	19.0	(2)
	AAE:	1.00	(3)
	3rd - iralibov
	SUMSQ:	38
	SUMSQ Z:	-0.527
	STP:	22.3	(8)
	TAE:	22.3	(5)
	AAE:	1.01	(4)
	HM - Mitchel Volk
	SUMSQ:	39
	SUMSQ Z:	-0.515
	STP:	16.4	(3)
	TAE:	20.2	(3)
	AAE:	0.96	(2)

SUMSQ:  sum of square errors (")
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
Dotted blue line below (above) solid red line ==> under (over) forecast

Snowfall analysis courtesy National Operational Hydrologic Remote Sensing Center
http://www.nohrsc.noaa.gov/interactive/html/map.html

Winter '17 / '18 - Snow Storm #4: Preliminary STP Verifications

Table of preliminary storm-total snowfall by station for WED and THU from CDUS41 (CLI) ... CXUS51 (CF6) and ... SAUS41 (METAR) bulletins.

Exceptions:
None

HYA - Trace
METAR KHYA 080656Z AUTO 33012G19KT 10SM BKN021 OVC085 02/M01 A2996 RMK AO2 RAE03UPB16E19SNB03E16

SLR not available for many stations with measureable snowfall b/c liquid and / or freezing precipitation also occurred during the verification period.

9 minutes heavy sleet event @ ALB
METAR KALB 072109Z 35009KT 1SM R01/6000VP6000FT +PL BR BKN007 OVC010 M06/M08 A2993

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Stations observing at least:
Trace - 19 (70%)
4" - 7 (37%)
6" - 5 (27%)
8" - 0

Melt-water
BGR - 0.53"
BGM - 0.52"
CAR - 0.52"

New daily records:
None

Surface analysis:  18z ... 07-FEB-18
  
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Please report errors in Comments along with a link to the correct data.
FINAL Results post expected ~11 PM EST ... SAT ... 10-FEB-18

Winter '17 / '18 - Sudden Stratospheric Warming: Watch #1 - Update 1

Full reversal at D+5 (12-FEB) comports very well with the earlier D+10 forecast.

 

Full reversal continues at least through D+10.

Huge implications for the weather associated typically with a negative Arctic Oscillation toward month's end and into MAR.

 

 

Where the AO/s full impact is wrt arctic/s cold air drainage appears to be on the other side of the globe under the 'W' ; however ... note the NW flow regime and +PNA is progged over CONUS.

Winter '17 / '18 - Season-total Snowfall Forecast Contest: JAN totals

Station snowfall summary for JAN-18.
Rank ordered by percent of monthly normal.

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Green ==> 75th - 100th percentile
White ==> Less than 75th and greater than 25th percentile
Red ==> 0 - 25th percentile

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Teleconnection indexes and month-over trend (updated as they become available)
AO:  -0.281⇩
NAO:  1.44⇧
PDO:  0.70⇧
QBO:  -19.02⇩
SOI:  8.9⇧

Winter '17 / '18 - Temperature Departure From Normal: Progress Report - January

Winter '17 / '18 - Snow Storm #4: The Forecasts!

Rookie   -
Intern   1
Journey  -
Senior   10
GOVT    1
PWSP    1
TOT  13

All forecasts posted to the Contest/s web site.
Direct link:  http://www.newx-forecasts.com/NEWxSFC_19/storms/storm4_forecasts_07Feb18.htm
Forecasts ranked by their verification period storm-total precipitation (STP).

BLUE ==> 25th percentile
RED ==> 75th percentile
White STP and 4cast cells range between the 25th and 75th percentile

NWS ER WFOs (GOVT) and PWSP (Private Weather Service Provider) forecasts derived from public issuances current at the deadline.

Heaviest snowfall (>= 7") consensus along and to the right of CAR - BGR - PWM - CON - BTV - CAR with an isolated action center INVOF BGM.   Snow cone expected at BGR.  Mainly a SNE event with nuisance amounts near much of its coast.

Tele-connection indexes floating high above the fray.  NAO still wandering alone in the wilderness.

 
Median station forecasts (Excel 2013 - Power Map)

Winter '17 / '18 - Snow Storm #4: RAW FORECASTS

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Apologies to those who did not receive a copy of their forecast.

Forecast confirmation emails sent from the Contest/s web site are being blocked by more ISPs such as Hotmail ... Yahoo ... Comcast ... and Mindspring.