Winter '16 / '17 - Caressing Snow by Adolf Fassbender (NYC 1947)

Winter '16 / '17 - Sudden Stratospheric Warming: Watch #2 - UPDATE 1

Displacement event/s peak progged for early next week.

 

PV displaced SW by warm pulse.

Center of anticyclone does not advance as far south as 31-JAN/s event.

 

 

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Strong anticyclonic couplet above 10 mb

Winter '16 / '17 - Interim Standings: 1

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

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Complete interim statistics table and charts at the Contest/s web site here.
Forecaster verification statistics for Winter '16 / '17 contest storms here.

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SUMSQ errors for each contest snow storm are normalized 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 '16 / '17 - VCP32: Criticizing the Lowbrows

Winter '16 / '17 - Season-total Snowfall Forecast Contest: JAN totals

Station snowfall summary for JAN-17.
Rank ordered by percent of monthly normal.

 

Station snowfall summary for Winter '16 / '17 - YTD JAN

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

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Teleconnection indexes and month-over trend (updated as they become available)
AO:  0.942 ⇩
NAO:  0.48 ⇔
PDO:  0.77 ⇩
QBO:  14.92 ⇩
SOI:  1.3 ⇩

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Winter '16 / '17 - Forecaster Storm Data

Here

Winter '16 / '17 - Sudden Stratospheric Warming: Watch #2

Could be the season/s final stratospheric warming event.
Images from 15-FEB-17 ECMWF run.


Weak high-altitude zonal flow returns after the recent SSW event.

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Flow above 30 mb reverses and strengthens as the PV is once again displaced.
Flow throughout the depth of the troposphere (evidence of the downward propagation from the previous SSW?) also reverses.

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Cold pool from previous SSW event progged to settle above the NOAM/s Arctic Circle near month/s end.

Stratosphere Diagnostics courtesy Freie Universität Berlin

Winter '16 / '17 - Snow Storm #3: FINAL Results

Forecaster verifications and storm summary at NEWxSFC/s home page.
http://www.newx-forecasts.com/

	1st - donsutherland1
	SUMSQ:	172
	SUMSQ Z:	-0.885
	STP:	6.2	(2)
	TAE:	40.4	(2)
	AAE:	2.25	(3)
	2nd - WeatherT
	SUMSQ:	184
	SUMSQ Z:	-0.814
	STP:	24.3	(6)
	TAE:	43.1	(4)
	AAE:	2.27	(4)
	3rd - Brad Yehl
	SUMSQ:	186
	SUMSQ Z:	-0.805
	STP:	17.3	(5)
	TAE:	42.0	(3)
	AAE:	2.21	(2)
	HM - TQ
	SUMSQ:	224
	SUMSQ Z:	-0.591
	STP:	3.3	(1)
	TAE:	38.9	(1)
	AAE:	2.16	(1)

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

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Winter '16 / '17 - Snow Storm #3: Preliminary Verification

Table of preliminary storm-total snowfalls for SUN and MON from CDUS41 and CXUS51 bulletins.

Exceptions:
HYA
Storm-total snowfall estimated by interpolation of vicinity PNSBOX reports and evaluation of METARs.

ORH
13-FEB/s daily CLI and CF6 bulletins carry 'MM' as daily snowfall at post-time.  Storm-total snowfall entered as reported by PNSGYX and evaluation of METARs.  Value subject to change pending CDUS41 and CXUS51 bulletin updates.

IAD
Daily climate bulletin carries 'T'; however ... no evidence of frozen precipitation in METARs.

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Stations observed at least:
Trace - 16
4" - 9
6" - 7
8" - 5
10" - 4
12" - 2
18" - 1

Max melt-water at PWM (1.57")
Other stations with > 1" melt-water:  BGR (1.04")

Snow-Liquid Ratios (SLR) for areas with mixed precipitation ... such as BDL and BOS ... are not reported.

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Two new daily records.
12-FEB-17
BTV - 7.6" (6.8"; 1988)

13-FEB-17
BGR - 21.5" (6.3"; 1977)

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Please report any errors in Comments along with a link to the correct data.

Final results NLT WED evening.

Winter '16 / '17 - Snow Storm #3: The Forecasts

Rookie 1
Intern 0
Journey 1
Senior 11
TOT 13

Includes NWS 'official' forecasts ... as of the deadline.

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Forecasts are ranked by their storm-total precipitation (STP).

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

Heaviest snowfall (>= 10") consensus along and the right of ALB - ORH - BGR - PWN - CON  - ALB.
Lollypop expected at BGR.

What's that conventional wisdom about the NAO and NE snowstorms again?

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Everyone/s station-by-station forecast posted to NEWxSFC/s web site @ http://www.newx-forecasts.com/

 

Preliminary snowfall verifications posted TUE evening.

FINAL results WED evening.

Winter '16 / '17 - Snow Storm #2: FINAL Results

Forecaster verifications and storm summary at NEWxSFC/s home page.
http://www.newx-forecasts.com/

	1st - emoran
	SUMSQ:	130
	SUMSQ Z:	-0.850
	STP:	7.6	(4)
	TAE:	40.1	(1)
	AAE:	1.74	(1)
	2nd - donsutherland1
	SUMSQ:	131
	SUMSQ Z:	-0.848
	STP:	20.6	(9)
	TAE:	45.2	(4)
	AAE:	1.81	(3)
	3rd - TQ
	SUMSQ:	133
	SUMSQ Z:	-0.842
	STP:	28.1	(12)
	TAE:	49.3	(6)
	AAE:	1.89	(4)
	HM - Brad Yehl
	SUMSQ:	161
	SUMSQ Z:	-0.728
	STP:	8.0	(5)
	TAE:	43.1	(2)
	AAE:	1.80	(2)

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

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Winter '16 / '17 - Snow Storm #3: RAW FORECASTS

Here

- courtesy Google Groups

Winter '16 / '17 - Snow Storm #2: Preliminary Verification

Table of preliminary storm-total snowfalls for THU and FRI from CDUS41 and CXUS51 bulletins.

Exceptions:
HYA
Storm-total snowfall estimated by interpolation of vicinity PNSBOX reports.

PWM
09-FEB/s daily CLI and CF6 bulletins carry 'MM' as daily snowfall at post-time.  Storm-total snowfall as reported by PNSGYX.  Value subject to change pending CDUS41 and CXUS51 bulletin updates.

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Stations observed at least:
Trace - 21
4" - 14
6" - 14
8" - 9
10" - 7
12" - 5
14" - 2

Max melt-water at ISP (1.3")
Other stations with > 1" melt-water:  BDL (1.19"); PVD (1.01")

Snow-Liquid Ratios (SLR) for areas with mixed precipitation ... such as PHL and MDT ... are not reported.

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Four new daily records.
09-FEB-17
ISP - 14.3" (11.1"; 2013)
PVD - 11.9" (9.9"; 1969)
ABE - 7.1" (5"; 1936)
BGM - 5.2" (4.6"; 1969)

Synoptic charts from the 1969 storm below.
New England stations reported up to 25".

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SFC:  09-FEB-69

SFC:  10-FEB-69

5H:  09-FEB-69

5H:  10-FEB-69

Synoptic charts courtesy U.S. Daily Weather Maps.

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Please report any errors in Comments along with a link to the correct data.

Final results NLT SUN evening.