Winter '14 / '15 - Global Forecast System Wishing You a Very Merry Christmas

Winter '14 / '15 - November/s AO Predicts The State Of Winter/s AO

Does the sign of NOV/s Arctic Oscillation index (AO) of -0.530 have any predictive power for the sign of this winter/s AO?

The 2x2 contingency table below suggests it does.

At the 95% confidence level ... the Chi-square 'Test of Independence shows the negative sign of NOV/s AO and the AO sign for D-J-F are not independent but are related.  There/s a 2.8% probability the test indicates falsely they are not related.

Over the AO/s 64 year period-of-record ... the data shows when NOV is negative ... the winter/s AO will be also negative.

There/s also a statistically significant relationship between the negative sign of NOV/s AO and the sign of DEC/s AO.

False + ==> prediction is False
True + ==> prediction is True

AO Contingency
p = 0.028	Nov +	Nov -	Total
D-J-F +	15	8	23
D-J-F -	15	26	41
Total	30	34	64
True +	50%	24%	False +
False +	50%	76%	True +

Winter '14 / '15 - 14th Annual 'Season-total' Snowfall Forecast Contest: Forecast Summary

Good to see everyone for the 14th Annual NE.Wx 'Season-total' snowfall forecast contest.
Sixteen forecasters this year.
All veterans.

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As always, a wide range of forecasts with one lone forecaster/s season-total precipitation (STP) going under the NCDC period-of-record normal (P-O-R-N) season-total snowfall (934").

MIN STP:  866"
P-O-R-N:  934"
MAX STP:  1,546"
AVG STP:  1,175"
Median STP:  1,162"

Total number of station forecasts:  375
OVER:  307
UNDER:  67
P-O-R-N:  1

Forecasts in the table below are ranked in ascending order by sum-total snowfall for all stations.

Blue cells:  <= 25th percentile
Red cells:  >= 75th percentile
P-O-R-N is the Period of Record Normal.
CONSENSUS is the average of all forecasts.

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No majority opinion for UNDER snows anywhere.
Unanimous opinion for OVER @ BGR .... CON ... and BOS.

Largest AVG OVER
PHL (168%)
BDR (146%)
BGR ... SBY (142%)

OVER / UNDER forecasts
RDU (9 / 7)
BDL ... BGM ... EWR (11 / 5)
ORH ... MDT ... SBY ... ORF (12 / 4)

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These prizes for 1st place will be delivered post-paid right to the forecaster/s front door.

"The Snow Booklet" by Nolan J. Doesken and Arthur Judson
http://ccc.atmos.colostate.edu/snowbooklet.php

"Snow in America" by Bernard Mergan (hardcover)
http://artsbeat.blogs.nytimes.com/2009/03/02/snows-of-yesteryear/?_r=0

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Everyone's forecast is available on the Contest/s web site.

Winter '14 / '15 - ENSO Takes A Second Step Toward el Niño Event

Is it el Niño or is it el Noño?

DEFINE the BEGUINE
One definition holds the Oceanic Niño Index (ONI) has to:

... met +0.5°C threshold for five straight months of a 3-month running mean.  For historical purposes warm 'episodes' are defined when the threshold is met for a minimum of 5 consecutive over-lapping seasons.

Another holds North America's operational definitions for El Niño, based on the ONI index is:        

El Niño: A phenomenon in the equatorial Pacific Ocean characterized by a positive sea surface temperature departure from normal (for the 1971-2000 base period) in the Niño 3.4 region greater than or equal in magnitude to 0.5 degrees C (0.9 degrees Fahrenheit), averaged over three consecutive months.

WHAT'S THE EVIDENCE?
The latest SST anomaly (SSTa) for ENSO Region 3.4 from NOAA's Climate Prediction Center (CPC) is +1.0°C (26-NOV-14).  This brings the 13-week (i.e., three months) moving SSTa average in ENSO Region 3.4 to 0.58°C.

Last week/s 13-week ENSO Region 3.4 moving SSTa average of 0.54°C breached the 0.5°C threshold for North America's operational definition for El Niño.  The week previous:  +0.492°C.


ENSO Region 3.4 SSTa (BLUE) and 13-week SSTa Moving AVG (ORANGE)
JAN-10 to Present

WTF?

In spite of these developments ... what's the hold-up in recognizing the beginning of el Niño 2014?  It is b/c of how a 'month' is defined?

A month starts on the 1st and ends on the 30th or 31st (piss off FEB). 
Anyone think there's a Gregorian calendar hanging over ENSO Region 3.4?

 Just b/c the ENSO Region 3.4 SSTa havn't been above the +0.5°C threshold for three consecutive calendar months doesn't mean +ENSO hasn't started.  The 13-week moving average (i.e., 3-month) ENSO Region 3.4 average SSTa exceeded the el Nino threshold during the week of 19-NOV-14.


CPC/s foot-dragger report
ENSO: Recent Evolution, Current Status and Predictions (01-DEC-14)

Winter '14 / 15 - Arctic Oscillation Analysis and Forecasts

New blog devoted to the Arctic Oscillation (AO) ... Siberian snow cover ... and more authored by Atmospheric and Environmental Research's (AER) Judah Cohen and Jason Furtado.

Cohen ... et al ... discovered the strong correlation between the areal coverage ... advancement rate of Eurasia/s OCT snow cover and the character of northern hemisphere's winter as modulated by the AO.

Snow Advancement Index (SAI)

The chart reports a correlation index (r) of 0.810 indicating the AO and SAI often move in tandem. 

Squaring the correlation index gives the 'coefficient of determination'; a measure of how much of the variability of one (DJFM AO) is explained by the other (SAI). The SAI 'explains' 66% of DJFM/s AO variability.

 

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Cohen/s 2013 interview with the WAPO

Cohen/s 2014 interview with the WAPO

Snow cover data from Rutgers Global Snow Lab

 

 

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AER offers a 'notify new post' form requiring personal contact information.

Or use the free Change Detection web page monitoring service.

Winter '14 / '15 - Storm #1: FINAL Results

Full forecast verifications and summary for Storm #1 at the Contest/s web site.

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	1st - Mitchel Volk
	SUMSQ:	71.56
	SUMSQ Z:	-1.234
	STP:	11.4	(5)
	TAE:	28.9	(1)
	AAE:	1.20	(1)
	2nd - donsutherland1
	SUMSQ:	119.32
	SUMSQ Z:	-0.817
	STP:	5.0	(3)
	TAE:	43.5	(3)
	AAE:	1.81	(3)
	3rd - snocat918
	SUMSQ:	128.1
	SUMSQ Z:	-0.740
	STP:	9.8	(4)
	TAE:	41.9	(2)
	AAE:	1.68	(2)
	HM - Herb@MAWS
	SUMSQ:	187.5
	SUMSQ Z:	-0.221
	STP:	1.1	(1)
	TAE:	49.5	(6)
	AAE:	2.06	(6)

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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
Click on images for higher resolution.

Winter '14 / '15 - Storm #1: Preliminary Verification

Preliminary storm-total snowfalls for Wednesay and Thursday from CDUS41 and CXUS51 bulletins.
Good coverage and reporting.

PWM/s 6.3 SN:H20 appears to be close since there was a brief period of mixed precipitation before turning to all snow.

Nine new daily snowfall records:
WED ... 26-NOV-14
CON - 10.3" (4.5"; 1956)
ALB - 9.6" (4.9"; 1888)
BGM - 9" (8.7"; 1977)
PWM - 7.4" (7"; 1885)
ORH - 5.3" (2.9"; 1921)
ABE - 4.9" (1.7"; 1925)
BDL - 4.6" (0.4"; 1985)
IAD - 1.6" (1.1"; 1978)
ACY - 0.05" (0.05"; 1977)

Two new daily rainfall records:
WED ... 26-NOV-14
ORH - 1.79" (1.78"; 1958)
RDU - 1.69" (0.98"; 1979)






Please report any errors in Comments along with a link to the correct data.
Final results Saturday evening.

Winter '14 / '15 - Snowiest NOV on Record in BGR

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE CARIBOU ME
831 AM EST THU NOV 27 2014
...SNOWIEST NOVEMBER ON RECORD IN BANGOR...

A MONTHLY TOTAL OF 25.9 INCHES OF SNOW HAS BEEN OBSERVED AS OF 7 AM THIS
MORNING AT BANGOR. THIS RANKS AS THE SNOWIEST NOVEMBER ON RECORD
SURPASSING THE PREVIOUS RECORD OF 24.6 INCHES SET IN 1962.

AT CARIBOU...A TOTAL OF 26.7 INCHES OF SNOW HAS BEEN OBSERVED THIS
NOVEMBER AS OF 7 AM THIS MORNING. THIS NOW RANKS AS THE 6TH
SNOWIEST NOVEMBER ON RECORD. THE ALL-TIME SNOWIEST NOVEMBER WAS
IN 1974 WHEN A TOTAL OF 34.9 INCHES OF SNOW WAS OBSERVED.
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Yesterday's 9.6" pushed BGR over the top.

Winter '14 / '15 - Storm #1: The Forecasts!

Rookies 0
Interns 0
Journeymen 1
Seniors 10
TOT 11

Total station forecasts: 245



Forecasts are ranked by their storm-total precipitation (STP).
BLUE ==> 25th percentile.
RED ==> 75th percentile.
STP cells without color are between the 25th and 75th percentile.

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Heaviest snowfall (+6") consensus across northern New England and inland portions of the M-A.

Again ... the primary teleconnections indices associated with heavy snow in the NE US are MIA.

Everyone/s station-by-station forecast at the Contest/s web site.

Winter '14 / '15 - Storm #1: RAW Forecasts

RAW forecasts here