CONTEST STATUS - Updated: THU ... 31-OCT-19 @ 12:16 PM EDT

Winter '19 / '20 - Snowfall Forecast Contests
21st Annual 'Regular Season' Snowfall Forecast Contest
Contest starts once the flakes start a'flyin'

---
19th Annual 'Season-total' Snowfall Forecast Contest
Deadline for entries: 11:59 PM EST ... SAT ... 30-NOV-19
Verification period: 01-DEC-19 through 31-MAR-20
Details here

---
Winter '18 / '19 - Snowfall Forecast Contests
20th Annual 'Regular Season' Snowfall Forecast Contest
FINAL Results here

---
18th Annual 'Season-total' Snowfall Forecast Contest
FINAL Results HERE
Forecaster verification table HERE

Thursday, November 14, 2019

Winter '19 / '20 - 19th Annual 'Season-total' Snowfall Forecast Contest: Call for Forecasts!

NEWxSFC/s Resident 'Season-total' Snowfall Forecaster

Here comes winter with its oscillating Arctic and North Atlantic indexes ... suddenly warming stratosphere ... so-so ENSO ... and if we/re lucky .... an endless parade of 'Miller A' LOWs raking the eastern seaboard.

NE.Wx/s 19th annual ‘Season-total' Snowfall Forecast Contest is the absolute best ... biggest ... and probably ONLY chance to be honored for your long-range forecasting acumen ;/

And it's s-o-o easy.
Cool prizes ... too!

All you have to do is issue the best forecast for the 'season-total' snowfall at 25 east coast stations between RDU and CAR!

---
Forecast element: season-total snowfall @ each station
Forecast period: 01-DEC-19 through 31-MAR-20

Error statistic: total absolute error [Σ abs(forecast - observed)]
Verification: NWS preliminary climate reports (CLM or CF6)

Low score wins.

Deadline: SAT ... 30-NOV-19 @ 11:59 PM EST (01-DEC-19 @ 4:59 UTC)

Visit the Contest's website to enter your forecast.
Follow the link at the top of the page to 'Enter Season-total Forecast.'

Update your forecast as often as you want prior to the deadline.
Only your last entry gets verified.

---
1st place prize (delivered post-paid right to your front door):
"Snow in America" by Bernard Mergan (hardcover) and
"The Snow Booklet" by Nolan J. Doesken and Arthur Judson (paperback) and
... the august title 'Chief Season-total Snowfall Forecaster' for Winter '20 / '21 and
... a well-deserved place of honor with past winners.

2nd place prize (delivered post-paid right to your front door):
"New England Weather, New England Climate" by Greg Zielinski and Barry Keim (paperback)

3rd place prize (delivered post-paid right to your front door):
"The Snow Booklet" by Nolan J. Doesken and Arthur Judson (paperback)

Tuesday, November 12, 2019

Winter '19 / '20 - Quasi-Biennial Oscillation (QBO): Leading Analogs' 500 mb Anomaly Height Composite ... as of OCT-19

Quasi-Biennial Oscillation (QBO) composites of 500 mb (5H) geopotential height anomalies (GPHa) and 2-meter air temperature (2m T) for analog winters '78/'79 ... '85/'86 ... '95/'96 ... '99/'00 ... '02/'03.

5H GPHa composite

- Ridge-W / Trof E

- Hi-latitude blocking over Greenland ==> NAO < 0

5H GPHa weighted-composite

2m T weighted-composite

---


KEY
ENSO:  nada- (-0.5 < Region 3.4 SSTa <  0); C- (weak La Nina); C+ (strong La Nina); W+ (strong El Niño)
NAO:  sign of D-J-F average
AO:  sign of D-J-F average
PDO:  sign of O-N-D-J-F-M average
QBO:  + ==> west; - ==> east

Sunday, November 10, 2019

Winter '19 / '20 - Arctic Oscillation: Leading Analogs' 500 mb Anomaly Height Composite ... as of OCT-19

Arctic Oscillation (AO) composites of 500 mb (5H) geopotential height anomalies (GPHa) and 2-meter air temperature (2m T) for analog winters '53/'54 ... '54/'55 ... '59/'60 ... '97/'98 ... '14/'15.

5H GPHa composite

- Overall North American pattern mimics Tropic/Northern Hemisphere's (TNH) negative phase often associated with +ENSO.

- Negative TNH ==> 1)  stronger than normal Pacific jet farther south of its normal axis and 2) well above normal temperatures in eastern North America.

- Active sub-tropical jet

- Positive GPHa over eastern Canada would 1) advect cP flow from hi-latitude snow fields into the eastern U.S. and 2) effectively displace the Hudson LOW from its climatologically favored location.

5H GPHa weighted-composite

2m T weighted-composite

---



KEY
ENSO:  nada- (-0.5 < Region 3.4 SSTa <  0); C- (weak La Nina); W- (weak El Niño); W (moderate El Niño); W+ (strong El Niño)
NAO:  sign of D-J-F average
AO:  sign of D-J-F average
PDO:  sign of O-N-D-J-F-M average
QBO:  + ==> west; - ==> east

CORRECTION:   Analog table - PDO:  should be '-'

Saturday, November 9, 2019

Winter '19 / '20 - 500 mb Geopotential Heights and 2m T Anomaly Composites: La Nada Years


La Nada or neutral ENSO comes in two flavors -
Cool (-0.5 < Region 3.4 SSTa < 0)
Warm (0 < Region 3.4 SSTa < 0.5)

Current consensus expects 'warm' La Nada for Winter '19 / '20.

Recent La Nada years by decade:
1967
1979
1981 ... 1982 ... 1986 ... 1990
1991 ... 1993 ... 1994 ... 1997
2002 ...2004
2013 ... 2014 ... 2017

5H GPHa composite - all La Nada years (n = 15)

Prevailing feature common to cool and warm La Nadas ...
- Positive 5H GPHa INVOF Aleutian Is. & negative 5H GPHa INVOF Hawaii = EPO < 0 ==> Arctic outbreaks into central CONUS

---
5H GPHa composite - cool La Nada years (n = 10)

Cool La Nada/s uniquely feature ...
- Ridge-W / Trof-E planetary flow regime over CONUS
- Positive 5H GPHa over Greenland ==> NAO < 0
- Negative 5H GPHa over North Pole & positive 5H GPHa INVOF Aleutian Is. ==> AO > 0
- Positive 5H GPHa over SE CONUS ==> primary storm track west of Appalachian mountains
- Negative 5H GPHa over south-central Canada & north-central CONUS ==> storm track above 40°N.
- Near normal 2m T across most of CONUS

2m T anomaly composite - cool La Nada years (n = 10)

---
5H GPHa composite - warm La Nada years (n = 5)

Warm La Nada/s uniquely feature ...
- Trof-W / Ridge-E planetary flow regime over CONUS
- Negative 5H GPHa over Greenland ==> NAO > 0
- Positive 5H GPHa over eastern CONUS ==> primary storm track across Central and Upper Plains
- Below normal 2m T across western ... north-central CONUS ... and New England
- Above normal 2m T over south and SE CONUS.

2m T anomaly composite - warm La Nada years (n = 5)

---
5H ≡ 500 mb
GPHa ≡ geopotential height anomaly
2m ≡ 2 meters above ground level
T ≡ dry-bulb air temperature
INVOF ≡ in the vicinity of
CONUS ≡ continental United States

Thursday, November 7, 2019

Winter '19 / '20 - Eurasia Snow Cover: OCT

Eurasia/s areal snow cover for OCT-19: ~ 12,800,000 SQ-KM
24% above 52-year P-O-R-N (~10,300,000 SQ-KM)
27% above 52-year median (~10,100,000 SQ-KM)

Rank: 7th
3rd highest past 10 years
4 of past 20 years below median ('05 ... '07 ... '08 ... '11)
OCT-18:  ~10,400,000 SQ-KM
OCT-19: 23% greater than OCT-18


Ranked analog years 500 mb anomaly height composite for Winter '19 / '20
('15 / '16 ... '16 / '17 ... '09 / '10 ... '01 / '02 ... '14 / '15)

- High 500 mb geopotential heights at hi-latitude ==> NAO & AO < 0
- EPO > 0 ==> fast zonal flow over CONUS & mild PAC air masses
-weak evidence of trof over coastal M-A & NE CONUS


ENSO:  nada- (-0.5 < Region 3.4 SSTa <  0); C- (weak La Nina); W- (weak El Niño)
NAO:  sign of D-J-F average
AO:  sign of D-J-F average
PDO:  sign of O-N-D-J-F-M average
QBO:  + ==> west; - ==> east

---
Weighted 5H anomaly composite

Weighted 2mT anomaly composite

---
Snow cover data courtesy Rutgers University Global Snow Lab
Mean composites courtesy Earth System Research Lab / Physical Sciences Division 

Tuesday, November 5, 2019

Winter '19 / '20 - North Atlantic Oscillation: Leading Analogs' 500 mb Anomaly Height Composite ... as of OCT-19

Analog 5H composite ('80/'81 ... '08/'09 ... '12/'13 ... '14/15 ... '16/'17) ... as of OCT-19


- EPO-like ridge offset slightly to the west of preferred position for a 'Trof-East' regime
- Azores HIGH ==> NAO > 0
- Low geopotential heights over pole ==> AO > 0
- Negative height anomaly over southeast Canada favors primary storm track through the Upper Plains and across the Great Lakes in line with current soil moisture axis

Weighted analog 5H composite

Weighted analog 2m T composite

---



KEY
ENSO:  nada- (-0.5 < Region 3.4 SSTa <  0); C- (weak La Nina); W- (weak El Niño)
AO:  sign of D-J-F average
AO:  sign of D-J-F average
PDO:  sign of O-N-D-J-F-M average
QBO:  + ==> west; - ==> east

Friday, November 1, 2019

Winter '19 / '20 - Eurasia/s OCT Snow Advancement

 UPDATE (31-OCT-19)
Dr. Cohen via Tweeter ..."... the snow cover advance index came in at +0.6.

 "This does suggest a negative winter Arctic Oscillation and upcoming #PolarVortex disruption."


---
UPDATE (29-OCT-19)
Dr. Cohen via Tweeter ... "October SCE will likely be more than one standard deviation above normal.

"My research shows this favors colder winter temperatures across the N Hemisphere mid-latitudes including East US (sic)"