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'

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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

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

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

Sunday, October 20, 2019

Winter '19 / '20 - What Is the Polar Vortex and How Does It Influence Weather?

"The term polar vortex has become part of the everyday vocabulary after the widespread media coverage of the extreme cold events over the United States during the early winter of 2014.

"However, there is some confusion in the media, general public, and even within the science community regarding what polar vortices are and how they are related to various weather events."
[...]
"... since surface weather disturbances are associated only with displacements of the vortex edge in limited areas rather than hemispheric-scale changes to the vortex, it is not clear ... invoking the term vortex clarifies anything, given ... the vortex is a hemispheric-scale structure.

"Use of the term without adequate explanation can suggest a more dramatic change to the global tropospheric circulation than has actually occurred (e.g., “The polar vortex is back!”)."

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Learn more about the PV from the full article courtesy the Bulletin of the American Meteorological Society (BAMS) here.

Friday, October 18, 2019

Winter '19 / '20 - Statistical Winter Outlook: Solar cycle and ENSO

Severe Weather Europe's (SWE) analysis of the solar cycle and ENSO analogs ...


"After removing all the cold phases and strong warm phases of ENSO, we get a very interesting and more defined picture. We see a high pressure area focused over Greenland and the Arctic, typical for negative NAO & AO.

"Lower pressure is displaced a bit further south, along with polar fronts and colder air. This type of pattern usually brings colder and snowy weather to Europe and USA."

SWE/s solar cycle / ENSO analysis in general agreement with our current QBO ... AO ... and Eurasia snow cover analogs.

Winter '19 / '20 - Outlooks

Thread updated periodically as new outlooks and forecasts become available from a variety of credible sources.

CPC ...



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Accuwx ...
“Whether or not it’s snowstorms, ice storms or mixed events, I do feel this is going to be an active year for the Northeast,” AccuWeather Expert Long-Range Forecaster Paul Pastelok) said.

"Above-normal snowfall could be in store for areas from New York City to Boston.

"Meanwhile, cities farther south, including Washington, D.C., and Baltimore, will be more likely to get a mix of rain and snow."

Tuesday, October 15, 2019

Winter '18 / '19 - The Woolly Bear Caterpillar Guide to Winter Weather Forecasting

It/s that time of year again when long-range wx forecasters scour the bowels looking for ... well ... wadda you say we don/t go there.

More better ... consult the Woolly Bear Caterpillar Guide to Winter Weather Forecasting.

(Lightly edited re-post from USENET news group ne.weather 11-OCT-03)

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In recent weeks ... a spate of news articles have appeared about the woolly bear caterpillar and its legendary ability to foretell the upcoming winter based on the color and width of its black and orange stripes.

With so much good information scattered across so many sources ... there appeared to be a need to compile the forecasting rules.

This handy forecasting guide can be printed and kept inside your coat pocket for easy reference.

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The Woolly Bear Caterpillars Among Us
There is more than one kind of woolly bear caterpillar.  The one you use when forecasting is the banded woolly caterpillar ... which becomes the Isabella moth (Pyrrharctia Isabella) in the spring.  Pictures of the caterpillar and moth can be seen here: Caterpillar Moth

Science is Skeptical
It should come as no surprise ... entomologists pooh-pooh the very idea banded woolly bear caterpillars can predict future events.  These naysayers claim variations in band color and width are evidence of a worm/s age and the fall weather conditions when the worm reached maturity.

Worms exhibiting more black than orange are older and grew in wet conditions.  Worms exhibiting less black than orange are younger and grew in dry conditions.  And therein we find the caterpillar's predictive value. 

Saturday, October 12, 2019

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

Analog 5H composite ('78/'79 ... '85/'86 ...'95/'96 ... '99/'00 ... '02/'03) ... as of SEP-19

- Ridge-W Trof-E
- Hi-latitude blocking ==> AO & NAO < 0
- EPO < 0

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Analog years for Winter '19 / '20

KEY
ENSO:  nada- (-0.5 < SSTa <  0); C- (weak La Nina); C+ (strong La Nina); W (moderate 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

Tuesday, October 8, 2019

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

Eurasia/s areal snow cover for SEP-19: ~1,570,000 SQ-KM

3% below 48-year P-O-R-N (~1,629,000 SQ-KM)
1% below 48-year Median (~1,588,000 SQ-KM)

Rank: 26th
4th lowest past 10 years
11 of past 20 years below median
SEP-18:  ~1,300,000 SQ-KM
SEP-19 21% greater than SEP-18

Analog years for Winter '19 / '20 (CORRECTION:  '16 / '17 nada-)
KEY
ENSO:  nada+ (0 < SSTa <  0.5); C- (weak La Nina); W- (weak El Niño); W (moderate El Niño); W+ (strong El Niño)
NAO:  sign of D-J-F average
PDO:  sign of O-N-D-J-F-M average
QBO:  + ==> west; - ==> east

Saturday, October 5, 2019

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

Analog 5H composite ('53/'54 ... '54/'55 ...'59/'60 ... '97/'98 ... '14/'15) ... as of SEP-19

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

- Positive height anomaly over eastern Canada displaces climatologically favored position of Hudson Bay trof limiting high-latitude cold air supply to the Lower 48.

- TNH associated with stronger than normal Pacific jet farther south of its normal axis and well above normal temperatures in eastern North America.


KEY
ENSO:  nada- (-0.5 < 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
PDO:  sign of O-N-D-J-F-M average
QBO:  + ==> west; - ==> east; +/- flipped west to east

Thursday, October 3, 2019

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

UPDATE:  SEP/s NAO did not change the analog years other than to shuffle the 4th and 5th ranks.

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Analog 5H composite ('50/'51 ... '08/'09 ... '12/'13 ... '16/17 ... '17/'18) ... as of AUG-19


- Another round of Trof West - Ridge East

- EPO-like ridge offset slightly to the west of preferred position for a 'Trof-East' regime

- Azores HIGH suggests NAO > 0

- Negative height anomaly over south-central Canada favors primary storm track through the Upper Plains and across the Great Lakes in line with current soil moisture axis.


Winter '19 / '20 NAO analog analysis here.