Saturday, November 30, 2019
Friday, November 29, 2019
Winter '19 / '20 - Snow Storm #1: Call for Forecasts!
 | |
| Haverhill ... MA 14-DEC-1890 |
Progs pointing to an initial period of over-running snows followed by Miller 'B' re-development off the Jersey Shore ... the parent LOW/s subsequent capture ... and a long-duration event.
---
Forecast element: each station/s storm-total snowfall
Deadline for entries: 10:00 PM EST ... SAT ... 30-NOV-19
Forecast verification period
Begins: 12:01 AM EST ... SUN ... 01-DEC-19
Ends: 11:59 PM EST when the flakes stop flyin'.
---
Enter your forecast at the NEWxSFC/s home page HERE.
Follow the top-of-page link from 'Enter Storm Forecast' or in the 'Call for Forecasts!' section.
See how well your forecast stacks up against other winter wx enthusiasts and NWS Eastern Region Weather Forecast Offices (turns out the ER WFOs are fairly easy to beat).
---
The forecasting contest for Snow Storm #1 may be cancelled prior to the deadline if at least six-to-eight stations are unlikely to observe at least a 4" storm-total snowfall.
Thursday, November 28, 2019
Winter '19 / '20 - Snow Storm #1: Outlook
A cold overland HIGH NW of the LOW is the missing element. Pinpointing the liquid / freezing / frozen transition zone will be challenging.
NWP model guidance suggests more than nuisance snows for at least six forecast stations qualify the season's inaugral storm as contest-worthy.
Likely 'Call for Forecasts': FRI ... 29-NOV-19
Deadline for entries would be SAT ... 30-NOV-19 @ 10 PM EST.
Sunday, November 24, 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)
Thursday, November 21, 2019
Winter '19 / '20 - Multivariate ENSO Index (MEI) - Leading Analogs' 500 mb Anomaly Height Composite ... as of OCT-19
Multivariate ENSO Index (MEI) composites of 500 mb (5H) geopotential height anomalies (GPHa) and
2-meter air temperature anomalies (2mTa) for analog winters '53 / '54 ... '59 / '60 ... '69 / '70 ... '80 / '81 ... '90 / '91.
- Ridge-W / Trof-E
- Negative 5H GPHa INVOF Aleutian Is. & positive 5H GPHa INVOF Hawaii ==> EPO > 0
- Azores-like positive 5H GPHa ==> NAO > 0
- Negative 5H GPHa / lo-latitude trof axis ==> active sub-tropical jet (STJ)
Wednesday, November 20, 2019
Winter '19 / '20 - Outlooks
Thread updated periodically as new outlooks and forecasts become available from a variety of credible sources.
---
CPC ...
---
From WCVB Boston...
"More cold outbreaks. More opportunities for snowstorms here along the East Coast. This could be a very active winter" said Dr. Judah Cohen (AER)
"Cohen thinks this winter may get off to a slow start but make up for lost time later in the winter. A disturbance of the polar vortex sometime in December could make for a very cold January and February.
"Boston could receive about 59 inches of snow ..." said Cohen.
Tuesday, November 19, 2019
Winter '19 / '20 - Severe Weather Europe: FINAL November Model Forecast for the Upcoming Winter
"Most forecasts are showing certain lower pressure in
the North Atlantic, and higher pressure over Europe and USA, which means
generally milder winter. The forecasts are on the same trend since
September, which is very rare.
"Across the Atlantic, models generally
agree on potential northerly flows over NW and NE USA and E Canada,
while central USA currently has lower chances for winter weather
overall.
"We still have the stratosphere as a major factor.
Long-range forecasts are generally not as good at forecasting
stratospheric dynamics in detail, which means they tend to underestimate
any potential sudden stratospheric warming events (SSW’s) since the
final forecast is made out of many individual calculations, which have
different ideas about the stratospheric development.
"An SSW event can
have a major impact on the circulation and can cause major pattern
changes in the Northern Hemisphere. So a potential SSW event is an
important factor that can change the course of winter in either way
across the North Hemisphere."
Monday, November 18, 2019
Winter '19 / '20 - Pacific Decadal Oscillation (PDO): Leading Analogs' 500 mb Anomaly Height Composite ... as of OCT-19
Pacific Decadal Oscillation (PDO)
composites of 500 mb (5H) geopotential height anomalies (GPHa) and
2-meter air temperature anomalies (2m Ta) for analog winters '66 / '67 ... '68 / '69 ... '90 / '91 ... '04 / '05 ... '17 / '18
- Trof-W / Ridge-E
- High GPHa INVOF Aleutian Is. & low GPHa INVOF Hawaii ==> EPO < 0
- Azores HIGH ==> NAO > 0
- High GPHa dipole Azores & Aleutian Is. ==> AO > 0
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 anomalies (2m Ta) for analog winters '78 / '79 ... '85 / '86
... '95 / '96 ... '99 / '00 ... '02 / '03.
- Ridge-W / Trof-E
- Hi-latitude blocking over Greenland ==> NAO < 0
Sunday, November 10, 2019
Winter '19 / '20 - Arctic Oscillation (AO): 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 anomalies (2m Ta) for analog winters '53 / '54 ... '54 / '55 ... '59 / '60 ... '97 / '98 ... '14 / '15.
- 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.
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
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
Friday, November 8, 2019
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
('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
CORRECTION: '15 / '16 & '09 / '10 ENSO should be 'W+'
Key
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
Tuesday, November 5, 2019
Winter '19 / '20 - North Atlantic Oscillation (NAO): 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
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)"
Subscribe to:
Posts (Atom)
Posts
