Winter '10 / '11 - Snow Storm #2 - Raw Forecasts

Times Square...NYC
16-JAN-1965

This evening/s early NWP solutions don/t appear to expect much of an exciting synoptic snowfall event QPF-wise; however...there may be some surprise station STPs given there are v-e-r-y cold columns capable of creating copious crystal dendrites with uncharacteristically high SN:H2O.

The raw forecasts have been posted to the NEWx GoogleGroup here.

Winter '10 / '11 - Snow Storm #2 - Call for Forecasts

Times Square...NYC
13-JAN-1954

Tonight/s 00z NAM consistent with earlier runs in its depiction of dynamically driven... meso-scale contest-worthy snowfall event over the northern mid-Atlantic and coastal New England regions.

Game on...at least for now.

Contest may be canceled prior to the deadline if NWP indicates a fizzling event.

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Deadline:10:30 PM EST THU...06-JAN-11
Forecast element: storm-total snowfall
Verification begins: 12:01 AM EST FRI...07-JAN-11
Verification ends: 11:59 PM EST SUN...09-JAN-11

Enter your forecast at the Contest web site here.
Follow the link from 'Enter Storm Forecast.'

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As always...there/s no cost...or fees...or advertising...or annoying requests for personal information to enter a forecast.  It's just a fun exercise among winter wx enthusiasts to see who can make the best synoptic-scale snowfall forecast.

If you are issuing your first forecast this winter...or you entered the 'season-total' forecast contest...you/ll need to create an account (user name / password / valid e-mail...if you want a copy of your forecast sent to your Inbox).

Want to be notified via e-mail when a 'Call for Forecasts' is issued?
Send your request to newx at newx-forecasts dot com.

Winter '10 / '11 - Stratospheric Warming - Take 3

Appears associated with the ECMWF's forecast for hi-latitude blocking over Siberia beginning 1/11/11.  Note the dramatic weakening of the stratosphere's polar vortex between the initial panel (west @60 m/s = ~120 kts) and its reversal on D+10 (east @15 m/s = ~30 kts).

Also depicted on D+10 zonal mean wind chart are deep layer easterlies throughout the troposphere suggesting a strongly negative AO.

Chat with Dr. Louie Uccellini - "NE Snowstorms" Co-Author

"...3:00 p.m. ET on Thursday Jan. 6 for a live online chat with winter weather expert Louis Uccellini, the director of the National Weather Service's National Center for Environmental Prediction (NCEP), to discuss the USA's winter weather."

More...

North Atlantic Oscillation - Trending South

Blue line is NAO's five-year moving average for meteorological winter (D-J-F) which at the end of last winter dipped below zero for the first time since 1982.

Note how the 5-yr moving average was negative for 21 years between 1953 and 1973...then a nine-year transition period when the sign flip-flopped after holding serve one way or the other briefly for four or five years...followed by 27 years where the NAO's moving average was positive.

Might this herald the start of a protracted...multi-decadal period of negative winter-time NAOs?

Source

In other news...DEC-10 NAO came in at -1.85...marking the 15th consecutive month it's been below zero and the 3rd lowest index value for December since 1950.  Second-lowest December was 1963.  All-time record minimum is DEC-09.

Closest analog year based on least-squares analysis is 1968 / 1969 which was +ENSO...-QBO...and -PDO.

Second-closest analog year based on least-squares analysis is 1977 / 1978 which was +ENSO...+QBO (month-one of west phase)...and mixed PDO.

Winter '10 / '11 - Snow Storm #1 - Final Results - UPDATE

F6 bulletins (CXUS51 - PRELIMINARY LOCAL CLIMATOLOGICAL DATA) for several forecast stations now have data entries or have been revised.  Forecast verifications have been updated to reflect the new information.

Original / Revised Station Data
BGR - 10.3" / 10.8"
PWM - 8.5" / 7.5"
CON - 6.6" / 7.1"
ORH - 17" / 12.7"
ACY - 19" / 20"

No change in the standings for the top three forecasts; however...'ejbauers' and 'Shillelagh' swap 4th and 5th places...'TQ' and 'iralibov' move ahead to 6th and 7th as 'weatherfella' drops to 8th...and 'snowman' jumps over 'Newa' from 11th to 10th after updating the results with new or amended verification data.
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Original Results
-1.277 1 Senior donsutherland1
-1.033 2 Senior Donald Rosenfeld
-0.929 3 Senior Mitchel Volk
-0.880 4 Intern ejbauers
-0.823 5 Senior Shillelagh
-0.509 6 Journeyman weathafella
-0.488 7 Senior TQ
-0.455 8 Chief iralibov
0.040 9 Journeyman WeatherT
0.179 10 Senior Newa
0.313 11 Senior snowman
0.922 12 Intern Roger Smith
1.331 13 Senior defman27
1.721 14 Journeyman MarkHofmann
1.889 15 Intern Weathermbug

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Revised Results
-1.274 1 Senior donsutherland1
-1.013 2 Senior Donald Rosenfeld
-0.986 3 Senior Mitchel Volk
-0.868 4 Senior Shillelagh
-0.866 5 Intern ejbauers
-0.512 6 Senior TQ
-0.466 7 Chief iralibov
-0.393 8 Journeyman weathafella
-0.021 9 Journeyman WeatherT
0.246 10 Senior snowman
0.263 11 Senior Newa
1.061 12 Intern Roger Smith
1.233 13 Senior defman27
1.795 14 Journeyman MarkHofmann
1.802 15 Intern Weathermbug

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The Forecast Verifcation page at the Contest web site will be updated but not the storm Summary page.

Winter '10 / '11 - Coastal Teaser #2

Look familiar?

GooFuS has a coastal storm on the 7th as well; however...its genesis is in the northern stream leaving the SW bowling ball behind.

Graphics courtesty Plymouth State Wx Center.

Winter '10 / '11 - Snow Storm #1 - Final Results

1st
Donsutherland1

SUMSQ: 385.44

SUMSQ Z: -1.277

STP: 3.45 (1)

TAE: 81.25 (1)

AAE: 3.01 (1)

2nd
Donald Rosenfeld

SUMSQ: 526.03

SUMSQ Z: -1.033

STP: 12.85 (4)

TAE: 95.85 (3)

AAE: 3.55 (3)

3rd
Mitchel Volk

SUMSQ: 585.48

SUMSQ Z: -0.929

STP: 20.65 (5)

TAE: 97.35 (4)

AAE: 3.61 (4)

Honorable mention
EJBauers
SUMSQ: 614.01
SUMSQ Z: -0.880
STP: 51.45 (8)
TAE: 104.25 (5)
AAE: 3.86 (5)

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

Full forecast verification and summary at the Contest web site.

Winter '10 / '11 - Snow Storm #1 - Snow Cover

Image courtesy NASA's Terra satellite.

Close-up of the NE here. 

Winter '10 / '11 - Snow Storm #1 - Teleconnections

Arctic and North Atlantic Oscillations have been below zero...with few exceptions...since mid-NOV thanks to strong hi-latitude blocking over the North Atlantic and Pacific Oceans.

Likewise...the PNA.