Winter '10 / '11 - Snow Storm #5 - Call for Forecasts

East Side...NYC
24-JAN-1908

Large-scale disagreement between today/s 12z NAM and GooFuS runs. HPC discounted the NAM solution as a 'slow outlier' in its afternoon discussion.

GooFuS keeps the LOW closer to the coast putting enough stations in play for a contest-worthy event.

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








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Deadline for entries:  10:30 PM EST TUE...25-JAN-11
Forecast element: storm-total snowfall

Verification period begins:  12:01 AM WED...26-JAN-11
Verification period ends:  11:59 PM THU...27-JAN-11

Enter your forecast at the Contest's home page here.
Follow the link from 'Enter Storm Forecast.'

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As always...there/s no cost...or fee...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 - WSI Expects Warm FEB

"“The end of the recent long-lived and extreme North Atlantic blocking episode, along with a return to more dateline blocking typical of late winter La Nina regimes, should result in a return of colder weather to the western half of the US in February while the eastern US finally experiences more moderate temperatures,” said WSI Chief Meteorologist Dr. Todd Crawford."

FEB - warmer
MAR - colder
APR - colder
More...

Winter's seasonal forecast for the northeast from WSI...
DEC - colder
JAN - warmer
FEB - warmer

"“The recent behavior of the North Atlantic Oscillation, along with the fact that current and recent atmospheric/oceanic patterns have closely resembled those from the 1950s-1970s period, has reinforced our hypothesis that there may have been a fundamental climate shift in 2008 that will result in weather patterns more similar to those found 40-60 years ago,” Dr. Crawford added."

Crawford/s reference to the NAO's recent behavior may be related to the index's 5-year moving average falling below zero for the first time in more than two decades. This chart shows the historical tendency for the NAO's moving average for meteorological winter (D-J-F) to remain positive or negative once the shift occurs.

Winter '10 / '11 - Stratospheric Warming - Take 4

Meant to post this over the weekend. Subsequent runs of the ECMWF have continued with the idea of a weakening polar vortex by month/s end suggesting a warming in the stratosphere with implications for cold temperatures toward the end of meteorological winter.

Note how the strong 85 m/s (~170 kts) PV in the left panel weakens to 35 m/s (~70 kts) by D+10 where the deep-layer blue highlights near 90°N indicates an east wind.  Favorable conditions are indicated for the Arctic Oscillation to fall well below zero in late February.

Not that significant warmth is expected anytime soon as the NAO ridge retrogrades toward Greenland and PNA remains positive with the most northern extension of the ridge reaching well above the Arctic Circle.  Short-wave energy migrating from this hi-latitude into the base of a deep eastern trough brings great potential to spin-up strong coastal storms off the SE CONUS.

Winter '10 / '11 - Snow Storm #4 - Final Results - UPDATED

The final results for Snow Storm #4 have been updated to include a forecast issued after the deadline.  Technical difficulties with the Contest's web site were experienced by Senior forecaster Mitch Volk Friday evening around 9:30 PM.  These difficulties prevented him from issuing a forecast before the deadline.

When I learned of this problem...I asked Mitch to send me the forecast he tried unsuccessfully to enter.  His forecast was included and verified along with the other forecasts.  Forecaster skill scores have been re-computed and posted to the Contest's web site.

Mitch has participated in the NEWxSFC every winter since its inception in 1999...issuing a timely forecast for almost every snow storm and every season-total contest.  Under the circumstances...accepting his forecast after the deadline is the right thing to do.
 
1st - Brad Yehl
SUMSQ: 75.76
SUMSQ Z: -1.032
STP: 7.50 (4)
TAE: 26.50 (2)
AAE: 1.10 (3)

Bride's Maid - Shillelagh
SUMSQ: 79.91
SUMSQ Z: -0.976
STP: 0.80 (2)
TAE: 26.90 (3)
AAE: 1.08 (2)

3rd - TQ
SUMSQ: 95.25
SUMSQ Z: -0.770
STP: 11.50 (7)
TAE: 27.90 (4)
AAE: 1.16 (4)

Honorable Mention - donsutherland1
SUMSQ: 100.19
SUMSQ Z: -0.703
STP: 17.60 (9)
TAE: 24.50 (1)
AAE: 1.07 (1)

SUMSQ: sum of square errors
STP: storm-total precipitation error
TAE: total absolute error
AAE: average absolute error
(rank)

Winter '10 / '11 - Snow Storm #4 - Final Results

SFC Analysis
12z 21-JAN-11

1st - Brad Yehl
SUMSQ: 75.76
SUMSQ Z: -0.945
STP: 7.50 (3)
TAE: 26.50 (2)
AAE: 1.10 (3)

Bride's Maid - Shillelagh
SUMSQ: 79.91
SUMSQ Z: -0.890
STP: 0.80 (2)
TAE: 26.90 (3)
AAE: 1.08 (2)

3rd - TQ
SUMSQ: 95.25
SUMSQ Z: -0.686
STP: 11.50 (6)
TAE: 27.90 (4)
AAE: 1.16 (4)

Honorable Mention - donsutherland1
SUMSQ: 100.19
SUMSQ Z: -0.621
STP: 17.60 (8)
TAE: 24.50 (1)
AAE: 1.07 (1)

SUMSQ: sum of square errors
STP: storm-total precipitation error
TAE: total absolute error
AAE: average absolute error
(rank)

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Full forecast verification and summary at the Contest/s home page.

Winter '10 / '11 - Snow Storm #4 - Preliminary Verification

Preliminary storm-total snowfalls for Friday from CDUS41...CXUS51...and PNS...as of 8 AM Saturday.

No snowfall report was carried in the NWS PNSBOX bulletin for HYA. Verifying storm-total snowfall of 0.5" was estimated from HYA/s Pxxxx METAR data.

A field formatting error in the data table shows ACY and IAD with 0.1".  Actual STP was a 'trace' (0.05") at both locations.
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Three new daily records.
FRI...21-JAN-11
BDR BGR - 17.3" (4.3"; 1946)
BOS - 7.3" (6.4"; 2001)
EWR - 4.5" (4.2"; 2001)

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Please report errors and drop a link to the correct data in Comments.
Final results and storm summary on Sunday.

Winter '10 / '11 - Snow Storm #4 - The Forecasts

11 entries

1 Rookie
2 Intern forecasters
2 Journeyman forecasters
6 Senior forecasters

Snow storm #4...while tame compared to the first three events...put down down respectable storm-total snowfalls over several New England stations.

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All forecasts have been posted to the Contest's home page.
Follow the link from Storm #4.

Entries are ranked in ascending order by 'storm-total' snowfall.
Please check you entry for accuracy.

Broad range of expected storm-total snowfall...
Min: 72" (donsutherland1)
Max: 147" (MarkHofman)
Avg: 95"
Median: 90"
STD: 21"

Heaviest snowfall axis expected to fall inside BGR - PWM - BOS - PVD - BDL - ORH - CON - BGR

Winter '10 / '11 - Snow Storm #4 - Raw Forecasts

Raw forecasts here.

Winter '10 / '11 - December Snow Cover

From NCDC...

"The Northern Hemisphere snow cover extent during December 2010 was much above-average, marking the fourth largest December snow cover extent on record — behind December 2009, 1985, and 1970."

"During December 2010, the North American snow cover extent was above average, ranking as the seventh largest on record. This marks the fourth consecutive December with above-average snow cover extent for the continent."

Global Snow Report here.
National Snow and Ice Report here.

Winter '10 / '11 - Snow Storm #4 - Call for Forecasts

Union...Maine
JAN-1926

Miller-B (.pdf) cyclogenesis forecast to occur off the Delmarva peninsula early FRI morning.

Progs aren/t all that juiced nor are the powerhouse dynamics we/ve seen with previous storms evident until the system lifts out to the NE.

Even so...the storm appears to be contest-worthy.

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

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Deadline for entries: 10:30 PM EST THU...20-JAN-11
Forecast element: storm-total snowfall

Verification begins: 12:01 AM EST FRI...21-JAN-11
Verification ends: 11:59 PM EST FRI...21-JAN-11

Enter your forecast at the Contest's home page here.
Follow the link from 'Enter Storm Forecast.'

---
As always...there/s no cost...or fee...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.