Winter '09 / '10 - Snow Storm #4 - Raw Forecasts

Raw forecasts here.

 

All forecasts will be posted to Contest web site and summary information on the web log by FRI evening.

Winter '09 / '10 - Snow Storm #4 - Call for Forecasts

Phasing streams...negative tilted 5H trof...incredible amounts of Gulf o'Mexico moisture invading the mid-Atlantic...significant comma head / deformation.  HPC seems to think a major winter event is in the offing this weekend...so it's high time for Contest #4.

Odd 'Miller A/B'- looking cyclone this go'round... altho secondary coastal development isn't in response to northern stream energy but a second....southern stream short-wave flying east after under-cutting the high-amplitude long-wave ridge along west coast.
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Deadline: 10:30 PM EST THU...04-FEB-10

Forecast element: storm-total snowfall
Verification begins: 12:01 AM EST FRI...05-FEB-10
Verification ends: 11:59 PM EST SAT...06-FEB-10

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

As always...there/s no cost...or fee...or annoying requests for personal information to enter. Just a fun exercise to see who can make the best synoptic-scale snowfall forecast.

If you are issuing your first forecast this year...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).

Winter '09 / '10 - Snow Storm #3 - Final Results

NEWxSFC Senior forecaster ilibov has won this season/s third snowfall forecast contest with a SUMSQ error of 85.3"...a 52% improvement over the average SUMSQ error of 176". Ilibov/s Z-score was a very strong -1.711.

Ilibov also placed 1st in every other categoory. 'Total absolute error' 25.9" (Z-score: -1.850)...'average absolute error' of 1.08" per station (24 stations forecast)....'storm total precipitation' error 3.1"...and an R-SQ of 67.7%.

Ilibov had the lowest station errors @BWI and DCA.

Congratulations Ilibov!

2nd Place: Shillelagh (SUMSQ error: 137.4"; Z-score: -0.727)
3rd Place: millersville_bauers* (140.6"; -0.668)
Honorable Mention: nnjwxguy78 (150.3; -0.483)

*Rookie

Full forecast verification...storm summary...and final results at the Contest web site here.

Winter '09 / '10 - Stratospheric Warming Event - II

Warming underway at 10mb...portends a cold end of month as hi-latitude blocking returns.

Imagery courtesy Climate Prediction Center.

Winter '09 / '10 - Snow Storm #3 - Preliminary Verification

Preliminary storm-total snowfalls for Friday and Saturday from CDUS41...PNS...and CF6 bulletins.

No climate report for SBY at post-time. The Salisbury CO-OP observer's 220 PM report carried in AKQNS was used.  Value may be revised if CDUS41 or CF6 bulletins are issued before final verification.

Two new daily records.

SAT...30-JAN-10
ACY - 7.6" (3.6"; 1966)
ORF - 6.1" (5"; 1965)

Please report errors and a link to the correct data in Comments.

Final results and storm summary Monday evening.

Winter '09 / '10 - Snow Storm #3 - The Forecasts

12 entries...including three Rookies...two Interns...and seven Senior forecasters issued 151 station forecasts for this winter/s third contest snow storm.

Forecasts are ranked by storm total precipitation (STP) in ascending order. Blue (red) values are in the 25th (75th) percentile.

Forecasts at the Contest web site.

Consensus for a southern mid-Atlantic event.

Arctic Oscillation heading quickly south while NAO and PNA flat-line.

Surface LOW over LA FRI evening forecast to exit stage left late Saturday and kick-out into the western Atlantic off the coastal Carolinas.

Verification period ends 11:59 PM EST...SAT...30-JAN-10.
Preliminary storm-total snowfall totals will be posted the evening of SUN...31-JAN-10.

Winter '09 / '10 - Snow Storm #3 - Raw Forecasts

Raw forecasts here.

All forecasts will be posted to Contest web site and summary information on the web log by FRI evening.

This snow storm appears to be a marginally contest-worthy storm given its potential impact on a limited number of forecast stations.

Then again...there's an added wrinkle to the forecast with the likelihood of accumulating snowfall over a few northern forecast stations during the verification period.

Winter '09 / '10 - Imminent Stratospheric Warming Event

End of FEB temperature outlook: C-C-COLD!

Winter '09 / '10 - Snow Storm #3 - Call for Forecasts

January's second contest snow storm combines juiced-up southern stream energy and bitter arctic cold from the snowfields of northern Canada.

Precipitation coming from weak low-level warm-advection and jet level divergence...with less than impressive mid-level dynamics as streams phase in confluent zone off the mid-Atlantic coast.

Models have been trending farther south past the few runs such that the bare minimum of stations for a contest-worthy storm are expected to be affected.

Last-minute contest cancellation possible if NWP consensus for the frozen precipitation shield dips below the DC metro area. Cancellation notice will be posted to the Contest web site and web log.

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Deadline: 10:30 PM EST THU...28-JAN-10

Forecast element: storm-total snowfall

Verification begins: 12:01 AM EST FRI...29-JAN-10
Verification ends: 11:59 PM EST SAT...30-JAN-10

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

As always...there/s no cost...or fee...or annoying requests for personal information to enter. Just a fun exercise to see who can make the best synoptic-scale snowfall forecast.

If you are issuing your first forecast this year...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) before submitting your entry.

Winter '09 / '10 - Coastal Teaser #3

NWP model solutions have been advertising a coastal storm late in the week with GooFuS starting the event a day sooner than the ECMWF.

PNA is forecast to peak near +2 STD...AO currently below -1 STD and decreasing...and the NAO is expected to rise sharply from -3 STD ahead of an event that could turn out to be a fair test of Archambault cool-season regime transition and its impact on NE precipitation (.ppt 3.5 mb)

A 'Call for Forecasts' may be issued late Wednesday with a 10:30PM EST deadline on Thursday...if shorter-range progs indicate a contest-worthy snow storm is likely to occur.

Stratosphere is showing signs of another warming during early FEB as the PV shifts away from the pole to a position over Great Britain where it splits in half with an anti-cyclone centered over extreme NE Alaska / NW Canada.

Oft times...it takes ~3 weeks for these signatures to work their way into the troposhere...heralding a return to bitter cold in the east by month's end featuring arctic air mass intrusions from the north pole.