Winter '09 / '10 - Snow Storm #5 - Call for Forecasts

Mid-level systems over NV and north of WI SUN evening are progged to phase over the next 24 hours and deliver a moderate-to-heavy snow event for the mid-Atlantic TUE/WED.  Current forecasts suggest coastal areas of SNE may be side-swipped by this storm.

NEWxSFC often does land office business in FEB and this year is no exception.  Snow storm #5 will be the third Contest snow storm in less than 10 days.

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Deadline: 10:30 PM EST MON...08-FEB-10

Forecast element: storm-total snowfall
Verification begins: 12:01 AM EST TUE...09-FEB-10
Verification ends: 11:59 PM EST WED...10-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 #4 - Preliminary Verification

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

No climate report for SBY at post-time. AKQPNS carried a report of 14" from the airport's emergency manager.  This value may be revised if CDUS41 or CF6 bulletins are issued before final verification.

Interesting to note ACY/s SN:H2O below 10:1.  No rain observed at the station.  Almost 20" of wet...frozen concrete.

Some controversy concerning amounts @BWI.
From The Baltimore Sun...

"The contractor measured every hour on the hour and added it up. That produced a total of 28.6 inches.

He also took a "snow depth" reading, meaning that he measured all the snow at once, after it stopped falling.

Because of compaction, that came to 24.7 inches." 

BWI/s STP may be revised if new information b/comes available.

Nine new daily records.

FRI...05-FEB-10
ACY - 3.6" (1"; 1948)
BWI - 9" (6.4"; 1899)
IAD - 14.9" (1"; 2001)
DCA - 8.7" (7.5"; 1892)

SAT...06-FEB-10
PHL - 22" (12.4"; 1978)
ACY - 14.6" (11.5"; 1978)
BWI - 17" (8.4"; 1978)
IAD - 17.5" (4.4"; 1983)
DCA - 9.1" (4.4"; 1983)

Please report errors and a link to the correct data in Comments.
Final results and storm summary Monday evening.

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

Forecaster Summary

Forecasts in the table below are ranked by storm total precipitation (STP) in ascending order. Blue (red) STP values are in the 25th (75th) percentile of all forecast STPs.

Average STP (138") per average number (17) of stations forecast:  8.1".

28 entries...including 10 Rookies... seven of which entered their first contest this winter...three Interns...one Journeyman...and 12 Senior forecasters...issued 446 station forecasts for the winter/s 4th contest snow storm.

Two entries were disqualified b/c forecasts included one station only.
Everyone's station forecasts have been posted on the Contest's web site.

Consensus for a mid-Atlantic event.

Arctic Oscillation (AO) remains well below zero...heading once again for historical extrema.  North Atlantic Oscillation (NAO) and Pacific-North American (PNA) indexes essentially flat-line neutral.

Anemic NAO ahead of a potentially historic mid-Atlantic snowfall puts another nail in the coffin of CW about its supposedly critical importance for east coast snow.

Miller 'A/B' surface LOW...currently over GA...expected to kick-out quickly to sea late SAT afternoon...leaving the east coast via HSE.

Verification period ends 11:59 PM EST...SAT 06-FEB-10.
Preliminary storm-total snowfall totals will be posted the evening of SUN 07-FEB-10.

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.