Saturday, March 28, 2015

Winter '14 / '15 - Sudden Stratospheric Warming: Watch #2 - Update 4

Incoming!

 
Deep layer Easter easterlies.
 
 
PV displacement
 
Split vortices.
 
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Major SSW event has begun!
 
 

Wednesday, March 25, 2015

Winter '14 / '15 - Sudden Stratospheric Warming: Watch #2 - Update 3

ECMWF continues its forecast for a SSW event in the near-term.

Monday, March 23, 2015

Winter '14 / '15 - Sudden Stratospheric Warming: Watch #2 - Update 2

Complete break down of the Polar vortex at month's end.
Deep ... deep layer wind reversal (easterlies up and down the Polar atmosphere) 
 

Prediction:  cold spring in the east.

Tuesday, March 17, 2015

Winter '14 / '15 - Sudden Stratospheric Warming: Watch #2

ECMWF predicts a reversal by displacement of the Polar vortex beginning 24-MAR-15 ...


... and a deep ... icy trough INVOF Baffin Bay.
 
mid-to-late April could turn out quite interesting.

Wednesday, March 11, 2015

Winter '14 / '15 - Season-total Snowfall Forecast Contest: FEB Totals

Monthly station snowfall summary for FEB-15.
Rank ordered by percent of monthly normal.


Green ==> 75th percentile
White ==> Less than 75th and greater than 25th percentile
Red ==> 25th percentile
 
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Teleconnection Indexes
AO:  +1.043
NAO:  +1.32
PNA:  +0.49
PDO:  +2.30 (monthly record)
QBO:  -28.62 (monthly record)
MEI:  +0.468 (JAN-FEB)

Monday, March 9, 2015

Winter '14 / '15 - Interim Standings: 5

Under the ‘two-thirds’ rule … forecasters who have entered at least FIVE forecasts are included in these interim standings.


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Complete interim statistics table and charts at the Contest/s web site here.
All verified forecast statistics from all forecasters for all Winter '14 / '15 contest storms here.

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SUMSQ errors for each contest snow storm are normalized with a 'Z-score' ... then averaged to compute the standings.

If a forecaster has issued forecasts for more than two-thirds of all snow storm contests ... then Z-scores from their 'best two-thirds' forecasts are used to calculate the Interim and Final standings. Same idea as dropping the lowest quiz score before computing the final grade.

Saturday, March 7, 2015

Winter '14 / '15 - Storm #7: FINAL Results

Full forecast verifications and summary for Storm #7 at the Contest/s web site.

     
 1st - Brad Yehl 
 SUMSQ:58.98  
 SUMSQ Z:-0.763  
 STP:14.3 (4) 
 TAE:24.8 (1) 
 AAE:1.08 (1) 
     
 2nd - Herb@MAWS 
 SUMSQ:69.13  
 SUMSQ Z:-0.689  
 STP:15.1 (7) 
 TAE:27.9 (2) 
 AAE:1.27 (3) 
     
 3rd - donsutherland1 
 SUMSQ:71.2  
 SUMSQ Z:-0.674  
 STP:8.0 (1) 
 TAE:30.6 (4) 
 AAE:1.22 (2) 
     
 HM - Donald Rosenfeld 
 SUMSQ:81.4  
 SUMSQ Z:-0.599  
 STP:18.9 (8) 
 TAE:28.2 (3) 
 AAE:1.28 (4) 
     

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

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Click images to enlarge.

Friday, March 6, 2015

Winter '14 / '15 - Storm #7: Preliminary Verification

Preliminary storm-total snowfalls for THU from CDUS41 and CXUS51 bulletins.

Good coverage and reporting.

SBY/s STP interpolated from PNSAKQ vicinity reports.

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Six new daily snowfall records
THU ... 05-MAR-15
IAD - 9.5" (1.0"; 2001)
ACY - 7.0" (0.3"; 1960)
PVD - 6.3" (3.8"; 1931)
ISP - 6.3" (1.0"; 1993)
DCA - 4.8" (4.4"; 1888)
BDR - 4.0" (1.3"; 1981)

Record daily precipitation at ACY (2.4")

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Please report any errors in Comments along with a link to the correct data.

Final results SAT evening.

Thursday, March 5, 2015

Winter '14 / '15 - Storm #7: The Forecasts!

Rookie 0
Intern 1
Journey 1
Senior 9
TOT 11


Forecasts are ranked by their storm-total precipitation (STP).

BLUE ==> 25th percentile.
RED ==> 75th percentile.
STP cells without color are between the 25th and 75th percentile.

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Heaviest snowfall (+6") consensus along and to the right of a line from PHL - ACY - DCA - IAD - BWI - PHL

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Opposite day.

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 Everyone/s station-by-station forecast at the Contest/s web site.

Tuesday, March 3, 2015

Winter '14 / '15 - Storm #7: Call for Forecasts!

ACY Boardwalk - 1928
Pattern change may be coming but not before  there's another contest-worthy snow storm. 

Real mess of mixed precipitation types and Arctic temperatures in the offing will make for a challenging late-season forecast.

Contest for Storm #7 may be cancelled prior to the deadline if fewer than six stations are likely to observe at least a 4" snowfall.

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Forecast element: storm-total snowfall
Deadline for entries:  10:30 PM EST ... WED ... 04-MAR-15

Verification begins:  12:01 AM EST ... THU ... 05-MAR-15
Verification ends:  when the snow stops falling

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Enter your forecast at the NEWxSFC/s home page here.

Follow the top-of-page link from 'Enter Storm Forecast.

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

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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).