Thursday, January 28, 2016

Winter '15 / 16 - Snow Storm #1: NESIS

Rank:  4
NESIS:  7.66
Category:  4
Description:  Crippling

Large format image here.

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The storm covered ~434,000 square miles and affected ~103 million people.

Of those, ~1.5 million people had more than 30" of snowfall; ~24 million had over 20".
- NOAA

Tuesday, January 26, 2016

Winter '15 / '16 - Snow Storm #1: FINAL Results

Full forecast verification and summary at NEWxSFC/s web site.

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 1st - Donald Rosenfeld 
 SUMSQ:1152.22  
 SUMSQ Z:-1.946  
 STP:14.0 (1) 
 TAE:135.8 (1) 
 AAE:5.22 (1) 
     
 2nd - TQ 
 SUMSQ:1802.59  
 SUMSQ Z:-0.968  
 STP:108.6 (6) 
 TAE:143.9 (3) 
 AAE:6.00 (3) 
     
 3rd - Mitchel Volk 
 SUMSQ:1942.0  
 SUMSQ Z:-0.759  
 STP:127.3 (7) 
 TAE:156.5 (5) 
 AAE:6.80 (6) 
     
 HM - donsutherland1 
 SUMSQ:2151.8  
 SUMSQ Z:-0.443  
 STP:142.2 (9) 
 TAE:160.7 (6) 
 AAE:6.70 (5) 
     

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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.

Monday, January 25, 2016

Winter '15 / '16 - Snow Storm #1: Preliminary Verification

Preliminary storm-total snowfalls for Friday though Sunday from CDUS41 and CXUS51 bulletins.  Good coverage and reporting.

DCA STP in question.
Vicinity reports suggest an under-measurement.
Sensitivity analysis on forecasts with a 30" verification shows no impact on top three finishers (HM flips) with minor shuffling in the pack's middle.
Note the SLRs are similar at IAD and BWI.

AP reporting on the controversy.
The two vicinity sites mentioned in the article are ~3 miles NNW (Adams Morgan neighborhood) and ~5 miles NW (Dalecarlia Reservoir) distant from DCA.

Meanwhile ... ~2 miles across the river to the east in Anacostia ... MD ... a trained spotter reported 19" and about the same distance to the SSE a 17" report from National Harbor ... VA

Reporting issues continue at SBY.
SBY/s 6" STP comes from a 'media' report carried in AKQ/s Public Information Statement (PNS).

HYA/s 14" STP comes from an 'amateur radio' report carried in BOX/s Public Information Statement (PNS).

Stations with STP but no SN:H2O had mixed freezing ... frozen ... and liquid precipitation.

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Boatload of new daily records for SAT ... 23-JAN-16
JFK - 30.3" (3.6"; 2005)
ABE - 30.2" (7.7"; 1966)
EWR - 27.5" (4.5"; 2005)
MDT - 26.4" (9.5"; 1982)
BWI - 25.5" (11.5"; 1935)
ISP - 23.4" (4.2"; 2005)
IAD - 22.1" (1.7"; 1982)
PHL - 19.4" (11.9"; 1935)
BDR - 12" (7.1"; 1965)
DCA - 11.3" (11"; 1935)
ACY - 10.1" (1.2"; 1948)
RIC - 5.3" (2.7"; 1908)
ORF - 1.2" (1"; 2000)
RDU - 1.2" (1.2", 1954) [22-JAN-16]

Areal coverage - The Great non-blizzard Blizzard JAN 2016
 
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Several new daily records exceeded those set in 1935.

Remarkably similar synoptics.
Parent HIGH over the upper Plains with an eastern extension over the NE.
Miller 'B' re-development off the Carolinas.
 
STP (liquid)
DC - 2.85"
BWI - 2.68"
RIC - 2.88"
 
 
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Please report any errors in Comments along with a link to the correct data.
Final results Tuesday evening.

Sunday, January 24, 2016

Winter '15 / '16 - Snow Storm #1: DCA STP #FAA_FAIL

24-JAN-16
The 2016 non-blizzard Blizzard
UPDATE 1/25:
AP reporting on the controversy.

The two vicinity sites mentioned in the article are ~3 miles NNW (Adams Morgan neighborhood) and ~5 miles NW (Dalecarlia Reservoir) distant from DCA. 

Meanwhile ... ~2 miles across the river to the east in Anacostia ... MD ... a trained spotter reported 19" and about the same distance to the SSE a 17" report from National Harbor ... VA.

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Apparently ... DCA reported 17.8" STP (1.47 liquid) yet IAD and BWI measured 29.3" (2.63 liquid) and 29.2" (2.13 liquid) ... respectively.

This disparity has lead to questions about how much snow actually fell @DCA.

NWS vicinity reports in the PNS bulletin also suggest a possible under-measured of snow at Raygun/National.

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Reported snow liquid ratios (SLR)
DCA 12.1
IAD 11.1
BWI 13.7

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FAA contract personnel measure snowfall at many major airports.  May be one reason why so many SLRs are 10:1. 

That ... and not being able to find the snowboard when it's time to measure.

Friday, January 22, 2016

Winter '15 / '16 - Snow Storm #1: The Forecasts!

Rookie 0
Intern 0
Journey 0
Senior 13
TOT 13

Congratulations to snocat918 on achieving Senior forecaster status this season.

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


BLUE ==> 25th percentile.
RED ==> 75th percentile.
Grey and white STP cells are between the 25th and 75th percentile.

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Heaviest snowfall (+12") consensus along and the the right of RIC - IAD - MDT - PHL - BWI - RIC.
Lollypop expected at IAD.

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Northern annular modes (AO / NAO) negative and rising.  Evidence of amplifying long wave seen in PNA/s rising index.

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

Winter '15 / '16 - Snow Storm #1: RAW Forecasts

Baltimore ... MD
28-JAN-22
RAW forecasts here.

All forecasts and summary statistics will be posted at the Contest web site and the web log ... respectively after lunch FRI.

Having issues with Excel this AM.

Thursday, January 21, 2016

Winter '15 / '16 - Season-total Snowfall Forecast Contest: DEC Totals

UPDATE:  tele-connection index values
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Monthly station snowfall summary for DEC-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:  1.444
NAO:  2.24
PNA:  N/A
PDO:  1.01
QBO:  11.4
MEI:  2.123

Wednesday, January 20, 2016

Winter '15 / '16 - Snow Storm #1: Call for Forecasts

Powerhouse winter storm setting its sights on the M-A and extreme SNE.  Progs planting a closed-upper LOW along the SE coast suggest a long-duration event as the SFC LOW/s progress slows to a crawl.

No question whether this is a contest-worthy storm.  Couldn't ask for a better mid-latitude cyclone to kick-off the season other than its tardy arrival a week past winter's mid-point.

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Forecast element: storm-total snowfall
Deadline for entries:  10:30 PM EST THU ... 21-JAN-16
Verification begins:  12:01 AM EST FRI ... 22-JAN-16
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.

Monday, January 18, 2016

Winter '15 / '16 - Coastal Teaser #3


Decent inter - and intra-run-to-run consistency suggesting this season's first contest-worthy snow storm may be in the offing toward week's end.

Timing the on-set of precipitation remains a moving target.  18-JAN / 00z GFS pointing toward FRI AM over southern portions of the forecast area.

'Call for Forecasts' possible WED evening (20-JAN).

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There have been five previous winters without a contest-worthy storm in DEC ('99-'00, '06-'07, '11-'12, and '14-'15).

The first storms those winters were:
1/20/00
2/14/07
1/21/12
1/26/15

Total snowfall forecasting contests those winters:
'99-'00:  5
'06-'07:  5
'11-'12:  2
'14-'15:  6

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Hang in there forecasters.
All is (probably) not lost.

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NWP image courtesy meteocentre.com

Wednesday, January 13, 2016

Winter '15 / '16 - Coastal Teaser #2

A little past the halfway point of meteorological winter ... another coastal teaser lurks on the horizon.


Should be noted the ECMWF didn't get the memo.
 
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NWP image courtesy meteocentre.com