Winter '12 / '13 - Storm #2: Final Results

1st - donsutherland1
SUMSQ:	77.41
SUMSQ Z:	-1.049
STP:	13.15	(5)
TAE:	30.45	(1)
AAE:	1.45	(2)
2nd - Brad Yehl
SUMSQ:	78.27
SUMSQ Z:	-1.040
STP:	10.15	(4)
TAE:	31.05	(2)
AAE:	1.29	(1)
3rd - snocat918
SUMSQ:	104.51
SUMSQ Z:	-0.752
STP:	7.55	(3)
TAE:	39.55	(5)
AAE:	1.72	(4)
HM - Donald Rosenfeld
SUMSQ:	112.59
SUMSQ Z:	-0.663
STP:	1.10	(1)
TAE:	40.20	(6)
AAE:	1.83	(6)

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

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

Winter '12 / '13 - Storm #1: Final Results

1st - dryslot
SUMSQ:	112.98
SUMSQ Z:	-0.887
STP:	5.26	(4)
TAE:	39.64	(6)
AAE:	1.80	(5)
2nd - herb@maws
SUMSQ:	119.42
SUMSQ Z:	-0.846
STP:	13.79	(7)
TAE:	36.79	(3)
AAE:	1.75	(3)
3rd - Brad Yehl
SUMSQ:	213.38
SUMSQ Z:	-0.782
STP:	2.65	(3)
TAE:	35.75	(2)
AAE:	1.62	(2)
HM - Donald Rosenfeld
SUMSQ:	140.87
SUMSQ Z:	-0.711
STP:	0.99	(1)
TAE:	33.99	(1)
AAE:	1.55	(1)

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

Full forecast verification and summary at the Contest/s web site.

Winter '12 / 13 - Storm #2: Preliminary Verification

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

Several stations in the data table do not have SN:H2O reported b/c their liquid totals included mixed precipitation.

CON STP of 2.6" at 10:1 is suspect given surrounding amounts and much higher ratios.

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Two new daily records.
SAT...29-DEC-12
BDR - 3.5" (3.1"; 1959)
IAD - 0.9" (0.3"; 1993)

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

Final results and storm summary Monday evening.

Winter '12 / '13 - Storm #2: The Forecasts

Consensus for a southern NE and northern M-A event.

12 forecasters

3 Rookies...two of which issued their 1st forecast for Storm #2.

Welcome Kevinmyattwx and quagmireweathercentral!

Forecaster answer7 is now an Intern.

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.

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

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Slight amplification in the long-wave flow regime suggested by +PNA.  -AO getting the job done again as its sister index the +NAO offers more evidence of how unimportant she is to snowfall on the east coast.

Winter '12 / '13 - Storm 1: Preliminary Verification

Preliminary storm-total snowfalls for Wednesday through Friday from CDUS41 and CXUS51 bulletins.

Several stations in the data table do not have SN:H2O reported b/c their liquid totals included mixed precipitation.

SN:H2O for CON appears low in light of METARs reported only SN.

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Two new daily records.
THU...27-DEC-12
PWM - 11.6" (8.8"; 1894)
CAR - 6.2" (6.2"; 2010)

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

Final results and storm summary Sunday evening.

Winter '12 / '13 - Storm #2: RAW Forecasts

NYC - 5th Avenue
1905

RAW forecasts here.

# Forecasters: 12
Two fresh Rookies.

Marginal event but what the hay.  Best case scenario...the plows will be out on the road.

In hindsight...should have left the verification period open ended.  When the 'Call for Forecasts' was issued on THU...NWP indicated most of the snow would have fallen by 11:59 PM SAT.  Later guidance suggested otherwise.

Storm #2 forecast summary and all individual forecasts will be posted to the Contest/s web log and / or web site by Saturday evening.

Winter '12 / '13 - Storm #2: Call for Forecasts!

NYC
27-DEC-47


Another Miller A-B hybrid storm heading toward the forecast area.

Southern stream LOW forms in the Gulf of Mexico.  Second decaying LOW INVOF the Great Lakes drifting east in the northern stream.

Stronger GOM LOW captures the Lake's LOW over the western M-A.  Rapid deepening near the 40/70 benchmark late in the period as the storm kicks out to sea.  Mainly a rain event over the water and contest-worthy snows over the northern M-A and SNE.

Storm #2 potential appears marginal at post time where the best case scenario produces widespread plowable snowfall; however...there are equal chances for widespread nuisance amounts.

The forecast contest for Storm #2 may be canceled prior to deadline if NWP indicates a fizzling event.

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Forecast element: storm-total snowfall
Deadline for entries: 10:30 PM EST FRI...28-DEC-12

Verification period begins: 12:01 AM SAT...29-DEC-12
Verification period ends: 11:59 PM SAT...29-DEC-12

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 for 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).
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Want to be notified via e-mail when the 'Call for Forecast' is issued?
Send requests to 'newx at newx-forecasts dot com'.

Winter '12 / '13 - Storm # 1: The Forecasts

Consensus for this season/s inaugural event has bonus snows for New England/s northern stations and crumbs for most inland locations along the mid-Atlantic.  The eight to 10 stations in play makes this a decent synoptic-scale winter storm despite rain for major cities along the I-95 corridor.



13 forecasters
11 veterans and 2 Rookies



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.

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

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Roger Smith is promoted to Senior forecaster this year.
Brad Yehl is now a Journeyman forecaster.
Dryslot is an Intern.

Forecaster status - Years Experience
Rookie - 0
Intern - 1
Journeyman - 2
Senior - 3
Chief - last year/s 'Regular' season contest winner.

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PNA at long last comes out of its long coma and a good looking AO although a fair case can be made the state of these indices played a relatively minor role.

Winter '12 / '13 - Storm #1: RAW Forecasts

Maine mill pond
12-28-1951

RAW forecasts posted at NEWxSFC/s GoogleGroup here.

# Forecasters: ~13
Welcome back Vets and welcome aboard to the one or two Rookies.

Where a forecaster issued more than one forecast...only the last one is verified.

Storm #1 forecast summary and all individual forecasts will be posted to the Contest/s web log and / or web site sometime Wednesday.

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Progs suggest an active period over the next week or two...so keep them pencils sharp!

Winter '12 / '13 - January 2013: Week One Outlook

From today/s PSD GFS ensembles...Week 2 anomaly forecasts (VT centered on 05-JAN-13).

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Area 1 depicts the Pacific/s polar jet at 250 mb riding up and over PNA ridge.

Area 2 is the sub-tropical jet (STJ) phasing with the polar jet over the upper MIssissippi river valley.

Area 3 is the negative height anomaly at 500 mb located over New Foundland...CN

Area 4 shows the 850 mb temperature anomaly drawing high-latitude cold air into the NE on the backside of the Newfoundland LOW and the warm advection onto the Greenland ice sheet which in turn would induce or strengthen a blocking HIGH and negative northern annular oscillation indexes (AO; NAO).

Area 5 highlights precipitation anomalies from Mexico to the mid-Atlantic states aligned with the STJ axis.  Note the northern edge of the anomaly coincides with negative 850 mb temperature anomalies.

Amplified flow + short wave energy + cold air + moisture = forecast for snow