Winter '18 / '19 - Snow Storm #4: Call for Forecasts!

Miller-B type cyclogenesis along the nearshore waters of the upper M-A coast associated with a mid-latitude cyclone tracking NE across the Great Lakes throughout the forecast period expected to produce the season/s 4th 'contest-worthy' snow storm.

Vertical temperature profiles from numerical weather prediction models suggest the possibility for mixed forms of frozen precipitation i.e., snow and sleet.  Verifying storm-total snowfall totals will include sleet accumulations.

The contest for Snow Storm #4 may be cancelled prior to the deadline if fewer than six stations are likely to observe at least a 4" storm-total snowfall.

---
Forecast element: each station's storm-total snowfall
Deadline for entries: 10:00 PM EST ... SUN ... 10-FEB-19
Verification begins: 12:01 AM EST ... MON ... 11-FEB-19
Verification ends: 11:59 PM EST ... WED ... 13-FEB-19

---
Enter your forecast at the NEWxSFC/s home page here. http://www.newx-forecasts.com/
Follow the top-of-page link from 'Enter Storm Forecast.

---
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.

You also get the chance to see how well your forecast stacks up against NWS Eastern Region Weather Forecast Offices (turns out they/ve been pretty easy to beat!)

---
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).

Winter '18 / '19 - Regular Season Interim Standings: #1

Under the ‘two-thirds’ rule … forecasters who have entered at least TWO forecasts are included in Interim standings #1.

Complete interim statistics table and chart at the Contest/s web site here (direct link)
Forecaster statistics for Winter '18 / '19 Regular season snow storm contest here (direct link)

 ---
SUMSQ errors for each contest snow storm are normalized (i.e., standardized) 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.

Similar idea as dropping the lowest test score before computing the final grade.

Winter '18 / '19 - VCP32: Nothing But Noses And Eyes

Winter '18 / '19 - Season-total Snowfall Forecast Contest: JAN Totals

JAN-19 snowfall summary by Contest forecast station.
Rank ordered descending by percent of monthly period-of-record-normal (P-O-R-N).

---
Green ==> 75th percentile
White ==> less than 75th and greater than 25th percentile (inter-quartile range)
Red ==> 25th percentile

---
JAN Forecast Station Highlights
CAR
Record monthly snowfall (59.8")
Old record:  44.5" (1994)

IAD ... DCA ... BTV
More than double monthly P-O-R-N

Biggest losers
Observed v P-O-R-N
RDU:  0" v 2.5"
ORH:  T v 2.9" (2%)
EWR:  0.9" v 8.3" (11%)
BDR:  1.2" v 8.9" (13%)
NYC:  1.1" v 7.5" (15%)
PVD:  1.6" v 10.2" (16%)

---
Season-to-Date
On average ... JAN contributes 275.6" (30%) toward the season-total snowfall (D-J-F-M) of 914".
JAN-19 observed snowfall:  296.3" (32% of season-total snowfall)

---
Teleconnection indexes and month-over tendency (updated as they become available)
AO:
NAO:
PDO:
QBO
SOI:
⇩⇧

Winter '18 / '19 - Snow Storm #3: FINAL Results

Forecasters' station verifications and the storm summary available at NEWxSFC/s home page.
http://www.newx-forecasts.com/

SUMSQ:  sum of square error (")
SUMSQ Z:  Z-score
STP:  storm total precipitation error (")
TAE:  total absolute error (")
AAE:  average absolute error (")
(#):  category rank

Forecast by Observed Snowfall Scatterplots for Top Forecasts
Dotted blue line below (above) solid red line ==> under (over) forecast

Station by Station Comparison of Top Forecasters

Winter '18 / '19 - Snow Storm #3: Preliminary STP Verification

Preliminary storm-total snowfalls for TUE and WED from CDUS41 (CLI) ... CXUS51 (CF6) ... and PNS bulletins.

Good coverage and reporting with exceptions at BDR and MDT.

BDR
No snowfall report carried in 30-JAN CLI or F6 bulletins.
METARs reported brief burst of heavy snow with late-day Arctic FROPA.
JFK and ISP observed 0.2" around the same time.
Final STP may be revised from reported value if update issued by WFO OKX.

MDT
No snowfall report carried in 30-JAN CLI or F6 bulletins.
METARs reported brief period of moderate snow with mid-day Arctic FROPA.
Final STP may be revised from reported value if update issued by WFO CTP.

HYA
Trace STP based on METAR analysis and the lack of spotter reports in PNSBOX.

---
Stations observing at least Trace - 24 (89%)
Given stations having a measurable snowfall ... stations observing at least:
4" - 8 (33%)
6" - 2 (8%)
8" - 0 (0%)

No new daily records

Image courtesy NOHRSC

SFC analysis:  06z ... 30-JAN-19

Please report any errors in Comments along with a link to the correct data.
FINAL results NLT SAT evening.

Winter '18 / '19 - Snow Storm #3: The Forecasts!

Rookie  1
Intern  -
Journey  1
Senior  10
GOVT  1
PWSP  -
TOT  13

Welcome Rookie forecaster Hollowman501
Good Luck!

Forecaster table ranked ascending by storm-total precipitation (STP)
Correction:  The forecaster class for JessicaCain should be 'Journeyman.'

BLUE ==> 25th percentile.
RED ==> 75th percentile.
WHITE and GREY STP cells range between the 25th and 75th percentile.

Heaviest snowfall (+6") consensus along and to the right of CAR - BGR - CON - ALB - BTV - CAR.  Lollypop expected at CAR.

Arctic Oscillation (AO) lurking just beneath the surface.
North Atlantic Oscillation (NAO) floating high above the fray (again).
Pacific-North American (PNA) flattening out.

Everyone/s station-by-station forecast at the Contest/s web site.
Direct link to the forecasts table.

Winter '18 / '19 - Snow Storm #3: RAW Forecasts

Here

Winter '18 / '19 - Snow Storm #3: Call for Forecasts!

Conservatory Lake - Central Park - NYC (10-FEB-34)

Clipper-type short wave progged to dive SE across north-central CONUS on MON ... then re-develop off the SNE coast TUE ... may turn out to be 'contest-worthy.'

Numerical weather prediction models sometimes don't converge on a consensus solution and don't show systems like this their 'game face' until ~24 hours before flakes start flyin' for real.

Seeing how there have been so few chances to forecast storm-total snowfall this winter ... we're issuing a 'Call for Forecasts' for Snow Storm #3.

The contest for Snow Storm #3 may be cancelled prior to the deadline if fewer than six stations are likely to observe at least a 4" storm-total snowfall.
.
---
Forecast element: each station's storm-total snowfall
Deadline for entries: 10:00 PM EST ... MON ... 28-JAN-19
Verification begins: 12:01 AM EST ... TUE ... 29-JAN-19
Verification ends: 11:59 PM EST ... WED ... 30-JAN-19
.
---
Enter your forecast at the NEWxSFC/s home page here. http://www.newx-forecasts.com/
Follow the top-of-page link from 'Enter Storm Forecast.
.
---
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.

You also get the chance to see how well your forecast stacks up against NWS Eastern Region Weather Forecast Offices (turns out they're pretty easy to beat!)
.
---
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).

Winter '18 / '19 - We're the Heckawi

Mid-Atlantic winter wx enthusiasts couldn't ask for better synoptics than the current long wave flow regime.

- High amplitude ridge to the West.
- Full latitude trof in the East.
- Sub-tropical jet in a split flow
- Split stratospheric polar vortex with the stronger daughter vortice over eastern North America to boot.

So WTF?
If times be so good ... then bro ... where's my fookin' snow?

Us snow crows nesting here in the eastern half of the mid-Atlantic will most often get our winter wx fix when ...
1) LOW pressure spawns over the Gulf of Mexico & proceeds to crawl slowly up the east coast and

2) A strong Arctic HIGH (1040-ish mb; 30.70" Hg) parks herself over Maine and

3) The wavelength between the Ridge-West / Trof-East pattern contracts i.e., becomes shorter.  As the wavelength shortens ... storms spin-up (intensify) the same way ice skaters spin-up when when they draw their arms inward (see  Conservation of Angular Momentum)

Wicked winter wx 'round here has always been a tricky combination of having a deep layer of Arctic / Polar air in place ... ready to interact with moisture surging from the south.

The current long wave flow regime is certainly delivering in spades with the cold air component; however ... it's coming on too strong ... in effect suppressing moisture from coming north.

FWIW ... the world-wide federation of numerical weather prediction (NWP) models have been tilting toward an adjustment to the long wave pattern in mid-range; a shuffling of the deck so to speak (more like re-setting the tumblers in a one-armed bandit).

Climatologically for snow crows ... FEB is our time 'round here ... especially the period either side of mid-month.  Whether the coming pattern change produces the weather we be waiting for is anyone's guess.

Even though long-range NWP offers us nothing more than possible outcomes ... outcomes more often fantasy than fact ... it's one of those j'ne sais WTF reasons why we all be Weather Weenies.

---