Contest # 2 - Call for Forecasts

Potent nor’easter poised to rake northern portions of the forecast area with a big contest snowfall late this weekend.

Deadline is earlier than usual b/c of the storm/s expected duration and the snowfall/s start time over upstream stations.

Deadline: 7:00 PM EST Saturday, 15 December 2007
Forecast verification begins: 7:00 PM EST Saturday, 15 December 2007

Forecasts must be entered via the Contest/s web site
Follow the link to 'Enter Storm Forecast.'

All forecasts will be posted by the Contest Administrator to the NE_Wx Google Group before 11 PM EST Saturday, 15 December 2007 and to the Contest web site by Sunday afternoon.

Contest subject to cancellation before the deadline…if forecast conditions warrant.

More information about the contest/s rules…forecast verification…and scoring can be found at the main web site.

Updates and announcement are posted on the Contest/s web log

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Forecasters need to register once before entering…even if they were registered last year.

Registration is simple… requiring only a username and password. If you provide a valid e-mail address…a copy of your forecast will be sent to you. Please ensure your browser is enabled to accept first-party cookies.

Each contest must have a minimum of seven (7) forecasters for the results to be included in the end-of-season standings.

Please enter 0.05 for trace amounts instead of a 'T.'

The NE.Wx Snowfall Forecast Contest (NEWxSFC) is a multi-month event that continues into late March or early April. In general…contests are held whenever a decent…synoptic-scale storm rears its head and threatens at least a half-dozen forecast stations with more than nuisance snowfall amounts. Forecasters are called to post their 'storm total' snowfall predictions…on deadline…for 27 NWS / FAA observing stations scattered about New England and the Mid-Atlantic regions. The Contest Administrator determines the deadlines for entries…verifies all forecasts…and publishes the final results to the Contest/s web site.

Please be sure to read the rules before entering the contest b/c your entry constitutes agreement to abide by them.

Contest Rules and additional information about error scoring…current monthly snowfall climatology from NCDC…daily CPC teleconnection indices…daily NESDIS N-Hemi snow cover…and NWS Daily Climate Bulletins (CDUS41)

Contest #2 - Sneak Preview

The mid-level system behind this weekend/s impending nor'easter...and Contest Storm #2...is coming ashore along the SW CONUS coast this evening. This will be the first opportunity for the upper air network to sample this feature and provide 'real' data about it during the 00z NWP model initialization.

All of the model runs up until now have incorporated ACARS and derived cloud track / H20v satellite-derived winds. These remote observing platforms provide valuable data to the models but it/s not as good as the data from rawindsondes.

Coastal Teaser #1

12z solns from the ECMWF and GooFuS suggest there/s a nor'easter...possibly a Miller 'B'...in the chamber for early next week.

Click to Animate ===>
Note the small LOW pressure center in the second frame over GA. This become the primary in the last frame over the coastal waters of SNE.


The GooFuS offers a similar feature...altho it/s depicted as a Miller 'A'...over GA at 120HR with cyclogenesis occurring off the NC coast 12 hours later.

Never want the progs looking too good at this time range...IOW...it/s always best not to have your station in the bulls-eye @ 120HR...so take today/s global model output as a reasonable indication of the potential for a potent nor'easter to evolve.

ECHAM/s November Outlook - Verification

Appears to be another miss grande.

In the ECHAM image...red (blue) indicates negative (positive) pressure anomalies.
In the PSD image...red (blue)indicates negative (positive) pressure anomalies.

ECHAM/s November forecast expected positive pressure anomalies along the International Date Line (180°) The verifying analysis shows positive pressure anomalies.

ECHAM/s November forecast expected negative pressure anomalies over the PAC NW and the North Atlantic. The verifying analysis shows positive pressure anomalies.

Alberta Clipper - 05 DEC 2007

Source:
NASA Earth Observatory

An energetic clipper system put 3 - 7" of high-fluff snow on the ground in the DCA - BWI - ACY area last Wednesday. Forecasts generally underestimated the storm-total snowfall.

Temperatures in the crystal factory were -12°C...the low end of favorable conditions for growing stellar dendrites. Other contributing factors were 1) strong veering vertical wind profile...2) 'moist' boundary layer...3) column stretching as the impulse migrated east of the mountains...4) track of the 5H vort max...and 5) SN:H20 of 30:1...all of which were well-modeled by NWP well in advance of the event.

More Like '55

The images shown below depict time-section plots @ 5H between 20N° and 90°N using NCEP daily data (operational and re-analysis) of CLIMO...current...and CPC/s seven La Nina years for the period 15 November through 07 December.

Any similarities / analogs between current conditions and conditions from past La Nina years?

1955...perhaps?


CLIMO..........Current..........1970..........1988

1950..........1955..........1973..........1975

The winter of '55 / '56 featured a strong La Nina that began in early '54 and continued for almost two years until the very end of '56. PDO was negative...as were most winters back then. PDO these days has bi-polar tendencies. QBO flipped E in January -- it/s E now having peaked in OCT. AO ranks 36 out of 57 years. NAO ranks 52 out of 57 years.

'55 doesn/t show up on any analog for this winter...but there it is. Best qualitative match with mid-level geo-potential heights during the past three weeks.


Make your own...
Time Plots / Hovmoller diagrams

Image credit:
NOAA/ESRL Physical Sciences Division, Boulder Colorado

Contest # 1 - Results

Chief Forecaster donsutherland1 issued the best forecast for Storm #1. He placed 1st in "SUMSQ Error'...'Total Absolute Error'...'Average Abosulte Error' and 'R²' categories of forecast skill.

Full results @ the Contest web site.
Follow the link to Forecast #1 to see full forecast verification
Follow the link to Results #1 to see forecast and contest summary information.


Click to Enlarge

Contest # 1 - Surface Analysis

Click to Animate

Contest # 1 - Verification

Preliminary storm-total snowfall based on final CDUS41 bulletins from Sunday...Monday...and Tuesday.

New daily records
12/4
BGR: 12.3" (8.8"; 1989)
JFK: 0.9" (0.1"; 2003)

12/5
BGM: 2.4" (1.4"; 1972)

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

Final results and contest summary will be posted Thursday evening.

Bully Wind

Rapid deepening of the surface LOW in the Gulf of ME today ginned-up a good bully wind along the east coast from VA to ME.

Buoy 44018 is 20 SE of Nantucket


The 24-hr pressure fall was ~1.2" Hg (~40 mb)...far exceeding NCEP/s 'Heavy Snow' prognostic expectation of a 20-30 mb deepening.

Strong WNW flow whipped around the backside of the LOW..too...screaming past Buoy OSGN6 from across Lake Ontario near Oswego...NY.


Make your own...
Northeast USA Recent Marine Data