Contest # 2 - Final Results

Full forecast verification and results summary at the web site.

Follow the links to 'Latest Forecasts' and 'Latest Results.'

Forecasters: 12
9 veteran
3 rookies

Station forecasts: 227
Average stations per forecaster: 19
Stations with observed snowfall: 22

Storm-total precipitation (STP), all stations
Forecast Minimum: 22.45" (Donald Rosenfeld)
Consensus Median: 52.75"
Maximum 116" (edhoffman503)

Observed: 55.3"
Max single station: 6.6" PVD
Shutout: BGR...PWM...BTV...ORF...and RDU

***************************************************
Storm #2 - Results Summary

Congratulations to the Winners!

1st Place - weathafella
SUMSQ Error: 64.5"
SUMSQ - Z: -0.919
STP: 4.3" (3rd)
TAE: 29.9" (1st)
AAE: 1.42" (1st)

2nd Place - herb@MAWS
SUMSQ Error: 73.9"
SUMSQ - Z: -0.837
STP: 6.29" (5th)
TAE: 30.49" (2nd)
AAE: 1.60" (2nd)

3rd Place - donaldsutherland1
SUMSQ Error: 75.3"
SUMSQ - Z: -0.825
STP: 12.4" (8th)
TAE: 30.6" (3rd)
AAE: 1.61" (3rd)

Honorable Mention - shanabe
SUMSQ Error: 114.3" (4th)
SUMSQ - Z: -0.489
STP: 6.15" (4th)
TAE: 35.95(4th)
AAE: 2.00" (5th)

SUMSQ: sum of square errors
STP: storm total precipitation
TAE: total absolute error
AAE: average absolute error

Contest # 3 - Call for Forecasts

Second storm cutting under the Rex block but with much more moisture than the first is on deck for Contest # 3.

Entry Deadline: Wednesday, 28 February 2007 @ 10:30 PM EST.

Verification begins 12:01 AM EST Friday, 2 March 2007 and ends 11:59 PM EST Saturday, 3 March 2007.

Your forecast must be entered via the Contest/s web site. Follow the link to ‘Enter Storm Forecast.’

Forecasters will need to register once before entering, even if they were registered last year. Registration is simple, requiring only a user name and password. If you provide a valid e-mail address, a copy of your forecast will be sent to you immediately after your entry is submitted. Please ensure your browser is enabled to accept first-party cookies.

All forecasts will be posted to the NE_Wx Google Group by the Contest Administrator before 11 PM EST Wednesday, February 28, 2007 and to the Contest web site by Thursday evening.

Contest updates are posted on the Contest/s web log.

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.

You can find the 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) at the contest/s web site.

Contest # 2 - Verification

Preliminary storm-total snowfall based on final CDUS41 bulletins from Sunday and Monday and today/s preliminary reports.

Sometimes the final CDUS41 bulletin (issued after midnight) reflects changes from the preliminary bulletin (issued around 5 PM); however, in this case, any changes would likely be small. Snowfall totals from today/s final reports will be used to verify the forecasts.

Report any errors in 'Remarks' along with a link to the correct data. Final results and contest summary will be posted tomorrow evening.

CAR 0.05
BGR 0.00
PWM 0.00
CON 0.90
BTV 0.00
BOS 1.60
HYA 4.10
ORH 4.10
PVD 5.50
BDR 4.00
BDL 5.40
ALB 1.40
BGM 3.30
ISP 2.60
JFK 1.80
ABE 2.20
MDT 1.20
PHL 1.50
ACY 0.40
EWR 2.10
BWI 4.30
IAD 4.50
DCA 2.90
SBY 0.30
RIC 0.05
ORF 0.00
RDU 0.00
TOT 54.20

Contest # 2 - Teleconnections

Storm begins with AO and NAO below zero but both converge toward zero as the event ends. PNA went negative and flat-lined after the Valentine/s Day storm and stayed that way.

Contest # 2 - Day Two Leader Board

Based on Sunday/s (final) and Monday/s (preliminary) CDUS41 bulletins.

donsutherland1
weathafella
herb@maws
Donald Rosenfeld
Raven
shanabe
wxfixer
mitchel volk
TQ
ilibov
DAROONEY
edhoffman503

-SN still falling over ALB...ORH...BDL...PVD...ISP...JFK...and BDR.

Valentine/s Day Storm - NESIS Category 3

In the top three storms to strike interior NE since 1940. Preliminary score is 5.63

Contest # 2 - Day One Leader Board

Based on Sunday/s snowfall data from CDUS41 bulletins.

Donald Rosenfeld
donsutherland1
Raven
weathafella
shanabe
herb@maws
wxfixer
mitchel volk
TQ
ilibov
DAROONEY
edhoffman503

Contest # 2 - Early Obs

The heavy snowfall over IAD / DCA / BWI earlier today was missed by all forecasters. PNS from LWX reported 2.9" at DCA with IAD and BWI each picking up 4.5". SN:H2O about 8:1 in the DC area...~10:1 at BWI.

Forecast soundings had depicted a relatively deep layer from ~1500 to 3500' AGL where the temperature was right at 0°C. 85H WAA ordinarily would have pushed the temperature trace to above freezing causing the snow to melt. Add to that the SE SFC wind with temperature at or slightly above 32°F should have spelled doom for snowfall...as well.

Strong UVM associated with the passage of the diffluent mid-level trof could have been reponsible for the dynamic cooling that keep the precipitation frozen all the way to the ground.

Contest # 2 - The Forecasts

Forecasters: 12
New: 3
Veterans: 9

Always good to see new forecasters along with the old hands. Good luck to all.


The consensus heavy snow axis runs from MDT - BGM - ISP - EWR - MDT with a max of 6" at ABE.

All individual forecasts have been posted to the NEWxSFC web site. Follow the link to 'Latest Forecasts.' The forecasts are ranked from minimum to maximum storm total snowfall (STP) for all stations.

Minimum STP: 22.45" - Donald Rosenfeld
Maximum STP: 116" - edhoffman503
Average STP: 58.95"
Median STP: 52.75"
10th percentile: 43.1"
90th percentile: 86.1"

Verification snowfall amounts will be posted Tuesday evening. They are considered preliminary and subject to change / challenge for 24 hours.

Contest # 2 - Call for Forecasts

The flat wave under-cutting the long wave ridge along 80W is expected to gin-up fair to good snowfalls across the northern M-A and SNE this weekend. Since beggars can/t be choosers this winter…this storm/s on deck for Contest #2.

Entry Deadline: Saturday, 24 February 2007 @ 10:30 PM EST.

Verification begins 12:01 AM EST Sunday, 25 February 2007 and ends 11:59 PM EST Tuesday, 27 February 2007.

Your forecast must be entered via the Contest/s web site. Follow the link to ‘Enter Storm Forecast.’

Forecasters will need to register once before entering, even if they were registered last year. Registration is simple, requiring only a user name and password. If you provide a valid e-mail address, a copy of your forecast will be sent to you immediately after your entry is submitted. Please ensure your browser is enabled to accept first-party cookies.

All forecasts will be posted to the NE_Wx Google Group by the Contest Administrator before 11 PM EST Saturday, February 24, 2007 and to the Contest/s web site by Sunday evening.

Contest updates are posted on the Contest/s web log.

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.

You can find the 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) by simply pointing your browser @ NEWxSFC

March of Winter/s End

Meteorological winter...defined as the three coldest months (DJF)...comes to a close in a few days but winter wx can and does continue throughout March over much of New England.

The latest monthly temperature outlook from the Climate Prediction Center (CPC) indicates above normal mean temperatures over the western quarter of the CONUS. The warm anomaly suggests the expected position of the mean long wave ridge axis.

If there/s a ridge in the west...then it follows there/ll be a trof in the east...which is good news for squeezing another storm or two out of this otherwise disappointing winter.

Coastal Teaser #5

MR progs depict active southern stream next week and the possibility for a coastal storm passing near the 40°N / 70°W 'benchmark.' Storms passing over the 'benchmark' generally produce respectable snows over SNE.

Latest GooFuS point forecasts suggest low levels would be cold enough to support frozen precipitation over interior portions of the M-A and NE.


Click image to animate loop.

Big Changes @ High Latitudes

The ECMWF/s 12z forecast from Friday shows an atmosphere quite different than the one observed all winter. The deep layer flow near the pole for much of the winter has been westerly except for the past few weeks when the weather turned bitterly cold in the E.


The ECMWF progs show a troposphere and stratosphere bathed in easterlies and the stratosphere warmed 20°C by February 24.

A warm stratosphere comes about when the troposphere is cold (lower heights in the troposphere means lower and therefore warmer heights in the stratosphere).


Deep easterlies mean the pole is dominated by HIGH pressure. Easterlies weaken the polar vortex (PV) or shift its position and leads to an increase in general storminess in the mid-latitudes.

Broad HIGH pressure at the poles is observed during the negative phases of the Northern Atlantic (NAO) and Arctic oscillations (AO). The negative phase favors arctic outbreaks in the E CONUS.

Taken together...deep easterlies...-AO...and -NAO suggest a good potential for additional winter wx along the EC toward the end of the month.

Click on cross-section images to animate.

Contest # 1 - Final Results

Full verification table and summary @ the Contest web site. Follow the links to 'Latest Forecasts' and 'Latest Results.' Finally...a contest snowstorm! Never in the eight-year history of the NE.Wx Snowfall Forecast Contest has the first storm formed so late in the season. In every other year...the first storm appeared no later than the end of December.

This storm was worth the wait. Ever changing progs in the medium range carried into the short-range period making this a difficult forecast. Loaded with sub-tropical moisture...a frisky short wave...and deep enough arctic air...record daily snowfall were observed across portions of central NY and VT. Arctic air lost out closer to the coast where strong maritime influences kept snowfall to a minimum.

1st Place - TQ
SUMSQ Error: 197.1”
SUMSQ - Z: -0.460
STP: 156.6” (4th)
TAE: 52” (2nd)
AAE: 2.08” (1st)

2nd Place - bruced
SUMSQ Error: 216.1”
SUMSQ - Z: -0.450
STP: 165.5” (6th)
TAE: 54.4” (3rd)
AAE: 2.27” (3rd)

3rd Place - donaldsutherland1
SUMSQ Error: 226.6”
SUMSQ - Z: -0.445
STP: 150.25” (1st)
TAE: 54.5” (4th)
AAE: 2.37” (4th)

Honorable Mention - noreasterjer07
SUMSQ Error: 253.5” (4th)
SUMSQ - Z: -0.427
STP: 188” (13th)
TAE: 49.1” (1st)
AAE: 2.23” (2nd)

SUMSQ: sum of square errors
STP: storm total precipitation
TAE: total absolute error
AAE: average absolute error

Contest # 1 - Verification

(Update 1) (Update 2)



Tracking down snowfall reports needed to verify forecasts sure ain/t what it used to be. The latest F6 and CDUS41 reports are now readily available through IWIN. Hot links take you directly to the latest bulletin.

Nothing like it used to be.

Many stations filed their final snowfall reports with yesterday/s CDUS41 reports. Additional snowfall reports are expected tonight from stations along the northern tier of the forecast area.

This post will be updated tomorrow morning with preliminary storm-total snowfall reports for the forecast verificaton. Snowfall totals are subject to challenge and may change...where appropriate.

Update 1
Preliminary Snowfall Totals
CAR 14.30
BGR 5.20
PWM 9.90
CON 9.50
BTV 25.70
BOS 2.50
HYA 0.00
ORH 10.30
PVD 0.50
BDR 2.00
BDL 2.40
ALB 16.80
BGM 18.50
ISP 0.50
JFK 1.50
ABE 7.60
MDT 6.00
PHL 4.30
ACY 0.80
EWR 3.40
BWI 2.70
IAD 3.00
DCA 2.20
SBY 0.50
RIC 0.00
ORF 0.00
RDU 0.00
TOT 150.10

Update 2
The preliminary storm-total snowfall amounts will become final on Saturday morning if there are no challenges. Final results will be posted Saturday evening.

Contest # 1 - The Day After

GOES12 1615z Visible - click to enlarge

Contest # 1 - Teleconnections

AO nice and low...NAO about normal - not that there/s anything wrong with that --...and PNA running a little hot.

Contest # 1 - Day Two Leader Board

Based on climo reports for 13th and 14th.
All precincts have not reported final results.

donsutherland1
TQ
bruced
bubbler86
MatthewRydzik
noreasterjer07
herb@maws
Raven
emoran
jefcled
shanabe
mattmfm
cdog127
ilibov
steveo
Donald Rosenfeld
noreaster
mitchel volk
joesco

Center of Attention

The surface LOW pressure center passed just S of Westhampton Beach , NY...home of the KFOK ASOS this afternoon. ASOS observed it passage just before 3 PM EST (20z).

Note the breezy 17G25KT wind from the ENE back into NW then N...and diminish to all of 3KT. Blowin' like stink one minute...almost dead calm the next. About 35 minutes of becalmed conditions ended when the backside of the LOW blew in on a 24G33KT wind bringing FZRA and sharply colder temperatures with it. The temperature fell 8°C (~14°F) in about 90 minutes. The 40°F mP dew point dropped to 25°F in cP.

141853Z 04017G25KT 1SM -RA BR BKN006 OVC010 03/02 A2899
141914Z 07011KT 1 1/4SM -RA BR OVC004 03/02 A2896
141953Z 33005KT 1 3/4SM -RA BR OVC004 05/04 A2895
142003Z 35003KT 2SM BR OVC004 04/03 A2894
142017Z 31007KT 1 1/2SM BR BKN004 OVC007 04/03 A2895
142043Z 33024G33KT 2SM -FZRA BR OVC002 M01/M02 A2896
142053Z 32023G29KT 2SM -FZRA BR OVC004 M02/M03 A2898
142116Z 32024G32KT 3SM -FZRA BR OVC004 M03/M04 A2903
142121Z 32027G34KT 2SM -FZRA BR OVC006 M03/M04 A2903
142129Z 31024G34KT 1 1/4SM -FZRA BR OVC006 M03/M04 A2904

The reason the horizontal wind stops blowing in the center of circulation is b/c all the air movement is going straight up.

Contest # 1 - Day One Leader Board

With plenty-o-storm left to go...the Day One leader board has bubbler86 in 1st, jefcled 2nd, and donsutherland1 3rd.

Not all precincts have reported final amounts.

bubbler86
jefcled
donsutherland1
herb@maws
MatthewRydzik
TQ
emoran
bruced
Raven
mattmfm
shanabe
cdog127
noreasterjer07
ilibov
steveo
noreaster
Donald Rosenfeld
mitchel volk
joesco


Click image to animate.

Secondary surface development over SC around 14/00z. Initial surface LOW pressure of 1003 mb falls rapidly between 06z and 18z to 978 mb @ 21z.


Click image to animate.

Center of circulation just E of Long Is., NY. Greatest pressure falls INVOF PWM indicating short-term storm track. Recent 88D VAD data showed center of 700 mb circulation south of BTV...east of ALB... and NW of GYX strongly suggesting the system still has some tilt with height left in it and further deepening of the surface LOW is likely.


GOES8 @ 3:45 PM EST (2045z) observation of frontal boundaries over the western Atlantic...the secondary LOW E of LI, NY...strong arctic CAA over SNE coastal waters producing FZRA INVOF Westhampton Beach, NY (KFOK)

Contest # 1 - The Forecasts

Forecasters: 19
New: 8
Veterans: 11

Welcome to all the new folks and welcome back to the old timers. Good luck to all.


The consensus heavy snow (12"+) axis runs from BGM - BTV - CAR - CON - BGM.

All individual forecasts have been posted to the NEWxSFC web site. Follow the link to 'Latest Forecasts.' The forecasts are ranked from minimum to maximum storm total snowfall (STP) for all stations.

Minimum STP: 94" - jefcled
Maximum STP: 536" - joesco
Average STP: 186"
10th percentile: 115"
90th percentile: 256"

Two entries were rejected b/c the more than 95% of the stations had zero as the forecast snowfall. One entry was rejected b/c it was received outside the grace period.

Verification snowfall amounts will be posted Friday evening. They are considered preliminary and subject to change / challenge for 24 hours.

Arctic Nation

Brisk cross-polar flow.



Click image to animate.

Watch arctic HIGHs migrate E from Siberia across CN/s NW Territory and into Lower 48.

The ECMWF/s Stealth Miller B

Does today/s 12z ECMWF D+5 forecast a deepening Great Lakes upper LOW capturing and intensifying the M-A surface LOW toward the 'benchmark' @ 40°N / 70°W...

...or does it excite a 'back-door' Miller B and drag it onshore?

The upper LOW is shown coming in the back-door from ern CN instead of its more common direct approach from the NW. The upper LOW would be expected to develop a surface reflection on the E side of the short-wave trof. Given the deep...unstable vertical temperature and moisture profile...cyclogenesis would be rapid and intense.

Note the orthogonal (90°) crossing angle of the MSLP isobars (equivalent to the geostrophic wind @ the boundary layer/s top) and 5H Z to the E of the LOW indicating veering vertical shear and strong UVM from WAA. These dynamics will build the downstream short-wave ridge enhanced by the release of latent heat and slow the easterly progression of the upper air features.

The low resolution of the model post-processing may prevent the depiction of this feature.

Should the 'back-door' scenario come to pass...the snows over the M-A would pale in comparison.

Standby for Contest #1! - Again

What could be this winter/s one and only contest storm appears likely to affect a good portion of the M-A and SNE early next week. MR progs continue to depict a strong frontal wave forming over the GOM states. The storm forecast track takes it ENE across the M-A on its way toward the western Atlantic Ocean where it undergoes cyclogenesis as it passes the benchmark @ 40°N / 70°W.

An easterly extension of the parent HIGH pressure...centered over western CN...into SNE and northern portions of the M-A will play a key role in determining the position of the RN / SN line.

Latest trend analysis shows the edge of 32°F SFC isotherm creeping slowly N + W with time. Should the trend continue...best snows would fall INVOF the DCA - BWI area. The main caveat in play...even within 24 hrs of the event...is NWP models long-held difficulty in resolving the southern extent of low-level arctic air. The models often fail to forecast the freeze line far enough south wrt to the verifying analysis.

If the upper LOW INVOF the Great Lakes is able to capture the surface LOW and pull it toward the coast...big snows would be in store for SNE...too.

LES is More

Big time lake effect snow event along the windward shore of Lake Ontario this past week with historic snowfalls recorded at some stations.

The observed conditions @ Watertown, NY on February 4 are of particular interest.

METAR KART 041756Z AUTO 28014G18KT M1/4SM +SN FZFG VV001 M12/M14
METAR KART 041856Z AUTO 27012G31KT M1/4SM +SN FZFG VV001 M11/M13
SPECI KART 041942Z AUTO 25015G33KT M1/4SM +SN FZFG M11/M13
METAR KART 041956Z AUTO 27019G31KT M1/4SM +SN FZFG M11/M13
SPECI KART 042014Z AUTO 26017G29KT M1/4SM +SN FZFG VV001 M11/M13
SPECI KART 042051Z AUTO 26016G24KT M1/4SM +SN FZFG M11/M13
METAR KART 042056Z AUTO 27012G22KT M1/4SM +SN FZFG M11/M13

From 1756z until 2056z...there was considerable falling or blowing snow. Visibility was frequently reduced to less than 1/4 SM. The wind frequently gusted to above 35 MPH (30 KTS). These observations depict near-blizzard conditions from lake-effect snow. Had these conditions lasted a little while longer...they would have meet the three hour threshold for a blizzard.

The theta diagram shown below shows deep layer instability from the surface up to ~750 mb.

The SkewT-logP diagram shows the vertical temperature profile is nearly dry adiabatic from the surface to ~750 mb...moist adiabatic from the LCL near 900 mb...and deep moisture in the column up to ~700 mb. With such an unstable sounding and cold temperatures aloft...it/s surprising there were no reports of +TSSN. Also note the low tropopause height near 350 mb (~25K')


More interesting and extreme LES obs from Buffalo, NY
SPECI KBUF 032210Z 24029G38KT 0SM R23/0600V2200FT +SN FZFG BLSN VV001 M08/M09
[...]
SPECI KBUF 032359Z 24032G40KT 0SM R23/1800VP6000FT +SN FZFG BLSN SCT004 BKN015 OVC040 M09/M12

Zero visibility although runway visual range reported a low value of 600' (~0.1 SM). Wind gusts to 46 MPH.

Snow Storms...They/re Only A Week Away

5H Z and MSLP


85H T and MSLP

MR models are at it again with teaser progs for this winter/s first significant EC snow storm and as usual...it/s just a week away.

This 'now-you-see-it...now-you don/t' scenario has played itself out several times this season. Sooner or later...odds are the atmosphere will get around to pulling the trigger instead of our thumb.

Today/s D+7 prog from the ECMWF depicts a classic cold air damming signature over the NE with strong arctic HIGH pressure centered over the Upper Great Lakes...supported downstream by an area of mid-level confluence...multiple sea-level isobars nosing SW along the Appalachian Mtns as far south as the GA / SC border...and an inverted trof along the SE seaboard indicative of a coastal front.



One big problem with the setup @ this point is the progressive nature of the flow regime as multiple short-waves are shown embedded in the westerlies. This suggests the storm might not be inclined to hang a left and hug the coast as it continues NE.

Snow Moon

Native American folklore holds February/s full moon...which occurs tonight...was known as the Full Snow Moon...supposedly b/c the heaviest snowfalls occurred during the second month of the year.

Maybe the tribes of northern and eastern America called it that...maybe they didn/t. All too often...Anglo-saxons have come up with pleasing stories about native peoples with little or no basis in fact.

Nevertheless...it would make for better folklore...regardless the origin...if it were based on observations that February is the climatologically favored time of year for good snows in the NE.

Too bad it/s not so. For most stations in the NE CONUS...January has the highest period of record normal (PORN) snowfall. In some cases...the difference between one month and the other is small...and maybe a statistical test on the difference between the two means would fail to reject the null hypothesis...but the data suggest the Snow Moon probably belongs to January.