CONTEST STATUS - Updated: WED ... 13-DEC-17 @ 8:30 PM EST

Winter '17 / '18 - Snowfall Forecast Contests
19th Annual 'Regular Season'
Snow Storm #1
Synoptiscope in VCP32

17th Annual 'Season-total'
Deadline for entries has passed
Forecasters' summary here

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Winter '16 / '17 - Snowfall Forecast Contests
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18th Annual 'Regular Season'
FINAL results here
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16th Annual 'Season-total'
FINAL results here

Monday, December 31, 2007

Contest # 4 - The Forecasts

Maximum...average...median...and minimum station forecasts

Seven veteran forecasters. No rookies who must all be out partying tonight.

MAX STP: jackzig 61.25"
MIN STP: TQ 42.45"
AVG STP: 53.50"

Another northern New England event where the consensus heavy snowfall axis is expected from CAR - BGR - PWM - CON - BTV - CAR.

All forecasts have been posted to the NEWxSFC web site. Follow the link from Storm Contest Forecasts 'Contest # 4'. Forecasts are ranked from minimum to maximum STP.

Contest # 3 - Teleconnections

Heavy snows fell across northern portions of the forecast area...yet so-called 'critical heavy snowfall' teleconnection indices are all on the wrong side of zero for this event.

Not surprising. It/s another meteorological myth that can/t stand the light of data.

Sunday, December 30, 2007

Contest # 3 - The Forecasts

Maximum...average...median...and minimum station forecasts

Forecasts have been posted to the Contest web site. Follow the link to Contest #3.

Minimum STP: GSB Snowman 43.15"
Maximum STP: wxduff 72.05"
AVG STP: 59.61"

Consensus heavy snow axis from BGR - PWM - CON - ORH - ALB - BGR.

Contest # 4 - Call for Forecasts


Northern stream short-wave progged to spread contest-worthy snows across the forecast area as it migrates east from the Great Lakes and excites cyclogenesis in the waters off SNE coast on New Year/s Day.

Deadline: 10:30 PM EST Monday...31 December 2007
Forecast verification begins: 12:01 AM EST Tuesday...01 January 2008

Enter your forecast via the Contest/s web site
Follow the link to 'Enter Storm Forecast.'

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

All forecasts will be posted by the Contest Administrator to the NE_Wx Google Group before 11 PM EST Monday...31 December 2007 and to the Contest web site by Tuesday 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 @ the web site.

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Forecasters 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. 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.

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.

You can find the Contest Rules and additional information about error scoring…current monthly snowfall climatology from NCDC…daily CPC teleconnection indices…daily NESDIS NHEMI snow cover…and NWS Daily Climate Bulletins (CDUS41) by pointing your browser here.

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Happy New Year - Contest # 4?


Sunday/s 12z progs suggest another contest-worthy event on New Year/s Day with cyclogenesis occurring in the Gulf of ME followed by an arctic outbreak.

Thermal profiles appear colder for this system..and like Storm # 3...it taps into hi-PW parcels from low latitudes.

Saturday, December 29, 2007

Contest # 3 - Call for Forecasts


Fairly decent snows on the northern edge of the precipitation shield are expected to attend a deepening wave passing over the 40°N / 70°W ‘benchmark’ late Sunday into New Year/s Eve.

Deadline: 8:00 PM EST Sunday, 30 December 2007
Forecast verification begins: 8:00 PM EST Sunday, 30 December 2007

Enter your forecast via the Contest/s web site
Follow the link to 'Enter Storm Forecast.'

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

All forecasts will be posted by the Contest Administrator to the NE_Wx Google Group before 11 PM EST Sunday, 30 December 2007 and to the Contest web site by Monday 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 @ http://newxsfc.blogspot.com


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Forecasters 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. 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.

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.

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 pointing your browser here.
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Contest # 3 - Definite Maybe


12z NAM depicts a narrow band of 'hard to get excited about' nuisance snows on the nrn edge of a rain dominated precip shield. OTOH...GooFuS is back in the decent contest storm category after venturing off the reservation last night.

Final decision pending tonight/s 00z runs.

Friday, December 28, 2007

Contest # 3 - Unfriendly Trend


Friday/s 12z GooFuS solns for a 'contest-worthy' event come Monday were a darn sight better than tonight/s 'low and away' look. Latest GFS short-term output is now much more in line with the earlier 'contest-hostile' solns from NAM.

Given the unfriendly trend...Contest # 3 awaits another day.

For that matter...next two weeks don/t look all that promising either.

Thursday, December 27, 2007

Happy New Year - One Step Closer

Today/s EC D+5 takes a big step closer toward a significant winter wx event for Northeast CONUS come New Year/s Day.

Note the depiction of greater amplitude to the wrn ridge and how the sfc LOW/s re-development off the mid-Atlantic coast is better defined than yesterday/s D+6 prog.

Whether it all gets there is still up on the air...but without a doubt...we be moving in the right direction.

Wednesday, December 26, 2007

Happy New Year


Today/s European model D+6 has real potential...despite the evolution and present placement of its major features.

The SE heat ridge has shifted its position once this winter...when it retrogressed about two weeks ago and widespread snows were observed in the NE. This time...a progressive planetary wave regime shoves the heat ridge well offshore by D+10 into the south-central ATL.

Is that soln reasonable given the how persistent the heat ridge has been to date...or might today/s soln be a tad too progressive? The implications for EC wx are significant if the soln truely is too progressive.

Also consider what/s progged to happen in the ern PAC where the model depicts deep layer WAA. Ordinarily...this would be expected to pump up or amplify the downstream S/W ridge.

In the event the SE heat ridge is not so progressive...and the wrn ridge b/comes more amplified by WAA...the wave length across CONUS would be shorter and the amplitude greater than presently progged.

Such an alternative scenario keeps the L/W trof closer to the EC where cyclogenesis would likely occur @ a latitude low enuf and a significant snowstorm is in play for much of the I-95 corridor.

Sunday, December 23, 2007

NHEMI Snow Cover Inventory Up 10%...Cryosphere Busy Making Up for Lost Time


Over @ Global Warming heretic Joe D/Aleo/s blog...these NHEMI snow cover charts come courtesy of Dr. Bob 'CoolWx' Hart of FSU fame...

The graphic on the left depicts the areal NHEMI snow cover...which is now 10% > CLIMO (1996 - 2005)

The upper part of the chart on the right shows a comparison between 'CLIMO' and 'Observed' snow cover. Note the lines cross in the upper right corner. The lower part of the same chart shows the trend in magnitude of the snow cover/s deficit / surplus.

Dr. Joe expects hi-latitude arctic air masses to visit the Lower 48 come JAN '08 resulting in big forecast busts for NOAA and PWSPs.

NEWxSFC looks forward to his forecast verifying in spades.

Friday, December 21, 2007

That 70s Show


Made a post @ StormVista this evening about what to 'expect' next month based on inferences from this winter/s leading analog year 1970. You can find it here. If you/re a SV member...you/ll see graphics embedded in the post. OTRW...you/ll have to click links...so go ahead a sign up.

It made sense to make the post over there b/c their platform has far superior graphic handling and text formatting capabilities than Blogger.

Gist of the post:
  • 1970 is a strong analog for this winter based on 'least squares' regression of MEI and QBO values.
  • MSLP analysis for 12/9 - 12/18 show remarkable similarity between '07 and '70.
  • Analysis of JAN 1971 5H Z and SFC T anomalies suggest a cold and stormy JAN '08 lay ahead.
  • Analogs are fun but not very reliable.
Cold and stormy are our watch words @ NEWxSFC.

Thursday, December 20, 2007

'49 / '50 Analog on Life Support


Accu-Wx went into a defensive crouch today with a missive by WxMatrix/s Jesse Ferrel where he advanced the arguments 'winter hasn/t started yet' and 'it/s not over...until it/s over'.

Both arguments are silly on their face.

If winter has yet to begin...then why does AW/s Winter Outlook include details about early and mid-DEC. Ferrel then argues their outlook covers NOV through MAR. So which is it?

The 'A forecast hasn/t busted until the event has come and gone' maxim is true altho that/s a mighty thin reed given the current state of winter to date and trends in LR NWP.

Accu-Wx/s Winter '07 / '08 outlook is heavily weighed by the '49 / '50 analog where cold temperatures @ the start of DEC flipped to abnormal warmth mid-month and stayed above normal through FEB.

The time series shows 5H geo-potential heights (left two images) and SLP (right two images) from the pole to 10°N during the first nine days of DEC for 1949 and 2007. Hard to see anything other than weak correlations.

The northern polar stereographic view for the same nine days @ 5H depicts one similar feature...the weak trofs off the west CONUS coast...and several that are at markedly @ odds with each other. Note the analog year trof INVOF the Azores and a ridge in the observed. There/s an analog year trof in the GOM and ridging in the observed. There/s a ridge INVOF the Hawaiian Is. in the analog year and an observed trof.

In the mass fields...both years have HIGH SLP over Siberia...altho it/s much stronger in the analog. Evidence of a GOM LOW in the analog is missing in the observed where a broad area of LOW pressure is centered along the International Date Line.

Not looking too good ATTM for our friends at Accu-Wx. They/ve made a lot of noise and thumped their chests since October hawking the near-certain expectation for a sudden...and dramatic about face in temperatures that would occur mid-DEC. At this point...the '49 / '50 analog might need to be placed on life support.

Calling Doctor Howard...Doctor Fine...Doctor Howard.

Had intended to post the analog / observed comparisons last week...but a good contest snow storm came along...and seeing how that/s the reason why we/re here...it was delayed. Will post an update with a look at the period that/s passed since then.

Wednesday, December 19, 2007

Return of Hi-Latitude Easterlies

Note the ECMWF/s D+8 forecast for the return of deep tropospheric...hi-latitude easterlies over the pole suggesting a return of a negative AO index toward the end of DEC.

The time-height section also shows the 70mb mean zonal wind from the east over the Equator...indicating the negative QBO.

Negative QBO favors a negative AO...which is associated with a less stable...and slower polar vortex. These conditions present good opportunities for arctic outbreaks....storminess...and the potential for hi-latitude blocking.

Contest # 2 - Results

Rookie Forecaster pjc368 issued the best forecast for NEWxSFC/s Snow Storm #2.


pjc368 placed 1st in 'SUMSQ Error'...'Total Absolute Error'...and 'R²' categories of forecast skill. Bold forecasts for CAR and BTV put him over the top.

Close call for 2nd place where donsutherland1 edged out TQ by 0.1 SUMSQ Error points!

Full results and summary @ the Contest web site.

Follow the link under Forecasts to 'Contest #2' to see the complete...station-by-station forecast verification.

Follow the link under Results to 'Contest #2' to see forecast and contest summary information.

Tuesday, December 18, 2007

Teslacles/s Deviant to Fudd/s Law

On the afternoon of December 16...a rapidly deepening secondary LOW had moved to a position over Lower NY Bay... having advanced NE hugging the shorelines of VA...MD...and NJ during the morning.

The center of circulation passed directly over NDBC/s moored buoy 44017 around sunset...evidenced by the becalmed wind observation just before the minimum pressure was recorded.

The green pressure trace below reveals a 24-HR pressure fall of 1.45" Hg (~49 mb) which...after Sanders... more than constitutes a 'meteorological bomb.'



Sanders 'bomb' definition related to explosive cyclogenesis where the 24-hour pressure fall was greater than or equal to 1 mb per hour @ 60°N.

The reason the surface wind had approached zero as it migrated past the buoy was b/c converging air...brought to the LOW/s center by the pressure gradient force...had no where else to go but up.

Here we have a real-time example of meteorology/s 'Continuity Equation'...which is all about 'Conservation of Mass'...also known in some quarters as 'Teslacale/s Deviant' corollary ("What goes in...must come out") to Fudd's Law (“If you push something hard enough, it will fall over”).

None of this purports to answer the age-old musical question..."How can you be in two places @ once...when you/re not a-n-y-where @ all?"

Contest # 2 - Verification

Preliminary storm-total snowfalls from CDUS41...CF6...and PNS bulletins for Saturday...Sunday...and Monday.

SN-to-H2O ratios are average values where combined storm-total snowfall is divided by storm-total melt water...which can mask the effect of changes in the vertical temperature profile SN:H2O was 12:1 on Saturday @ BTV and 18:1 on Sunday. BGM/s ratio is not reported b/c it was contaminated by Saturday/s freezing precipitation; however...Monday/s 1.2" FES SN:H2O was 40:1.

New daily records
12/16
BOS - 7.6" (5"; 1896)
ORH - 8.4" (6"; 1896)

12/17
CAR - 9.2" (7.3"; 1978)

Final results and storm summary on Wednesday.
Please report errors in 'Remarks.'

Monday, December 17, 2007

Sunday, December 16, 2007

Contest # 2 - Teleconnections

Contest Storm #2 got no help from the PNA index as it was negative during the period. Positive PNA is frequently cited as an important ingredient for decent snowfalls in the NE CONUS. A positive PNA index doesn/t hurt b/c it oft times favors cyclogenesis off the SE CONUS coast...but it/s not an absolutely necessary ingredient.

LOW heights dominating the NHEMI polar region resulted in an above normal AO index as the s/w trof lifted NE into the forecast area. The index declined slightly while the event unfolded on Sunday.

The negative NAO index...currently @ nadir...was a likely consequence of the decaying Rex block over Europe with the westerly extension its trof axis INVOF the Azores rather than significant ridging over Greenland. The vortex over NE CN / Davis Straits was also a contributing factor.

The teleconnection indices associated with Contest Storm #2 offer more evidence that +PNA and -AO / -NAO are not prerequisites...as all too commonly presumed...for decent snows across the NE.

Saturday, December 15, 2007

Contest # 2 - The Forecasts

Maximum...average...median...and minimum station forecasts

Eighteen forecasters...three rookies.

Storm Total Precipitation (STP) forecasts range from a low of 46" (Superstorm) to a high of 145.8" (smadsen8486).

Average STP: 87.9"
Median STP: 80.6"

Forecasters expect this snow storm...like the first contest storm...to be a northern New England event...where the consensus heavy snow (6"+) axis extends from BGM - ALB - BTV - CAR - BGR - PWM - ORH - BGM.

All forecasts have been posted to the NEWxSFC web site. Follow the link from Storm Contest Forecasts 'Contest # 2'. Forecasts are ranked from minimum to maximum STP.

Distribution of normalized STP forecasts by forecaster

Click images to enlarge.

Friday, December 14, 2007

Missed Opportunity

The deadline for Contest #2 is Saturday evening but in hindsight...it should have been Thursday evening given the respectable amount of snow that fell across SNE today.

Always hate to miss a good opportunity to hold a forecasting contest...especially given the dearth of decent events the past few years.

The NAM/s 00z Wednesday run continued it/s previous scenario for a marginal contest event (less than six (6) stations; nuisance snowfall) across the forecast area. The 12z GFS had shown good continuity from earlier runs but b/c we/re inside 48HRS...model consensus is an important factor when deciding whether an event is contest-worthy. NCEP and ALR/s servers were jammed Tuesday evening when the 00z Wednesday runs were posted and the GFS was not accessable.

Next go'round...when there/s uncertainty about how the event might unfold...a 'call for forecasts' will be issued and if it later becomes apparent the storm is heading for the crapper...the contest will be canceled.

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)

Thursday, December 13, 2007

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.

Monday, December 10, 2007

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.

Sunday, December 9, 2007

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.

Saturday, December 8, 2007

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

Thursday, December 6, 2007

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

Wednesday, December 5, 2007

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.

Monday, December 3, 2007

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

Trends in NHEMI Snow Cover


Tony Wood of the Philadelphia Inquirer writes in his Weather or Not column today about trends in NHEMI snow cover. Areal coverage has been decreasing and the spring melt has come earlier. An earlier post on NEWxSFC suggested similar trends.

Tony reports some interesting observations made by Rutgers University/s geography professor David Robinson and AER atmospheric scientist Judah Cohen on the subject and what it all might mean.

"First, and curiously, the snow cover in other seasons (summer, fall and winter) hasn't shown big changes, Robinson says.

"Second, after falling off in the late 1980s, reaching a record low in 1990, the snow cover rebounded - until three years ago. So the decreases in complete calendar years 2004, 2005 and 2006 could constitute an anomaly.

"Third, Robinson, who contributed to the blue-ribbon Intergovernmental Panel on Climate Change (IPCC) reports, says that one could make the interesting argument that the world is warmer because of less snow.

"It's a chicken-egg question," he says.

Judah Cohen adds...
"The physical mechanism isn't fully understood, Cohen says, but fall snow coverage evidently affects air pressure patterns that influence other changes: An above-normal snowpack in Siberia in October correlates with below-normal temperatures in the United States in winter.

"October is the key, Cohen believes, because when the sun is strongest (summer), the snow is scarce; when the snow cover peaks (winter), the sun is absent. October has both."

More...
Rutgers University Snow Lab
sCAST from AER...Inc

Sunday, December 2, 2007

Contest # 1 - Teleconnections


Sharp decline in AO and NAO the right before the storm day. Small rise in otherwise flat / negative PNA.

Near-simultaneous drop in AO / NAO and rise in PNA reflect L/W amplification associated with the storm.

Contest # 1 - The Forecasts

(updated below)


Click to Enlarge

Sixteen Fifteen forecasters...one rookie...and one late entry pending approval

Storm Total Precipitation (STP) forecasts range from a low of 55.7" (smadsen8486) to a high of 108" (Mitchel Volk).

Average STP is 78.9"

Clearly a northern New England event...where the consensus heavy snow axis (+6") extends from BTV - CAR - BGR - PWM - CON - BTV.

All individual forecasts have been posted to the NEWxSFC web site. Follow the link to 'Contest # 1 - The Forecasts'. The forecasts are ranked from minimum to maximum STP for all stations.

UPDATE: The 16th entry was disqualified b/c the forecaster took into account model data not available to other forecasters who entered on deadline.

The forecasts posted on the web site will be updated during verification.

Saturday, December 1, 2007

Contest # 1 - Call for Forecasts


Hot on the heels of the ‘season-total’ contest deadline…the first storm of the new ‘individual storm’ season is progged to affect a good portion of the forecast area Sunday through early Tuesday. We/re off to a good start compared to last year when the first contest storm didn/t happen until February.14.

Deadline: 10:30 PM EST Saturday, 01 December 2007
Forecast verification begins: 12:01 AM EST Sunday, 02 December 2007

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

Forecasters 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. 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, 01 December 2007 and to the Contest web site by Sunday evening.

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

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

Please enter 0.05 for trace amounts instead of a 'T.' if no snow is expected at a station, please do not enter a zero, just leave it blank, instead.

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.

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 pointing your browser @ www.newx-forecasts.com

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Tuesday, November 27, 2007

The Retro Heat Ridge

Today/s D+10 ECMWF and GooFuS progs have kissed and made up following their recent spate of dissonant solns regarding the evolution of a La Nina-style heat-ridge parked over the SW ATL Ocean. Also note the hi-latitude block indicative of a strong negative phase of the Arctic Oscillation.


Should be good and chilly in the E and with the full latitude trof...good baroclinicity and opportunities for coastal storms.



There/s been talk of late in some 'well respected' quarters about a mid-month return to warmth -- as in 'abnormally warm' warmth -- when the full fx of La Nina become firmly established. It/s hard to see where that/s indicated or even remotely suggested if the D+10 and D+15 GFS ensemble means are to be believed.

Saturday, November 24, 2007

Folklore - December


A green Christmas; a white Easter.

If there's thunder during Christmas week...
The Winter will be anything but meek.

The nearer the New Moon to Christmas Day...the harder the Winter.

If Christmas day be bright and clear
There’ll be two winters in the year.

Thunder in December presages fine weather.

Like in December like all the year long.

Friday, November 23, 2007

Winter '07 / '08 - What Is It About Week One?


Is there something special about the first week in December or is it merely a case of undue importance being placed on more recent events that makes it seem that way?

Questions about Week One/s seemingly 'stormy nature' have been raised b/c GooFuS LR solutions...as they/re wont to do now that winter grand entrance is waiting in the wings...have again begun dangling shiny objects before our eyes.

The first week of DEC has been a good period for snow storms in the NE the past half-decade. The table shows the number of contest stations reporting snow by year and day of week.

The only other period since 1948 where the first week of DEC was that active - defined as number of stations affected - was between 1954 and 1958.

CAR and BGM have the best chance (20 - 30%) of a measurable snowfall on any day during Week One. BGR has a 20% probability on three of the seven days.

Thursday, November 22, 2007

As November 21st...so the winter


If that/s the case...then this winter will hew closely to the CW for 'above normal' temperatures...especially in SNE and the M-A.

A few stations in the NE were below normal yesterday. BGR - PWM - BOS - BDL - CON had departures from -1 to -3°F...due in large part to low overcast and light rain.

Elsewhere...
+1 to +4°F: CAR - BTV - PVD - BDR - ISP - JFK - EWR
+7 to +10°F: ALB - ABE - MDT - PHL
+12 to +20°: ACY - SBY - RIC - RDU - IAD - DCA - BWI

IAD took top honors at +20°F.

Tuesday, November 20, 2007

ECHAM/s October Outlook - Verification



Appears to be a miss grande.


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

Cooler (warmer) colors in the PSD image are negative (positive) pressure anomalies.

Trends in NHEMI Snow Cover


Plot of CPC/s NH snow area data...as of the end of SEP.

The black line near the chart/s center is the yearly average from the start of the period-of-record.

In 1977...the 5-year moving average snow area was 25.3 x 10^6 km^2. In 2006...the 5-year moving average snow area was 24.1 x 10^6 km^2...a change of ~1.2 million square kilometers.

The data generally show modest year-to-year variability...the exception being OCT...which has slowly increased by 6.7 million square kilometers since 1988.

WSI/s Foundering Winter '07 / '08 Forecast


"Typically, in the eastern U.S., La Nina means a warm October and a cold
December," Crawford said in the press release. But ocean temperatures in
the northern Pacific indicate a colder October in the Northeast, he said."

WSI got off to a slow start with its winter LR forecast issued in SEP calling for a 'below normal' OCT in the Northeast. OCT temperatures in the NE and mid-Atlantic came in 7 - 9°F above normal. Crawford went on to predict 'above normal' temperatures in NOV...but that call is going up in flames...as well.

WSI stuck to its 'warmer than normal' NOV forecast in its late OCT update...which also called for DEC to be 'below normal' and JAN 'above normal.'

The latest WSI forecast...issued a week ago...continues to expect DEC to be 'below normal' and JAN 'above normal.' The FEB forecast...appearing for the first time...is 'above normal.'

Beating CLIMO demonstrates forecast skill. The shorter the lead time the better chance there is to getting it right. So far this year...these guys got nothing.

Monday, November 19, 2007

Swiss Alps - Biggest Snowfall in 55 Years

Starved of snow the past few years...the Swiss Alps are making up for lost time this month. Up to 120 cm (~4') have been observed during the past ten days...with 62 cm (~2') falling in one 24-hour period in eastern Switzerland (elev. 1,560 m...~5200').

More...

Saturday, November 17, 2007

Snowstorm Contest Season

The season starts when the storms start and continues until it/s obvious winter is over. The season runs normally from early December through the middle of March; however, IIRC, the earliest contest storm occurred in late November and the latest storm was in April. Most years there have been ten contest storms.

Not every snowstorm that affects the forecast area will trigger a contest. The criteria used to decide whether a storm is contest-worthy are loosely defined as one that/s expected to:

  1. Affect at least six to eight forecast stations and
  2. Produce more than a nuisance snowfall (>= 4") and
  3. Be well-progged by NWP ~36 to 48 hours before snow is observed at any one station.
Visit the website for more information about how to enter a forecast and how forecasts are verified and scored.

Base Leg...Turning Final - Part II


In addition to the 500 mb time-series of 'MEI-preferred' La Nina years presented in a previous post...these examples also generally depict much different flow regimes than are presently observed...altho '75 is ballpark-ish.

1950...1955...1973...1975
500 mb time-series for early NOV from prior La Nina years.


Will have to look into the winter of '75 / '76 to see how the forecast area was treated.

Bump: Winter '07 / '08 Season-total Snowfall Forecast Contest


Visit NEWxSFC/s web site to enter. Follow the link to 'Enter Season-total Forecast.'

Deadline: 30 November 2007 @ 11:59 PM EST

Details

Friday, November 16, 2007

Base Leg...Turning Final


Climo...2007...1988...1970

Time series of SLP CLIMO...current wx...and 'preferred' MEI-analog Novembers.

First half of NOV 2007 SLPs mimic CLIMO/s low pressure signature over E-PAC. Both 'preferred' MEI-based 'La Nina' analog years are similar but they show a lower correlation with 2007...although '70 leans a bit more toward current conditions at end of period over E-PAC.

Current SLP time-series raises a measure of doubt about this year/s developing consensus for the "warm 'n dry" version of Nina-style winters.

Even stronger evidence of how useless analog forecasting can be...can be seen at 500 mb...


500 mb Climo...2007...1988...1970


Early winter at least...lookin/ more-n-more normal as December approaches.

Thursday, November 15, 2007

Heresy in Harrisburg


"...colder than average and snowier than average..."

CBS-affiliate WHP-21/s wx heretic Tom Russell jumps into the winter forecast fray with both boots by taking the contrarian view.

His is the perennial favorite...'cold 'n snowy.' What/s not to like about that?

Bastardi Bold


"...(F)orecaster Joe Bastardi of AccuWeather on Tuesday reiterated his forecast for a warm winter in the Northeast, although the weather has been running colder than normal since Nov. 1. In an interview with MarketWatch, he said it will stay cold until the middle of December and then run about four degrees above normal in the northeastern U.S."

Rather BOLD prediction given December/s temperature departures during past -ENSO events. Much of NE has been one-half to one standard deviation below normal...the same being true for large portions of the M-A.

Monday, November 5, 2007

Nieves de La Nina


Take your pick.



D-J-F snowfall maps for seven La Nina Years Selected by Climate Predition Center using ocean criteria (1942-43...1950-51...1955-56...1970-71...1973-74...1975-76...1988-89)

Make your own.

Saturday, November 3, 2007

November/s ENSO Anomaly Forecast




Latest consensus ensemble mean forecast for ENSO Region 3.4 this MET winter (D-J-F) is ~-1.8°C...indicating 'strong' La Nina conditions are expected. Five of the six latest model runs are less than or equal to the forecast ensemble mean. Forecast values have delined each month since May (-0.6°C). Last month/s forecast was -1.6°C.


Monday, October 29, 2007

Winter '07 / '08 - Place Your Bets


Plenty-o-conventional wisdom underfoot this fall about a moderate-to-strong La Nina holding court over the upcoming winter. There/s even more CW obviously based on multi-event composites about how "warm 'n dry" it/s gonna be for the CONUS east of the much 'wetter' Lucky Ducks in OH / TN River valleys.

Too bad there/s no emoticon for skeptical chin-stroking with deep furrowed brow; otherwise...it might go here. Instead...take a look at the long-term composites for temperature and precipitation...

Temperature.................Precipitation


Mean temperature normal to 1°F above normal and mean precipitation '-2" to normal' extreme southern forecast area to 'normal to +2"' elsewhere.

The La Nina Analogs
The current MEI index 'trend match' has its best fit to '70 / '71...although the subsequent winter was almost over before the -ENSO event became strong. The latest numerical and statistical model output forecast a strong event (le -1.5°C) throughout all of met winter.


Note the highly ranked precipitation area (blue) across the GOM states and greater than median values along the EC and interior NE.

The next best MEI matches occurred prior to the non-Nina winters of '78 / 79 and '59 / '60. That leaves '88 / '89 as this winter/s runner-up MEI analog.


The '88 / '89 analog winter is closer to this year/s CW 'La Nina' winter forecast of 'warm and dry.'


Other Indices and MEI -- BFF or What?
PDO - '70 / '71 was 'warm' during its long-term 'cool' phase. This year/s PDO is 'cool' during a 'warm' phase. No benefits from these friends.

QBO...perhaps? The '70 QBO analog is ranked 5th; however...considering its 'E phase' in '70 / '71 flipped to W in March...two months earlier than the expected change in direction this winter. This flip/s timing could well be important this year b/c the QBO/s E phase is a leading indicator for a -AO and its associated increase in EC cold / storminess through the process of downward wave propagation.

AO...NAO...PNA...EP...and other like indices are thought to have skillful forecast ranges of about two weeks. There could be some utility in LR forecasting with these values if a multi-year trend is present.

The '70 / '71 analog demonstrates the variability of La Nina winters and suggests the coming winter won/t wind up 'warm and dry' in the NE or M-A.