Wednesday, March 23, 2011

Grades for the (Mostly) Unwanted Storm of March 22-23


Our standard disclaimer: The grades we provide are not scientific. However, they represent our best effort to assess the performance of Twin City weather outlets. Our grades are based on established grading criteria and we maintain forecast histories for each event. It might also be helpful to read our “Weather Watcher’s Bill of Rights” to get a sense of our perspective.

Over the last several weeks, it seems, the ferocity of a storm seems inversely related to the amount of media hype. This storm was no exception. For the progressive forecast by weather outlet for this storm, click here.

In general, the rain/sleet/snowstorm of March 22-23 was tough to forecast. Until about 12 hours before the onset of the storm, most forecasters believed the heaviest snow would fall well north of the Twin Cities and that the storm’s calling card would be a small, slushy nuisance accumulation. In the end, the inner core of the Twin Cities was significantly affected as evidenced by the huge number of accidents reported (although the highest amounts of snow did fall just north of the central cities).

The late change in the storm’s track clearly had forecasters scrambling and ensured that a top grade was not attainable (except in one case). In addition, it seemed that some forecasters embraced late model changes while others seemed to discount them.

Here are the grades for what many hope will be the last significant snow of the season:

WCCO: C+ From a presentation standpoint, we have issues with WCCO’s visual depiction of what a certain model says when the forecaster goes on to say he doesn’t believe it and that it just provides an idea. The fact is that television news is all about visuals and we think that if people see 6.9” printed out for the metro and 18” totals for parts of northern Minnesota that that’s what they’re going to take home with them. We think that viewers are far better served by the meteorologist creating a fresh, non-model produced graphic that reflects what he/she thinks will really happen. OK, off our soapbox. TMF readers, do you agree? Beyond the presentation matter, WCCO did pick up on the final twists and turns of the storm, correctly predicting 4-6 inches as of the 10 p.m. newscast. However, as with most other prognosticators, they underestimated the magnitude of the storm in the days leading up to the event.

KSTP: A- This was a very good performance by KSTP. They were the first to latch on to the possibility of more than 1-3 inches of snow (on Monday night) and they were steady in their predictions from that point on. And, they were generally accurate with predictions of 3-5 inches of snow for the south metro and 6-10 inches on the north side. Our one complaint with KSTP was that they dropped the use of their confidence ratings, a tool we thought would have served viewers particularly well in this storm, particularly given the high uncertainty of the timing of the changeover to snow.

FOX: B- FOX was generally in the middle of the pack on this one. They were in the 1-3” boat like most others until the final bell, when their final forecast was for 3-5 inches. To their credit, FOX made a clear and unequivocable case for the bad road conditions that would greet commuters in the morning.

KARE: D It’s always a little hard to assess KARE given the cautious way they state their predictions, but it seems pretty evident they never got a good handle on this storm. On Friday evening, when all other weathercasters were allowing for the possibility of accumulating snow, KARE said it was “looking like mostly rain Tuesday night into Wednesday.” On Tuesday’s evening, KARE predicted 1-3 inches, a prediction they stayed with through Wednesday night’s 10 p.m. forecast, a time at which virtually all other outlets predicted higher, and more accurate, amounts. It seemed to us that KARE was asleep at the wheel.

Star Tribune: B The interesting situation with the Strib column this past week was that the regular blogger was on vacation during much of the time the storm was evolving, leaving one to wonder what might have otherwise been predicted in the days preceding of the storm. Nonetheless, the Strib’s blog was generally in the weather forecaster mainstream until yesterday evening, when readers were put on alert that there was an unmistakable change occurring. We give credit to the Strib for putting out the timeliest update (6:30 p.m.) of the important forecast change, one that seemed to turn the storm from a nuisance storm to something with considerably greater impact. The updated snow estimate of 4-8 inches was generally on target.

MPR: B- As we’ve mentioned before, evaluations of MPR must take into consideration that for the most part it’s a one-man operation. It also emphasizes statewide weather given the nature of its readers and listeners. So we’re never sure whether to include it with our grading. That said, MPR blended with most other weather outlets for this storm. We applaud the alert as to the general escalation of snow totals; however, it was issued at 11:10 p.m., likely a little late for most people to plan accordingly.

NWS: B+ It’s challenging to assign a grade for the NWS this time around. The weather discussions and early forecasts suggested that the storm would be more than a nuisance. They called for a 70 percent chance of snow as early as Friday evening and included accumulation totals of one sort or another from that time forward. This was all good. However, they were late in issuing warnings and advisories. And the eventual declaration of a Winter Storm Warning when there was never a prior Winter Storm Watch can’t be the way they draw things up at the NWS. Then again other media outlets aren’t burdened with the duty to declare watches and warnings.

Agree or disagree with our forecaster grades? Let us know what you think (that includes our beloved forecasters whose performance we judge).

40 comments:

  1. Based on the descriptions provided, the grades seem fair. The "D" for KARE seems high, not just on the 1-3" metro slushy prediction, but on the lead up to the storm.
    Until someone can consistently outpace the NWS, my trust is with them. I still wish the NWS would provide more than the twice a day update to their forecast discussions (not including the updates for aviation). Luckily we are not grading the NWS-Duluth office which had 12-16" predictions, hoisted Blizzard Warnings, yet Duluth only ended up with 0.4".
    Loved the comments on this blog last night - randy excellent predictions. Also, "Joel" good call on the deformation zone and "P" with the gravity wave comment (although this is above my knowledge base). Fun to watch it all play out.

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  2. Here's a comment from "P" that didn't seem to take to the site:

    P has left a new comment on your post "Grades for the (Mostly) Unwanted Storm of March 22...":

    I'll agree with you that showing what one model predicts while forecasting something else is disingenuous and more of a CYA.

    As for the NWS watches/warnings... it is preferred that a watch precede a warning but by no means is it necessary. There are times, like this storms, where confidence of warning-level criteria being reached is not high enough early enough to put a watch out. Then things change and all of a sudden you have a warning situation on your hands - as we all know weather can be rather unpredictable at times.

    NWS operates under the guidance that an Outlook be issued when there is 30% confidence of criteria being reached, a watch at 50% confidence, and a warning at 80%. Note that this is the confidence of warning criteria (ex. 6"+ of snow in 12 hours, flash floods, a tornado, etc.) being reached and is not at all comparable to rain/snow chances (0.01" of rain/0.1" of snow in 12 hours).

    If you are REALLY interested on the internal workings of the NWS, you can read basically their how-to manual at weather.gov/directives.

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  3. Bill I agree with most of your grades,I would have failed KARE11 and understand what you are saying about MPR(one man show)but I dont believe you should be grading them then when they take 3-5 day hiatus leading up to a storm!
    Novak-good call on northern mn bust(duluth only .5 inches of snow).
    Randyinchamplin you should be a met somewhere(or were you at one time)your predictions around the interstates were spot on(I give you a grade of A+).
    Also Bill if you recall my NJ bet I am up 88-58(add in the 24 pt/inch spread)I am still up by 6 inches with 7 days to go,cross your fingers!
    So I ask you all was that winters last hurrah or is there anything interesting in the crystal ball.

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  4. The NWS forecast in my area certainly wasn't a B+ performance. "Less than an inch accumulation" my eye.

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  6. Good stuff Bill. Keep up the hard work.

    What are everyone's thoughts on a potential storm for early next week. GFS is robust while the ECMWF keeps skies clear; I true contradiction between the two.

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  7. Novak, whatever models you experts look at it better dang well be RAIN! Warm liquid rain!

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  8. I'd give NWS a C or a D, at least how it played out locally where I live. I would up KARE-11's grade to a C or B - they were spot-on for my city/locale - but this was definitely hard all the way around as the storm track changed at the last minute and there were great variations within the precipitation, just over small distances, not surprising for a spring storm.

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  9. Interesting that with the last storm it was the GFS that first showed a more "northerly" solution, then the EC model came further north but not quite as far north as the GFS. So I would maybe lean to the GFS and see if EC model catches on again like last time.

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  10. I agree with the marks, except for Kare, we should have been failed.
    Novak is bringing up a good point... the 24/12z GFS is really hinting at another snowstorm early next week, but can it be trusted?
    Also I seem to have noticed a weird trend this winter: storms that a few days before looked small became monsters the day before the event (the Dec11th 17+ incher was a good example) whereas storms advertised as big well in advance became nothing as we got closer to them. It seems this persistent La Nina and negative NAO has been wreaking havoc with the models. Any thoughts?

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  11. Our one complaint with KSTP was that they dropped the use of their confidence ratings, a tool we thought would have served viewers particularly well in this storm,

    I find this to be worthless information, unreliable, and outright confusing to the viewer. I'd avoid the use of it and find that it only makes the forecast distracting

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  12. Totally agree about the comment of the NAO and La Nina affecting predictions and computer generated weather models - the NAO is a relatively uncommon pattern - and to have it two years in a row even more unusual - combining that with La Nina (which finally is weakening - I personally hope the CPC prediction for 30% chance of "colder than average" through June is wrong) is likely unfamiliar to the data the models runs off of - this pattern has been more chaotic than predictable - an at times just downright bizarre. The current NAO set-up, which in itself is unexpected based on models just a week ago, is not blocking just over Greenland, but now to the west too, which is why the high pressure is just sitting over us with the unseasonably cold air again... It is like the jet stream has been pinched into a tear drop over us and the midwest. I suspect it will block any systems well south next week with the high pressure staying in control over Minnesota, so the model showing a storm may not be accounting for this double blocking pattern? I'm not, by any stretch of the imagination, an expert in any of this, but are just my thoughts as I read through this blog.

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  13. Dave Dahl mentioned on 6pm newscast for the possibility of an snowstorm for tues/wed of next week(40% chance)as well as the NWS has slight chance for snow(20%)for wed. night/thursday are these 2 different storms or both the same just reading the timing wrong? And Novak or Randychamplin what are your feelings on these possiblities do they have merit?

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  14. MNWeatherFan and Big Daddy:

    Thanks for the props

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  15. About next week:

    Yes DD and MPX were talking about the same storm, the operational GFS model looked much more impressive this morning, than it does tonight. However this mornings run had almost zero support from the GFS ensemble means, whereas tonight their is better support from the ensemble, it is still a bit south of the operational run. However this morning I couldn't find any support from a another model, other than the Nam as it came on shore, and it's still there tonight. In other words...I really don't know if this thing has legs or not, it will take a lot to flatten this ridge out that is currently over us, and as of tonight this system doesn't have the upper air support it had this morning.

    Sorry best I can do now, will have to wait till later for other models to come in

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  16. Randyinchamplin looks as though the 00z run the EC came further north with more qpf not quite matching the gfs but closer,any thoughts on that,DD on morning radio said we are on the northern edge of snowfall,calling it light snowfall as of now but threw out that things can change stay tuned.

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  17. Quite frankly, I don't trust the GFS right now. Whenever it throws a BIG storm solution at us, I take it with a grain of salt. It painted death & destruction for early next week yesterday AM & I simply was not buying into it. Now look at what the GFS is predicting...basically nothing as it shoves the storm further south. The ECMWF was consistently keeping storms south over the next 7 days.

    In a nutshell, when you get burned enough times, you finally learn. I don't trust the GFS right now.

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  18. Novak

    nicely said, right now I can find some other acronyms for the GFS other than the Global Forecasting System, LOL

    A footnote...this looks to be setting up for a very cold pattern for this time of year, i would expect some sites to highlight the GFS temps around the 1st of the month showing temps in the 50's...but the Gem and ECMWF 850mb temp profiles just flat out don't support it, maybe 40-45 or so.

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  19. Randy, I'll never read GFS the same way again!

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  20. True the GFS has performed lousy almost the entire winter.
    But the NAM has not been much better either. It was completely busted for the March 8-9 apparent snowstorm (the 15 inches that became 1)even 24 hours out when it was still printing close to 6 inches for MSP.
    As duly noted by other comments, this negative NAO/La Nina pattern has been creating a lot of problems for the numerical models.

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  21. Snow or no snow what is the chance of it first week of April

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  22. This last storm is just a prime example of how thing can change so quickly at the last minute. Models drifted south with the system at pretty much the last moment, and struggled with the handling of the transition from rain to sleet/snow as well. We can blame it on La Nina, or we can blame it on an oscillation, but the bottom line is, especially during this time frame, anything that shows up more than 3 days out should really be taken with a grain of salt. That being said, the week is looking quiet with maybe a little light snow. Next week, however, could throw us back into an active pattern. Lets just hope that at least comes with some warmer temps so we can, once again, get rid of this snow cover.

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  23. snow chances still lurking for first week of april according to models, north of metro area,but if it performs like last storm I wouldnt count out our snow chances here in metro,time will tell,if you have read PD blogs this week he feels we arent done with accumalating snows,says he feels there maybe one or two more instances,ah dont you love spring in minnesota!

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  24. So what are you plans for the Spring/Summer? Severe weather isn't something you can track like snow since all the media use the same Storm Prediction Center forecast.

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  25. Models showing storm tracking south of area sunday/monday timeframe,with snow in central/northern MN,question is how far south the colder air gets dragged down by storm to see if the metro gets a changeover(could be set-up like last storm),like PD likes to say just a messanger!(reading DD blog last night he hinted at an changeover possibility) We'll see,something to watch this week,Bill your winter tracking grades may not be over just yet!

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  26. Randyinchamplin you always have some good insight on the long-range forecasting,is bigdaddy smoking crack or does it have some legs,tell me snow/winter is over!I read the farmers' alamnac(not always accurate)but they state snow chances well into mid/late april for upper midwest,even metioning signficiant snowfall mid-month,come on!

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  27. CWY2190,
    Good question as I know it will be a different situation. It may be something as simple as grading weekend forecasts based on Wednesday forecasts (i.e., so, in theory, you could decide which forecaster to place your faith in when it comes to making weekend plans. I'm certainly open to ideas.

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  28. Anonymous:

    I have no idea what is going to happen....the operational run of the GFS keeps the PNA positive, but the ensemble run wants to take it strongly negative (same thing with the EPO I might add). In the case of the negative PNA, a northwesterly flow might come out of Canada, instead of a pacific zonal flow. I wished I could verify that with the ECMWF, but I can't find that anywhere, but what I do now is that the NAO is forecast to go positive by both.

    But what concerns me is the end of April as the GFS has the stratosphere warming considerably.
    http://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/gif_files/gfs_t10_nh_f192.gif

    That could mean a nice shot of colder air again,
    for a video of that go to....http://www.weatherbell.com/
    the premium channel is still free until April 1st, click on it and go to Joe Bastardi's blog,and read that he has promised a video on that under the atmospheric avenger for later today.

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  29. Silly me, that link I posted for the stratosphere forecast is from the latest run out to 192 hrs.
    It can be found here under NCEP/GFS Analyses and Forecast. http://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/

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  30. Randyinchamplin,
    If what Joe Bastardi says pans out we could be way cold for mid-late April compared to average we will be running 15-20 degrees below normal which would translate to highs in the 30's and well below freezing at night with any precip chances we would have to mention snow,what crazy times. Also storm for late in weekend doing the cha-cha-cha dance on track,could very well snow again if track goes between gfs and ecmwf. thoughts?

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  31. big daddy

    I have checked the ecmwf,gfs,gem and nogaps, the operational run of the ecmwf seems to be a outlier, but looking deeper, I believe it will come back. Two links, the first one is the ecmwf operational, the second one is the ensemble mean. I think you will see the difference.

    http://raleighwx.americanwx.com/models/euro/00zeuro850mbTSLPUS168.gif

    http://raleighwx.americanwx.com/models/ecmwfens/00zecmwfens850mbTSLPUS168.gif

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  32. Thanks for the info Randyinchamplin,
    the ensemble mean track(into Milwakaee area) could very well bring rain changing to snow with cold air draining down the back side,still 5-6 days out but interesting nonetheless,the winter that keeps on giving doesnt want to go away,you think the cold for mid-late april has legs?

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  33. endless WINTER, summer sucks!

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  34. Plymouth Weather LoverMarch 29, 2011 at 8:51 PM

    I am very curious about this storm for Sunday and Monday. There is a ton of moisture that will be available from the Gulf. Recent model runs have pushed this to the south. Initially, that means that the storm, still a longs ways off, was forecast to move initially through Minnesota to just south, through Iowa. This is a favorable path for heavy precipitation for Southern Minnesota. However, it seems like a bulk of the moisture may go to our south. I do believe this MAY look a lot like the storm from last week that started as heavy rain and ended as sleet/heavy snow. There could very well be cold air in place. But, like other storms, once it comes on shore, which is a while yet, the models will struggle with handling this. We will see, but this could be the storm that jumps us into the top 3 or 4 all-time for winter snow. NWS mentioned some snow comments in their forecast discussion. Interestingly, Dave Dahl didn't even talk about this storm on the KSTP site. He usually will say something. Any other thoughts?

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  35. So Randyinchamplin or other weather nuts are we adding to our yearly snow totals over the next week(I hear mention of SNOW both thursday night and sunday night)also any truth about this so-called mid April cold that big daddy speaks of(I couldnt find the blog/entry at weatherbell)

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  36. NWS has just snow as the precip typ for the possible sunday storm. Agree? I think its time for the blogger to start another thread, apparently winter is dying but not dead yet.

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  37. Bill looks like another thread needed snow chances increasing Sunday night,DD and NWS both going with the idea of more snow then rain with a high that was 50+ the other day now only 39 the winter that keeps on giving I could see 3rd or even 2nd all-time snowfall be had if storm is all snow

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  38. Holy! For my location (Red Wing) the GFS text model prints out roughly 1.40 inch liquid around the 10th and 11th. And the temp looks like it could be cold enough for snow! This could be epic...

    Here's what I'm looking at:

    http://wxweb.meteostar.com/sample/sample.shtml?text=KRGK

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  39. Just added a new post to track the next two events coming down the pike!

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  40. Most of the stations tonight are saying mostly rain for the Sunday/Monday event, NWS is the only one showing all snow and their graphics and descriptions are horrible for assessing timing, changeover, etc. All stations say that there may be a little snow on the back side of both systems. Even KSTP's forecast (DD, 6 pm) is showing mostly rain, 50% chance of changeover to snow late night Sunday into early Monday, "possible light accumulation".
    Looks like we're not alone - heavy snow in the northeast - PA, NY, MA, up to 12 inches, yikes.

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