Thursday, March 13, 2014

And Seemingly Out of the Blue May Come More White

Wednesday's sunset after another melty day.
Our last blog entry created some buzz about the value of mid- to long-range forecasts. We all want to know if winter is effectively over or if more snow and cold lurks. Many weather outlets -- both television and the major Twin Cities blogs -- mentioned just yesterday (and even this morning) that conditions were not ripe for significant snows over the next several weeks (though many did include caveats about March snowstorms often popping up out of nowhere).

Commenter Disco, a frequent contributor to the blog, mentioned that statistician Nate Silver's book, The Signal and the Noise, details how forecasts nine days out and more are actually less accurate than if climatological norms were predicted. We researched this concept and found a great description here. It's worth the read, as is Nate Silver's book, and will leave you wondering why anyone bothers trying to forecast beyond nine days -- at least given the current state of the science of meteorology.

And... drum roll... as if on cue, mother nature appears to be trying to teach a lesson to those who would make general statements about weather beyond a week out. The latest weather models are suggesting that "a storm to watch" will head into the Midwest by around Tuesday of next week. Here's Tom Novak's first take on the scenario.



39 comments:

  1. This comment has been removed by a blog administrator.

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    1. Thanks, but really did you have to cut and paste pretty much all of the NWS discussion, we could easily go to the website and read it, which I already did or Bill could have attached it to his new thread if he deemed necessary. I much rather read your comments on the possible storm, thats why I come to this site.

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    2. Agree. I'm going to delete the comment so the scroll doesn't get too long too quickly.

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  2. So Novak is 'hinting' at a potential for a snowstorm, he even references the ECMWF(euro) in the video. Funny Paul Douglas shows the ECMWF forecast for next week and says rain/snow mix with a high of 42. Bill I am confused, same model, two totally different forecasts/outlooks just hours apart, what gives.

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  3. Ok, many of you that come to this site realize that I have been harping on the 18-24th time period, as I thought a strong system may materialize based on several indices. Well storm #1 is on the maps and its looks impressive based on the 14/0z model run of the GFS. And Tom did a real good job on his upper air analysis with the video. But lets look at this storm first at the surface.

    http://climate.cod.edu/data/forecast/GFS/00/US/gfsUS_sfc_prec_102.gif

    Notice that we have a strong low pressure system in the favored area of around 900mb, that is quite strong. But what's concerning to me is that there is no precipitation in the warm sector east and south se of the center of low pressure center. Yet the 14/0z run of the GFS shows heavy snows exceeding 10" for the metro as the storm progresses.

    While Tom likes to look at upper level jet streak, I prefer to look at the lower level jet streak, typically found at the 850mb level as that shows the low level moisture feed. Here is the low level jet streak at the same that I posted the surface map, depicting the moisture feed.

    http://climate.cod.edu/data/forecast/GFS/00/US/gfsUS_850_spd_102.gif

    It looks like a 70 knot lower level jet streak which is very strong, but look at it's origin, it straight out the the Sonora area which is very dry. At the same time there is a large area of difluence (sp) over us, which would hint at a major snow storm.

    I have seen this a couple a times over the last three years, when things look really good 4-6 days out according to the models but only dry up as the event gets closer, that dry low level jet is concerning.





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    1. Randy,
      I agree with your assessment in regards to low level winds, especially if you are forecasting severe weather/precipitation along & south of a warm frontal boundary of a maturing storm. With that being said, I don't see next week's storm system as being a big precip. producer along & south of the surface low track since it will be too dry with little influence from the Gulf.

      However, this is why I pay so much attention to mid & upper level dynamics. Reason being is that a storm system can do a lot with little if the dynamics are strong, especially north of the surface & 850mb low. A good example is with a strong 'Clipper' with good dynamics. Even though a 'Clipper' has little moisture to work with, it can "wring-out" every last drop of moisture in the atmosphere as long as mid & upper level dynamics are good.

      So, when putting this all together, as long as the upper level dynamics continue to look good, I will be expecting a significant swath of snow north of the surface low track. In fact, I wouldn't be surprised to see this as a wide swath of snow that extends a good 100 to 200 miles north of track especially if we get good divergence aloft & a strong coupled jet structure. Right now, this appears to be the case, but of course, a lot will change over the next few days.

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    2. Tom, thanks for the insight, I appreciate it.

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  4. However, I truly hate trying to predict if/when changeover will occur. I've got a bad feeling that this storm will feature a lot of warm air early on. This will be tough to overcome, especially in southern MN, IA & a good chunk of WI.

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    1. well let's put this way: the 12z run of the GFS was not a good thing for snow lovers. Hopefully things will change.

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    2. So it begins, yesterday it was a snowstorm on the video discussion and now comes the inject of terms that will make this not a major snow. Warm air needs to be overcome, then warm air aloft, sleet and rain possible. I guess Paul Douglas hit it right right off the bat. Seems to me the video was to early if its not going to include a major dump of snow in and around the metro.

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    3. It was a first take, nothing more and nothing less. And I prefer to think of the videos as opportunities to learn about meteorology, uncertainty and all.

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  5. Plymouth Weather LoverMarch 14, 2014 at 4:43 PM

    I haven't chimed in for a while, but Bring It!! Any POTENTIAL big storm on the horizon is awesome to hear about, think about, dream about, and wonder about! We know that a mix of something is always a possibility at this time of the year, but we also know that some huge snow storms can come out of this kind of slop storm. So, bring it. No need to be all critical and negative and judgmental. Just Bring It. And Bring the videos and discussion as well. I will dance and you all Bring It!!!!

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  6. NWS just has a chance for "light mixed precip" both Tue and Wed per their Facebook page @ 6:45pm.

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  7. This has been a boring ass month! Thought this winter would at least go out with a bang or two.

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  8. Nothing to see here folks. This is going to be a flop and some slop at best Tuesday/Wednesday. This was a great winter, but it's over. March wimped out. Bring the sunny and 72 degree weather.

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  9. Yeah I must admit March has been a dud, half done without any storms. Some on here says winter will return, a few colder then average days doesn't mean "winter has returned". Winter returning would mean snowfalls, snowblowers chiming, shovels scraping and enough cold air to support it. A few 30's with no snow and then 40's and 50's is not winter. Here's hoping that the El Nino next winter brings more snow since it won't be as cold.

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  10. Latest NWS post says 1 inch of snow for the Metro with this storm (after a round of sleet, freezing rain, etc.). 3 inches for central MN. 5-9 for northern MN.

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  11. This is one tough system to forecast. But I do have some observations. First of all the Weather Prediction Center is suggesting using a NAM/GFS/GGEM compromise. I do question that as I believe the right solution is the 15/12z Euro, UKMET compromise.

    All modeling points to some ridging over us as we go into late Monday evening, early Tuesday morning at the 500mb levels. I am using that level for almost all of this disco.

    The 15/12z run of the Euro has come into good agreement with the UKMET as of Tuesday morning. The UKMET closes off the 500mb low over southeastern WY and north central CO. The Euro does so over western KS, both by 7am Tuesday. Due to the ridging over us and to the east I think this idea is correct as I think the 500mb should dig this far south.

    At the surface the UKMET has a rather strong surface cyclone over KS/NE border which would make sense as most surface lows develop east and slightly south of a closed H5 low. The Euro on the other hand has a doubled barreled low, one near Sioux Falls, the other one over the KS/NE border, but by 1pm on Tues it consolidates it around the southern solution.

    The American models however do not dig the energy as far south as those two models do at the 500mb level, say somewhere close to Sioux Falls, but yet the surface low forms north and slightly east of that area, I find that somewhat suspicious IMO.

    Thermal profiles will be a problem of course, best guess at this time, taken with a large gain of salt, is 2-6" across the metro, less south more north. I don't normally throw totals out this far early but some friends asked me to give it a shot.

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    1. Good stuff, Randy. Always appreciate your input as it gives us a chance to learn something.

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    2. Thanks Bill. All one can get beyond 72hrs on the UKMET is 500mb heights and surface low pressure out to 144hrs at 24 hr intervals, but It has been very consistent in the placement of the surface cyclone.

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  12. For a quick look I like the Snow forecast Ensembles from the Euro. Of its 51 members, about 40% are less than 2 inches for MSP, 40% are 2 to 5", and about 10% are >5" with 1 of the 51 members going 7 to 8".

    Note: Models have a habit of overestimating snowfall during heavy snow/mixed precip events.

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  13. @Bigdaddy, where in Jersey does your brother live? You probably already know that there is a winter storm warning for the southern half of Jersey and all of Delaware. My family in Delaware is expecting 6-10 inches tonight/tomorrow. I hate being the bearer of bad news, but please don't shoot the messenger! lol

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  14. Current thinking is that the metro will see 3" far south, 7" far north, confidence level is 5 out of 10 with this system. A shift father south with the low pressure track and than tracking into central WI will increase these total's drastically, a shift south and than further east into the Milwaukee will lower those totals. Best guess at this time is that totals may be ramped after the 17/0z runs come in.

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  15. Latest video with The Doctor, Tom Novak. https://www.youtube.com/watch?v=91E0iadRINA

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  16. Warnings and watches are up!.....NWS has 4-8 thru the metro with more possible if storm shifts further southeast. @Schnee Meister, my brother is in Jackson,NJ(Central Jersey)...I know all well about their snow, at last minute it decided to go further north, they were only suppose to get 1-2 but then a winter storm warning was hoisted for their area for 3-6....Im awaiting word on the damage....score was MN-62 NJ-60 as of last night....its definitely going to be a uphill climb now....but I have till 4/10 so we'll see what happens.

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    1. @Bigdaddy, good luck to you. I hope our storm shifts a little farther southeast. My sister said that they picked up 8 inches so far in central Delaware.

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    2. My brother came in with another field goal.....so NJ-63 MN-62....I have a slim chance....we'll see if these next few storms can add up to 21"in Golden Valley, seems unlikely but anything is possible.

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  17. Long-term forecast sadly looking like January garbage. Lucky for me, I'm getting out of this frozen hellhole and heading to California for a week. I'll be sure to enjoy not seeing snow. Can't wait!

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    1. I'll be moving there in 12 days (for good). :-))

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  18. Finally, the purge of the 'Riff-Raff' has commenced. Mother Nature's way of getting rid of the weak. Good riddance! :-)

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    1. Nice one, Novak! Told u Bill Dr. Novak was going to find some storms for your send off....looks like tommorrow/Wednesday is not the only storms on the map, NWS speaks of two others.

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  19. The metro area will be going to a winter weather advisory shortly, and I agree with that assessment at this time, 3" far south metro, 6" far north metro.

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    1. So in other words like the storms before it will end up somewhere between 1-4, so not a major storm for the metro. Excellent!

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  20. Spanking new video with Dr. Novak, who comes out of the close: https://www.youtube.com/watch?v=SfqIlCTiX9E

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  21. Watched the Video after I saw the 18z Nam data, but before the 18z GFS. Keep in mind something that Tom said in his video about the 18z model runs. They do ingest some important data and thats from commercial flights that take northern flight path from the US to the Asia markets, some of them feed important data into the 18z runs regarding winds at about 35k feet. A small part of the equation, but nonetheless very critical.

    Using the temp profiles off the 17/0z Euro and the precip amounts of the 17/18z GFS, which I think is the prudent thing to do, I have to make a adjustment to the prediction.....3" far south metro, 8" far north metro. That includes far nw Henn. county and almost all of Anoka county

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  22. Looks like we're gonna be in or near the bullseye here in St. Cloud.

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  23. Dr. Novak appears to be on a roll. While I'm bummed Bill is leaving us, do we really need to give him these going away storms? My golf clubs are getting lonely.

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    1. I can take 'em or leave 'em. :-)

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