Tuesday, May 31, 2016

Severe Weather on the Horizon?

It finally seems safe to bury the snow shovel in the northland. But that means that severe weather can't be far off. Might that come on Friday?

84 comments:

  1. At this point it looks like SOMETHING is out there, but then again we have had not so great effects with forecasts a few days out. Hopefully we can get a nice little storm, really was a pretty bleak May. Even a bleak few years for that matter. Fingers crossed.

    ReplyDelete
  2. Stormgeek, I was wondering if I was the only one who had noticed that we've had very few strong storms before June the past few years. I can't remember a stormy spring since the year of the Minneapolis tornado.

    ReplyDelete
    Replies
    1. Indeed, it seems things have been quite slow. I may have to look into the numbers to see just how accurate that thought is.

      Delete
    2. I think you are both correct.
      it's been either too cool (not enough instability) or too warm (capping).
      I remember a few instances where the dynamics were there in theory, but the cap never broke to allow development.
      I don't remember who exactly (maybe Joe Bastardi?) that a few years ago came up with this theory of extra warming at 700mb which is suppressing severe weather on a larger scale.

      Delete
  3. Friday still looks like a day to pay close attention to. There will be enough spin in the atmosphere to make things interesting for sure. The question remains, will we be able to recover after morning convection? Those areas that see morning storms will have a hard time. My latest thoughts is severe weather is possible over the southern 2/3rds of Minnesota. However its quite possible that SE Minnesota may stay away from morning storms and actually will get some sun during peak heating which will destabilize the area quite nicely. Therefore, I believe that if a severe event happens it will be south of line from west of Albert Lea, extending to the Faribult area, over to Wabasha and south to the Iowa border. Its what I call Minnestoa's tornado alley.

    ReplyDelete
  4. What a dud. Even the moderate thundershowers west of the Twin Cities just fizzled.

    ReplyDelete
  5. First hail of the year around 3 AM. Didn't see that coming. Novak is talking about potential severe weather late Friday.

    ReplyDelete
  6. Where did everyone go? Predictions for Friday night? Novak is talking quite a bit about the potential for some big storms.

    ReplyDelete
  7. Love the energy set-up for tomorrow. CAPE values will approach 4,000+ jkg & there will be outflow boundaries all over the place. This has the makings of a quick explosion of T'Storms between 3pm-6pm over central MN. These storms have the potential to be supercells at first, but they should quickly evolve into a solid line of powerful T'Storms by sunset. This line will race southeast through MSP, RST & EAU during the evening.

    ReplyDelete
    Replies
    1. Agree with Tom on this one. Shear values are weak, but may be sufficient with the incredible amount of cape for supercells, but the chances of rotating updrafts is very low, but not zero therefore a weak tornado may be possible.

      Because lapse rates aloft will be sufficient along and ahead of the cold front(actually more of a wind shift) we could see updraft speeds up to 70knts, which would indicate a chance for large hail.

      As far as the storms congealing into a line and causing a bow echo effect and picking up forward speed, I think the chance is low. The reason is the steering winds aloft are very weak, thus I think the storms will be moving slower than some think they will be.

      That brings me to another problem, when storms initiate they will quickly grow to severe levels, but because they could be moving slower, it may be hard to sustain themselves as they could use up the energy around them and without the forward speed they may weaken rapidly. That would cause the updrafts to quickly weaken and caplase(sp) on top of the cell causing severe down bursts.

      If I'm right these down burst winds could exceed 100 mph. If I'm wrong and a line of storms congeal into one line, winds would exceed severe levels.

      At any rate be aware of your surroundings tomorrow

      Delete
  8. I'm becoming more and more concerned that training T'Storms are going to form dangerously close, if not in, the MSP metro. Of course, this would produce a narrow corridor of flooding rains.

    It appears that this weak front will stall over MN/WI later tonight as the upper level winds become parallel to the front. Gut feeling is that this happens somewhere near or in between MSP/RST on east to near EAU.

    ReplyDelete
  9. NWS reducing pops despite there being an enhanced risk on the NE side of the cities. Any idea on what they may be looking at? Down to 40% in some places

    ReplyDelete
  10. Any chance the atmosphere will be capped?

    ReplyDelete
    Replies
    1. I was wondering that myself, but after looking around it appears there will be a strong enough trigger. At least that is what I have seen.

      Delete
  11. Very prominent outflow boundary stretching across most of the state.

    ReplyDelete
  12. Looks like it is staying to the south of the main metro. Novak seems this popped a little more SE of what you expected?

    ReplyDelete
  13. Absolutely brutal storm forecasting lately. Terrible. Next time someone says there's a possibility of severe weather, grab your towel and head for the beach. You can't lose.

    ReplyDelete
    Replies
    1. p.s. the above comment refers to the Twin Cities only. I realize my hometown EAU got hammered today.

      Delete
  14. Somewhat of change this evening for the early morning forecast. It looks increasingly likely that a 850mb frontal boundary will be approaching the metro early in the morning and will likely stall out. Elevated instability looks to be quite high so I would not rule out severe weather. However it looks like portion of the metro or close to it could see 2-4" of rain before 10am. What happens after that I'm not sure (haven't looked close)

    ReplyDelete
  15. Quite a tragedy with all the misses lately, hopefully tonight can produce.

    ReplyDelete
  16. Randy nailed it on the heavy rain just east of the metro this morning. Novak is calling for heavy storms around sunset for the metro and stronger storms Tuesday PM

    ReplyDelete
  17. Not much has materialized for the core metro recently. I visited Minnehaha park on Saturday and noticed that the ground was becoming very dry and plants in the gardens were starting to look parched. I would prefer that changes. Some nice rain this morning, but we'll need more.

    ReplyDelete
  18. Where is everyone? Biggest severe weather outbreak in a long time. Curious if the rain from this morning will have removed enough energy from the metro to prevent the severe stuff. Tornado on the ground about 50 miles south.

    ReplyDelete
    Replies
    1. I really wasn't a fan of the severe threat for the metro. Warm front (although once again it was more of a wind shift) sparked some rain late in the morning through noon or 1 o'clock. Although we may have been in or close to the warm sector, the chances of seeing sunshine were not great. No sunshine no cape (instability) for the storms to work with.

      Delete
  19. Thoughts on Sunday? Will the ingredients be there with a cap or will the cap not be there and neither will the ingredients? I don't think instability will be an issue with this one...

    ReplyDelete
  20. Anybody who wants to study the heat island's effect on storms, come to the Twin Cities! It's on full display this summer! :( :( :(

    ReplyDelete
  21. I disagreed with the spc's to issue a sever thunderstorm watcg I think. Me thinks it should have been a tornado watch.

    ReplyDelete
  22. Did anyone here watch Friday's storms as they pummeled SW MN. My hometown (Sleepy Eye) and vicinity was hit hard by one the worst storms many in my family remember. The fields near Morgan were stripped clean of crops. A small tornado damaged a couple farms SE of Sleepy Eye.

    One of the eye-popping details of the storm was the hard turn it took at Sleepy Eye, from heading due South to heading almost due East.

    And I realize that metro media is focused on the metro area, but they used to be so much better about out-state weather. My mother complained that not a single Twin Cities outlet gave any information on the storm. I was listening to WCCO radio at the time, when a listener texted from New Ulm asking for a storm update because it was starting to look really scary. John Williams simply repeated the general forecast noting that storms were possible. It seems that the rural areas are getting forgotten except during blizzards. All the more reason for them to have a weather radio, I suppose.

    ReplyDelete
  23. in response to anonymous 6/17 at 9pm.
    it is in full display in winter as well, unfortunately...

    ReplyDelete
  24. This requires that one be well aware of their surroundings on Saturday, if your traveling be aware of which county your are in, warnings are issued by county. Spc upgraded us to enhanced from slight. I fully expected that, however I didn't want to jump the gun on our local media mets. I do believe that with the day one update issued around 1am on 06/25 that most of metro and north to Duluth will again be upgraded, this time to a moderate chance. Pay attention to the sky after 12 pm, if we get sun all bets are off.

    ReplyDelete
    Replies
    1. I think we have a pretty decent chance at some sun. One of the scarier setups in a while if we get good heating...

      Delete
    2. 1 AM remained at enhanced. Looks to be very warm and humid, still wonder about exactly where the worst will hit.

      Delete
  25. As always, I'll believe it when I see it. I fully expect a good skunking.

    ReplyDelete
  26. are the storms already starting to pop down near red wing and rochester or is that just a preview?

    ReplyDelete
  27. Even I will call this the dud of duds for the metro. Curious about an explanation from Novak on this one. Too many of these and people will ignore the watches.

    ReplyDelete
  28. Cap was much stronger than anticipated and forcing for ascent not strong enough to break it. Also the SPC mentioned that the main mid-layer shear was somewhat lagging the front.

    ReplyDelete
  29. I don't blame the NWS. There were strong storms north of the Twin Cities.

    But when the sun was still shining at 4.30pm with a very strong, very dry southwest wind, I knew we were done for. We had no business being in ENH risk and no business in a severe t-storm watch.

    What is this, the second busted weekend in a row? Not that I really care, but my grass is getting dry -- evidence of busted forecasts.

    ReplyDelete
  30. A couple of the short term convective allowing models (CAM)show an increasing chance of severe storms over the metro on Tuesday July 5th. They are showing a large super cell over the metro. Up until today it looked like the wind profiles did not really support much of tornado threat. That has changed as some of the shorter term models are now showing surface winds backed to the south south-east while winds aloft veer to the west south west, a strong indication of rotating updrafts. As a matter of fact a couple of the cams show a rather high updraft helicity number once again pointing to rotating updrafts. While the Euro is not technically a cam,it shows the same wind profiles over the metro by 1pm. Please be aware of you surroundings late tomorrow after noon into the evening.

    ReplyDelete
    Replies
    1. Is it possible that the front is lagging a bit on the best UH? Or have some things changed because I saw a few maps with some awful high UH values over the TC.

      Delete
    2. Looks to me like the warm front will extend from roughly western Minnesota to the north metro, maybe as far north as St Cloud by say 3 or 4pm when storms along it will fire off. That should stall the warm front and warm frontal storms seem to be particularly nasty. It will be interesting to see what the Storm Prediction Center does with their day 1 outlook. I don't think a upgrade to moderate is in the cards, however I could see a 15% chance for tornado.

      Delete
  31. Randy bold prediction in the summer of the dome over the metro. I'm in Bill's home state for a while so it probably will be a rough storm.

    ReplyDelete
  32. Something possibly brewing for the 7th?

    ReplyDelete
  33. Can't believe there were no comments on Tuesday's storm. Our power just came back on today, making a total of approximately 42 powerless hours.

    This one was not that impressive on radar, but it sure as hell performed. NWS/SPC called it.

    ReplyDelete
  34. everyone is to afraid to comment since they haven't been to on with their forecasts.

    ReplyDelete
  35. Tomorrow looks like a cap event with low level shear appearing to lag behind. However, it also appears that we will have quite a bit of energy and deep level shear appears to be enough. Interested to see what comes of it. It will likely come down to the cap breaking in which we did no fare well last time that was the case.

    ReplyDelete
  36. It's interesting to watch the storms just ride the edge of the urban heat island. When does NWS cancel the watch for the Twin Cities?

    ReplyDelete
    Replies
    1. They are not riding the urban heat island, they are riding the 700mb 12° isotherm that is putting a cap over all of SE MN including the metro.

      Delete
    2. Either way, this setup appears very much like the one a few Saturdays back when MN to the NW of the Twin Cities got smoked and the metro got skunked.

      Delete
    3. Why complain about the lack of severe storms in the Twin Cities.

      Delete
    4. Some storms trying to get going over the SW metro now. This is one time I don't mind the Metro missing out. Tornados in Stearns and brutal flooding up around Brainerd. Metro hasn't seen much, but quite a bit of damage elsewhere in MN

      Delete
  37. Any thoughts about the "unbearable" heat they're predicting for the end of this week? MM ;-)

    ReplyDelete
  38. I predict a few comments on this blog on Friday and Saturday disecting the decision by the NWS to issue the Excessive Heat Warning.
    As far as the heat itself I do not see all the hype myself: it is mid-july, and so a couple of days of 100 degrees heat index should be expected.

    ReplyDelete
  39. Really depends on the dew points. If they indeed get into the upper 70s than I think it's warranted. People without A/C can be in a real bind when this happens.

    I'm curious if we will see all of the rain expected tonight. Waiting for Novak to weigh in.

    ReplyDelete
  40. I think it can be said without offending anyone that the flash flood watch was possibly a bit overdone.
    Worst than a winter storm warning for 0.1 inches of snow.

    ReplyDelete
  41. Not sure where everyone has gone, but I agree the flash flood watch was a huge swing and miss by the NWS. Wondering what model showed the rain?

    It was odd because the watch came out of no where, like a model popped. I looked at some models late last night and didn't see the rain.

    Throughout the day, the NWS went from 2 to 4, to 1 to 2, to 1/2 to 3/4. Many places had a trace to .1. Really curious how they missed across the forecast area.

    ReplyDelete
    Replies
    1. Agreed. Flash flood watch and not a drop of rain.

      What happened?

      Delete
  42. You need to remember that a "Watch" is just that. Sure it was a swing & miss, but I would've been more shocked if they had upgraded to a warning. ;)

    Seriously though, it is impossible to predict exactly where T'Storms will pop, especially in this type of environment when you don't have an obvious trigger. Keep in mind that portions of MN, esp. along the I-90 corridor, did receive healthy rains WED am. Granted, they weren't flooding rains, but storms did develop.

    On a different note, I'm becoming more & more concerned with severe potential for late Saturday. This really looks like an explosive environment that WILL have a obvious trigger.

    ReplyDelete
    Replies
    1. Agree with Saturday. While 0-6km sheer values look somewhat tame they are enough as winds at the surface are backed to south south east and veer to the west at 6km. Helicity index in the lowest 1km would be supportive of week rotating updrafts, but becomes very strong at 3km. Helicity is the measure of spin in the column of air. This looks to me like an upgrade is coming with the new day 2 outlook from the SPC.

      Delete
  43. Uhm... it's almost noon and still 83, and getting cloudy
    (Woodbury area).
    I am starting to wonder whether tomorrow and Saturday may end up getting hotter than today that wa supposed to be the peak of the heat wave.
    Let's see what happens this afternoon...

    ReplyDelete
  44. spc left it a slight risk, but mentioned that areas with a enhanced risk is defined as of yet.

    ReplyDelete
  45. Well at 1.53pm MSP:
    Temperature 95
    Heat Index 91
    To me, it makes no sense that the heat index is lower than the air temperature.
    yes, mathematically because of how humidity is taken into consideration it can be possible, but it just makes no sense.
    Technically if the perceived temperature is below the air temperature it should be a sort of 'chill' index.
    Makes no sense.

    ReplyDelete
  46. Randy or Noval]k if you are out there. I'm watching some decent storms from the south pulling into the massive storms to the north. Looks like they will combine over the south metro. What causes this?

    ReplyDelete
  47. Wrong site Dave, this is the Minnesota Winter Weather Only Forecaster.

    ReplyDelete
  48. Guess you right anony. Miss the folks that hang around here. Crazy amounts of rain tonight and more storms out west and in SD.

    ReplyDelete
  49. Dave, fronts act like a magnet. The storms that are merging over the MSP metro are due to a more localized front that is slowly sagging south. It is not surprising when rogue storms develop out ahead of a front then get "sucked" into it.

    Of course, the main issue tonight is the potential for flooding rains. A fairly strong CAP exists near the I-90 corridor in so. MN. This CAP should effectively stop the front in its tracks near or in the MSP metro. Not good as training T'Storms would be the result.

    ReplyDelete
  50. That little storm that got sucked into the big storm:

    (from Wunderground radar)

    http://bit.ly/1nbFRHB

    Look at how fast that little storm moved north!

    ReplyDelete
  51. Oops, wrong link. Try this one:

    http://bit.ly/2b5yXy4

    ReplyDelete
  52. Anonymous, I noticed that too. It looked like it was moving 100mph.

    ReplyDelete
  53. Crazy late afternoon. I'm in SE Shakopee by Prior Lake and Savage. 2 inches of rain in about 45 minutes, now a flash flood warning. Interesting watching the predictions and models for today. Didn't see this coming, looked more like a slight severe risk west of here.

    ReplyDelete
  54. Pattern change coming? new thread?

    ReplyDelete
    Replies
    1. Not sure what you mean by pattern change. We certainly won't see a change to dryer cooler conditions until a least next weekend. As a matter of fact Monday is looking like the best severe set up we have seen all season. Models are hinting that the most important severe indices,(cape,helicity and 0-6km shear) should be co-located over Minnesota, the exact location is yet to be determined. Watch Monday closely, if we get 2-4hrs of sunshine during peak heating all bets are off. Because we will be getting into a wet period, I think the chances of sun during peak heating is only about 30%.

      Delete
  55. There is 60% chance that a weather watch will be needed in the next hour or so, extending from SW MN to just west of the Twin City metro. Most likely a severe thunderstorm, but a tornado can't be ruled out.

    ReplyDelete
  56. Guess it didn't work out today. Still looking like lots of rain coming though.

    ReplyDelete
  57. best severe set up we have seen all season....

    ReplyDelete
  58. I am curious- what does the historical data say regarding wet summers and how that translates into snow levels? How much rain have we had this year compared to average?

    ReplyDelete
    Replies
    1. I had tried to answer such a question a few years ago.
      What I found was that:
      1) There was no significant correlation between summer rain amounts and the following winter snowfall.
      2) There was also no significant correlation between a summer's temperature vs average and the following winter's snowfall (in other words a colder/warmer than average summer did not have any meaningful impact on the winter's snowfall).
      What was interesting though was that I found a significant correlation between the fall temperature -- especially the period October 20th-November 10th -- and the following winter snowfall. In the vast majority of the cases when that period was colder than average by more than 1.75 degrees the following winter ended up with higher than average snowfall. This held true even when controlling for the Halloween Blizzard outlier.
      Again, this is based on data up until a few years ago, I wish I had some time to update it with the latest data (maybe in the next months).

      Delete
  59. Blown forecast today / tomorrow. A lot less rain than expected.

    ReplyDelete
  60. La Nina alert dropped:

    "The chances of La Niña this fall were 75% in June, but they fell to around 55-60% in July, and again in August to 40%. Sea surface temperatures were cooling, but the pace of cooling has slowed. ENSO conditions are likely to remain neutral through fall. Forecasters have dropped the La Niña watch. The next update will be October 13."

    https://www.climate.gov/enso

    ReplyDelete
  61. Crazy couple of days coming up for late September. Following Novak posts, he nailed this one (so far). Curious how far north the heavy rain will occur. Looks more Mankato to Rochester so far.

    ReplyDelete
  62. Excellent forecasting on this one. Big-time storm!

    ReplyDelete
  63. Isn't it time for a new post?

    ReplyDelete
    Replies
    1. Yes. I just posted a new post, though it doesn't say much.

      Delete