Wednesday, October 1, 2014

"S" Word Makes Annual Debut (Kinda Early)

If winter's not your thing (in which case what the heck are you living in Minnesota for?), you're probably quaking in your boots. If you're a winter lover, your day is drawing near, possibly much sooner than you dreamed possible.

Several weather outlets are introducing the possibility of a little snow Friday night into Saturday morning. An arresting thought to be sure. Seems like it's almost time to cue up one of our favorite songs.

Here are a few graphics that capture the potentially wintry weather headed our way just days into the official beginning of meteorologic fall.




NWS Forecast

45 comments:

  1. There is NO WAY that I would predict snow for so. MN @ this stage of the game. It is October 2nd for God's sake! Some people are throwing out snow accumulation maps & that is extremely risky even if they don't believe it will accumulate. The public views that map & they go into panic mode.

    ReplyDelete
    Replies
    1. Who's putting out snow accumulation maps?

      Delete
  2. Just saw one on my Twitter feed. I won't name names but....

    BTW, I wouldn't be surprised if no. MN receives some accumulations.

    ReplyDelete
  3. @Bill, not sure if what Dr. Novak is referring to is what both Paul's(Huttner/Douglas) put out.......last nights Paul Douglas blog over on Star Tribune had model output snow accumulation map for MSP and Paul Huttner shows the same thing over at MPR today......not exactly snow accumulation maps done by them just what the models are saying. Anyhow its just fun to even be talking about it on the second day of October, bring on the cooler weather!......if your wondering I have entered another snow competition with my brother, I gave him a 24" spread, yeah I know call me crazy its alot especially with a potential el nino pattern favoring major east coast storms....but he threw in a incentive I couldnt resist....so we now tally our snow totals from "flake to flake"(simply means from the first flake to the last flake at our locations) before it used to be a shorter window.....so Im banking on some early snowstorms and late snowstorms(like the past two springs). Hope ur enjoying snowless California.

    ReplyDelete
    Replies
    1. @BigDaddy At this point, I'm enjoying snowless California (though there was some snow toward Tahoe last week -- about a 3-hour drive). Just finished a baseball season (senior team for +50) that was a blast. No rainouts and no bugs... though several fly balls lost in the sun! It was 98 today (Sunday) but it's a dry heat and it cools down so much at night that AC is optional. Do find I'm missing the fall colors (there's a bit here) but, much as I like snow, do not miss the idea of freezing weather for six months. Hope it's a great snow season for you and that you win the annual war with your brother!

      Delete
  4. I thank you in advance for guaranteeing an early Spring.

    ReplyDelete
  5. Hey Novak look again, NWS now forecasting a trace-1" across the metro. Man it was just 80+ on Sunday, never a dull moment.

    ReplyDelete
  6. Novak whats your thought on the overly aggressive NAM painting 2-4", which includes the metro. Now I know it wont stick on streets but thats alot even for grassy surfaces.

    ReplyDelete
  7. I just can't imagine accumulating snow for anyone in so. MN, incl. MSP. Sure, there will be some flakes falling from the sky later FRI, but it will never get a chance to accumulate on the ground. Temp never drops below 35° overnight & winds stay strong. Tough to get anything to stick with those conditions.

    ReplyDelete
  8. Anyone getting nervous about the last few GFS runs for the October 13th timeframe?!

    ReplyDelete
    Replies
    1. @JAW, why? what is it showing to be nervous. NWS mentions something in their discussion but say it will be south of MN.

      Delete
  9. First flakes of the season have been spotted.....mark the calendar!

    ReplyDelete
  10. bigdaddy, this kind of goes back to the last thread. I'm looking at several different models even looking as deep as low temp analogies vs hi temp analogies. First guess is that you are safe giving your brother the 24" from first flake to last. It will take up to two more weeks for me to compile the info and than spend 2 hrs or so typing the reasons why. With Bills permission I would like to post my winter forecast on this site.

    ReplyDelete
    Replies
    1. Of course, Randy! Go right ahead.

      Delete
  11. A major part of my winter forecast is based on current sea surface temps. Here is the latest values currently.

    http://www.ospo.noaa.gov/data/sst/anomaly/2014/anomnight.10.6.2014.gif

    I would like to draw your attention to the sea surface temps just off the SE US coast. Notice that they are above normal, as of this time I don't see a tropical storm forming and impacting that area that could cause some upwelling ( bringing cooler sea surface temps to the surface.) With the warmer sea surface temps lasting into the winter months, that could very well lead to a ridge setting up over the SE US more often than not. The Euro and Japanese climate models have been hinting at that and I would expect some of the other models to start showing this.

    As a matter of fact the New CFSv2 (the major us climate model) has started to show this.

    Here is the CFSv2 showing temp anomalies based on conditions from September 16 thru Sept 25. Notice that the temp anomalies over the SE US are near normal, and the NW US is torching.

    http://www.cpc.ncep.noaa.gov/products/CFSv2/imagesInd2/usT2mSeaInd3.gif

    Now lets take a look at what the CFS is showing based on conditions from September 26 through Oct 5th. Notice that it has backed off on the warmth over the NW US and now has warmer temps over the SE US. I think this will continue to be the dominant pattern that the model sees, and it will continue to get warmer over the SE.

    http://www.cpc.ncep.noaa.gov/products/CFSv2/imagesInd3/usT2mSeaInd3.gif

    This would lead me to think that storm systems coming off the US West Coast would not dig far enough south to cut up the east coast, ie Norester.

    What that means for us is yet to be determined







    ReplyDelete
    Replies
    1. Sounds like Chicago to Detroit will be the sweet spot for snow if you think Noreasters wont be the dominate pattern, is that correct Randy?

      Delete
    2. Sam, you are essentially correct in the assumption. I wouldn't rule out a couple of strong Noreasters, but I don't think that will be the mean storm track. Current thinking is that clipper systems will take their normal track over the northern plains, working towards the Mid Atlantic area, however if the SE ridge does set up those systems may not have much moisture to work with. I think the main storm track will be from the Western Great Lakes to the Eastern Great Lakes, keep in mind that often times areas on the eastern side of the low pressure track will be warmer. So the heavier snow belt could be anywhere from MN to the Detroit area, possibly just east of there. See my post below in response to Anonymous 10:54

      Delete
  12. Randy
    It seems like the predictions for this winter are some of the most divergent I have ever seen. Some forecasters are saying El Nino is coming so warmer weather than last year and some seem to be saying that patterns look the same as last year so the winter should be similar to last year (colder). I am really looking forward to your take on the upcoming winter.

    ReplyDelete
    Replies
    1. I'm not concentrating so much on El Nino, if a moderate El Nino develops it may take a couple of months for the atmosphere to respond, if that be the case we may well see a warmer late February thru March develop.

      There are a couple of things I'm watching right now. #1 is whether or not the stormier pattern that we are seeing near the Gulf of Alaska will cool the waters, moving us to a neutral or maybe a positive EPO. The jury is out on that one.

      #2 is something that I started to follow last year and that is the October Pattern Index referred to as the OPI. As you may guess this indicator doesn't even start to produce data until Oct 1st What it tries to do is to predict how strong the Arctic Oscillation will be during the winter months based on October values.

      How it works is that at the start of the month it's 100% based on the GFS model of what the wind pattern will look like at 500mb. As the month moves forward it starts to assimilate observed conditions, ie real time data. Since the GFS is a 16 day model, by the time it gets to the middle of month, it gets more heavily reliant on real time conditions as the OPI uses only October data. When we get to the end of the month it is solely based real time data and not model data.

      So what is the Arctic Oscillation (AO) and how does the OPI values correlate to it?

      A positive AO value would mean that the Polar Vortex would be somewhat strong, the higher the value the stronger it is. In other words the higher the value, the less likely the Polar Vortex could be displaced. The more negative the AO goes the more likely it could be displaced.

      The OPI uses the same + and - values. The lower the OPI goes the greater the chance that the polar vortex will be weaker and could be displaced.

      Currently the OPI is trending very strongly to the negative side and getting more negative as the month goes on. Time will tell if that holds, lets see how it looks after Oct 15th.

      Ok so lets assume that the trend continues (a great leap of faith.) What will that mean for us? That's yet to be determined, if the polar vortex is weakened and it gets displaced, which side of the pole will it drop into? The Euro side or the North American side?

      The reason for this long post is to show how difficult long range forecasting is. The items I mentioned represent just a small amount of what goes into such a outlook. I would suggest that when I post my final forecast the last week of October you take it with a huge grain of salt.

      If the Japanese model continues to show what it is currently showing for DEC/JAN/FEB when it updates around the 25th of Oct, I may just have to bite hook line and sinker.

      Delete
  13. Golden Valley hit the magical 32° mark at 7am this morning for the first time this fall....so the first flakes and freezing mark has been observed within the first ten days of October......I'm sure neither has occured at MSP thus far.....but as the old saying goes.......nobody lives at the airport. So whats everyones guess on our first inch of snow.....my guess is Halloween into the first week of November.

    ReplyDelete
  14. Looking at tonights radar sure reminds me of one of those southern/sharp cutoff in precip winter storms.....looks like Rochester, LaCrosse, and Eau Claire are getting a good soaking tonight!

    ReplyDelete
  15. 6-10 and 8-14 day extended outlooks are looking fantastic and warm. November looks good too!

    ReplyDelete
    Replies
    1. Yeah its mild and warm now and most of the rest of the month but GFS has had a consistent signal for below-average, cold enough for snow chill in time for Halloween, trick or treaters may need a heavy coat under their costumes.

      Delete
    2. Sorry, look again. Extended GFS (whatever that's worth, which isn't much) shows temps around 50 on Halloween evening. No snow.

      Temps into the 60s thru next weekend. No snow. No chill.

      Delete
    3. When I made my comments the GFS was showing a colder solution then their depiction this morning, regardless it is still showing a return to cooler weather then what were experiencing this week into the weekend, keep in mind low 50's is average for the last days of October and their latest runs shows some 40's which would be below average. I never said it was going to snow, just said the earlier runs of the GFS showed cold enough temps for snow, either way you slice it the weather for the trick or treaters wont be as beautiful as this weeks weather!

      Delete
  16. First forecasts for Halloween are trickling in, looks chilly. Weather.com has a high of 48 and low of 36, not as nice as the next couple of days but we all know it could be worse!

    ReplyDelete
  17. Much COOLER weather settles in after Monday of next week, relative to where we've been this week. Highs have a tough time cranking 50 all next week!

    ReplyDelete
  18. Paul Huttner over at MPR using the Euro model showing a pretty chilly time for trick or treaters with temps between 33°-36°........at least my girls choose warm costumes this year!!

    @Bill......off the subject here but are u going to take in a World Series game in San Fran.?? are you a Giants fan now?

    ReplyDelete
    Replies
    1. Ha ha, my statement the other day wasnt so far off base when I said it will be "cold enough for snow".

      Delete
  19. Ok it's time to post my winter forecast, but instead of just posting it I want to make one thing clear. This is a weather board and most people that read it to a certain degree are weather enthusiasts, If I should happen to say good winter, that would be one that equates to cold and snowy, not warm and dry.

    It will be done in a series of posts instead of a long one, and will highlight several indices that when taken as a whole can give some insight into the upcoming winter. So lets get started.

    Will this year be as cold as the last one? To start with lets look at the real driver behind last years winter, the EPO or Eastern Pacific Oscillation. When its considered to be in the positive phase, it means more troughs and stormier conditions in the Gulf of Alaska, in its negative phase there is more ridging in the Gulf of Alaska. Ridging would normally mean warmer than normal sea surface temps in the gulf.

    Last years EPO index was an exceptionally strong negative one producing long lasting ridging. When ridging takes place the wind moves in a clockwise pattern, so just imagine the clockwise winds in the Gulf rotating through Alaska than north of Alaska and than south into Canada and the USA pulling all that cold air from the Arctic Circle with it.

    Here is the Sea Surface temp analogies for the middle of Winter last year.

    http://www.ospo.noaa.gov/data/sst/anomaly/2014/anomnight.1.27.2014.gif
    Notice the warm waters. That pattern continued into to the summer months which gave us our pleasant temps and rather quiet severe season.

    So what about this fall??? Are the warm sea surface temps still there? Here is the map from OCT. 2nd

    http://www.ospo.noaa.gov/data/sst/anomaly/2014/anomnight.10.2.2014.gif

    and now for Oct 27th, as you can see the Gulf of Alaska has started to take on a cooling pattern. The result is that I don't think the EPO will stay negative and if it does it's likely to be much weaker.

    So does that point to a warmer winter this year? Maybe not.

    The next post will deal with what I think the ENSO will show, in other words the El Nino/La Nina effect. That will be followed by a discussion of the Atlantic Oscillation and what can effect it. It's at that point that you will get a strong hint at what I'm thinking.


    ReplyDelete
    Replies
    1. yikes I forgot to put the map from the 27th in. Here it is.

      http://www.ospo.noaa.gov/data/sst/anomaly/2014/anomnight.10.27.2014.gif

      Delete
  20. There is always a lot of hemming and hawing this time of year with regards to winter forecasts. Many times they're spectacularly wrong (see winter of 2011/2012).

    I'm looking at the CPC's 6-10- and 8-14-day extended outlook and seeing a 70% chance of temperatures being ABOVE normal.

    Halloween is going to suck, but things are looking brighter for next week, with lighter winds and warmer temps.

    ReplyDelete
  21. Moving on to the ENSO or El Nino/La Nina forecast. This measures the sea surface temp along the equatorial Pacific. There are 4 different regions that are monitored, while all regions can have an impact on our winter weather, we normally look to region 3.4.

    http://www.srh.noaa.gov/images/mlb/enso/nino-regions.gif

    When we are said to be in a La Nina, the sea surface temps are below normal or negative. The opposite is true when we are in a El Nino. We are said to be in a weak ENSO state when temps are + or - .5 or better of normal. We don't get into a moderate state until temps are plus or minus 1° of normal. When temps are between 0 and plus or minus .5° we are said to be in either warm or cool neutral conditions.

    Some of us have heard since spring that this year could be dominated by a moderate or strong EL Nino which would normally mean warmer and dryer conditions for us. Will that come to fruition? The answer seems to be in and that would be no. The waters really have not responded and it now appears that most models are in agreement. The follow link shows the latest ENSO plumes and below that in plain text what each model is showing. Notice what the averages are between the Dynamic Models and the Statistical Models.

    http://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/

    They show us that a weak El Nino is very probable not a moderate and surely not a strong one, as the average are around .6 or .7.

    Lets explore the difference in the placement of the Jet Stream between a moderate to strong El Nino and a weak one. The first link is for the moderate to storng El Nino the second one for a weak Nino.

    http://ticker.mesonet.org/archive/20120622/el-nino-impacts.jpg

    http://www.almanac.com/sites/new.almanac.com/files/images/Weak%20El%20Nino%20map.jpg

    Notice how in a strong Nino the northern jet is placed well north of us as opposed to the jet we have during a weak El Nino, and notice the intrusion of cold air we see in the weaker solution.

    I have looked at past years and have come up with those that would appear to good matches for this year. Those are 1958/59, 1976/77, 1977/78 and 1979/80. These years will become more important when we discuss the forecast for the Arctic Oscillation (A0) which will come in the next post.

    ReplyDelete
    Replies
    1. Regarding the link that shows the plumes. Click on the plume map on the bottom right image.

      Delete
  22. Time to enter into the meat of the forecast as we begin to discuss what the Arctic Oscillation (AO) will do this winter. When the AO is said to be in it's positive state it means that the polar vortex is very strong and will not likely be displaced, meaning the coldest air should stay north of the US. When its in the negative state it means the polar vortex is weaker and can be displaced.

    To give you a visual, imagine you were looking down on the north pole, from that vantage point any point on earth would be south of the pole. The Polar Vortex describes the wind circulation around the pole and if it's strong enough it should stay in place.

    Last year the AO was in its positive state most all of the winter season, so why was it so cold?? Look at my post from OCT 29th at 12:09 am where I discussed the strong EPO.

    Now lets look at what the AO is expected to do this year and what forces can move it into it's negative state. There are three forces that can work on the AO. The Quasi-Biennial Oscillation (QBO) Index, the Snow Advance Index (SAI) and a new index called the October Pattern Index (OPI)

    The QBO is a index that looks at the winds at the stratospheric level, ie the upper levels of the atmosphere. When the QBO is in it's positive state the winds are out of the west and they tend to strengthen the polar vortex. When the QBO is in its negative state the winds are out of the east and tend to weaken the Polar Vortex. The QBO index flipped from positive to negative in May and has gotten stronger in each succeeding month and is expected to stay negative through the winter season.

    The Snow Advance Index (SAI) measures the amount of snow over Eurasia during the month of October. When the snow area is rather small it doesn't have much affect on the AO. However when the snowfall is widespread and it moves into northern Canada it can cause the AO to go negative. I haven't studied the SAI in detail so I cant provide a link to prove it, but many that know more than I say it's in near record territory with only 1976 showing more snow advance.

    The October Pattern Index (OPI) was discussed in some detail in my post dated Oct 9th at 12:24 am. It has stayed negative all month and strongly suggests a negative AO will develop this winter.

    To summarize, based on the QBO, SAI and the OPI I expect the AO to go strongly negative this year meaning pieces of the Polar Vortex will break off this year a drift into the CONUS, that would indicate colder than normal temps.

    Now take a look at the jet stream map that I posted during a weak El Nino event.

    http://www.almanac.com/sites/new.almanac.com/files/images/Weak%20El%20Nino%20map.jpg

    Now keep in mind the AO should go negative as well and drop even colder air than normal over the upper midwest, I would expect that northern jet should buckle further south than usual. Therefore I would expect this Dec-Feb will realize temps on the order of -2 to -4 compared to normal and that may be conservative. I would expect the Western Lakes into the Eastern lakes to be colder than that. Look for most of the Ohio Valley to be in -3-5 range.

    ReplyDelete
  23. Replies
    1. Yep......some awesome work Randy, why don't you work for NWS or Weather Channel, you definitely have a knack/passion for weather. So million dollar question.......what is your snow prediction for MSP or for that matter since MSP is always not the most accurate picture of a winter......pick four cities(north,south,east and west of MSP) and predict their snow totals.
      BTW.....looks like today maybe the last mild/above average temp for awhile......temps on the decrease starting tommorrow and NWS and other outlets mention artic air coming down early next week as well as snow chances being introduced as early as Wednesday........good thing I just got done with my 24 bags of leaves, now I am ready for winter......BRING IT!!

      Delete
    2. bigdaddy: I'm very conflicted on this years snowfall forecast, it's very difficult this year, most years in my analog package were below normal, but I'm not sure I'm buying that as of yet. Having said that lets wait to see what happens with the storm track this Monday, it could tell the story for the year.

      Also and this could be huge. All models, bar none, are showing a very strong storm impacting the Bearing Sea area. There is even some talk that it may set the all time low pressure reading for Alaska. I fell confident that the storm will develop. The question is what kind of impact it will have on the lower 48 around the thanksgiving time frame. Time will tell.

      Delete
  24. Novak intrigued by a storm system sunday into monday....... please discuss.

    ReplyDelete
  25. GFS doesn't show it but EURO is latching on. I'm buying the potential.

    I'm always intrigued when our first real true Arctic airmass visits the Upper Midwest early in the snow season. We will certainly have Arctic air in place by this weekend & it appears that a classic block near the north pole will keep that Arctic air in place into early next week. All medium range models appear to agree on this. Of course, probably the most important ingredient for a snow storm is cold air & we will have it.

    If the ECMWF is correct and a disturbance pulls out of the Rockies on Monday & taps Gulf moisture, Watch Out! Euro shows a beautiful coupled jet structure on Monday & this only enhances my interest. My confidence is high that someone in MN/WI/IA will receive a significant snow early next week.

    ReplyDelete
  26. Local forecasters are predicting that today is the last we'll see of temps in the 50's this season. Agree? Disagree? MM ;-)

    ReplyDelete
  27. Regarding early next week. The jury is still out, the Euro has been inconsistent going from a storm for us or being suppressed to our south as the cold air comes in to early. I'm one that normally leans to the side of precipitation just before we get a major change. Having said that, the air to our north that is set to come at us is very cold, don't know if Ma Nature can hold it off. Let me be clear, It will be cold enough to snow for sure, but if the real cold air gets here to fast suppression is likely.

    ReplyDelete
  28. Concerning next week. The 11/05/0z run of the GFS is now in general agreement with the Euro. Here is the thing that bothers me though. It's way to early to get giddy. The last couple of years the Euro hasn't been as good at forecasting winter storms 8 days out like it was in 2009-2011. The major concern is that both models show us with winter storm warning criteria this far out, hope they are right, but to much can change. The one thing that I think is certain.....WOW at the temps behind this system. If we get this snow, it may very well be with us until next spring.

    ReplyDelete