Winter weather forecasting in the South - it's not for the faint of heart

Winter weather forecasting in the South has a way of reminding us (meteorologists) that we are human and NOT in control.  It reminds us that, though we know so much more than we did a year ago, five years ago, or twenty years ago, there is still so much more to learn.  It reminds us that meteorology sometimes is more art than science. Indeed, it can be humbling.  The winter weather forecast is THE most difficult forecast a southern meteorologist makes, bar none.

After an event like Tuesday (and Sunday), I end up asking many of the same questions you, the public, do (although maybe phrased in my mind a little differently) even though I've been doing this for 17 years and have the training and experience to make a well-reasoned and educated forecast. Frequently, I hear things like "why does ____ ALWAYS go around us?" and "why does ____ NEVER occur in Memphis?"  The questions I ask myself are similar, though they are phrased more like "why did it ____ THIS time?" and "why did it ___ THERE but not HERE?"  First, there are no absolutes - it doesn't ALWAYS.  As humorous as the picture to the left is, we DO occasionally get a "good snow" in Memphis.  I submit Exhibit A, from February 8, 2010, below.

Bartlett, TN - February 8, 2010.  See, we do occasionally get "good snow!"

There are many possible answers to your questions, as well as those that I have about why the atmosphere behaves the way it does.  I'd like to borrow a couple thoughts that I happen to agree 100% with that I heard on a national weather-weenies podcast called "WeatherBrains" Monday night.  The topic was the Birmingham/Atlanta winter weather debacle the previous week.  I think the points are appropriate here as well.

Winter weather in the south is something that we don't get a lot of practice at, and when it does occur the impact is much greater than the same event "up north."  Combine those two facts together and you have a recipe for disaster.  When an atmospheric setup occurs over and over again, it gets more predictable, or at least we know the range of potential outcomes.  When it happens a handful of times a year (at most) and every one is a different shade of grey, it becomes that much harder.

Then throw in the fact that temperatures (surface and aloft, both are absolutely critical) are never clear cut in the south.  Something is always "borderline."  Literally, a degree either way can make a huge difference in the outcome.  Throw in the fact that we don't deal with winter weather well and aren't prepared like northern cities and that single degree can make the difference between a cold, wet day that is an inconvenience and an ice storm with a huge impact.  Consider the difference between Tipton County, with power outages, trees down, and 1/2"+ of ice on everything, and Shelby County, where it's mainly been just wet, the past few days.  (And I am not even going into things like amount and placement of moisture, atmospheric lift, etc. that also all factor into a winter weather forecast. It isn't just about what the surface temperature is.)

Significant ice in Randolph, Tipton County, TN. Photo credit Kent Cates.

Another part of this discussion, I believe, lies in the state of the science and the fact that (believe it or not) we are a victim of our own accuracy.  (Some of you just about spit whatever you were drinking out of your nose...)  Meteorology has come so far in the past couple of decades, that it's rare that we DON'T know what to expect!  I'm not talking about being off a degree or two on the high temperature.  I'm talking about the events with the greatest impact. If there's a chance of winter weather, everyone knows about it.  (Don't believe me? Go to the bread aisle at the grocery store the night before a forecast snow or ice event.)

If the possibility of severe weather exists, most everyone knows.  Whether they understand the threat is something altogether different, but there really are few true "surprises" in weather forecasting anymore. Someone/somewhere has talked about the possibility.  That wasn't true 20 years ago.  And because the accuracy is much higher than years ago, it is now EXPECTED that we will be right most, if not all, of the time.  That simply isn't the case and it's not because we didn't know about the possibility, it's because we made a forecast that we felt was the most likely outcome based on numerous possibilities.

Folks, I'm not making excuses.  When I miss a forecast, I go back and try to learn what went wrong and how I can do better.  I am fairly confident this applies to most in my field.  There are not a lot of jobs out there where the people in that industry are, as a whole, truly passionate about what they do.  The weather community is one of them.  It's generally a visible position, which means when we screw up, you know about it and we are open to criticism.  And that's OK.  You're upset and need a place to vent and the cause of your frustration is the guy or gal that led you astray.  If I didn't want the criticism, I'd do something else.  Thick skin helps in this business!  What it tells me though is that you care!  The information MWN provides is important to you (even if Facebook thinks otherwise and filters it...).  Yes, sometimes I wish people would stop using the joke about "getting it wrong 50% of the time and keeping your job," but that's part of the job.

So as to the past two events, which many seem to think were forecast busts, I'll offer this. Look 20 miles north or west from where your "forecast bust" happened.  You will find significant impacts that caused the people in those locations to personally feel the effects.  So it rained all day where you were.  Did you know that when the Winter Storm Warning that "shouldn't have been issued" WAS sent, the temperature had stopped climbing and was sitting at 32.5, trees were actually icing up in many areas in the warned area, and power outages were increasing, all as torrents of precipitation streamed through the area?  Heaven forbid a warning was issued and nothing happened. 

Perhaps you believe staying in a winter weather "advisory" rather than upgrading to a "warning" would have been more appropriate?  Please, come sit in the seat of the warning meteorologist and play roulette with Mother Nature.  I assure you that the National Weather Service did not upgrade to hype the event.  When the atmosphere is already not acting according to plan and there is reasonable probability that it could take a turn for the worse, I personally would issue that warning every time.  We simply are not good enough to draw a line around your neighborhood and exempt you from potential impact. A single degree made the difference between what Covington received and what most in Shelby County saw on Tuesday.  And the models were already too warm by 4-6 degrees during that time.  In other words, they were useless. Given the knowns and unknowns, the NWS unapologetically erred on the side of caution and we stand behind them 100%.

Ice storm damage in Ripley, TN. Photo credit Renee Nelson.

Lastly, I think we in the weather community can do a better job.  Not necessarily in forecasting the weather (though there is always room for improvement in that regard), but in telling you how it will impact you.  Once again, I agree with my colleagues on WeatherBrains Monday night. We can tell you that you are under this warning or that advisory or you will get this much or it will be x degrees, but unless we tell you what that actually means to you, we have failed.  We also need to do a better job of communicating uncertainty, rather than trying to be so cut and dry.

At MWN, we try and provide impacts as much as we can, particularly in our forecast discussion blogs, knowing that in some cases we simply don't know what the impacts will be.  We can provide an estimate or a range of possibilities when we aren't certain and we can do a better job of telling you what the probability is of something happening (though admittedly the public doesn't generally think in terms of probabilities - "just tell me what it's going to do"). However, we have to do better as an enterprise in that regard.  We will continue to make that effort at MWN.  I already have some ideas in mind.

To all of you who have written or spoken your words of appreciation, thank you.  It's a passion, it's exciting, it can be stressful, but it's the reason I do what I do each day. I'm not looking for kudos. I just want you to know that I always strive to improve, to figure out what went wrong when it does, and to communicate to you all in a way that you understand and will take action on. Thank you all for your continued support!

Have a comment on the topic? We want to know what you think. Leave it below and we'll be sure to read it!

--Erik Proseus, MWN Meteorologist

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