March 31, 2011
If somebody came up to you and told you there might be a big snowstorm tonight into tomorrow morning...you might think it was all a prank. April Fools Day is tomorrow, but this storm is no joke. And neither is trying to predict it. Rather than break everything down with a fine tooth comb, I wanted to focus this article more on the difficulties surrounding the forecasting of this storm. Don't worry, I will still give you my best guess as to what is going to happen...however, at this point, that's all it is...a guess.
You can get the latest PrecisionCast runs, the full discussion, and of course that famous gotta-have-it snow totals map on our weather page, but the real facts and figures lie beneath the surface. A trough is digging itself out in the upper atmosphere as we speak and sliding its way eastward. As it moves over our area later tonight, it will need to be placed in the sweet spot for us to get a major storm. I'm not convinced the coastal low will be placed in the sweet spot just yet, but I must admit the trough looks pretty decent. In addition to the trough, let's list all the variables at play here in determining how much, if any, snow we will get overnight...
1.) Placement of upper air trough (stated above)
2.) Placement of coastal low
3.) Will the system have a lot of moisture with it?
4.) What will the temperature profile look like overnight?
5.) How long will the event last? (Right now, it looks like a quick mover)
6.) Will any rain mix in and if so...how much? (This would limit snow totals)
7.) Will the snow be at a 10:1 ratio or less? (Probably much less considering we are in spring now...this will be a heavy, wet, packable snow type)
I could go on...but hopefully you get the idea that we are dealing with a complicated beasty. Storms are more unpredictable later in the season, but normally most of the computer guidance will come into agreement on the aforementioned variables by this point (less than 24 hours out from the event). Today is a much different story, however. Some models hug the low to the coast and give us a good snowfall, while others (and one in particular that I tend to trust) takes the low out to sea and gives us basically squat.
Now what? How do I prepare all of you for what may or may not happen? Some folks think you have to be "gusty"...make a call and stick with it! That's all well and good...but I believe honesty is the best policy. If I truly can't pin a storm down or don't know exactly what is going to happen...why not be honest about it. That's the way I felt this morning. An old professor of mine used to say, "Tell the people what you know, plain and simple"...well what I know this morning is that I don't know. The amount of uncertainly with this storm is HUGE. I can't emphasize that enough.
Will some folks be upset that you can't commit and give them EXACT totals...sure. These are the same folks, though, who don't realize the science behind the 3 minute TV segment. If I asked somebody a question that they didn't know the answer to, I would want them to say that...not just make up something from thin air. Sometimes, very rarely, that happens in forecasting. I refuse to simply make up something for the sake of giving an answer. I will always be as honest as I can with the viewers because that's what I would want.
This is also not to suggest that I will stand on TV for 3 minutes and say nothing....quite the contrary. Sometimes when you don't know exactly what will happen you have more to talk about. I like to discuss the variables as listed above and go through my thought process...much as I am now. At the end of the day, I will always put forth my best educated guess about the forecast. You can find my full forecast for tonight's storm on our weather page and I encourage you to go there and read the discussion. Do the same tonight once Eric posts his thoughts.
In the meantime, it's back to work trying to look at all the available data and sift through the possibilities of what will happen tonight. For those of you that like this stuff, I hope you enjoy one more taste of winter (possibly). For those that are more than ready for spring, temperatures should hit 60 degrees next week! Thanks for letting me explain myself here on the blog and taking the time to read all the entries. 95% of the time I can look at somebody and give them a forecast that I feel 100% confident in...the other 5% of the time is where the uncertainties come into play. This storm is in that 5%...and that is no joke.