• Category Archives Weather Classroom
  • Brief Shots Of Cool Weather In An Otherwise Warm Pattern

    Good Wednesday afternoon! As we analyze the latest data, one thing that screams out to us is that our warmer than normal pattern is going to continue at least for the next couple weeks. That’s not saying we won’t see bouts of cool air (it is October, after all), but it is saying that when you total everything up, we think temperatures are warmer than average, and most likely significantly so, over the next couple weeks.

    The PNA is currently driving the pattern and I see nothing to signify a radical change in the near future. Troughs and associated cold air will plunge into the western half of the nation and as they (“they” refers to the cool air masses in this particular case) come east, the air will modify in significant fashion.

    Here’s a look at the PNA. We note there’s at least some attempt to get back closer to neutral or slightly positive towards the middle of the month. We’ll keep an eye on this. Should the data remain consistent on signaling a mid month PNA change to positive, that could signal a more sustained cool period for the back end of October.

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    Latest data for the mid range period suggests a highly amplified look. We feel the European model is the way to lean as the current PNA forecast would lead to a deeper trough and associated colder look for the Plains and points west, with milder conditions here. BTW, my old stomping grounds of Breckenridge, CO should do quite well in the early season snow department with this type of pattern. To be fair, both models are in fairly good agreement here, but we want to emphasize the slightly further west placement of the trough in the 8-10 day seems to be the best idea at this point, per the European.

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    Speaking of the European, ensemble data suggests a warmer than average, to much warmer than average, pattern persists over the next (10) days, despite a slight “set back” Sunday and Monday. In fact, taken verbatim, the European suggests the 80s return here later next week.

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    The GFS sees a warmer than normal Ohio Valley and Great Lakes region, as well, over the next (16) days.

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    Finally, the Climate Prediction Center (otherwise referred to as CPC) sees October shaping up like this: warmer than average over our region.

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    At the end of the day, only Mother Nature will either confirm or deny whether our current thinking is the right one! 🙂 Again, I want to stress we’re not saying that we won’t see bouts of chill through the month of October. That’s not the case at all. We’re just trying to make sure we’re clear with our thinking over the next couple of weeks that we remain in a pattern that should yield additional above average warmth.

    Your complete forecast will be posted here later this evening, Indy!


  • A Look Ahead: Sunday Evening Rambles

    It’s been a relaxing weekend here at IndyWx.com headquarters, complete with lots of time visiting with family and friends, and enjoying what’s truly important in this life. Auburn was off this week so I was able to relax Saturday more so than normal. Next up? Ole Miss Saturday evening on ESPNU for those that are interested! 🙂

    Okay, on to the weather.

    While we’re certainly heading into a more active pattern ahead, I don’t see anything brewing that will ultimately lead to a “sustained” cool pattern. We’re in a negative PNA pattern and this is currently the driver. Despite the NAO/ AO suggesting chill should rule, we’ve covered why these teleconnections simply don’t have as much meaning in terms of our sensible weather this time of year. Please note that I’m not saying it (current indices) can’t be a signal of what may lie ahead in the colder, stormy winter months ahead, but out of the big three teleconnections this time of year, the behavior of the PNA is going to have the greatest impact on central Indiana’s “sensible weather.”

    The PNA remains negative as we move forward. Also, please note how horribly the verification has been on the modeling. In some cases, individual model runs are busting in big time fashion. Let’s keep an eye on this as we move ahead…

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    Despite the coming chill of the weekend, it’s a pattern surrounded by warmer than average temperatures, at least according to the ECMWF ensembles. I know this may be hard to see, but here’s a look at the temperatures, compared to average, over the next couple weeks. Note the chill progressing east late week/ weekend. Also note the warming set to take hold shortly after.

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    The European ensembles/ operational run aligned side-by-side are in decent agreement. Notice the progressive nature of the pattern, suggesting the chilly air inbound for the upcoming weekend doesn’t hold. The ensembles are even more emphatic (deeper) with next Sunday’s trough than the 12z operational run today.

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    The PSD offers up a similar look.

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    Latest model guidance highlights renewed rain and potential gusty thunderstorms late week, in advance of the strong cold front followed by a sharp temperature decline for the second half of the weekend into early next week. Are upper 30s in our future early next week? I would say chances are high, especially away from the 465 “loop.”

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    Much more later, friends!


  • The European Model Isn’t Without Sin…

    You probably hear myself, and many other weather sources, speak of the European forecast model (ECMWF) as one of the best in the business. While that’s true, it does not mean the model doesn’t have “issues” of it’s own. Let’s just look at the inconsistent behavior of the model handling the trough for next weekend. Look at how poor the European has been next weekend, centered on Sunday- October 6th.

    We took a screen shot of each model run (0z and 12z) for next Sunday, dating back to Thursday, 09.26 up until the very latest run of this morning, 09.29 0z. By the way, our complete forecast for the week ahead will be posted later tonight. Have a great Sunday!

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