Wednesday, January 11, 2012

Wednesday Morning Update

The next round of computer model data is coming in this morning and the models are keeping the upward trend. Last night I mentioned it would be interesting to see how this morning’s runs handle the moisture. Do they take it up, keep it the same or drop it?
I look at several computer forecast models when putting together the forecast. During snow storms I’ll look at upwards of eight different models from various worldwide forecast agencies. So far this morning, NOAA’s global forecast model (GFS) is in along with the RPM.

Let’s take a look at the breakdown of how much water the models are suggesting will be available for snow production.

  • Cape Girardeau: 0.10” | +0.03”
  • Indianapolis: 0.22” | +0.06”
  • St. Louis: 0.16” | +0.03”
Looking at the change from last night it may not look like a big change. However, when forecasting snow, it doesn’t take much to make more snow. For Cape Girardeau and St. Louis the 0.03” difference could add an additional half inch and for Indianapolis the additional 0.06” could add an additional inch of snow.

With the amount of cold air coming in with the cold front, I am looking for snow to rain ratios of 14 to 1 or as high as 17 to 1. Going strictly from the GFS model that would put down:
  • Cape Girardeau: ¾” to 1.5” of snow
  • Indianapolis: 3”-4” of snow
  • St. Louis: 2”-3” of snow
I am still waiting to see what the European forecast agency’s computer model comes up with. All I have to look at right now are the numbers from last night’s run. They are fairly comparable to this morning’s GFS. Cape Girardeau – 0.09” | Indianapolis – 0.19” | St. Louis – 0.19”. Numbers from this morning’s European model will be in later this afternoon and I’ll try to give an update when they come out.

Timing: The snow should begin to fall in St. Louis during the pre-dawn hours (2am-4am CT), in Cape Girardeau during pre-dawn hours (5am-7am CT) and in Indianapolis by early afternoon (12pm-3pm ET).

As for my “Freak-Out-Meter”… I am going to keep it at a 3 out of 10 for St. Louis and Cape Girardeau and move it to a 4 out of 10 for Indianapolis. The “Freak-Out-Meter” is hard to score because there are two ways to do it. I could score it on how people’s reaction will be or how the reaction should be. I try to score it to how people’s reaction should be.

Remember you can follow me for more timely updates via Twitter @johndissauer and via my Facebook page.

-Posted from my iPhone

1 comment:

Anonymous said...

Thanks John for the updates...wonder about the Poplar Bluff area... sounds like maybe 1/2 inch or less?