Friday, January 11, 2013

3:00pm Weather Update: Shift in Time

The morning computer model data is in and everything appears to be running straight and normal.  That means that all of the various computer models have different solutions to the Sunday-Tuesday time frame.

One thing that is becoming more apparent is the time frame.  Everything seems to be pointing to a slightly earlier and not as long of duration for wintery precipitation.  The way it looks now…
  • St. Louis metro:  Saturday night through early Sunday morning.
  • Southeast Missouri:  Sunday morning through early afternoon.
  • Southern Illinois:  Sunday
  • Western Kentucky:  Sunday afternoon through Sunday evening.
  • Central Indiana:  Sunday afternoon through Sunday evening.
The precipitation type is still too early to pin down.  I don’t think snow is going to be a big player.  In a few locations there could be a brief period of snow but the bigger deal will be either sleet and/or freezing rain.

A quick breakdown of what the models are suggesting…
  • European Forecast Agency global model (ECMWF):  Continues to suggest a layer of warm air (above freezing) a few thousand feet above the surface with cold air (below freezing) undercutting the warm air.  This would be friendly to freezing rain/sleet production.
  • NOAA’s global forecast model (GFS):  Is starting to trend the way of the Euro by keeping a layer of slightly warmer (above freezing) over the top of cold air (below freezing).  This would lean more towards sleet with maybe freezing rain.
  • North American Mesoscale Model (NAM):  Suggests air type (cold or warm) will arrive through the entire column (both at the surface and a few thousand feet up).  This would keep it either snow or rain depending on location.
Finally, here is the latest meteogram for St. Louis.  This shows computer model projections of freezing rain accumulation.  Each colored line is a different computer model run.  The white line indicates the average of all the forecast models.  Note:  The meteogram does not display European computer model.
Click image to see larger version.
I’m starting to think there could be a band of icing that runs from the Arkansas/Missouri border eastern/southeast Missouri through southern Illinois and in to west central Indiana.  Some of the locations that could be impacted would be St. Louis, Perryville (MO), Carbondale, Effingham, Terre Haute, Indianapolis, Bloomington (IN) and Columbus (IN).  (Before people start to question… No, these are not ALL of the locations, these are SOME of the locations.)

Bottom line… There will be a decent amount of rain falling Saturday.  Eventually the rain should change over to something.  There are still several details that need to be ironed out, but the potential does exist for ice but at this point.  For those in southeast Missouri and western Kentucky this does not look to be anything like the 2009 ice storm.

  • Southeast Missouri:  3
  • Southern Illinois:  3
  • Western Kentucky:  2
  • Central Indiana:  3
  • St. Louis metro:  3


Anonymous said...

John, what is the range of your freak out meter?

John Dissauer said...

It is 0 to 10 with 10 being FREAK OUT!!!!

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