Winter Weather Discussion for December 9 – 11, 2007.
– Winter Storm Watch for much of Oklahoma, except southeast 1/3rd, starting Sunday morning and lasting until Tuesday morning.
00z models continue to prior trends of lifting at least part of the closed/cutoff low over the southwest U.S. eastward across the region. At the surface, a shallow cold airmass is expected to be across parts of Oklahoma. The issue, as it has been the past few days, is where will this cold air be when precipitation starts.
There will be some precipitation the next few days as weak shortwave trofs move across the region. Late Sunday the upper system should start moving towards the region. This will produce widespread isentropic lift across Oklahoma with precipitation occurring over the shallow cold dome. The result should be freezing rain across parts of the region. As time goes on warm air advection and latent heat release should push the cold air north. 00z GFS soundings show a small window of freezing rain potential for OKC Monday morning. The QPF map at this time period shows little in the way of rainfall and this is not a shocker as the 00z models have slowed te upper system. The WAA increases in earnest Monday afternoon with the NAM showing 1.25 inches for OKC with the GFS a little later around Tuesday morning for the heavy precip. However, despite which model you look at, both of them are awfully warm.
As such, I think the best potential for frozen precipitation will be in the northwest quadrant of Oklahoma. The heaviest area is likely to be Elk City to Putnam to Enid. OKC will probably see a glaze Monday morning, but I doubt much more than that at this point. I think the winter storm watch is way premature, but as always I follow any highlights the NWS issues. There are plenty of issues about this event that may change during the next 60 hours. I do not see any indicators that points to a classic heavy icing event. Nothing compared to 01/2007, 01/2002, and 12/2000.
We shall see, I may be dead wrong, but at least we'll know soon.
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