Winter Weather Discussion for January 12 – 15, 2007.
– Arctic air on they way, initial surge arrives late Thursday, big surge around Sunday.
– Winter weather precipitation is still expected across much of Oklahoma and Texas late Friday into the weekend.
No change to prior forecast or reasoning. The GFS went on a holiday for four runs and then came back to the real world this morning at 12z. Unfortunately this reversal is recent and still not what is expected. However, the 12z GFS is much more reasonable than the runs yesterday and will be given greater consideration for this forecast package.
00z ECMWF is a little more progressive than the prior runs, but nothing significant. The 00z ECMWF/12z GFS look similar at 132 hours but think they are still too fast. That issue isn't too important at this juncture as the agreement does seem to seal the deal that Oklahoma and parts of Texas will experience freezing rain. How much freezing rain will be a function of future model runs. Rich Gulf moisture (for January) remains available for this weekend and should be easily drawn north over the cold dome. Current speed of the GFS would reduce the time for moisture transport, resulting in around 0.25 inches of freezing rain. I do not have the ECMWF precip progs and the NAM is still out of range, however any reduction in forward speed will increase the freezing rain threat. The nature of prior systems and the track this one is taking should yield a slowing trend over the next few days.
As noted yesterday, even if the freezing rain doesn't occur as progged, temperatures will get bitterly cold by late in the weekend. Current GFS temperature progs show some very cold air over the region with temperatures in the teens on Monday. MOS data are missing the boat with a high of 33F on Monday, we'll be lucky to see 25F. This is all a week away, but much colder temperatures do appear likely.
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