Severe Weather Discussion for January 14 – 20, 2008.
– Cooler this week with temperatures in the 50s today and tomorrow; then dropping to the 40s Wednesday – Sunday.
– Chance of snow Wednesday into early Thursday, most likely area is eastern half of Oklahoma.
– Severe Thunderstorms in Oklahoma: < 5%
– Storm Chase: < 5%
– Winter Precip: 20%
Today and Tuesday will be the nicest days of the week as pattern change occurs across the lower 48. Models are in decent agreement and rather consistent at this point. Main implications occur just beyond this forecast period and could involve Day 7 but for now not a problem.
As noted, today will be quite nice into early Wednesday as a full latitude trof develops over the central U.S. This trof should form into a longwave trof during the week as a longwave ridge develops just off the west coast. Initially there is little to no Arctic air in Canada, so the cold front on Wednesday is expected to be Pacific origin. Even though the cold front isn't Arctic, it will have a bite to it and drop temperatures into the 40s across the state on Wednesday. High temperatures will likely occur in the morning as the airmass change happens behind the front. There is a chance of showers as the front passes and then snow during the night as the upper system moves overhead. Closed and cutoff southern stream system over Mexico may add some moisture to the mix but over all is not expected to impact Oklahoma too much. Both of these systems will be converging on the state late Wednesday. Best chance of snow looks to be the eastern half, with parts of central Oklahoma
getting some action. Snow accumulations are possible of 2-4 inches in east central Oklahoma, depending on when the changeover to snow occurs and if the GFS or NAM is correct. NAM is a little more precip happy than the GFS. Trof clears the area on Thursday with Oklahoma in strong northwesterly flow.
Thursday – Sunday appear to be quiet with cool weather expected. Temperature should be in the 40s across the state. Changes then look to occur late Sunday into next week as another trof digs southward along the Pacific coast and on the downstream side of the ridge. Arctic air or at least Canadian air looks to be in-place by this point with a southward surge likely. The new GFS looks to have trended west with this system and if this verifies there may be a snow threat the 21st – 23rd. Additionally, seeing QPF in northern Oklahoma on Monday the 21st, which should be snow. More details to follow and special discussions may be required late in the week.
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