Wednesday Evening Forecast Discussion – 6:25 p.m.
August 22, 2012 Leave a comment
This afternoon a stalled weak boundary just to the southeast of the area is keeping the clouds and showers out of West alabama. We are not expecting any other rain here until Saturday because high pressure will remain in control. By the weekend just enough weakening in the ridge could cause a few isolated storms as the ridge pulls northeast some, allowing for just enough return flow. Very nice August temperatures overnight for the next couple of nights with calm winds and mostly clear nights.
By midday Sunday, our forecast models appear to have a parting of the ways. The GFS indicates a weakness in the upper ridge and allows Isaac to move northward from Cuba to the west coast of Florida toward the big bend Tuesday night, absorbed into the upper trough and back into the Atlantic by next Friday morning, leaving Central Alabama high and dry for the most part. On the flip side, the Euro does not indicate the weakness in the ridge as soon and therefore takes Isaac further west into the gulf before bringing it northward toward the southeast Louisiana/Mississippi gulf coast. This scenario allows the system to build in the warm gulf waters longer and so has a much tighter stronger low pressure, and not until Thursday does this possibility make landfall, with Central Alabama on the wet right side. The latest 12z Euro is faster and further east than the 00z run. The latest 12z GFS is faster by 6-12 hrs and thus not as strong being over the warm gulf for a shorter period of time. 12z Euro is in the middle of its ensemble members while the 12z GFS was on the east side. Needless to say still much uncertainty for the beginning to middle of next week.