Thursday, March 30, 2017
The atmosphere may, or may not, be primed for severe storms later this afternoon/evening. The confusion was apparent yesterday as the GFS and NAM far apart in their solutions for today’s weather/thunderstorm possibilities – the GFS wasn’t too keen on severe thunderstorms while the NAM jumped on severe weather big time. Today, the GFS and NAM are closer, but still at odds. Meanwhile the short term models, while agreeing in general about how things will evolve, are also divergent about the expected strength of any thunderstorms.
Going with the suspicion that each model has something good to add to the discussion, here’s how I believe the weather will evolve this afternoon/evening: First, the amount of cloud cover that remains this afternoon is very important. Remains from storms to our west overnight have been hanging around this morning. We should get enough brakes in the clouds this afternoon to allow some sunshine to build up heat (and energy) for some storms. More sunshine is likely over KY than IN. Lack of sunshine will diminish the severe storm threat. Satellite data shows the clouds thinning as of Noon.
Second, we have strong upper air dynamics over the midwest working their way slowly eastward, but surface conditions are a mishmash ( a highly technical term) of ill-defined air masses, outflow boundaries, and, so-far, ill-fated attempts to form a surface low pressure center and a cold front. It looks as though it’ll take 4-8 hours or longer for things to get more organized. By that time, the main threat for severe weather will shift east of the I-65 corridor.
Third, with lack of coordination between the upper and lower levels, things are just going to happen in a seeming random fashion this afternoon. Quick-moving thunderstorms should pop up in a “hit ‘n’ miss” fashion over western and central KY and (mostly) IN. Most of these will be strong with gusty winds and hail possible. Some could even reach “severe” limits, though these are likely to be few and far between. By 6-7 P.M. the majority of these pop-up storms should be east of the I-65 corridor. By this time, any severe weather threat should be over for the Louisville area. Primary threat for severe storms this afternoon will be over central and northern Indiana.
Four, by 7-8 P.M. the surface part of this system will be better organized and is expected to create a large area of rain and thunderstorms (non-severe) over western KY and IN. This will bring us a very wet evening. Even a little flash flooding is possible. Rain should diminish shortly after Midnight.
I see from this morning’s CJ that Rick and Cal are the two highest paid college basketball coaches in the land. But, the educational ratings of the schools they coach are low. We should gain an important bit of knowledge from the first two sentences.