5:45 P.M. Friday, April 21, 2017
Model solutions have done a flip-flop in the past 24 hours. Yesterday, the NAM gave by far the best weather outlook for Saturday’s events. Today the GFS is our friend. Which one is right? Good question! I’ve asked myself the same question many, many times over the years. Usually, there’s at least some “truth” in both models. The NAM, as expected, had a better take on today’s weather. Tomorrow, it appears to me that the GFS has a better handle on the situation. Here’s how I see it evolving:
First of the heavier rain systems moves into the Louisville area between 7 and 8 P.M. Rain could get heavy at times late tonight and tomorrow morning. Rain ends during the midday hours (Noon – 2 P.M.). Cloudy and cold rest of afternoon into the evening (50-ish temperatures likely). So, air show should be dry but a low-hanging cloud cover may hinder some of the action. For the fireworks, it’ll be breezy and cold (near 50). And, here’s where the NAM adds to the forecast – there’ll be about a 50-50 chance for light rain and/or drizzle during the show.
4:30 P.M. Thursday, April 20, 2017
Weak upper air system moving through the Great Lakes may create strong thunderstorms over NE Indiana and Michigan for the next few hours. We, however, are too far south to join in on the stronger dynamics with this system. Enough energy is left for us to (probably) see two episodes of showers and thunderstorms over the next 6-8 hours. A loosely organized line of showers/thunderstorms will move across the Louisville metro area between now and 6 P.M.
A second, better organized, system should bring a more widespread area of rain/thunder between 8 P.M. and 11 P.M. tonight.
Note: Models can’t agree about tomorrow: NAM brings a large area of rain over us tomorrow afternoon. GFS keeps us dry tomorrow with rain arriving tomorrow night. Either way, it will be cooler. (NAM looks better to me)
Both models are developing the next weather system faster than they had earlier in the week. If this trend continues, it signals a better outlook for Saturday. Steady, heavier rains look to end by midday. Cloudy skies remain during the air show, but at least it should be dry. As cooler air arrives during the afternoon/evening we’ll see temperatures drop to the low to mid 50’s. Add breezy winds and a winter coat will feel good for the fireworks. In addition, Saturday evening could also be hit with a cold drizzle. Still, better than earlier forecasts.
10:30 A.M. Wed., April 5, 2017
Atmosphere appears set up to do some damage later today – especially east of the I-65 corridor. Strong upper air system is approaching and ample moisture is streaming northward. That sets up a pretty high chance for thunderstorms as well as severe storms. System will be slow to develop and will just be getting rolling about the time it hits central KY. Strong/severe line of storms should pass Louisville area between 5 P.M. and 8 P.M. Hail and high winds appear likely. Storm line will intensify as it moves east of I-65 and heads toward I-75. Also, higher risk for storms, some severe, over southern KY from I-65 eastward.
Much colder air arrives tomorrow.