4:30  P.M. Thursday, April 20, 2017

Current situation:

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)

Air Show/Thunder:

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.