It’s a surprisingly tricky forecast given the lack of any strong weather systems. A weak low-pressure system will lead to increasing clouds tonight, especially after 06z, limiting radiational cooling. The low-pressure system will bring a band of light to moderate rain late tonight into tomorrow morning that happens to nail Louisville, which will lead to a pronounced cooldown due to evaporational cooling into the initially very dry low-level air. The dry air and lack of strong dynamics will preclude truly heavy rainfall, though Louisville may hit the jackpot with >0.2”. The strongest winds could actually occur at the onset of the rain, as a gust front emanating from the rain-cooled air could bring briefly 10-15 kt, similarly to how a thunderstorm’s cold pool leads to a brief period of strong winds, but in a weaker sense in this case.
Clouds will break with only partly cloudy skies by later tomorrow afternoon, leading to a decent warmup eventually, but there is considerable model disagreement on the exact track of the low-pressure system and whether the clouds will break earlier or later in the afternoon, or perhaps even somewhat linger if the cloud shield doesn’t retreat to the north and east as fast as modeled. There also appears to be a temperature gradient due to the low-pressure system, and exactly how far north or south it is will also affect how warm it is. I suspect the high will be above some of the model guidance again, but it is probably not a day to go too warm with the potential for more persistent cloud cover and cooler temperature as well.
With only partly cloudy skies and light wind tomorrow evening, some radiational cooling is likely, with a slight chance of the low occurring at the end (Wednesday 06z), though clouds could increase again around that time ahead of another weak low-pressure system.
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| Source: PivotalWeather |
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| Source: PivotalWeather |
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