Don’t worry: It’s a dry heat

I was in Frankfort the other day when a Lexington TV meteorologist said in a teaser for the 11 pm newscast that the recent weather was more like July than May. Actually, he would have been more correct if he had said the recent weather was more like mid-April…for Phoenix, Arizona!!

No experienced weather watcher would suggest that the recent very warm but dry airmass is reminiscent of July. After all, July in Kentucky is associated with temperatures in the upper 80s with lows in the upper 60s. Dewpoint temperatures are typically between 65-70 in July and rarely fall below 60, as we have seen in recent days. In fact, despite afternoon temperatures in the upper 80s, I have yet to turn on the air conditioner since the evenings have cooled off so nicely, as evidenced by our morning lows in the 50s.

The reason for the relatively dry air mass is the low-level flow. Even though winds are southerly, there is not a direct connection to the Gulf, as shown by the 850 mb map. This high is originally the same cold canadian high that brought patchy frost to parts of KY last weekend. This high has modified and warmed up over the Southeast which has kept RH levels lower than what would be expected for such high temperatures. Also contributing to the dry airmass is the fact that soil moisture over much of the SE is very low right now due to drought conditions. While KY is not officially included in the SE drought, it would not surprise me to see increasing soil moisture deficits across south-central KY over the next few weeks.

We probably won’t see dewpoints climb much above 60 until Sunday-Monday, when the next weak front arrives with a chance of scattered showers and thunderstorms. The next big rain chance may not arrive until the middle of next week, although at this time there is not a lot of agreement in the models.

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