Monday afternoon's high temperature of 93 degrees just missed the 94 degree record for May 3rd. It was pretty hot, but not so humid. We're used to feeling temperatures in the low 90s for most of the summer here in Acadiana, but usually there's suffocating humidity to go with it. The air mass will remain very dry today and tomorrow, so sunshine should be able to heat the temperatures back to around 90 at least through mid week.
You've probably heard me say it over and over. Dry air heats and cools easier than humid air. When the cool fronts move in during the fall and the dry air sets in, cool mornings usually give way to rather warm afternoons. Having a 30 degree temperature swing between the high and low isn't that unusual when dry air is in place. But when the summer rolls around, that difference usually drops to 15-20 degrees because the air is more humid.
During the summer, most of the moisture comes from the Gulf of Mexico. But evaporation of water in or on the ground also adds moisture. When the ground is dry during drought periods, humidity levels will be lower. And remember what I said, dry air heats and cools easier than humid air.
Let's go back to 2009. After a relatively normal January to April time period, things became quite dry in Acadiana during May and especially June. Some parts of Acadiana went more than 30 days in a row without rainfall. The ground dries, the humidity lowers, and the temps start to rise. The second half of June, high temps were above 95 each day, and 4 of those days were over 100. This heat continued into the first week of July. By the middle part of the month, the normal afternoon showers and storms returned, and the temperatures dropped back to near normal.
The summer of 2000 was similar. After nearly a year of drought, the late summer heat took hold. Most of August our temperatures were in the upper 90s, but by the Labor Day weekend, those 100 degree temps stuck with us for a solid week.
Already we are running 10 inches below normal for 2010. April was the third driest on record with just over 1/2" of rain. March saw only about half the normal rainfall amount. Low humidity, and dry weather is expected to last most of this week, and rain chances are fairly slim for the next 7 to 10 days. If the dry weather holds on, don't be surprised to see upper 90s taking hold in a few weeks with 100 degree weather possible too.

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