The biggest benefit of the front will be a temporary reprieve from very humid conditions we have had for several days. If you follow the MWN Blog much, you know that we talk a fair amount about dewpoint. Rather than speak of relative humidity, which only really has meaning when pairing it with temperature, the dewpoint is a great measure of the amount of moisture in the air. Lately, our dewpoints have been in the lower 70s, which is very moist (and sticky) air. Dewpoints in the 60s, especially mid 60s, is much more comfortable. Dewpoints in the 50s is indeed an unusual event during a Memphis summer.
The graph below takes a little explaining, but it is a time cross-section at Memphis taken from the morning GFS computer model showing plots of temperature (red line) and dewpoint (green line), relative humidity (red, green, blue background), and rain amounts (green vertical bars). It is read backwards with the earliest time on the right and going into the future by reading right to left ( <--- ). The far left is Saturday morning. Altitude increases as you go up the graph.
|6/27/11 (7am) GFS computer model output through Sat AM (click for larger image)|
Bottom line: drier and cooler air will exist after we get through tomorrow's thunderstorm chances and the front passes through. By the way, I didn't show it, but the heat and humidity return for the holiday weekend! Details in the MWN Forecast.
(We're also on the edge of a Slight Risk for severe weather with the frontal passage tomorrow. I expect to see the most organized severe weather threat over north Mississippi during the afternoon hours. An isolated high wind gust or hail report are not unlikely though over the metro area. More in the MWN Storm Center.)
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