Monday, June 10, 2013

Getting Drier -- and hotter -- this week!

Jay Grymes / WAFB Storm Team

Titan9 Doppler was showing a few showers on Monday afternoon with a couple of stronger t-storms to the south and east of Baton Rouge, with most of the action loosely linked to the afternoon “sea breeze.” We expect all of that action to die-down as we head into the evening and go to mainly fair skies overnight.
Tuesday will begin with a few clouds and sunrise temps in the low 70°s for metro BR. We’ll go to partly cloudy skies for the afternoon, with rain chances on Tuesday at less than 20%. 
It looks like the main weather story for Tuesday and the rest of the work week will be about the heat. Our forecast is calling for highs in the low to mid 90°s across metro Baton Rouge for Tuesday, with highs on most days this week up around the mid 90°s. Factor in the humidity and we’re talking about peak afternoon Heat Index numbers climbing into the triple-digits just about every day this week.
At the same time, we’re calling for a run of “mainly dry” days, with rain chances for most WAFB neighborhoods running at under 20% each day right into the weekend.
Why the “hot-and-dry” spell? As you know, in the summertime, the two go hand-in-hand. Reduced cloud cover means less chance for rain and more direct solar heating. 
Our forecast for the next couple of days calls for upper-level ridging (high pressure in the mid to upper levels of the atmosphere) to take charge and persist right into the weekend. Ridging suppresses cloud development and actually causes the upper-levels to sink towards the surface -- literally pushing downward from above. This downward motion effectively puts a cap on the lower levels of the atmosphere, minimizing the ability to hot, humid air to rise (and to develop into clouds).
The cap isn’t always perfect, so some rising still can occur, allowing for occasional, spotty showers. But the upper-level ridging and resulting cap means little or no chance for rains like we saw over the weekend -- at least not for the next several days, and probably not through the weekend.
So get ready for some serious summer season heat all week long.
So far so good in the tropics -- all remains “quiet” there.

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