Monday, May 5, 2014

Increasing Humidity This Week

By Jay Grymes & Steve Caparotta

Happy Cinco de Mayo! The sunshine certainly cooperated for a little celebration time today, even though the mid to upper 80°s we've dealt with the past few days is a bit on the 'warm' side for early May. And it looks like we stay warm and dry for the next few days. 

Plan on highs in the mid to upper 80°s for the next few days, at least, with little or no rain through Wednesday. The polar jet has retreated well to the north and a broad ridge of high pressure has settled over the nation's mid-section. At the surface, high pressure is currently centered over the north-central Gulf but will shift eastward in the coming days.

We're really getting dry around the viewing area and that combination of a ridge aloft and surface high pressure nearby typically means continued dry weather. The surface high will shift east over the coming days, and that will set-up "return flow" -- low-level moisture coming in off the Gulf along southeasterly and southerly winds. You'll not only feel it and see it in the rising dew point readings (increased humidity) over the next few days but it will also be reflected by warmer, muggier morning starts. The low-level moisture will contribute to the potential for patchy fog each morning too.

Yet even with the more humid air in place, we still have to wait for a breakdown in the upper-level ridge to take the “lid” off the atmosphere and allow rainclouds to develop. That breakdown in the ridge should be underway by mid to late Thursday, providing good chances for some needed rains by Friday and into the weekend. 

We don't need a string of gully washers, just some decent rains to water the lawns and gardens. The latest NWS projections show a cool front approaching the Bayou State later this week but stalling to our north and west. However, by then the air along the Gulf Coast should be sufficiently moist and unstable to support afternoon showers and a few t-storms as we head towards the weekend. We'll go with 50% to 60% rain chances -- mainly the afternoon and early evening variety -- for Friday and Saturday, possibly extending those percentages into Sunday. 

The latest 7-day rain-total projections from the NWS Weather Prediction Center indicate most of the WAFB viewing area should receive 1.0" to 1.5" between now and next Monday morning. That's close to normal for this time of year and would be most welcomed. But for some lawns, a little help from the garden hose between now and the weekend might not be a bad idea!

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