Wednesday, June 10, 2015

Increasing Rain Chances...

By Jay Grymes & Steve Caparotta

June 10th WAFB First Alert Quickcast:

- rain chances increasing through the next several days
- most see highs below 90° through the weekend

Rains were far less widespread today compared to Tuesday, but maybe more importantly, there were no Flash Flood or Severe T-Storm Warnings issued in or around our area this afternoon.

The upper-air pattern over the lower Mississippi River Valley wasn’t much different today compared to Tuesday, so why so much “quieter?” Because unlike yesterday, there were no upper-level disturbances rolling through the region along the eastern flank of the upper-air high-pressure dome (centered to our west and southwest). In fact, water vapor imagery today suggested the complete opposite for this afternoon compared to yesterday, with much drier air aloft coming in from the north rather than a pair of disturbances like we saw yesterday.

With the drier air in the mid/upper-levels, clouds were slow to develop vertically this afternoon. That not only meant less rain but also much more mid-day sunshine. The temperature at Metro Airport (BTR) was already at 86° by noon and the continued sunshine allowed highs to get into the low 90°s this afternoon for many communities.

How long does this dry air aloft remain in play? We don’t expect for it to last even one more day. As a result, back come scattered mainly-afternoon rains to our forecast for Thursday. By Friday, we’re expecting even better rain chances as the upper-air ridge to the west becomes less important to our local weather. In addition, at least one of our models is hinting at a little added boost to the regional lift (instability) thanks to a weak non-tropical trough drifting across the north-central Gulf on Friday. Indeed, even if this feature fails to materialize, our moist Gulf air mass -- with little in the way of any atmospheric “cap” -- warrants a “rain likely” for cast for Friday.

Heading into the weekend, we don’t expect much to change. The way things look right now, plan for scattered-to-likely rains for both Saturday and Sunday, with Saturday being the wetter of the two days. We don’t expect all-day rains on either day, so you’ll still have the opportunity to get in some outdoor time -- just watch the skies.

And so, for the rest of this week and the weekend, let’s plan for morning starts in the low 70°s for the Red Stick, with patchy shallow fog possible -- especially in the usual places. The mornings will be dry for most, although isolated showers -- especially closer to the coast -- are a possibility for most mornings too.

For the afternoons, have the umbrella within reach or be ready to head indoors if you plan to spend much time out-and-about. For Thursday through Sunday, highs for most communities should top-out in the mid to upper 80°s. The humidity will be a factor too, routinely adding another 5° to 10° to the ‘feels like’ temperature of the air, even in the shade.

And just in case you were wondering: we are watching a little “bubbling convection” in the western Caribbean, but it currently shows little or no threat to become a tropical system. Elsewhere, it is quiet across the tropical Atlantic.

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