Wednesday, September 10, 2014

Rains Returning to the Forecast

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- afternoon highs in the 90°s continue through Friday
- increasing rain chances from Thursday into the weekend
- no Louisiana threats in the tropics

Just about everyone stayed dry today as expected, with only brief spotty rains developing over the WAFB area. Look for any lingering activity to subside around sunset. We’ll stay dry again through the night and the morning, with mostly fair skies and a few patches of mainly-light fog for the Thursday morning commute. Sunrise temps for the Red Stick will be in the low to mid 70°s. For Thursday afternoon, the weak high-pressure lid on the atmosphere that kept most dry today weakens at tad, allowing for a little greater cloud coverage and ultimately a 20% to 30% coverage of showers with a few rumbles of thunder. Highs for Thursday will again reach the low 90°s -- and “feel like” 98° to 103° for many neighborhoods in terms of peak afternoon Heat Indices.

Unfortunately, there is no improvement in the wishful thinking of the approaching “cool” front: as we feared, the guidance is now suggesting that the front may not even make it as far Baton Rouge before Friday evening. And after that, it is expected to stall along or near the southern parishes for the weekend: so much for our hopes of a “taste of fall weather” for the weekend.

Friday starts out mainly-dry with sunrise temperatures in the low to mid 70°s. Highs for many WAFB communities will reach 90° or above for the afternoon, but we’re going with scattered showers and t-storms for Friday afternoon and evening -- not great news for this week’s downtown ‘Live After Five’ or Friday night high school football. But we do expect the rains to subside a bit as we head into the evening hours, so we can hope for a decent evening.

The front is then expected to slowly sag southward for Saturday and Sunday, serving as a rain enhancing feature for the weekend. Yes, highs will far short of the 90°s over the weekend for many WAFB communities, but the reason will be more about the clouds and rains than the result of a changing air mass as the front slowly slips by. Set rain chances for Saturday at 50% or better, then around 40% or so for Sunday.

LSU, Southern and Southeastern football fans will once again be encouraged to tote the rain gear for gameday festivities, especially for the pre-game tailgating. With a little luck -- like all three campuses had last week -- game time conditions should be at least a bit more agreeable.

The outlook through the first half of next week keeps scattered mainly-afternoon showers and t-storms in the regional forecast, with lows near 70° and highs in the upper 80°s to near 90° for Monday through Wednesday.

In the tropics, the National Hurricane Center (NHC) is still tracking Invest 91L in the east-central Atlantic. 91L hasn’t shown any real development over the past 24 hours but it still has some potential to become our next tropical cyclone (a depression or tropical storm) down the road - - the NHC currently posts 91L with a 70% chance for cyclone development in the next five days. Regardless, the early forecast guidance appears to keep 91L over the open Atlantic regardless of what development may transpire.

The NHC also upgraded the area of low pressure centered near the Bahamas: by “upgrade” we mean declaring it as an invest (Invest 92L). Development potential -- still posted at just 20% over the next five days as of 2PM -- is likely to be increased later this evening given the latest satellite presentations. Remember, when the NHC defines a disturbance as an “invest,” it sets more extensive tropical analyses into motion, not just with the NHC experts, but also with a number of supporting agencies and university research groups. Look for “spaghetti model plots” to begin arriving over the coming hours with the forecast consensus likely taking the system (whatever it becomes) into the eastern Gulf. Stay tuned …

No comments:

Post a Comment