Thursday, May 7, 2015

Only Isolated Showers into the Weekend

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

May 7th WAFB First Alert Quickcast:
- isolated showers into the weekend
- Invest 90L has an 80% chance of becoming Ana

Areas of dense fog developed during the morning drive as our muggy Gulf air mass reached saturation -- relative humidity at 100% -- across much of the area. Thankfully, the morning sun dispatched that fog fairly quickly.

After a string of mainly dry days, we saw a bit more action on Doppler radar today, although coverage was still rather limited. And what rains did develop this afternoon -- a result of our moist air and daytime heating -- die off into the evening. Look for fair skies by the evening with clouds and pockets of fog slowly returning after midnight. It should be a dry start for Friday’s morning drive and bus ride with temperatures in the upper 60°s.

It’s another warm and somewhat humid Friday afternoon on the way with highs in the mid to upper 80°s for the WAFB viewing area. Given the set-up, spotty-to-isolated showers can be expected for the afternoon but whatever does develop won’t last long -- let’s call it rain chances at 20% or less. All in all, looking good for Friday evening’s ‘Live After Five,’ LSU Baseball, or anything else around the area.

Saturday's forecast? Ditto on Friday: upper 60°s for sunrise with pockets of fog, afternoon highs in the mid to upper 80°s and rain chances at 20% or less.

What about Mother’s Day? If you’ve been following our forecasts this week, we’ve been generally going with a 30% chance of afternoon showers for Sunday. The news is a little better as of this afternoon: we’ll go with just a 20% chance of rain and a forecast for the day that is nearly a carbon-copy of Friday and Saturday.

After that very wet April, our recent run of mostly-dry days has been welcomed. But we don’t want to get too dry, and it looks like Mother Nature will accommodate. A storm system over the Central Plains this weekend will send a cold front our way for early next week. Plan for scattered rains on Monday with scattered-to-likely rains on Tuesday. The extended guidance is somewhat divided on what happens after that -- does the front sweep through far enough to deliver a noticeable cool-down and a return of dry days or does it linger in the region as a stalled front that keeps our weather unsettled? 

For now, we suspect only a limited drop in temperatures with this front and we are currently leaning to continued scattered rains for Wednesday and Thursday.

As for “Invest 90L” off the southeastern Atlantic Coast, the National Hurricane Center (NHC) has again increased the chances for tropical or sub-tropical development, now giving 90L an 80% chance of becoming Ana over the next two to 5 days (as of 12:45pm today). Based on the latest satellite presentations, it seems probable that the NHC will ‘upgrade’ 90L to Ana in the next two days and define it as a sub-tropical storm.

As a reminder, sub-tropical systems are hybrid systems caught midway between extra-tropical lows and fully tropical systems, showing some characteristics of both. While sub-tropical storms tend to be less energetic in terms of damage potential, they tend to be more expansive than tropical storms and hurricanes. Interests along the U.S. Eastern Seaboard -- especially the Carolinas -- need to pay close attention to this system, but it offers no threat to the Gulf. 

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