Wednesday, May 6, 2015

Slightly Better Rain Chances on Thursday

By Jay Grymes & Steve Caparotta

May 6th WAFB First Alert Quickcast:

- local weather status quo: isolated showers possible through Saturday
- “Invest 90L” no threat to the Gulf

Our recent set-up of mostly-dry days with isolated showers and highs in the 80°s continued today and is expected to hold through Saturday.

While the breezes may have done a number on your hair today, they are helping to make our warm and somewhat-humid afternoons reasonably comfortable.

We got a little cooler than expected this morning, with Metro Airport (BTR) dropping to a low of 61°, in part because we had less cloud-cover than expected.  For this afternoon, we picked up a couple of Doppler radar returns through the afternoon but it was very limited ... and anything that fell was generally on the light side with little if any thunder in our viewing area.

Our forecast for Thursday calls for a slightly higher chance for a backyard shower and we do expect both the morning lows and afternoon highs to be a smidge higher.  Let’s go with Red Stick area sun-up temperatures in the mid 60°s for Thursday morning and afternoon highs in the mid 80°s with a 20% to 30% chance of afternoon and early evening showers.

Friday and Saturday may be a slight bit warmer.  Plan for muggy mornings in the upper 60°s for both days, largely due to a slow-but-steady increase in dew point temperatures (a measure of low-level humidity).  Afternoons will be a little warmer and stickier too for most WAFB neighborhoods: we’ll go with mid to upper 80°s for both days.  As for rain chances?  20% or less for both afternoons.

For Sunday -- Mother’s Day -- we’ve been hovering in the 20% to 30% range for rain chances over the past several days and we’ll keep it there.  Plan for a muggier morning, with sunrise temperatures in the upper 60°s to near 70° for the Capital City and an afternoon high in the mid to upper 80°s.  What rain that does fall should be relatively short-lived, so stick with any outdoor plans that you have put together for Mom.

Headed into next week, we’re still anticipating a cold front to make its way into the lower Mississippi Valley, most likely arriving early Tuesday.  But the latest charts from the NWS Weather Prediction Center (WPC) suggest that the trailing end of that front may fizzle out before pushing through our viewing area.  We’ll go with scattered showers and t-storms for Monday and Tuesday for now, with the weather potentially remaining a little unsettled into Wednesday.  However, a fizzling front suggests no significant reduction in area temperatures, and maybe more importantly, no break from this week’s Gulf humidity.

As for the pre-season chatter about tropical development east of Florida?  Overnight the National Hurricane Center (NHC) labeled the area as “Invest 90L” (investigation area) and as of this morning the NHC significantly increased their forecasted development chances: 60% chance of development during the next two days and over the course of the next five days.  (The NHC’s 2:00pm update keeps those percentages at 60% for both the 2- and 5-day projections.)

As of this afternoon, there has been no confirmed center of closed circulation for 90L.  (As an aside, it is likely that when a surface low is confirmed it will be a non-tropical low.)  Until we have a closed low, forecasting the system’s track, intensity and even its potential evolution into a tropical structure is little more than educated guesswork based mainly on model projections.

In fact, the lack of a well-developed center is probably at least one reason why the NHC scrubbed the aircraft mission schedule for earlier today.  (Two flights are currently scheduled for Thursday with a third on the books for a pre-dawn mission Friday.)

Many, but certainly not all, computer models are ‘bullish’ on this system.  Residents along the Southeast U.S. coast- - from Georgia to the Carolinas - - should begin preparations for a potential landfall of either a sub-tropical or tropical storm by or even before the weekend.  If 90L does reach one of these stages, it would be named ‘Ana.’

Yes, it’s early but it’s not entirely rare for tropical storms to form before June 1st.  In fact, there have been pre-season storms (including hurricanes, tropical storms or sub-tropical storms) in 10 of the past 50 years, with two pre-season storms forming in 2012 (TS Alberto & TS Beryl).

No comments:

Post a Comment