Friday, September 13, 2013

A Few Showers Overnight

By Jay Grymes & Steve Caparotta

We’re watching pockets of showers and isolated t-storms slide from north-to-south over portions of the Florida Parishes and SW Mississippi, so we can’t say “no rain” for this evening’s ‘Live After 5’ nor for some area high-school football.  But so far, most of the lightning has remained north of the LA/MS state line, so it looks like it will be a fairly quiet evening for most of us.
A weak cool front will pass through the viewing area overnight.  The front will be draped close to the I-10/12 corridor around midnight and is expected to reach the coastal parishes by Saturday’s sunrise.  With the front passing by, we’ll toss in a 20% (to maybe 30%) rain chance into the overnight forecast.  While we can’t rule out some rumbles of thunder, there’s no concern for severe weather.  And if you need some rain, this won’t really be of much help -- don’t expect much in the way of accumulations even if you get a rain tonight.
With the front to our south on Saturday morning, many of us can expect Saturday morning lows in the upper 60°s to around 70° with fair to partly cloudy skies for the Red Stick. 
The front stalls and lingers along or near the coast through the weekend.  Don’t be surprised by a shower or two during Saturday afternoon, but again we put rain chances at a modest 20% (or less) for the day and into early Saturday evening.  Tailgaters may want to keep a watch on the skies, but anything that does develop during the afternoon is expected to be short-lived.
And for the two big college contests in town -- kick-offs for Southern and LSU are both at 6PM -- we may see a shower or two early but we expect mainly-dry weather through most or all of both games.

Even with Baton Rouge on the north side of the front, highs will still get into the 90° to 92° range for Saturday and Sunday.  However, dew points should slip into the mid to upper 60°s for the weekend, so the front will deliver at least a little relief from our traditional summer humidity.  Notice we say “a little relief” -- there is not going to be a big change occurring with tonight’s frontal passage and by early next week our dewpoints will be back to “summer like” numbers.
Sunday looks to be a mostly-dry day and we’ll post rain chances at about 20% or so for Monday.  After that, we’ll “up” those percentages to 30% to 40% or so for Tuesday through Friday.  By mid-week, highs may top out in the upper 80°s: far from cool, but at least not the 90°s!
To our south, T.D. #10 was ‘upgraded’ to T.S. INGRID at 10AM this morning.  INGRID has continued to drift westward over the Bay of Campeche, but the National Hurricane Center (NHC) is calling for a slow motion towards the NNW later today and into early Saturday.  The NHC then forecasts a turn to the NW late Saturday, taking a moderately strong tropical storm into Mexico late Sunday or early Monday.  Computer guidance is on-board with this scenario, so it looks like we can dismiss any lingering concerns about a strengthening INGRID meandering in the SW Gulf into next week.
GABRIELLE weakened to tropical-depression strength earlier today and has continued to degenerate through the today, with the NHC issuing ‘her’ last advisory at 4PM.  The remnant low will continue to accelerate to the NNE and is expected to merge with a cold front on the way into Atlantic Canada.
And lastly ... HUMBERTO was downgraded to a tropical storm at 10AM, with the weakening largely the result of southwesterly wind shear.  The NHC forecast calls for additional weakening in the short term due to continued, possibly increased, wind shear and cooler sea-surface temperatures along HUMBERTO’s forecast track.  Yet somewhat surprisingly, the NHC’s extended forecast currently calls for HUMBERTO to return to hurricane intensity by day 5 as the storm turns to the north, taking the system away from the strong shear and moving towards slightly warmer waters.  We’ll watch to see if this actually pans out, but regardless, HUMBERTO will be no threat to land. 

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