Monday, March 19, 2012

Windy Tuesday...Heavy Rains Midweek

By Jay Grymes & Steve Caparotta

Trivia buffs: the ‘astronomical’ start of spring -- the Spring, or Vernal, Equinox -- occurs overnight at 12:14am CDT. Are you ready to join the “Egg-Balancing Olympics?”

It’s been a breezy Monday under mostly cloudy skies and our forecast keeps the clouds and the breezes with us through the night and into Tuesday morning. The continued inflow of Gulf moisture and warmth means another sunrise start on Tuesday in the mid and upper 60°s for most of us, with the low-level winds sufficient to minimize any concern for widespread morning fog.

We’ll stay under mostly cloudy skies through Tuesday, with winds picking up and running sustained in the ‘teens and 20s (mph) with gusts occasionally in the 30s! We’ll also introduce a slight chance of rain in the afternoon forecast -- 20% to 30% -- mainly in the form of showers but some of us could hear a rumble or two of thunder. Highs on Tuesday will once again return to the 80°s.

Titan9 RPM model projection for 1 p.m. Tuesday showing isolated showers and t-storms in our area, with heavy rains in east Texas.
Our forecast for the week calls for progressively wetter weather, with the highest rain chances arriving Wednesday and Thursday, but with a true ”dry-out” not kicking-in until the weekend. The southern end of a slow-moving storm system will creep across Texas tonight and tomorrow and likely take all of Wednesday and Thursday to cross the Bayou State.

The weather over portions of the Southern Plains has been rather active already today, with Thunderstorm and Tornado Watches posted during the afternoon. The NWS Storm Prediction Center puts the western half of Louisiana under a “Slight Risk” of severe weather for Tuesday morning into early Wednesday, and our thinking is that we’ll remain under a “Slight Risk” for Wednesday into Thursday.

The driver for this run of active weather is an upper-level “cut-off low” which has become separated from the main upper-level jet stream. With the upper-level low “cut-off” from the polar jet stream, it really doesn’t have a steering mechanism to move it along. Instead, it is expected to drift over the Southern and Central Plains for the next few days. Given this set-up, the surface storm system and frontal complex associated with that cut-off upper-low will also be a slow mover -- hence the slow, prolonged march of the stormy weather from west-to-east.

This slow-moving system could become a real headache for portions of east Texas, the ArkLaTex and the western half of Louisiana over the next few days. Preliminary rain forecast totals from our in-house Titan9 RPM model are indicating widespread totals in excess of 3” to 5” by noon on Thursday for areas from Baton Rouge westward, with totals running as much as 7” to 10” or more near the LA/TX state line!

And given the slow eastward progression of this storm system, some WAFB communities could still be seeing rains well into Friday. The NWS Hydrometeorological Prediction Center is suggesting that most of the WAFB viewing area could see totals of 2” to 5” by week's end.

Thankfully, the weekend should show much improvement across the area, with clearing skies on Saturday giving way to a beauty of a Sunday.


  1. Will this system be one of those significant tornado outbreak systems for us?

  2. We can't rule out an isolated tornado, but the main concern is heavy rainfall.