Tuesday, March 6, 2012

Warm, More Humid Days Ahead

By Jay Grymes & Steve Caparotta

Two things to consider with today’s forecast: (1) the weather just doesn’t get much better than what we’ve enjoyed the last couple of days, and (2) weather like this usually doesn’t last long.

You’ll start to note the first signs of chance by Wednesday, with more clouds throughout the day.  Although it will still be a relatively comfortable day, you almost certainly notice a modest increase in humidity levels.  As we saw today, winds will again stay up on Wednesday thanks to a decent pressure gradient across the central Gulf Coast.  Wednesday will start off warmer -- with sunrise temps in the 50°s.  Afternoon highs will climb to around 80°F.

More clouds and more humidity by Thursday means a very slight chance of rain by the afternoon -- less than 20% -- but a sure signal that the lower atmosphere is moistening up.

By Thursday morning, a western storm system will have worked eastward, with an elongated frontal system extending from eastern Canada across the Great lakes and southwestward into Texas.  Normally at this time of year, such a set-up would usually mean that the front slides into and through Louisiana early in the weekend.

Titan9 RPM model projection for 7 a.m. Thursday showing a cool front attempting to approach from the west.
This time, however, the models seem a bit mixed as to how it all plays out.  Most of the guidance suggests that the southern end of the frontal system will slow -- even stall -- for one or more days over Texas, setting sections of northern and central Texas up for some very heavy rains.  At the same time, with the front to our north and east, the WAFB viewing area will be in the “warm sector” with unstable air, keeping the weather “unsettled” for Friday and the weekend.

An upper-level trough currently in the Pacific Northwest will be the driver for this developing weather scenario.  Where the confusion comes into the forecast process is the potential for the trough to spin-off a “cut off” upper low -- a circulation feature that stays located over the Central or Southern Plains rather than progressing to the east with the main jetstream flow. 

The eventual evolution of an upper-level trough currently along the West Coast will be a big determining factor in how wet our weekend turns out and how long the rains last.
These cut-off lows can be pesky weather-makers and make forecasting more difficult as they can meander for days before finally moving out of the region.  A shift in location to the east or west during its meandering can make all the difference between “dry” and “stormy” weather locally.

Some guidance even suggests that the weather remains “wet” into the early part of next week.  Hopefully the picture for the weekend will get a little clearer in the coming day or so, but for now we suggest that your weekend plans include dodging some raindrops.


  1. Hey Steve, are we expecting a widespread severe even like last weekend? Will we need our NOAA radios?

  2. There appears to be little threat of severe weather in the coming days. We can't rule out an isolated strong storm or two over the weekend, but we're not expecting anything widespread at this point.