Afternoon storms and the remnants of TD 5 weaken

Broken line of showers and thunderstorms that developed along a strong outflow boundary (many locations across the city saw 30-40mph winds as it passed by) from storms over LA is now well southwest of the metro-Houston area and will likely continue for the next couple of hours. Much cooler temps in the upper 70's and lower 80s along with some stratiform rain, associated with a meso-high that has developed in the wake of the storms, is all the remains across the city. Another impulse can be seen generating scattered convection over LA moving southwest; however I think that the atmosphere will be to stable to support its continuation much past sunset. We will have to keep an eye on any outflow boundaries which maybe located across the region for a possible focus for thunderstorm development tomorrow afternoon.

Conditions will remain favorable for at least scattered afternoon and evening shower and thunderstorm activity as we see deep moisture remain in place...being pulled around the western side of the remnant low from TD 5.

The remnants of TD 5 are showing much less organization this evening with the low level center becoming completely exposed to the northeast of the convection. The latest surface maps also shows the pressure gradient at the surface might be weakening, as seen with some westerly winds being noted north of the center (opposed to easterly winds which would be expected from a stronger closed low). It might try and re-form a center under some of the convection seen south of the Mississippi coast over the next 12-20 hours or so, however it is quickly running out of time to do much as it continues off to the west. With the system having not strengthened much today, am still not expecting very much in the way of an impact to our local weather other then to keep moisture levels high, and bring the occasional disturbance across the area helping develop local showers and thunderstorms.

KHGX radar image with meso-high and outflow denoted:

Wind Speeds showing passing of outflow at UHMT:

Satellite and surface obs showing the weakening pressure gradient (The circled winds were being influenced by the system earlier today...not any more):


18z Model Guidance on remnant's of TD 5:

Weak front and remnants of TD 5 organize in northern Gulf

Latest surface analysis this morning indicates a very weak frontal boundary (more like a wind shift line) is currently located across north Texas between Dallas and Waco. It is looking like the Texas end of the boundary is pulling up stationary and will likely start to wash out later this afternoon and evening. Surface winds across southeast Texas are out of the west and northwest in agreement with the GFS model which indicates that we will continue to see winds veer around to the northeast and east by late afternoon.

Morning and model soundings show that the atmosphere across the region is extremely moist and unstable with precip water values in the 2.2 - 2.3'' range, a K-index around 40 (numbers above 30 would tend to indicate scattered to numerous convection), and convective temps in the lower 90s. The only fly in the ointment for some cooling rain would be some capping indicated in the GFS model soundings for this afternoon. The isolated showers that developed earlier this morning across Montgomery county and eastern Harris county look to have been associated with an outflow boundary from convection in Louisiana. I would expect at least some scattered shower and thunderstorm activity around the area this afternoon as temps warm into the lower to mid 90s. Soundings do indicate a slight chance for some strong winds under the stronger storms that can manage to develop.

Of greater interest is the remnant low from TD 5 which is now out over open water south of the Pensacola, FL/Mobile, Al area. The latest tropical weather outlook from NHC gives the system a 60 percent chance of development over the next 48 hours or so. At this time the 00z hurricane models show the system moving into southern or southeastern Louisiana around the middle of the week. Morning visible satellite imagery shows some possible banding features taking shape to the north of the center of circulation...possibly an indication that the low will start trying to wrap up over the next few hours or so. A hurricane hunter aircraft is currently scheduled to investigate the system this afternoon. Should something develop today, look for an update to the blog. At this time it looks like effects on our local weather from this low will be minimal, however that could change quickly with just a small adjustment in the track westward so this will be something to watch very closely over the next day or so.

Surface map showing gulf Low, Satellite imagery, and 12z Model Tracks

Weak Front and Remnants of TD 5

It looks like an interesting first half of the week across southeast Texas as several features could potentially impact the region. The first feature to watch will be a weak frontal boundary currently (1pm Sunday) located across northern Oklahoma which is moving south. The second will be the remnant low of TD 5 that is spinning across southwest Georgia; currently forecast to possibly move south into the north central Gulf and run about a 30 percent chance for tropical cyclone development over the next 48 hours. Both of the systems will likely play an important roll and tend to complicate in our wind forecast the next few days.

Wind direction will be the main challenge....if the weak front can make it as far south as the Houston area, we will likely see more northeasterly and potentially easterly winds; however, as we will be on the western side of the low forecast to slowly develop over the northern Gulf, our winds may turn more north-northwesterly, to possibly westerly depending on the future track and strength of the low. A stronger low and more westerly track would give us a much more northwesterly wind flow....a weaker low and a further easterly track might not have much influence on our local winds at all, keeping them more northeast should the front make it down here.

The 12z models have some timing differences but do generally agree in bringing northerly winds, changing to northeast then east-southeast through the day Monday across the Houston area. The NAM shows southwesterly winds during the morning turning north-northwesterly towards noon then back around to the southeast by the late afternoon and evening. The GFS keeps weak northwesterly winds across the region during the morning turning northeast to east by the afternoon. Therefore it looks like the best window for easterly winds will be 18-00z Monday. Otherwise we will likely see northerly winds during the day which could bring down pollution from the Dallas area. All in all, it looks like an interest few days.

12z Forecasting Sounding for Hobby Airport showing how winds change during the day.