Storm concerns have wrapped up for the day
Cloud cover and light rain helped keep the “lid” on the atmosphere
BRYAN, Texas (KBTX) - Thursday brought a very interesting rain and storm set up that the Brazos Valley just could not cash in on. This is probably for the best, as any storm that could have tapped into that potential had the chance to spin up severe very quickly. Below is a running list of updates throughout Thursday as well as the days leading up.
Most of the Brazos Valley woke up to overcast skies and even some areas of light drizzle. Through the lunch hour, most of us have kept those same conditions in place. Like we have talked about this week, if we can keep that light rain and cloud cover it will greatly calm our severe weather potential. That being said, the dynamics above our heads are still very promising if we can tap into them.
**THURSDAY 2PM UPDATE**
The 2pm update from the Storm Prediction Center continues to downgrade the storm potential across the Brazos Valley. The only remaining counties in the 2 out of 5 risk are Montgomery and San Jacinto Counties. The rest of the area has been included in the 1 out of 5 risk, while the westernmost reaches of Lee and Milam counties have been trimmed from the severe risk entirely. We will continue to monitor for the potential that a stray storm can tap into the good dynamics overhead, but that chance is looking less likely as the afternoon goes on.
**THURSDAY AFTERNOON UPDATE**
Morning clouds have stuck around into the afternoon hours, at times providing some pretty aggressive drizzle. If we can keep this lighter rain and mist ongoing, it should help in keeping the severe concern at bay into the afternoon. However, like we have talked about all week, the dynamics above the stable layer of air we have been able to hold are primed and ready for stronger storms.
Thursday afternoon will continue to be one to stay weather aware as the dynamics could easily, and quickly, be put to use by the atmosphere.
**THURSDAY 10:30 AM UPDATE**
The midmorning update from the Storm Prediction Center completely erased the 3 out of 5 risk from southeast Texas. The southeastern corner of the Brazos Valley is still included in the 2 out of 5 risk for severe weather, especially heading into the afternoon hours. The rest of the area has been downgraded to the marginal 1 out of 5 risk for the remainder of Thursday.
**THURSDAY MORNING UPDATE**
Latest data rolling in this morning keeps the forecast and messaging consistent - at least a couple severe storms are expected today, somewhere between B/CS and the greater Houston area.
A weather balloon launched by the Atmospheric Sciences Department at Texas A&M has confirmed what we have forecasted for a few days now: Low-level winds are rotating with height, meaning any storm that gets going today will have the capability of turning strong quickly, and potentially spawning at least a brief tornado.
Gulf moisture is being pulled in from the aforementioned low pressure system, giving us a southeast wind here at the surface that turns westward as you move up in the atmosphere. This “twisting” with height can allow any storms that form to have at least a broad rotation. IF these storms form, they can quickly spawn brief tornadoes.
While there are still a lot of other factors working against this potential, this will still bear watching through mid/late afternoon, when the more stable air starts to move in just ahead of the cold front this evening.
**THURSDAY MIDNIGHT UPDATE**
The Storm Prediction center released an update regarding Thursday’s severe weather potential at midnight. While the overall theme and expectation of the day has not changed, the highest risk -- a 3 out of 5 category -- for severe storms has shifted to the west and south. This now encompasses the Southern and Central Brazos Valley, from South Brazos & Burleson, to North Grimes and South Walker Counties, and points south.
While a few stronger or even damaging wind gusts are not ruled out with any of the strongest activity of the day, the tornado risk remains the main concern should storms become severe. Areas in this brown, 3 out of 5 risk hold a 10% chance for a tornado to form Thursday, which those in the yellow, 2 out of 5 risk fall under a 5% chance.
**WEDNESDAY NIGHT UPDATE**
New data tonight confirms widespread rain and thunderstorms moving through the Brazos Valley in waves throughout the day Thursday. While cautious optimism, the highest parameter for potential spin in the low-to-mid levels of the atmosphere, which could, in turn, create a few tornado concerns, has been adjusted to the south of the Brazos Valley. Still, there remains a concern for that potential to be realized between noon and 4pm.
STRONG-TO-SEVERE STORMS ARE NOT PROMISED, BUT CERTAINLY NOT RULED OUT
Rain and thunderstorms are possible as early as the pre-sunrise hours Thursday morning. Overcast skies and the chance of an early round of scattered showers will likely keep a “cap” -- basically limiting factors -- for thunderstorms to build and reach the greatest instability the atmosphere holds early in the day.
Breaks in the clouds by early afternoon will allow for temperatures to rise into the 70s and the atmosphere to destabilize. The high moisture content, combined with daytime heating and lift along the front, will provide some fuel for storms to develop. As winds increase and turn in direction with height, this will create “spin” in the atmosphere conducive for rotating and potential supercell thunderstorms. If storms manage to break past the limiting factors and tap into these dynamics, all types of severe weather would need to be monitored for, including:
- Damaging, strong wind in excess of 40-60mph
- A tornado or two
- Large hail between the size of a quarter and an egg in diameter
- Frequent lightning
- Minor street or low-lying flooding
As of Wednesday afternoon, the Storm Prediction Center has placed the southeastern portions of the Brazos Valley in a 3 out of 5 risk for severe weather, particularly late morning through early afternoon. The northwestern corner of the area has been trimmed out of that category but still holds in a 2 out of 5 risk. While widespread rain is expected, the atmosphere may support a couple of supercell thunderstorms, which will be capable of producing some strong winds or even a couple tornadoes.
Thursday’s setup brings some of the most convincing severe weather parameters that we have seen since spring. The main concern with this setup: Thunderstorms that form may turn severe quickly, bringing little warning. Storms will need to be watched for quick “tightening” of rotation, which could quickly spawn brief, but strong tornadoes. Thursday will be a day to keep about your regular plans, but have a way to receive weather alerts and be aware of your surroundings.
TIMING
We still expect the bulk of activity (and the biggest severe potential) to be from mid-morning through mid-afternoon. Late in the day and in the evening, we should quickly wind things down and step into a mainly quiet Friday and weekend.
HOW MUCH RAIN ARE WE TALKING ABOUT HERE?
There is plenty of tropical moisture to tap into as this next rain event passes through Central and Southeast Texas. While rainfall totals are not expected to be uniform area-wide, 0.25″ to 1″ of rain very well could be common. Stronger thunderstorms could release a quick 1.5″ to 2″ as they race from west to east. These storms should be quick movers -- storm motion is currently forecast around 40 mph. Overall flooding concern is low, but the typical haunts when heavy rain falls in a short amount of time will need to be monitored. For this reason, the majority of the Brazos Valley is also included in the Excessive Rainfall Outlook for Thursday as well.
As we get closer to this event, confidence has grown that several ingredients for severe weather will be in place, but this is still a conditional risk, where we’ll be constantly coming over new data into Thursday. Updates can be found as we have them here on KBTX.com, in your KBTX PinPoint Weather app, and on-air.
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