



Even with limited possibilities of moisture return today in advance of the approaching cold front, we’re still chasing…because that’s what we do! Jenny is gracing me with her presence today and will hopefully bring us some good fortune in our efforts this evening. We are streaming live video as we head towards our initial target in Bowie, TX. Watch us at www.texasstormchasers.com/live
Much like Sunday, supercells are expected to develop over West Texas and further north into the Texas Panhandle during the late afternoon and evening hours. On Sunday, thunderstorms developed just east of the Texas/New Mexico border around 6:30 PM. Initially, there were only two storms west of Lubbock, both of which became prolific hail producers. After sunset, a number of storms developed further north as the low level jet helped increase warm air advection and the associated lift. The reason I mention this in detail is because those storms left boundaries all over the place. Later today those boundaries are going to act as focal points for new thunderstorms to develop.
Before I get even more nerdy, let me go ahead and outline today’s risk zones so folks who don’t care about weather too much can get on with their day. Above are several graphics showing the overall severe weather risk zones for today.
Brown Shaded Zones – 5% chance of severe weather within 25 miles of any given point (like your house/business). – Low Risk
Orange Shaded Zones – 15% chance of severe weather within 25 miles of any given point (like your house/business). – Standard Risk
Red Shaded Zones – 30% chance of severe weather within 25 miles of any given point (like your house/business). – Elevated Risk
The main severe weather threat at first will be very large, damaging hail. Across the elevated risk zones (red shading), there will also be a tornado threat and straight-line wind threat.
This graphic comes from the high resolution North American Model and shows projected instability values at 6 PM this afternoon. You can see the location of the dryline on this graphic, running along and east of Odessa to Lubbock and Amarillo line. You can see that the dryline bulges out between Amarillo and Lubbock. This feature is often helps increase forcing locally and develop thunderstorms to the east of that bulge. As a whole, instability values over 3,000 joules per kilgoram (J/Kg) support an organized severe weather threat, assuming that wind shear is in place.
This graphic comes from the same model for 6 PM Monday and shows Storm Relative Helicity. This algorithm helps meterologists determine the overall amount of spin available for storms. It looks like this one model has a warm front running along a Canyon, Childress, to Wichita Falls line. To the north of this warm front, wind shear values are over 300 m2/s2. Anything over 200 m2/s2 is favorable for organized thunderstorms, including supercells. To the south of this boundary, shear values are lower but still sufficant for slow moving supercell thunderstorms capable of producing big hail. The threat for tornadoes will be highest along any outflow boundaries left over from yesterday’s convection along with the warm front where shear increases. Additionally, some models are suggesting that a strong complex of storms may track along this warm front overnight. If that does materialize, not only will the threat of large hail continue but a considerable straight-line wind threat could also develop.
I would expect storms to begin developing by 5 PM in the Texas Panhandle and West Texas along the dryline with the possibility of quickly becoming severe. Remember that not everyone will see severe storms today, but refer to the outlook graphics above for the specific chances.
I’ll be chasing in Northwest Texas today and will have the live video feed running for what will end up being the last time on this specific website as our new site will be up sometime later this week.
This graphic shows the chance of severe weather occurring within 25 miles of your location this afternoon and early this evening. The orange line you see is the zone where the storm prediction center has placed a standard risk of severe weather, meaning there is a 15 percent chance of severe weather occurring within 25 miles of any given location within that zone. The risk extends all the way from Southwest Texas northeastward into western sections of North Texas and Southern Oklahoma. Midland, San Angelo, Abiliene, Vernon, Wichita Falls, Decatur, Denton, Sherman, and Bonham are just a few cities included in this risk. The timeframe will be from 4 PM to 10 PM.
Today’s severe weather threat will be in the form of large hail (quarters to half dollar size) and downburst winds around 60 MPH in the strongest storms. In addition, localized flooding could become an issue later tonight when storms are expected to become widespread. The severe weather threat (hail and wind threats) are expected to remain more isolated and a widespread severe weather issue is not expected. Tornadoes are not expected today.
This graphic shows the probability of severe weather occurring within 25 miles of any given point (such as a house) on Saturday, mainly during the afternoon and early evening hours. The standard severe weather risk, a 15 percent chance of severe weather occuring within 25 miles of any given point, is in effect from Southwest Texas northeastward into Southern Oklahoma. This risk includes Texas cities such as San Angelo, Midland, Big Spring, Abilene, Vernon, Wichita Falls, Weatherford, Decatur, Denton, Gainesville, Sherman. In addition, Southern Oklahoma is also in the standard risk. Surrounding the standard risk, a lower risk of severe weather encompasses more of Texas.
Saturday’s setup will be one with moderate instability and low wind shear. A cold front will be moving south across the affected regions on Saturday. During the peak heating hours in the afternoon, some storms may become marginally severe as the cold front provides atmospheric lift. The primary threat on Saturday will be ‘coin-size’ hail (nickel to quarters) and a few downbursts capable of producing winds around 60 MPH. Because of very weak low level wind shear and the overall lack of any mesoscale features capable of enhancing wind shear (as what occurred on Tuesday), the tornado threat should be low.
I’m actually sitting in Philadelphia International Airport right now waiting to board my flight back to Dallas. I was originally scheduled to fly out tomorrow afternoon, but decided to push it up to avoid the flight delays on Saturday along with possibly chasing if the setup warrants.