Severe Weather Potential - SATURDAY (San Antonio, Austin: house, tornadoes, moving)

[AnthonySA]

After looking at the models and reading analysis of the National Weather Services offices and Storm Prediction Center in Norman, Oklahoma, I feel that it's necessary that tomorrow's storms do get a thread of their own.

The dynamics are still there and setting up for a rather impressive severe weather outbreak across the entire region with the strongest storms forming from Medina county on east.

As explained earlier, we have the following ingredients in place:

• Strong Wind Shear. At the surface winds have been breezy from the southeast. Today it has been difficult to determine the movement of the clouds from the surface because of all the fog/mist/drizzle. However, the higher up you go... by a thousand feet or so, the wind direction is nearly perpendicular as windflow is from the southwest. The directional shear is critical when for forecasting tornadoes as this is the source for rotation.
• Plenty of Moisture from both the Pacific and Gulf of Mexico. You can't really have a strong severe weather outbreak without a strong supply of moisture. But again, the mist and drizzle that we have floating around should tell you that the moisture supply is building rather than depleting.
• Strong Lifting Mechanism in the form of a powerful cold front. It was -20 in Minnesota and wintry precipition is expected as far south as West Texas and Oklahoma. That means that we have a strong clash of warm, tropical air and cold arctic air. The highest point of instability and lift will occur along this boundary which happens to be stalling over our area.

So what will happen?

I expect that tonight we'll have a few thunderstorms pop up with maybe one or two reaching severe limits. The instability isnt quite to a level yet necessary for a widespread outbreak.

Tomorrow, however, I expect a different story. These ingredients I mentioned above are indeed coming together as expected and it is a question of where the dynamics will be strongest. Right now, as stated earlier, it appears to be further east but still including the San Antonio area. The storms that do develop will be capable of producing large hail, damaging winds, and tornadoes. We will see a few supercell thunderstorms pop up especially east of town and eventually forming into a squall line as the storm system heads east. In addition to that, the moisture supply will be deep enough to generate spots that recieve 2 or more inches of rain in relatively short periods of time. That means that isolated pockets of flash flooding due to the runoff is also a possibility.

If you have outdoor plans tomorrow, make sure you keep a close eye on the weather. Also note that even if we do miss out on the severe weather, the probability of precipitation now through Saturday night is 100%. I don't mean to overhype a situation, but the dynamics are there, and thus the potential also exists.

Here are the links that I recommend for tracking the storms as they develop:

Storm Prediction Center: Storm Prediction Center

National Weather Service in New Braunfels: National Weather Service Forecast Office - Austin/San Antonio

Weather Underground NEXRAD Radars:
New Braunfels
Current Austin-San Antonio Nexrad Radar Map : Weather Underground

Laughlin AFB
Current Del Rio Nexrad Radar Map : Weather Underground

[gwrober]

Wow, thanks for the info, great post! I was planning on geocaching tomorrow, I might have to wait.

[AnthonySA]

That may not be a bad idea. Sunday is looking really nice

[SnappyBob]

I am going to go way out on a limb here and see if I can stick both feet in my mouth. Anthony, I wish I had your weather knowledge because I have always found it to be a fascinating subject and hope you are right because we really need the rain and I for one love a good thunderstorm. Anyway now for the foot in mouth part. I have gut feeling that come tomorrow we will see all the rain go to the north and east of us as always. Leaving us high and dry as usual or at least reading our rain gages with magnifying glasses. It will be fun to see which organ prevails, my gut or Anthony's brain. Tune in tomorrow for the exciting conclusion. Note to self: Don't forget to wash your feet tonight.

[AnthonySA]

Thanks for the compliment... weather is indeed a very fascinating subject! You can't go into this field, or make predictions without the anticipation that you'll have your foot in your mouth!

I agree wholeheartedly that the bulk of the severe weather will be to our North and East, the dynamics will simply be more established over there. However the dynamics are strong enough here that there isnt anything out there to stop a strong storm moving through our area.

Tomorrow will be an interesting day and I will do my best to keep everyone updated, whether here or further east.

[the_dimwit]

Well, I guess my wife and mother won't be going to the Round Rock IKEA tomorrow...

Thanks for the update, Anthony.

--Dim

[Bowie]

So many of these rainmakers have turned out to be a bust for SA lately. That makes it hard to get a lot of hope up for this one.

[AnthonySA]

The rain won't dissappoint... everyone will at least see a little bit! In fact the people who get stuck in some of the heavier storms could easily pick up a couple inches of rain.

With the other systems in the past (which I never was too excited about) had limited moisture supplies as we were in a very progressive quick weather pattern. That means that storms were traveling west to east at a fast pace. This system now that is moving through our area is far enough south, powerful enough, and moving at the right speed to ensure quality substantial precipitation.

The moisture supply is also there. At the surface winds are coming from the east to southeast (predominately -- I've experienced some gusts from the north at times as well today.) Aloft, we have a moisture tap from the Pacific. That means that all levels of the atmosphere is gaining appreciable moisture. Because this is a rather powerful system, it will ring out a lot of the excess moisture that has built up in the form of heavy rainfall -- some of which will fall as early as this evening and tonight.

The only question, in my opinion, is how severe the storms will get. We'll find the answer to that tomorrow.


PS: Thank you everyone for the positive encouragement I really appreciate it!

[rd2007]

holy crap! I can actually hear rain at my house (West Creek)..

That sure is a nice noise

[AnthonySA]

Yes storms are bubbling up across the entire region right now.



Note at the wind shear. You clearly see on the radar the showers are coming from the southeast. Contrast that with the national satellite:



You'll notice that the clouds aloft are coming from the southeast. That is a sure sign that we have a strong moisture supply building, and also a lot of wind shear.