WWU074
- Weather Weenie
- Dec 28, 2024
- 3 min read
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MY WINTER SEVERE WEATHER WEENIES,We have a threat for some severe weather tomorrow night into Sunday morning. This is a pretty recently formed system - so even local stations have really just begun talking about it. It spent some time roughing up Texas and Louisiana yesterday, and will likely drop a few naders in Mississippi today. For us, this event all comes down to the amount of sunlight/heat we get during the day Saturday. More sun = more naders  As a refresher, the first image is the categorical risk for the day. Meaning all forms of severe weather (tornadoes, hail, wind). The above image shows only the tornado risk. As of right now, we have a 5% chance of a tornado within any given point in most of the state. 5% doesn't sound high, but it's high when the chance is usually close to 0%. ---------------------------------------------------------------------------------------- Below is our local office's take on the event. Same graphics, just closer. As you can also see, there is a pretty long range of severe weather timing. Essentially a 12 hour span for anywhere across the state. Something neat to note - Far western AL begins at 3pm, central at 4pm, and far eastern also at 4pm. How can central and eastern start at the same time? That's when the ingredients happen. The state generally gets hot all at the same time, so when heating is the catalyst and/or the limiting factor for storms that day, you get interesting timings.  Next let's weenie about the radar setup for this. |
 Alrighty Weenies. This system, at its core, is still a cold-front-driven system. So we will have a nice long line of storms that will probably extend up to the far north east. The problem here will be the little bubbler storms in front of the main line. Again, the limiting factor will be the daytime temperature. The sun doing what it does this time of year helps us a lot with this, there is simply less direct sun. The sun we do get, however, is going to land in an environment that REALLY wants some sun. If we get up in the high 60s, we could have a spinny situation. Hodographs for the day are absolutely cranking, and moisture is bountiful. |
 Let's introduce a new map since it shows the setup really well. This is CAPE and Hodographs. CAPE is the Convective Available Potential Energy, and is represented by the background colors (seasoned weenies will know this as the Hot Ham Air™). The dancing worms are the hodographs. When the worms are curled over themselves, it means they've done their part to make storms. The different colored chunks of each worm represent different levels of the atmosphere, higher as it gets toward the yellow. Red/pink is near the surface. This is where the wind shear is. When wind at the surface goes this way, and wind higher goes that way, it makes spin. We have spin, so now we need lift to make that spinning column of air go from a horizontal spin to a vertical one that actually does something. That is our CAPE. When air is really warm at the surface, and really cool high in the atmosphere, it wants to rise. Imagine a hot air balloon. When the warm air scoops up the spin, it makes some spicy storms. Here's a cute little graphic that shows it better.  CAPE higher than 500 is capable of creating severe storms given the right conditions, over 3,000 is going to create violent storms (again if the rest of the conditions are there). Models for tomorrow are ranging anywhere from low 300s to near 1,700. Why the disagreement? We won't know the available energy until the sun comes out to play or not tomorrow. There is no way to predict where clouds will be or won't be, just general percent coverage over a large area. So watch your favorite local stations this weekend, and if you see swirling clouds, don't wait until you hear a tornado siren to go inside. |
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