Okay, so let’s talk about the upcoming pattern change. We’ve finally transitioned into our typical spring weather pattern across Oklahoma (broad SW upper level flow indicated by map below) which means severe storms and yes, tornadoes. There are a few days coming up over the next 10 that should produce both.
Upper jet stream pattern. Lines denote upper level shortwaves (disturbances).
I’ve been watching the model trends just like every other weather guru and noticing that sometimes certain models paint a nefarious picture. Other times they don’t. The agreement in the global models is not at all uniform nor consistent. If I were to put out a threat for tornadoes for every model run that blows in the wind, I’d be crying wolf most of the time. It takes a very strict set of ingredients to make a tornado and often times those are not seen by the models until we’re 24-36 hours out.
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Many things can wreck what looks like a gloomy day:
- Dryline surges too far east, or dry air mixes down out ahead of the dryline on SW winds.
- The upper storm system comes in 6-12 hours slower causing its best influence to affect the state during the night rather than during the peak heating of the afternoon.
- Models overestimate the wind speed and direction needed for producing strong rotating updrafts.
- CAP strength underestimated which prevents any storms from developing.
- Morning rain that stabilizes the atmosphere for the rest of the day.
These are just a few of the things that can and often do happen to cause a concern for tornadoes to turn into calming sunshine. So now that you know the background, what do I think will happen?
Moisture and instability will return on Sunday. That will then be in place Monday and Tuesday, and shift to the far SE on Wednesday. A cold front I mentioned in a prior discussion should push the instability south into Texas for the rest of the week. Not all models agree on that scenario, meaning if the front hangs back then yes, the rest of the week would be a little more bumpy. We can address that in the coming days.
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So at this point I think isolated severe storms, in a conditional setup (meaning not guaranteed), are possible late Sunday, primarily in NW OK, and on Monday in C OK, but will only affect very few people as it looks right now. Both days storms would produce large hail, damaging winds and the potential for a couple of tornadoes. Tuesday the dryline will be the big player and should trigger several supercell storms. Those would have the potential for producing tornadoes as well. However, the European model is hinting at something which occurred a few weeks back with our last event, dry air mixing down ahead of the dryline scouring out the low level moisture and convergence along that boundary. The euro is calling for a non-event if that happens and this is a complete 180 from its prior outcomes. So I wouldn’t bet the farm on it just yet, but it is something to watch for. Any storms that do fire late Tuesday should move to the SE on Wednesday. Then quiet for awhile until scattered showers Thursday night and heavy rain Friday night. I’m sure some of these details will change, so I will update as necessary.
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Here are a few computer model images for each day Sun-Tue where I’ve highlighted the greatest threat area for tornadoes given the data today. Which will likely change by the time we get to the day of each (potential) event.
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Highest threat area for Sunday.
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Highest threat area for Monday.
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Highest threat area for Tuesday.
In the meantime, just go about your business as usual but do two things for me. Review your tornado plan for the family on what to wear and where to go. Secondly clean out those closets and storm shelters if you haven’t already, and put your bugout bag kit in them filled with items you can’t live without for at least 12-24 hours. Also read my latest blog on lilapsophobia (fear of tornadoes) if you haven’t already. A lot of helpful information in there. Thanks! -AT
