Extended Forecast

extended map

Above is a very rough map showing the best tornado threat area for Sunday, and the general threat areas for Monday-Friday. I’m a tornado chaser first and foremost, so I tried to draw those boxes where I could see tornado potential occurring on any given day (I drew those with a fairly broad brush and I’m sure they’ll get tweaked), so keep in mind the lower end severe threat areas will likely extend beyond those boxes. I almost ran out of colors to use lol. That map will likely change in the coming days, but it’s my best guess at this point.

Little hiatus from the blog lol. I needed to take a few days off in anticipation of a busy week ahead. I have been glancing over the models everyday though and although it looks fairly active, there is still a lot of uncertainty with the exact location and extent of the severe/tornado threat with any given day next week. Due to that I’m not going to get into much detail tonight. I want to see another run or two before I started getting into that level of detail.

Basically what we are looking at is a long wave trough setting up over the west coast bringing SW flow aloft into the plains starting Saturday. High quality moisture with dewpoints in the 70’s currently resides over the Gulf of Mexico. As the long wave trough sets up over the Rockies, high pressure will settle in off the SE US, setting up an ideal synoptic scale pattern for pumping moisture into the plains. Sunday through Friday of next week will be characterized by a maritime tropical airmass over the plains with SW flow aloft, so pretty much any day through that 6 day stretch could pose a severe/tornado threat over some portion of the plains.

The first day with any severe weather threat will be Saturday, but I do not expect any meaningful severe/tornado threat though. Although it looks like decent moisture will advect northward into the west central plains by Saturday afternoon, stronger mid/upper level flow will still be lagging to the west keeping deep layer shear profiles fairly weak. I seriously doubt I chase Saturday unless the stronger mid/upper level winds start to nose into the plains earlier than forecast, which seems unlikely.

Sunday starts to look a little better as stronger mid/upper level winds associated with a southern stream jet streak noses into Texas and stronger winds along the southern periphery of trough moving into Canada overlaps the western edge of the central/northern plains. What looks to be about the biggest dryline you’ll ever see is going to be the focus for convection lol. Below is the GFS 18Z dewpoint map, showing a dryline running all the way from Canada to Mexico. sunday drylineThe NAM has a little different solution at the surface with a surface low a tad farther south in eastern Colorado and a strong moisture wrap around setting up just north of it in SW Nebraska. I trust the NAM more than the GFS and it’s been consistent in every run so far in showing this. Assuming it’s true, which I think it is, I think the greatest tornado threat on Sunday afternoon will be over SW Nebraska just north and northeast of the surface low in Colorado. It is showing impressive thermodynamics and strong low level shear ahead of the dryline bulge and north of the surface low. The upper portion of hodographs don’t look that good, but forecast sounding show almost 50kts of deep layer shear and that should be just fine. I’m just worried that with fairly weak SR upper level winds storms may trend towards HP later in the day when low level shear really ramps up. I am pretty dead set on bagging a strong tornado, so I’m likely heading to SW Nebraska Sunday rather than chasing Kansas. Below is where I think the best tornado threat will be Sunday. If the NAM is telling the truth, I think a strong tornado or two may be possible with any discrete storms over that area late in the day Sunday. In fairness the area farther south in Texas along the dryline looks alright too, but with the mid level jet and a dryline bulge setting up over SW Nebraska, I think the area I boxed in on the map looks better.

Sunday tornado threat

Monday and Tuesday look to be lower end days, but there is little confidence in that this far out. The lead jet streak/trough will be moving off to the northeast and only moderate mid level winds are expected over the plains. However there will be strong instability with high quality moisture in place, so despite the modest winds aloft, these days both bear close watching and very well may be chase days. The area of interest looks to be Kansas and Oklahoma both days along a surface trough/dryline. Tuesday looks to be the bigger of the two days as stronger upper level winds start to move into the central plains. I’ll leave it there for now, but I’ll probably start to elaborate on the setup and threat level tomorrow.

Wednesday will likely have severe weather potential, possibly with the greatest threat in north central Texas, but it doesn’t look like a big day and 850mb winds may be veering a bit which would hurt the tornado potential. I’ll hold off on Wednesday until tomorrow’s forecast post.

Still a long ways out, but I think Thursday and Friday could be the biggest days for next week. The base of the long wave trough starts ejecting into the plains and with it a seasonably strong upper level jet. Given the rich moisture that should already be in place across the plains, the conditions seem to be in place across a large area for a higher end severe weather threat.

Sorry for the lack of detail on any given day, but it really is premature at this point. The details still remain unclear this far out. I’ll be updating every day and will get into a little more detail with each post. This kind of reminds me of the last week in May 2013. I chased 5 days straight, with the final day being the El Reno tornado. It’s the most consecutive days I’ve ever chased. I was absolutely exhausted by the end of that week and got to top it off with my car windows getting blown out lol. Hopefully that doesn’t happen this time. Although there is high confidence we will get tornadoes in the plains next week (you don’t get troughs coming through the plains with good quality moisture and not get tornadoes this time of year), it’s tough to pin much down this far out. My best guess is we are looking at lower to moderate end setups, with maybe a localized higher tornado threat over some portion of the plains Sunday-Wednesday and then the potential for higher end events Thursday and Friday. I am probably going to chase Sunday. Monday and Tuesday could be close to home so I will likely chase both those days. Then I am thinking I”ll probably take work off Thursday afternoon and Friday to chase both those days if things still look on track for higher end events. That’s going to be 5 chase days out of 6 for me. I’m excited for it obviously, but I’m going to be dragging ass by the end of the week. Thankfully it all looks to wrap up on a Friday so I’ll have the weekend to recover. I’m going to get my 10k maintenance done on my car tomorrow so I’m all ready to rack up another 5k miles next week lol. I’ve put 10k on that car so fast. It doesn’t take me long to rack up mileage during chase season. Last year was fairly slow and I still covered 9,800 miles chasing.

That’s all for tonight, but I’ll try to make a quick post at lunch tomorrow and then I’ll get a new forecast post up tomorrow evening/night.

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