A Potentially Dangerous Week Ahead (4/6/15-4/10/15)

First off, happy Easter! Thanks for taking the time to read my thoughts on this special day.

Let’s jump right into it. We have a potentially very stormy week across the southern plains and up into the Midwest by late week. Some of these days could feature very significant severe weather, so we will talk about each day in detail. This isn’t a hype cast or scare post, I am very objective in mentioning that storms may have trouble forming on many of these days. But by Weds/Thurs when storm formation is more certain, things could be quite potent. Just remember, models and forecasts change, don’t take everything for truth right now. Also, read my concerns with the forecast, they are just as important as the reasons why I think big things could happen!

Monday: 

I wrote about Monday last night, so here’s a good post to look at. Monday’s concerns lie in the upper level pattern yielding some subsidence, or sinking air. For obvious reasons, this can hinder thunderstorm development. Monday is a day that chasers call “boom or bust”, where if a storm goes, it could be nasty, but the actual chance of a storm is low.

12z data from this morning shows, what I interpret as slightly better chances for severe storm development tomorrow afternoon. The morning models have trended just slightly better with moisture in the lowest 2 km tomorrow afternoon and evening. The dryline circulation appears to be a bit deeper, typically it is most pronounced through the top of the moisture plume in the boundary layer. You will also see that this looks to bring parcels closer to their LFC tomorrow afternoon. Additionally, 12z data hints at the 850mb low deepening more than previous, which could aid in keeping parcels tied to the dryline (west southwest flow pushes them east as they rise up). Moisture is doing well currently, with upper 60 dew points across south Texas that will make their way northward tonight.

The 12z run of the SPC 4km WRF has a storm go up tomorrow in northwest Oklahoma, though it only lasts an hour, likely the model struggling with the warm air aloft. The background environment is just super impressive, so it’s pointless to spend much time there… IF a storm goes, you can bet it will be a powerful supercell. I attached some images in a gallery below.

Remember, SPC has to base their outlooks on probability and coverage of storms.. A marginal does not mean weak storms, it just means the coverage and potential for storms is low. Be aware. Watch the skies! GET A WEATHER RADIO!

Click an image below to open a gallery of Monday’s images

Tuesday: 

Tuesday features a northeast southwest cold front and dryline in southern KS through OK. Not the best, typical, north south strong dryline like we see Monday and will see again Wednesday. Monday has a decent surface low in western Colorado to keep things looking prettier. Looking at soundings, they appear to have even more issues with warm air aloft than Monday. While Monday has a decent dryline circulation to weaken the inhibition, Tuesday doesn’t appear to be as such. The main focus for ascent appears to be along the cold front in southeast Kansas. There may be a rogue storm that develops along the dryline in central Oklahoma, but point soundings are pretty warm, and without a strong dryline circulation, or especially a nice wave, storms may have troubles forming. Again, if a storm develops, the background shear/instability profiles would support a severe weather threat.

Click an image below to open a gallery of Tuesday’s images

Wednesday:

This is one of the day beginning to get a lot of attention. Appreciable upper level energy finally makes its way out onto the plains. This yields a deepening surface low in southwest Kansas with a sharp dryline from KS into Texas. Strong ascent will overspread the region and I would expect, at least in Kansas where the better upper level support will overspread, will see at least a few supercells form along the dryline. Further south, into Oklahoma, warmer air is a bit more of a problem. This may keep storms more isolated, or they may not form at all. Both the latest NAM and GFS support this notion of a dryline laid north south across Kansas/Oklahoma. The GFS is a bit more aggressive in breaking out precipitation further south, but again, analyzing point soundings across central and northern Oklahoma, there is a lot of warm air to compete with further south. Ultimately, the evolution of the upper level wave will determine the most likely focal points for initiation. Instability and wind shear will not be a problem, so the key to picking a target here is finding the best potential for storm initiation. Personally, I like the look of the “triple point” up in central Kansas, however, if storms further south along the dryline near the OK/KS border, they will certainly be discrete and have the potential to produce tornadoes, some that could even be strong.

Click an image below to open a gallery of Wednesday’s images

Thursday:

I know you thought I was going to talk about this big huge day that everyone has been talking about, but there are just too many differences in the models right now to get into Thursday! Stay tuned! The GFS has the front/dryline into central Misourri Thursday evening, while the 0z ECMWF last night had the dryline back in central KS just east of I35/135. Time will tell! Regardless, pattern recognition, moisture/wind fields and thermodynamics say severe weather is certainly likely. Here is the SPC outlook.