The first multi-day severe weather threat of the 2018 season is set to take shape across the Central and Southern Plains (perhaps into Northern Plains) early next week. While models are still varying significantly on localized details, we can dig into a few synoptic scale details that stand out at the moment. For the first time this season, we will have a large reservoir of high moisture values (dew points ~65 degrees+) and CAPE (2000+ j/KG) in place ahead of a dry line across KS/OK/TX for potential severe weather.
This will all occur underneath a modest fetch of southwesterly mid-level flow that will push into the Southern and Central United States. This will set the stage for a couple days of severe thunderstorms across the Plains region. Its far too early to go into details as for what we can expect, threat wise, however anything from large hail to tornadoes is certainly on the table at this point until we can hammer out the smaller details.
One major feature that stands out to me currently is the strength of the low level jet (in the lowest 1500 meters of the atmosphere). This is highly conducive for tornadic development from studies that have been done with values are generally over 30 knots. In this case, we are looking at values between 30 and 40 knots out of the southeast, which would be ideal given a southwesterly direction of the winds aloft. Again very hard to say for sure exact threats, but this is one particular piece of the pie that I look at when forecasting potential severe weather/tornado events in the spring and something that significantly stood out to me.
The threat will exist for generally the same regions on Wednesday, however for the sake of not digging too far out into “fantasy land”, I’ll refrain from posting those graphics because it will likely change over the next several days. Global models have differed with the speed of this particular system as well with some models having only a day or so of severe weather, while others show upwards of three days of severe weather. Too soon to say for certain. One thing we can say is that the 2018 severe weather season is about to kick into gear after a long and cold spring so far. So stay tuned!!