A fairly cool and calm weekend under northwest flow aloft, with highs in the 60s and overnight lows into the lower 40s. This 'chilly' weather is coming to an end already with a return of southerly winds at the surface by tomorrow. Temperatures rose into the upper 60s and a few 70s across much of the area today, with a few 50s still prevalent over the High Plains regions where down-slope hasn't aided their warm-up yet. A few small impulses of energy under northwest flow will bring the chance of showers and thunderstorms to the Central Plains on Tuesday into Wednesday. And beyond that we'll turn the attention to our next big trough that will come onto the Plains Thursday/Friday and likely become a vertically stacked low by the weekend. This trough and associated thermodynamic features will likely create the potential for a significant severe weather event, perhaps one of the first more prolific tornado producing events of the year.
Have to take at least a quick look at the northwest flow event for Tuesday into Wednesday as that will at least bring the chance of rain. A decent shortwave impulse currently along the Montana/Wyoming border will continue southeast, likely located in southern Nebraska by Tuesday afternoon. This should be enough to create the potential for showers and thunderstorms over south-central Nebraska into north-central Kansas by Tuesday evening. There is at least some elevated instability present, and while not likely being enough for anything severe it will at least bring in the chance of rumbles. Another location of interest will fall along the High Plains where at least modest moisture of upper 40s to near 50 surface dew points combined with ~70 degree temperatures should yield 500-1000 J/kg of surface based instability. This in conjunction with sufficient shear values and lifted indicies, and little inhibition, should warrant the potential for at least strong thunderstorms along western Kansas and the Kansas/Colorado borders tomorrow late afternoon and evening. While these thunderstorms may fade after dark, the low level jet should continue to support more organized showers/thunderstorms over central Kansas, and given upper level support at least showers over eastern Kansas as well. A few lingering showers can be expected Wednesday morning along the Kansas/Missouri borders, otherwise a dry day for the Plains on Wednesday.
This dry day on Wednesday with southerly flow will continue the moisture return to the Plains, aiding in the potential for at least a High Plains thunderstorm event on Thursday. A potent trough will be nearing the four-corners region by Thursday evening, promoting height falls across the High Plains and likely at least the initialization of a surface low along the Lee of the Rockies. Potential exists for both a dryline and warm front becoming pronounced by Thursday evening, promoting convective development along the Panhandles of Texas/Oklahoma and further north into southwest Kansas and adjacent areas of Colorado. Sufficient shear should be in place given southeast flow at the surface and increasing 500hPa flow from the southwest. At least elevated supercells would appear likely, with any surface based convection definitely yielding severe potential...
Friday is shaping up to be the day of interest as the trough ejects onto the Plains, centered along the eastern Colorado border. A surface low somewhere near/along the Kansas/Nebraska border should also set the stage for both a warm front and dryline intersection. A pronounced dryline should surge eastward during the day Friday, making it well into central Kansas/Oklahoma. Strong moisture return both at the surface and aloft, at least according to models, should yield surface-based instability of at least 1500 J/kg. While shear is expected to be strong given fairly significant wind speeds in both the mid and lower levels, there is some concern based on recent model runs of too much uni-directional flow leading to fast storm motions and the potential for broken lines of convection. Nonetheless, the potential for severe weather is definitely there and likely warrant at least a higher-end slight risk by the SPC. A lot of details will need to be worked out, such as the arrival of a shortwave disturbance and any morning convection and cloud cover. These such details will be discussed later as the event nears and the short-term models can have their opinions voiced on the matter.
Onto the weekend, it would appear that our vertically stacked low pressure system will meander across the Central Plains on both Saturday and Sunday. Given the cold air aloft, thunderstorms do appear possible on Saturday for areas of Kansas/Missouri and perhaps areas just north. Sunday appears to be a day of cloud cover and showers at this moment, which doesn't bode well for my Royals/Twins baseball game that I plan to attend. I'll continue to watch and hope for the push of the low to the east for Sunday and next week. Well into the future, expect the low to move out early next week and lead to at least some short-term ridging of the Plains, promoting a return of warm and moist air. Our next round of thunderstorms and perhaps severe weather will come with the next trough, currently slated by the GFS and ECMWF to come in for the first few days of May.
More details regarding any thunderstorms tomorrow evening will be posted tomorrow along with another look at the potential for the late week severe weather episode.
