The chance for severe storms, including large hail and long-track, strong tornadoes, will remain across the area this afternoon and tonight. Daytime highs in the mid 80s will be likely with strong southeast winds.
The severe weather threat is expected to be very high today across the southern plains including the possibility of a tornado outbreak across portions of Oklahoma and Kansas. The main ingredients for this event include rich low level moisture, wind shear, surface instability, and a major upper level system. All of these ingredients are expected to be in place this afternoon and early evening across the region. A dry line will be surging into central OK by 4 to 5pm as the major upper level system to our northwest begins to take on a "negative tilt " position. This basically means the dynamics of the system will be enhanced in certain regions, including Kansas and Oklahoma. The morning clouds are expected to give way to party sunny conditions later today which will enhance the surface instability parameters. The CAPE or potential convective energy is expected to be very high. Helicity values (basically the spin in the lower portion of the atmosphere) is also expected to be in the high category. A powerful upper level jet streak will move over the state later today from the southwest to the northeast creating winds that change direction and speed with height. Storms may reach severe levels quickly, possibly within less than 15 minutes of genesis. The start time for the event may be as early as 4pm across the I-35 area, but more than likely, the window for most of the eastern OK area will be from 5pm to 1am.
The storms are expected to move east of the state by midnight or around 3am Wednesday. The upper level system will be moving across northern and eastern Kansas Wednesday , but some additional energy may foster down the back side of the low Wednesday afternoon and evening helping to usher in the actual surface cold front. A few showers or storms will be likely Wednesday evening as this occurs, but these storms are not expected to be severe.
Gusty northwest surface winds will be likely Thursday with a relatively cool and dry air mass resulting in daytime highs in the lower 70s.
Friday appears good with highs in the mid 70s after morning lows in the 50s, but we continue to have controversy regarding the Friday night and Saturday morning.
The extended data has been flipping on the weekend solution, but for the last 2 days we have seen a surface low formation in the model data across northwestern OK by Friday evening with a weak surface boundary sliding into northern OK. This would necessitate a slight mention for storms during the period of Friday night into Saturday morning across northern OK. We have been hoping to keep this probability off the map, but we may eventually need to add this slight chance into the forecast for the weekend.
The ensembles have continued to support a mid level ridge building across Texas early next week, but the individual operational models are not quite as bullish on this ridge. This means we may still see some storm chances early to the middle part of next week, but nothing compared to the current stretch of active weather.
A quick note about today: Please remain aware of your weather surroundings this afternoon and early evening. The "pattern" has the makings of a "classic "tornado outbreak for the southern plains. There is still much to learn about tornado formation and why some storms produce tornadoes while others don't, but the conditions needed for tornado development will be in place across the area today. I expect a tornado watch to be posted for the area by at least 3 to 4pm that may last through the late evening hours. Remember a WATCH means that conditions are favorable for tornadoes in and close to the watch area. A WARNING means a tornado has been spotted by a trained storm spotter, or radar indicates the possibility of a tornado forming quickly. A WARNING requires immediate action on your part by seeking shelter in a safe location until the threat as ended in your area.
Warnings are issued by our friends from the National Weather Service, and they do an excellent job.