After an incredibly stormy start to our weekend, we wrapped it up with about the nicest weather you could ask for. Just as a recap, Friday was the 4th wettest April day in Tulsa history with 3” to 5” of rain falling across the metro area. We are getting a much-needed chance to dry after this drought-smashing rain fell across Green Country. Unfortunately, it may not be long enough before more rain and severe storms come our way this week.
The work week will begin on a quiet note with dry, cool air in place. High pressure shifting to our east means south winds come back and we continue our warming trend the next few days: upper 70s by Monday afternoon and well into the 80s by Tuesday. The first round of active weather arrives Tuesday evening with a cold front. Along it, strong to severe storms with the potential for large hail may form. The likeliest area for these storms will be northeast of Tulsa after dark. The two limiting factors with this storm system will be the CAP (warm, suppressing air aloft) and the return of moisture from the Gulf. Our weekend cold front went clear through the Gulf, cooling it down and limiting evaporation rates. This influences how quickly moisture levels recover up our way.
We will also cool down following Tuesday night’s front. We’ll be back in the 60s for highs on Wednesday with lingering cloud cover and showers. The next storm system will be quick on its heels. Cloud cover and showers will start to overspread the area Thursday with the passage of a warm front that night into Friday, expanding the warmer, more unstable air mass across the air. That sets the stage for several rounds of potential severe weather.
The timing for this slow-moving and strong storm system is not the greatest as we approach the weekend. It’ll likely impact a lot of outdoor events and plans given the longer duration that rain and storms will be in the area. You can see the set-up above. A slow-moving, deep upper level low pressure will sit and spin its wheels to our west late this week. This induces Southwesterly Flow in the jet stream, a wind pattern that ushers up Gulf moisture from the surface, enhances wind shear and brings other ingredients in place for severe weather. As early as Friday morning, strong storms with hail may break out. Later that day, severe storms will likely form along a dry line and cold front to our west and make a run at our area. On Saturday, those boundaries don’t move much. Renewed upper level energy will spark more widespread storms that will push through Green Country. By Sunday, this system should finally kick eastward, clearing us out.
The severe threat appears sizable Friday and Saturday given the severe ingredient trifecta in place: substantial low & high-level wind shear, instability and moisture. Given the slow-moving nature of the system, storms may build over each other, limiting supercell structure at times and, thus, tornado potential. However, we’ll be watching these days closely and will hone in on the main time windows and locations for the potential rough weather as it gets closer. Above is our general outlook for severe weather at the end of the week.
The other big concern will be the amount of rain that could fall. Combined with our midweek system, our stormy pattern for the upcoming weekend could leave us with widespread 3” to 5” of rain and locally higher amounts. Our soil is now (finally) saturated and additional heavy rain will quickly run off and cause flash flooding. River and lake levels may rise further as well if this storm system is as slow as it appears in our computer models.
Clearly, it will be a very interesting end to the month of April. As we head into the heart of severe weather season (May), it appears we’ll see a small reprieve from the active weather. Another storm system shows up in that first week. That first week also features a few cool spells. We won’t be rushing too quickly into the May Muggies.