The end of April is deemed the beginning of our core severe weather season in Oklahoma. It looks like we’re right on schedule. We’ve had a few instances of it already this year, most notably, the Tulsa area tornado on March 30th. However, the atmosphere is now primed for severe thunderstorms on a more regular basis, and we’ll see our first potential outbreak of dangerous weather on Tuesday. Unfortunately, that won’t be the only day where big storms threaten Green Country this week.
Tonight’s severe weather threat is a dud for the state. The capping inversion (warm layer of air aloft) prevented any storm development southward along a dry line in western Oklahoma today. The main upper level energy also is passing to the north, keeping the threat held into the central Plains. This storm system will pass by without much ado as our air mass gets juicier ahead of the stronger upper level low moving ashore in the western U.S. right now. This means we’ll see additional moisture and low-level clouds into Monday with a continued fetch of wind from the Gulf of Mexico. We might see a few light showers on Monday and perhaps a few brief storms that night in northeast Oklahoma. However, the main energy won’t arrive until Tuesday afternoon.
The moisture, instability, upper-level forcing and wind shear in the second half of Tuesday indicate a classic severe weather outbreak for our area. The dry line centered west of I-35 will be the focus for initial storm development. Storms that form in the late afternoon will quickly become severe and rotate. In fact, within an hour of forming, these storms could pose a tornado threat. This is why it’s imperative to be prepared before Tuesday afternoon for the severe weather threat. On top of possible tornadoes, these storms could produce very large hail (think baseballs in some instances) and damaging winds. It’s a little too early to hone in on the highest threat areas quite yet, but certainly the Highway 75 corridor (including the Tulsa metro area) and points west could experience these storms as discrete supercellular storms before congealing into more of a squall line as they trek eastward. The timing of these storms isn’t nailed down yet. They won’t likely form before 3pm. It’s most likely Green Country will deal with severe weather between 6pm and midnight. The severe weather could last overnight, especially for areas east and south of Tulsa. However, the tornado threat may lessen at this point a bit. The map below shows a model depiction of storm coverage Tuesday at 5pm, just west of Tulsa.
The frontal boundary may clear most of the area Wednesday morning, but locations near the Oklahoma/Arkansas border may see a flare up of storms during that day that could quickly become severe before exiting the region. At this point, it looks like any lingering showers or storms will be done around Tulsa by midday or earlier on Wednesday.
After a brief respite on Thursday, another storm system in the series will arrive on Friday. It’s too early to say how much severe weather will impact Green Country because this upper level low may take a more southerly trek, limiting the returning heat and moisture to our region. However, it may bring heavy rains that could create a flooding hazard by the start of the weekend. Over the next week, up to half a FOOT of rain may fall across parts of eastern Oklahoma. That doesn’t bode well when our soils are already saturated.
We’ll face a flurry of threats in the week to coming (minus flurries of course). Now is the time to adjust schedules and make a plan in case severe weather threatens your location. We’ll enjoy some nice, mild weather for the start of our work week, but we know that can quickly turn on us this time of year. For more on the incoming severe weather, be sure to follow me on Twitter: @GroganontheGO and on my Facebook page.