Our upper air pattern has transformed back to spring! As mentioned here earlier this week, the ridge has flattened and basically developed into two distinct areas. One across the far southeastern U.S into the Gulf and the other across the Mexican Plateau region. This has effectively allowed the faster westerlies aloft to temporarily migrate southward. One closed low is exiting the Missouri Valley now but in its wake will be a series of short wave disturbances embedded in the fast flow. Another stout looking trough will eject Sunday into early next week before mid-level heights expand. What does all of this mean for our forecast?
Our main issues revolve around the potential for another storm complex to roll across the area late tonight into Saturday morning and the possibility of additional storms Saturday afternoon and evening. Another front may briefly impact the area late Monday night into Tuesday morning with some storm chances across the northern areas. Highs today will remain in the upper 80s to lower 90s with relatively mild conditions for late June standards. Showers and storms are likely this morning through midday across part of western Oklahoma, but as this activity draws more eastward it should begin to dissipate. Our focus will remain for later tonight into the weekend.
Most data (not all) support another MCS ( convective complex of storms) to develop tonight out of the panhandle region and quickly expand east to southeast. The main severe weather threats for eastern Oklahoma will be damaging straight-line winds, heavy rainfall and some hail. The quickness of the system should mitigate the potential for any significant flooding or drainage issues. The timing of this system may continue to change but it has been consistent for the last few runs. Storms will develop around 6 pm to 7 pm across the far northwestern Oklahoma areas and expand eastward. The leading edge of this complex may be nearing the Osage to Pawnee to Payne county areas from 11 pm to midnight tonight, nearing the metro highway 75 corridor around 1 am, moving across east-central Oklahoma around 2 am and exiting far southeastern Oklahoma around 3 am to 4 am. These timings are for the leading edge of the complex. Some rainfall should continue behind the system for a few hours and may not subside until just before dawn Saturday morning.
The rest of the thunderstorm forecast will be highly conditional depending upon the positioning of at least one outflow boundary from the overnight storms. Unstable conditions are expected to rapidly develop by Saturday afternoon and early evening along and south of the effective outflow. We’ll not know the position of this area until sometime tomorrow morning, or even possibly only a few hours before additional storms attempt to develop Saturday afternoon or evening. Severe parameters for super cell thunderstorms will increase by Saturday afternoon and evening with large hail and damaging winds possible. Additionally, any super cells that can root along the boundary may have enhanced helicity fields that could produce a tornado. If I had to decide now based on early morning data, this boundary may be more pronounced somewhere around the I-40 corridor. The wild card may also be a small area of low pressure that is projected to develop Saturday afternoon and quickly deepen. This may act to initially cause the boundary to lift northward for a few hours before shifting southeast again by later in the evening. Most storm activity should end or move out of the area by later Saturday night into pre-dawn Sunday. We may be able to yank the Sunday morning period pops but this will be a last minute, game time decision for the forecast. A few additional storms will be possible Sunday afternoon or evening across far northwestern sections into southern Kansas.
Early next week another stout looking upper level trough will move across the central plains before the mid-level ridge begins to expand. This may shove a front near the area Monday night into Tuesday morning with a few storms before the heat and humidity become our dominate weather concerns for the middle to end of next week.
In summary, a few storms are likely during the day well west of our area. Our main chances will arrive later tonight into early Saturday morning, and then again possibly Saturday afternoon and evening. Severe weather threats will be possible.
Thanks for reading the Friday morning weather discussion and blog.