Welcome to Summer

Tuesday, June 21st 2011, 4:11 am
By: News On 6

Welcome to summer.  The start of summer begins today at 12:15PM and ironically, with afternoon highs cooler today than the past several days.  A front will cross the area later today with a slight chance of storms, mainly across far eastern and southeastern OK.

 A cold front is slowly moving eastward this morning but showers and storms have moved well to the east and southeast of the front. These storms packed quite a bunch last night with strong wind and hail in some locations.  This morning we've seen a few severe storms continuing across far southeastern and western Arkansas but the trend will be for these storms to weaken soon as the upper level support is now to the northeast.  The boundary will not move over the region until later today and there will continue a slight chance of additional strong to severe storms across far eastern and southeastern OK later this afternoon.  Southwest winds in the Tulsa area will veer to the northwest later this evening as the true cold front pushes southward.  This will bring a nice break to the region tomorrow with relatively dry air and mild conditions making Wednesday the best weather day of the week.  This afternoon I expect highs in the upper 80s or lower 90s with mostly sunny conditions after a few morning clouds.

 The data supports controversy for Thursday.

The NAM now keeps us in the northerly surface flow through Thursday while the GFS tends to bring the boundary back northward Thursday while also offering a hefty MCS developing Thursday night across southern Kansas and moving directly into northern OK early Friday morning.  The NAM is not quite as bullish as the GFS but does offer a signal for some precip Thursday evening into Friday morning.  The GFS has been horrible latterly, but the pattern most definitely adds support to the GFS solution of cranking out the MCS. I'll increase the pop Thursday night into Friday morning to 30%, but I'll also keep Thursday's winds mainly from the northeast for most of the day before bringing southeast winds back into the area Thursday night. Has that for a model compromise?

Friday into the weekend the upper air flow will be from the west to northwest as a mid level ridge of high pressure will be suppressed to the south.  This will allow storm complexes to that form in Kansas to move southeast with time and possibly brush Northeastern OK and southeastern Kansas.  This upper air flow is a very common feature for June, but usually occurs during the first week or so of the month.  These expected MCS's can also provide severe weather opportunities with mainly strong to severe winds and hail.  The exact trajectory of the expected flow is not known with any certainties at this point, which means the complexes this weekend may barely brush the area, or they may take aim at the main portion of our viewing area.  We'll have to wait until Friday morning to have any confidence on the exact flow, but at this point, we have decided to keep a 30% pop for each late night and early morning period of the extended forecast. 

The extended operational and ensembles bring the ridge back into the state Monday and keep it intact for a few days next week. If this solution is correct, the MCS machine will be pushed out of the state Monday and Tuesday as more of the hot and humid stuff moves back into the region.