TULSA, Oklahoma - A freeze warning is posted for part of central and northern Oklahoma this morning for a few hours with some locations temps near and or slightly below freezing for a few hours early this morning.  Some patchy fog or frost may also occur in a few spots.  After this morning, we’re beginning a warming trend with highs this afternoon moving into the lower to mid-60s with sunshine and light winds.   The stronger south winds will return Wednesday through the end of the week with a robust warm-up, well above the seasonal average until another front moves across the area Friday with a chance of storms followed by another shot of cooler air.  A few of the storms Friday may be strong to severe. 

The thinking regarding the general outcome of the pattern has not changed compared to yesterday’s update.   Yet there are some differences regarding the exit phase of Friday’s upper level system.

Wednesday into Thursday a large and broad upper trough will establish across the western U.S., mainly across the inter mountain region into the PAC northwest.  A surface area of low pressure will deepen to our northwest and allow very strong south winds developing Wednesday into Thursday.  We may be near or slightly below advisory levels by Thursday for part of the state. 

Thursday a dry line is likely to establish across far western Oklahoma with the surface low centering across the central plains as a lead impulse rounds the basal portion of the trough and ejects into the central plains.  This would normal crank up a few storms off the dry line to the west, but current data support a strong capping inversion in place across the state that would limit or more than likely prohibit storms from forming.  

Friday morning the upper trough is ejecting into the central plains while a surface cold front will quickly sweep across northwestern Oklahoma into the eastern third of the state by midday.  Scattered storms may develop early Friday in the warm air regime across central to eastern Oklahoma as the main upper level trough ejects quickly into the central plains before slowing down a bit into the afternoon and evening.  Later Friday midday to afternoon, the dry line will begin moving eastward and may cross the metro during the early afternoon while continuing to force thunderstorm activity across far eastern Oklahoma and western Arkansas.  Some of these storms will more than likely be severe with point soundings indicating all modes of severe weather a possibility.

The GFS brings an elongated chunk of the trough quickly across the state and effectivity shoves the dry line and cold front across the state Friday afternoon and evening.  The EURO is slower with this process.  The last few runs are hinting that the dry line may stall briefly across far eastern Oklahoma overnight into Saturday morning with some additional storms still possible Saturday across extreme eastern Oklahoma before moving into Arkansas midday.  While this scenario is unlikely, it has happened in the past.  Our forecast will stick with the rather consistent and progressive GFS scenario for the weekend.

Strong northwest winds behind the boundary will bring much drier air into the area that will reside across eastern Oklahoma this weekend with clear sky and cool weather this weekend.  It’s possible we could have another minor freeze Sunday morning in some valley locations.  The next front would zip across the area next Tuesday but low-level moisture may not have time to recover into the area.

Thanks for reading the Tuesday morning weather discussion and blog.