Strongly advise keeping a close eye on the sky through the day Saturday as we are still anticipating a very volatile situation with regard to storm development and severity.  If you have any weekend plans involving outdoor activities or going to an area lake, then be particularly weather aware as storm development will likely be explosive and there may not be much warning lead time.  I mentioned this in yesterday’s discussion regarding the extremely high CAPE (Convective Available Potential Energy) values that are projected for Saturday afternoon/evening and those parameters have not changed with the data runs so far today.  Notice the map which is showing values in excess of 6000 over a large area of E OK.  Notice also, the sharp drop-off in SE KS and W MO; that area is immediately behind a complex of storms that had already moved through those locations leaving much more stable air in its place at that time and according to this particular solution.  

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Bottom line is that the atmosphere will be extremely unstable through the day Saturday, but there will also be a very strong capping inversion in place limiting storm development.  That will be changing late in the day and that night as a cool front pushes across the state providing the mechanical lift needed to break the cap and likely resulting in a line of storms progressing to the SE producing severe weather.  As you can see, the likelihood of severe storms has ramped up even more.

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Storm mode is also a concern.  The extremely high CAPE values indicate extreme instability which means when storms develop, they will form very rapidly with explosive growth.  That, in turn, suggests an enhanced potential for very large hail, baseball size or larger certainly possible, along with damaging down burst winds which may exceed 80 mph.  The winds aloft show good directional shear, that is changing wind direction with elevation, but limited speed shear as the dynamics are not overly strong above the surface.  Even so, tornadoes will also be a potential threat.

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As for tonight, the very warm and humid air that is now in place will keep us from cooling much with temperatures holding in the 70s through the overnight hours.  There may also be a few isolated storms form this evening over the more eastern counties and the potential for a few storms dropping down out of KS during the late night hours.  Those chances are relatively small, but as you can see on our forecast page, the chances will be much better for the afternoon and into the night time hours of Saturday.  The current time line suggests storms could be developing or moving into the area around the 4PM time frame, but will be much more likely by the 6-7 time frame and then moving on rather quickly to the SE overnight.  That should limit the flooding potential as the storms will be making steady progress, but brief periods of very heavy rainfall will still be possible and could result in local drainage issues.

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Hot & humid conditions preceding the storms should result in daytime highs near 90 and heat index values well into the 90s before the storms develop.  By the way, we made 90 today for only the second time this year, but the hottest temperature so far this year is still the 92 back on Mar 20.  Here are the max/min values across the state so far today.

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As you can see on our forecast page, the storms will be out of the area by Sunday morning followed by clearing skies during the day and northerly winds bringing drier and somewhat cooler air back over the state.  That will make for very pleasant conditions for Sun/Mon/Tue.  However, a more unsettled pattern looks to return by the middle through the latter part of next week.

The longer range guidance for the 8-14 day period is still suggesting another active period along with a trend to more seasonal temperatures as we go on into June.  So, stay tuned for updates.

Dick Faurot