Many of us received our first decent rain in quite some time early Friday morning. The map on the right, courtesy of the OK Mesonet, is for the last 48 hours and shows the rains from Thursday night/Friday morning. Do we need more? Certainly! But, that was a step in the right direction.
Another complex of storms is moving eastward along the OK/KS state line first thing this morning, but that activity is weakening as it moves eastward and will primarily affect locations along and north of Hwy 412. Yet another complex of storms is expected to be developing in W KS later today and that activity is expected to be moving to the E and SE for the evening and overnight hours. That will provide another decent shot of some badly needed rainfall, but there will also be a chance of some severe weather with those storms. Locally damaging winds and possibly some marginally severe hail will be the primary threats from those storms.
We refer to these systems as Mesoscale Convective Systems, or MCS for short. They are usually associated with a NW flow aloft which often has some weak, embedded disturbances in the upper level wind pattern. These are difficult to anticipate and due to their scale are often not very well sampled by the observational network. As a result, our numerical models typically do not do a very good job with them which creates additional uncertainty and sometimes leads to ‘surprises'. During the late Spring and early Summer, this type pattern is often the dominant rainmaker for us; something that was largely absent for the month of May. So, although these systems can be troublemakers and often create headaches for the forecast community, they are an important source of rain for us, particularly at this time of year.
Any overnight showers/storms may be followed by a chance of some redevelopment later in the day Sunday, so will keep a chance of afternoon/evening showers/storms for Father's Day. After that, the pattern aloft should become more stable and we will be going into a hot/humid pattern for the rest of the coming week. Gusty southerly winds will maintain abundant low level moisture, but conditions aloft will be less favorable so only a very slight chance of some isolated showers/storms are in the forecast after Sunday.
Temperatures will be around 90 today, the upper 80s on Sunday, and then back into the lower 90s for much of the coming week. This is just a bit above normal for this time of year and will also be reflected in overnight lows in the upper 60s tonight and the 70s for the rest of the week. Heat index values will be several degrees above the air temperature for the coming week as well.
So, stay tuned and check back for updates.