SO MUCH FOR PERFECTION...
As the saying goes, all good things must come to an end and so it is with the near perfect weather we've enjoyed the past few days. The culprit in this reversal is a front that wavers around the region into early next week. It provides the forcing and focus for scattered showers and thunderstorms beginning Saturday and lasting into at least Monday morning.
Friday evening you can see the contrast in temperatures along the boundary as it sets up along the Iowa Missouri border. There's a good 10 degree difference between my northern and southern counties.
You can also see by the increase in cloudiness out west that moisture is on the increase.
Dew points at noon Friday were only in the 40s.
CAPE (instability) was virtually non-existent over the central Midwest.
By Sunday evening dew points have soared into the mid to upper 60s, a significant increase in moisture.
That drives a notable increase in CAPE that will be fuel for showers and storms, especially Sunday night and early Monday morning.
While some showers (maybe a couple thunderstorms) will pop up Saturday, the effects of residual dry air will still be felt in most areas keeping the rains spotty and light. That's not the case in the far north where rain could accumulate to 1/4 to 1/2 inch under a low overcast that will keep temperatures only in the upper 50s to low 60s. Further south, under the influence of the warm front (especially I-80 south), it will be considerably warmer and drier with readings in the low to mid 70s. Here's what the GFS shows for highs Saturday..
Rain coverage Saturday night and much of Sunday looks spotty as the primary short wave energy gets organized out west over Nebraska. That should allow highs in the north Sunday to reach the mid 70s with upper 70s to low 80s likely in the south. When the Plains energy streaks across the region Sunday night and Monday in tandem with the low level jet, a distinct increase in shower and thunderstorm activity is expected. Models have shown a trend for some locally heavy rain in excess of an inch, particularly where thunderstorms can fire near and north of the front. A couple of strong storms are possible but so far the severe threat seems minimal. SPC doesn't even indicate a slight risk but if higher levels of heating and instability can be achieved Sunday stronger storms could come into play.
For precipitation alone, the Weather Prediction Center has put out a broad marginal risk outlook for excessive rains over much of my area Sunday.
As for rainfall, here's what models are currently suggesting for potential totals. The WPC amounts are significantly higher than what was shown 24 hours ago.
The GFS indicates this for rainfall through Monday.
The EURO is in relative agreement with a slightly northward depiction of the heavier rains.
Tuesday the front makes a push further south into Missouri where it grinds to a halt much of next week. Models do indicate a couple more rain threats next week (mainly Wednesday and Friday) as additional energy ripples along the boundary. However, the better dynamics and forcing remain to the south indicating generally light amounts to the north where my area resides.
With periods of clouds and precipitation the 5-10 day period continues to look cool. The GFS shows significant departures over the central Midwest June 8th-June 13th.
However, as I alluded to in my last post, the GFS has been flip flopping on the cool pattern breaking mid June. Today the signals are consistent on both the GFS and EURO that a warmer period is evolving after mid June. The GFS temperature anomalies for June 14th-19th show the warming trend.
In the meantime, the coming weekend will have a more unsettled look with clouds and eventually showers and thunderstorms making their presence known. Have a solid weekend and roll weather...TS
