IS THAT FALL I SMELL...
It's been one heck of a week weather wise. After a fall like start with 60s for highs on Monday, a steady diet of sunshine and warm air allowed temperatures to reach 80 by Wednesday and remain there the rest of the week. Here's the tale of the tape in the Quad Cities. Notice too the predominance of warmth so far this month with 11 of the 16 days at 80 or above. Normal highs are now in the mid 70s.
We've got a good 5 more days of this type of warmth before a pattern change is implemented next week. If my schnoz is working correctly, I smell fall like temperatures in our not to distant future. I'll get to that in a moment. First, let's talk the weekend and how long our summer fling will continue.
In regards to weekend temperatures, one of the driving factors will be clouds, the other potential precipitation. The way things currently stand, much of the showers and storms that develop are expected to be nocturnal and tied to forcing Saturday night and again Sunday evening. With that being the case, enough sunshine is expected both days to drive highs into the low to mid 80s, warmest in the south. Moisture has also been steadily increasing with 2 days of southerly flow and dew points will reach the range of 65 to 70, with the highest levels Sunday when water vapor pools ahead of a cool front. Humidity will be a noticeable feature through at least Tuesday of next week.
Here's what the EURO indicates for highs in the Quad Cities through Monday.
That brings us to rain chances and they are certainly there. As mentioned most of the showers and storms are expected to be during the overnight hours. That does not preclude a few early in the day both Saturday and Sunday, especially in my western counties in Iowa.
Coverage Saturday night looks to increase as the low level jet ramps up after sunset and impinges on the instability built up during the day. However, there is still a large spread regarding the areal coverage and extent of any storms. It currently appears the risk of strong storms would remain to the west of my area. What remains of these storms could produce pockets of heavy downpours as they get into parts of the region later Saturday night. SPC currently has a slight risk out for isolated severe weather southwest of a line from Ames to Newton and back to Lamoni.
Any lingering storms depart early Sunday allowing the atmosphere to destabilize with heating in the afternoon. Late in the day or evening, convection is expected to pop up ahead of a cold front. Current indications show the front progressing into my central counties when this occurs. That argues for the greater rain chances Sunday night to be over the southern half of my region, roughly I-80 south. The 3k NAM builds some respectable CAPE indicating enough instability for a few strong storms in that part of my area,
SPC has much of the region near and south of HWY 30 highlighted in a slight severe weather risk Sunday evening. I could see SPC moving the risk outlook further south towards I-80 if tonight's trends hold.