Current Conditions at Sanborn Field 

 

Monday: Mostly sunny. High: 77

 

 

Monday Night: Clear. Low: 56

 

 

Tuesday: Sunny. High: 82

 

 

Tuesday Night: Clear. Low: 58

 

 

Wednesday: Sunny. High: 88

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Discussion:

Summer is holding on by a thread this week. The region experienced some relatively cooler temperatures Sunday, but a warmup for the work week is on the way. High pressure overhead will keep the sky clear to start off the week. This will help temperatures to climb back into the upper 80s by Wednesday. Morning low temperatures will still feel cool, but likely not as chilly as Monday morning.

Travis

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Forecasters: Schneringer, Samson, Travis

Date Issued: 09/12/2022 10:00AM CDT

Technical Discussion:

 

It is not often that forecasts can be summed up in a mere three words. This is one of those rare days and the three words are as follows: dry, cloudless, warmup. Consensus between the GFS and NAM led to the use of a blend between the two models. Additionally, consulted the National Blend for temperatures.

An upper-level low that brought widespread rain to the region early Sunday morning is currently seen in GOES upper-level water vapor imagery spinning over southern Lake Michigan. Infrared satellite imagery shows some upper-level clouds wrapping around the back side of this low making their way into NE Missouri. As this low moves to the ENE, a upper ridge will build in behind it. Unsurprisingly, a lack of any sort of dynamic forcing for ascent is seen in the upper-levels beneath the ridge as its crest and the associated supergeostrophic motions are confined to south-central Canada. 

Low- and mid-level relative humidity will remain low for the duration of the forecast period. Model soundings show, for the most part, a fully dry column until the forecast period ends Wednesday evening save for near saturation in the upper levels on Monday that could support high cirrus clouds wrapping behind the low mentioned earlier. Beyond Monday morning, the sky will be largely void of clouds. This will allow for efficient insolation during the day and efficient radiational cooling at night. Expecting overnight lows in the upper 50s and daytime highs in the 80s for Tuesday and Wednesday. WAA solenoids are evident in the MSLP and 1000-500-hPa thickness fields beginning Monday night. That said, 850-hPa winds remain out of the northwest for the entirety of Tuesday, so keeping temperatures in the low 80s. Surface to 850-hPa winds turn out of the SW Tuesday night into Wednesday which will allow highs to reach the upper 80s (creeping to near 90). 

 

The presence of WAA and plenty of daytime heating led to the belief that the NBM has a slight cold bias of 2-3 degrees. While consulted for temperatures, did not place heavy emphasis on its guidance. Future shifts should pay close attention to this bias.

Travis