Current Conditions at Sanborn Field

Wednesday Night - Becoming partly cloudy after sunset. Temps rising overnight. Low 58-62

Thursday - Partly cloudy. Breezy. High: 80-84

Thursday Night - Becoming cloudy. Scattered showers and thunderstorms beginning late. Low 58-62                                    

Friday - Showers tapering off by late afternoon. Temps falling during the day. High: 52-56                

Saturday - Partly cloudy skies. High: 46-50

 

 

                          

 

 Thanks to IconArchive.com for the icons!

 

Discussion: 

The roller coaster of temperatures continues this week. While highs for Wednesday afternoon only reached into the mid 50s, temperatures will be on the rise into Thursday after the passage of a warm front late Wednesday night. Thursday will see a brief shot clearer skies and unseasonably warm temperatures reaching into the low 80s. Clouds return Thursday night out ahead of a cold front that will blow through mid-Missouri late Thursday night into early Friday morning. This will bring with it chances for scattered showers with some rumbles of thunder possible. Showers look to exit the area by Friday afternoon giving way to more pleasant and seasonable weather to start the weekend.

===============================================================================

 

Forecaster: Travis

Issued:  5 PM CDT 21 October 2020

 

Technical Discussion (The nerdy stuff we are discussing in class)

Another period of unsettled weather is in store for the region. The main focus for the period is yet another shot of unseasonably warm temperatures quickly beaten down by a cold front. Good consensus between the GFS and NAM on the timing of the warm front Wednesday night, and cold front Friday morning. As such, went with a blend of GFS and NAM and GEFS/SREF ensembles for temperatures and QPF.

Rap analysis loops of 700-hPa RH and LSX radar both show the bulk of the residual moisture exiting mid-Missouri to the NE. GFS and NAM plots of 250-hPa height and wind show the NH storm track just off to our north as a moderately weaker LW trough sits over south-central Canada intruding into the Upper Midwest. Both GFS and NAM keep the center of this LW and associated jet streak well to our north and should help keep cold air locked up with it. Wednesday night into Thursday both models show good consensus of a surface warm front passing between 03 and 05z Thursday. Low-level flow shifts out of the southwest as both models show a moderate southwesterly LLJ kicking up Thursday night into Thursday day. Temperatures will continue to rise throughout the night and WAA will dominate into Thursday afternoon. This is what will drive the above average temperatures. GFS soundings keep lower-level saturation throughout the day with moderate instability. As such expecting partly cloudy skies with mainly fair weather cumuliform clouds. 

Thursday night, the next system moves into the region. GFS and NAM 500-hPa heights and vorticity show the aforementioned longwave trough amplifying and digging further into the northern plains. Reflected at the surface is a mid-lattitude cyclone and prominent cold front moving through the area. GFS and NAM are in good agreement that cold fropa will occur between 06 and 09z. GFS soundings show increased saturation ahead of the front as skies become cloudy. By 09z GFS soundings show a full saturation of the column with moderate elevated instability (571 J/kg of MUCAPE). The NAM is much more aggressive, showing close to 1800 J/kg of MUCAPE and even moderate SFC based CAPE as well. Would not be surprised to see isolated stronger storms embedded in the stratiform precip. SREF ensemble shows a mean of ~1100 J/kg at the time of fropa with GEFS showing less (~600 J/kg). Severe weather still looks unlikely due to the lack of deep moisture and surfaced based instability. 

By Friday afternoon, model soundings dry out the column as precip exits the region. Behind the front, skies will partially clear, but model soundings never hint at a full clearing. Very cold air will stay locked up to the north as mentioned earlier and average temperatures and pleasant weather starts out our weekend as surface high pressure builds in.