Current Conditions at Sanborn Field

Friday Night - Clear. Low: 32-26
 

 

Saturday - Sunny skies. High: 58-62
 

 

Saturday Night - Clear. Low: 40-44
 

 

Sunday - Becoming mostly cloudy by sunset. High: 60-64

 

 

Monday -  Cloudy. Rain beginning in the afternoon. High: 58-62

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Discussion: 

 

A beautiful weekend is taking shape for mid-Missouri. This is all due high pressure and associated southerly winds that will keep the region clear and warm it up as the weekend progresses. As the high pressure slides off to the east, southerly winds will remain, but rain returns ahead of the next system set to blow through here Monday night into Tuesday. Beginning of the rain is looking likely after 4pm on Monday. Fortunately not expecting a widespread heavy rain event like what the region saw on Wednesday and Thursday.

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Forecaster: Travis

Issued: 6:00 PM CST 19 March 2021

 

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

A quiet forecast period is ahead for the remainder of the weekend. By Monday, much of the region will see the effects from our next storm system chugging across the country. Went with GFS guidance as the NAM's handling of 2 meter temperatures for mid-Missouri was continuously running about 12 to 15 degrees F above observed temperatures at KCOU. Due to a scheduled supercomputer outage at NCEP, went with SREF plumes for insight on temperatures and precip QPF.

GFS upper-level height fields show the continued eastward progression of the global scale wave that brought a major burst of energy to the central and SE CONUS in the form of a winter storm and tornado outbreak associate with the same mid-latitude cyclone. Behind it, an upper-level ridge will build, but GFS is not too supportive of deamplification as both 250-hPa height and winds and 500-hPa height and vorticity suggest a continued meridional flow regime. This will result in pleasant weather for Saturday and Sunday, but it will not stick around for long. Large-scale, upper-level flow returns to a trough-ridge pattern set up over the CONUS suggesting an active storm track setting up right over the center of the country yet again. By Sunday night and into Monday, GFS 250-hPa wind speed and wind divergence place Missouri at the poleward exit region of the ULJ thus enhancing upper-level divergence/forcing for ascent. 500-hPa vorticity plots depict strong circulation building in from the southwest as Missouri sits underneath the inflection point of the synoptic-scale wave. 

Saturday and most of Sunday remain cloudless as 700-hPa plots of height and vertical velocity show a closed mid-level ridge and associated subsidence suppressing any upward motion. The Midwest is also devoid of any saturated or near-saturated air. As the weekend progresses, so too does the mid-level ridge eastward. Behind it, a mid-level trough and a plethora of saturated air follows. By Monday, the huge area of saturated air will have made it to mid-Missouri. GFS Soundings indicated that the mid-levels are the absolute last layer to saturate as the column is almost fully saturated save for the 700-hPa and immediately surrounding pressure levels. By 00z Tuesday (Monday evening), the column fully saturates. Likely expect precip to start between 21z and 00z. 

WAA will also dominate the forecast period, as winds at 850 hPa will turn out of the southwest by Saturday morning and remain so until the next frontal passage beyond this forecasting period. The result will be a much enjoyed warming trend. Sunday will be slightly warmer than Saturday which will be slightly warmer than Friday. This is backed up by broad WAA solenoids seen in the 1000-500-hPa and MSLP fields. Clear skies will help drive temperatures up further, but will act as a double edged sword allowing overnight lows to dip far down into the upper 30s. The region is definitely into that time of the year where layers are needed in the morning, but not in the afternoon. By Monday, clouds return and should not allow temperatures to reach Sunday level highs. Went on the warmer side of things based on current model guidance, but Monday morning forecasters should watch for the possibility of adjusting Monday's high depending on the extent of cloud cover. 

Fortunately, GFS soundings for Monday's rain event do not look too favorable for a lot of precipitation. With PWATs below an inch and K indices in the mid 20s, not expecting a wash out like Wednesday and Thursday. SREF total QPF by Tuesday at 00z only totals 0.40 inches (but the event will continue past SREF's limit). This is good news for already flooded areas of mid-Missouri. River Flood Warnings do remain in effect along the Missouri River as it remains at moderate flood stage at several gauges, but according to NWS River forecasts, the Missouri has already crested in all of these locations. The river will dip below minor flood stages by Saturday night.