Current Conditions at Sanborn Field

 

 

Friday: Showers in the afternoon and into the evening. High: 46

 

      

Friday Night: Rainy, possible thunder. Low: 40

 

Saturday: Possible drizzle then partly cloudy. High: 54

Saturday Night: Cloudy, possible light rain. Low: 39

Sunday: Partly Cloudy, increasing in the afternoon. High: 57

 

  

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Discussion: 

It's going to be a rainy weekend to start off our Spring Break, with the heaviest rain to our south and possible thunder in our region Friday and Friday night. Temperatures this weekend range from high 30s to mid 50s. Have a good Spring Break!

-Allen

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Forecasters: Sallot, Allen

Date Issued: 03/24/2023 10:00AM CDT

Technical Discussion:

 

 
The main concern of this forecast period is rain and possible thunderstorms Friday into Saturday. Both the GFS and the NAM were used to construct this forecast as models had good handle on current conditions.

A deep trough, residing over the four corners region as of Friday 12z, will be the main weather system for the forecast period. By Friday around 15-18z, the trough continues to push east, and, as a jet streak situated on the right side of the trough axis moves eastward, the trough switches from a positive tilt to a negative tilt. Divergence increases over the forecast area as this jet streak, now meridional over central TX and western OK, couples with a stronger, zonal jet streak that stretches from eastern IA through the Great Lakes and into the Atlantic. The forecast area sits in the right entrance region of this stronger jet streak, supporting the upward motion encouraging the cloud cover and precipitation on Friday and Friday night. This upper level divergence maximizes around Friday 21z to Saturday 00z, as the jet streaks couple.

At 500mb, a shortwave ahead of the trough will pass through MO around Friday 21z, advecting vorticity to the forecast area and supporting storms and rain on Friday into Saturday.The vorticity over the forecast area reaches a maximum around Saturday 9z as the trough axis passes through the MO. It is important to note that the vorticity max associated with this trough remains south of the forecast area in southern MO and OK/AR.

At 700mb there is rising motion supportive of storms and precipitation on Friday and Friday night. Although much of this rising motion remains south of the forecast area, in southeastern MO, there is substantial vertical motion in the forecast area from Friday 18z to Saturday 12z, with a peak around Saturday 3z.

The surface low pressure system associated with the deep trough tracks from northern OK and southern KS through Mid-MO Friday 21z to Saturday 06z. The placement of the surface low will keep Columbia out of the warm sector of this mid-latitude cyclone and hence, the area with the greatest potential for severe weather. The great amount of energy and lift with this storm system will bring rain to the forecast area and possibly some thunder on Friday and Friday night, but without the threat for any severe weather. Soundings show a mostly saturated column, with a dry layer at about 450mb around Friday 12z, which becomes a fully saturated column by Friday 18z. Thick daytime cloud cover will help suppress convection, leading to rainstorms Friday and Friday night rather than intense thunderstorms. We expect the precipitation to total to about 0.5” to 0.75” over the course of Friday through Saturday morning.

The jet stream will remain over the forecast area starting around Saturday 15z through the end of the forecast period as it takes on a zonal flow, bringing westerly winds aloft.

Chances for precipitation persist into Saturday as the storm system continues to track east into the Great Lakes, with wrap-around moisture entering the forecast area. This wrap-around moisture is visible at both 700 and 850mb, but is not accompanied by the same vertical motion seen on Friday and Friday night. As such, we expect to see much lighter rain on Saturday, ending by 15z, with Saturday accumulations amounting to trace to 0.05”.

Conditions will start to dry up in the afternoon, with the sun warming up temperatures as the clouds clear up throughout the day on Saturday. Sunday will be even warmer as winds shift to the south as we are no longer affected by the low pressure system. The next forecast shift should be aware of the next incoming low pressure system coming Sunday night from northeast OK and southeast KS which may bring another round of precipitation.


Sallot, Allen