Thursday, March 16, 2023

 



Thursday:
Rain. High: 56

 


Thursday Night:
Light rain with chance of flurries. Low: 25



 

Friday
:
Mostly sunny and breezy. High: 43

 
 

Friday Night:
Partly cloudy. Low: 23




Saturday:
Mostly sunny and windy. High: 32

 
  

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Discussion: 

A cold front will arrive over Columbia this afternoon sweeping our warm temperatures away and causing rainfall over the region. In total you should expect between 0.25 to 0.5 inches of rain to occur later today. Thankfully, cloud cover will decrease leaving sunny but windy conditions to end the week.
 
-Hefner
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Forecasters: Hefner, Samson, Macko

Date Issued: 03/16/2023 10:00 AM CDT

Technical Discussion:
 

The focus of this forecast was the precipitation brought on by the low-pressure system approaching mid-Missouri. Additionally, for this forecast the NAM12 was used due to its better handling of initial conditions; specifically a more accurate representation of surface temperatures and upper-level moisture. Furthermore, HRRR soundings were used to determine the timing and p-type for this evening's event for a more precise look at the short-term weather patterns influencing precipitation. 


At 250mb, a long wave trough centered over the Great Plains will traverse over Columbia late this afternoon. Associated with this trough is a low-pressure system with a cold front attached. Measurable vorticity, coupled with upper-level moisture due to transport from the gulf, and warm air advection ahead of the cold front will result in precipitation over mid-Missouri, this will happen due to the rising air from the vorticity values, combined with available moisture to lead to condensing clouds.


At the time of constructing this report, trace amounts of rainfall are occurring over Columbia. However, measurable precipitation isn’t expected until 18Z today. At this time, the dry layer at the surface will begin to saturate and negative Omega values will be introduced into the column. Negative Omega will lead to atmospheric instability at this time. The heaviest rainfall is expected to occur at 21Z today before the profile will gradually begin to be cut off from rising air. Precipitation will persist until stopping on Friday at 09Z. In total, 0.25” to 0.5” of precipitation accumulation is expected to occur. 


It is important to note the cold front passage will quickly be decreasing temperatures during this same time period. Around 03Z Friday, upper-level temperatures within the cloud layer begin to cool enough for ice crystal initiation to occur and surface temperatures will drop to below freezing. Top-down winter weather sounding analysis indicates a transition in p-type from light rain to light snowfall and flurries is possible. However, due to soil temperatures currently being in the 40s, ground temperatures will be too warm for any snowfall accumulation to occur. 


Thankfully, after the cold front passage we will be transitioning to zonal flow and less active weather for our region. A lack of upper-level moisture in both the 700 and 850mb level will result in sunshine returning to Columbia.

 

-Hefner 

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