Current Conditions at Sanborn Field

           

Monday Night: Clear. Low: 37

Tuesday: Sunny. High: 63

 

Tuesday Night: Mostly clear. Low: 41

Wednesday: Partly cloudy. High: 71

 

  

Wednesday Night: Cloudy with chance of showers later. Low: 53

 

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Discussion: 

 

Columbia should be seeing some warmer weather for the first part of the week, but not before some cool temperatures tonight! A Frost Advisory has been issued for Monday night, so be sure to cover any outdoor vegetation that may be harmed by frost. After that, temperatures should warm and the sky should remain sunny with only a few clouds. There is a slight chance for showers late Wednesday night, but total rainfall amounts are expected to be trace.


- McMullen


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Forecasters: McMullen, Millsap

Date Issued: 04/25/2022 5:00PM CDT

Technical Discussion:

The GFS was chosen as the model for guidance in this forecast due to higher accuracy in regards to surface temperature. The placement of the occluded low pressure center in NE Canada as well as the high pressure center in central Canada were also closer in accuracy compared to the NAM. A highly occluded low pressure system centered over the southern tip of the Hudson Bay is associated with a long string of cold fronts extending through the Ohio River Valley and into the Lower Mississippi Valley. This series of boundaries is pushing multiple bands of precipitation to the east along with thunderstorms in the southern CONUS. A large-scale high pressure system centered in central Canada is pushing a second cold front to the south as a broad field of stratiform clouds follow closely behind the frontal boundary.

The 250 mb plot of winds and divergence indicates an active trough-ridge pattern through the CONUS. A jet streak forming over the Middle Mississippi Valley is spawning large amounts of upper level divergence in the right entrance region. This could be partially indicative of the thunderstorms occurring in Texas and Louisiana since it insinuates surface convergence and instability. This area of divergence aloft remains to the south of the CWA as the jet streak exits to the east and minor ridging builds up over the Great Plains. Another area of divergence aloft is also shown starting on Thursday at 09Z, although the model does not show any extreme values in this regard. The 500 mb vorticity map shows a vort max centered on a upper level low traversing across southern Canada and bleeding into the Great Lakes starting Tuesday at 12Z. This circulation pushes the trough associated with the low to the east as a ridge takes shape closely behind to the west. Also, a small band of vorticity develops in the central Plains that appears right on our doorstep Thursday morning.

700 mb plots of relative humidity shows the majority of deep moisture remaining to the north and east until Thursday morning. The majority of the atmosphere remains dry as the CWA becomes sandwiched between a pair of high pressure systems to the north and south, maintaining stable conditions and preventing cloudy conditions. 850 mb plots of relative humidity and winds show moisture exiting the region by 12Z Tuesday as high pressures keep the low levels dry until early Thursday morning. By 12Z Thursday, the LLJ, with wind speeds of up to 40 kts, will enter the picture and provide moisture into the Plains and Mississippi Valley. Surface winds maintain a northerly component until Tuesday evening as calm, southerly winds quickly become the predominant direction. The 1000-500 mb thickness map compared to mean sea level pressure does not show strong signs of advection seeing as winds maintain speeds no greater than 10 kts.


Soundings indicate a generally dry atmosphere with only occasional areas of near-saturation at the mid-levels, which could indicate a few passing clouds. One point of interest on the sounding data occurs Wednesday between 09 and 12Z when the surface dew point depression reaches 6 °C. Surface temperatures are too warm to warrant a frost advisory according to the soundings, so the NBM was consulted for Monday night’s low temperature. A range of 37 to 35 °F is indicated for tonight, which is sufficiently colder and helps justify the need to warn for potential frost. On another note, future forecasters should be aware of the potential of active weather approaching Thursday morning as soundings indicate a gradually saturated profile and increasing omega developing beforehand.

 -Millsap