Monday, November 28, 2022

 


 

Monday -
Sunny. High: 53
 
 
Monday Night - Mostly clear. Low: 44
 

Tuesday -
Partly cloudy. High: 64
 

Tuesday Night -
Mostly cloudy. Cold. Low: 26
 

Wednesday -
Sunny. High: 35

 

 

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Discussion: 

After some good rain over the weekend, a warmup is on the way for the early week. Winds predominately out of the south will warm daytime highs into the 60s by Tuesday before winter-like temperatures come back with a vengeance. A cold front will move through the region Tuesday night dropping temperatures down into the 20s by Wednesday morning. Steady, northwest winds around 10-15 mph Wednesday will make the forecast high in the 30s feel much colder. 

- Travis
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Forecasters: Travis

Date Issued: 11/28/2022 9:00am CST

Technical Discussion:

The main concern for the short term is a strong cold front that will move through the region Tuesday evening behind which a blast of arctic air will cause temperatures to plummet back to below average. With no significant differences between the NAM and GFS, a blend of the two models was used in consort with MOS for temperatures leading up to frontal passage (fropa). 

A longwave trough over the western half of the Lower 48 will keep the atmosphere deceivingly active for the early part of the week. A southern push of the jet stream will keep the storm track well to the south in the Lower Mississippi River Valley where severe weather is expected Tuesday. As the trough slides to the east, it will amplify and push an embedded shortwave through the Great Plains and into the Mid Mississippi Valley by Tuesday evening. Ahead of said trough, flow at all levels will be out of the southwest. In the upper levels, this will aid in positive vorticity advection (PVA) while in the lower levels, this will aid in efficient WAA. 

Ingredients are present for active weather associated with this system, but what we lack is any semblance of timing. Mid- to low-level WAA will be present well ahead of the attendant cold front, but deep-layer saturation will not come to fruition until after the passage of the cold front Tuesday evening when WAA induced forcing is gone. Behind the front, a broad area of PVA gives the impression that dynamic forcing for ascent will be sufficient for precipitation. However, model soundings reveal a different story with a lack of deep saturation at any forecast hour. The best opportunity for precipitation (from thermodynamic profiles alone) looks to occur overnight Tuesday into Wednesday (Wed 06-09Z), but skepticism remains high. First, dry layers in the lower levels will hurt ice crystals' chances at reaching the ground. Second, the PVA mentioned above was plotted for the 700-300-hPa layer which, above about 600 hPa, is bone dry. Without any forcing for ascent in the more moist lower levels, hydrometeors will struggle to grow and will likely not make it through the near-surface dry layer. Currently thinking is not to expect any precipitation with this fropa, but an increase in low-level moisture could support some light flurries early Wednesday morning.

So, while this cold front will be strong enough to cause temperatures to plummet about 40 degrees in 12 hours, it appears that will be all it does. Behind the front, cold, dry, arctic, air sets up with high pressure that will build in Wednesday. Though sunshine will be plentiful, high temperatures will struggle to reach the upper 30s. 

- Travis

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