Monday, November 9, 2020

Current Conditions at Sanborn Field




Monday -
Partly cloudy. High: 72-76  


Monday Night -
Increasing clouds. Low: 62-66


Tuesday -
Cloudy with showers and thunderstorms until early afternoon then becoming mostly sunny. Temperatures falling during the afternoon. High: 70-74

Tuesday Night -
Mostly clear. Low: 32-36

Wednesday -
Sunny. High: 52-56

 
==================================================== 
 Thanks to IconArchive.com for the icons!

Discussion: 
Today, warm weather continues as mid-Missouri remains underneath a ridge of high pressure, with high temperatures this afternoon approaching the record of 78. Clouds will be on the increase tonight, resulting in overnight lows only dropping into the low- to mid-60s. Moving into Tuesday, rain and thunderstorms  can be expected during the middle of the day as a cold front pushes through. After the front passes, skies will rapid clear and temperatures will begin to fall, bottoming out in the mid-30s by early Wednesday morning. On Wednesday, pleasant, albeit cooler weather can be expected, with afternoon highs in the mid-50s.

===========================================================================
 
Forecaster: Ethridge and Ritter
Issued:  10 AM CST 9 November 2020
 
Technical Discussion (The nerdy stuff we are discussing in class)

The primary concern early this week is the timing of a strong cold frontal passage and precipitation associated with it. For this forecast, the GFS was used for guidance as it resolves the longwave trough currently in the western CONUS reasonably well.

As mentioned earlier, a deep longwave trough is currently located over the western CONUS. Curving around the base of this deep trough are a couple of >110-kt 250-hPa jet streaks. Additionally, several vorticity maxima were noted within the trough. An upper-level ridge was located over the eastern CONUS, so Missouri falls right between these two features, setting up southwesterly flow at the upper levels at the time of writing. In the lower levels, the flow was more southerly over mid-Missouri, helping to draw in warmth and moisture from the Gulf of Mexico. At the surface, a strong cold front stretched from Lake Superior into southern New Mexico, with a surface high centered over the northern Appalachian Mountains.

Looking ahead to the forecast period, the GFS shows the upper-level longwave trough remaining to our west during the day today. GFS Skew-T's also show veering with height in the lower levels of the atmosphere this morning, transitioning to southwesterly flow throughout the column this afternoon. The Skew-T's also show some moisture below 850 hPa, suggesting that low clouds will be with us throughout much of the day. All told, today will be another very warm day, with highs near yesterday's high of 76. It is, however, conceivable that Columbia meets or perhaps exceeds the record high of 78 if there is less cloud cover than currently anticipated.

By tonight, the upper-level longwave trough will begin to move east. Along with this, a 250-hPa jet streak should develop and move over the region by Wednesday morning. The GFS shows quite a bit of upper-level divergence associated with this feature. PVA at 500 hPa is also being advertised by the GFS. Additionally, the GFS shows a 50-kt 850-hPa LLJ developing over mid-Missouri during the morning hours on Wednesday. All told, this system has very impressive dynamics. Where this system lacks, however, is moisture. Because of Tropical Storm Eta, a lot of the low-level moisture over the Gulf is being used to fuel that storm, so there is less moisture for this system to draw in. Therefore, low-level moisture will be somewhat difficult to come by. In addition, with it being November, instability is hard to come by anyway. Moreover, the GFS is generated values for CAPE lower than 500 J/kg. Also, with the expected timing of storms being around lunchtime, they will not be striking at peak atmospheric instability. Therefore, while this system has many dynamic factors that could support severe thunderstorms, lack of moisture and instability will temper greatly any chance of severe thunderstorms.

After storms pass Tuesday, the cold front will pass, too, resulting in rapidly clearing skies and dropping temperatures by mid-afternoon. The longwave trough will move in and stay from Tuesday night through the remainder of the forecast period. This will result in much more fall-like temperatures than what we have seen this past week, with clear skies prevailing.

 

No comments:

Post a Comment