Thursday, December 5, 2019




Thursday- Sunny, Increasing PM Clouds. High: 56-60

Thursday Night- Cloudy with possible rain. Low: 34-38


Friday- Cloudy, AM rain, PM clearing. High: 40-44

Friday Night - Partly Cloudy. Low: 34-38

Saturday- Mostly Sunny. High: 46-50











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Discussion: 
Today, the sun will stick around for most of the morning hours. Temperatures will warm up for today, but won't stick around. Clouds will increase throughout the evening hours into Thursday night because of a cold front pushing its way into the area. That will bring with it the possibility of rain, but mainly sticking south of I-70. As the cold front passes Friday morning, temperatures won't be warming up as much. Winds will be coming from the North and clouds will stick around for the majority of Friday. Clouds will move out in the overnight hours leaving Saturday to be mostly sunny with winds switching to the south.
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Forecasters: Munley, Gallahan, Pauley
Issued:  10:00am December 05, 2019

Technical Discussion (The nerdy stuff we are discussing in class)
WPC model guidance recommends going with Non-CMC blend with 00z mean GEFS for temperatures, so 06z GFS was used with 00z GEFS mean for temperatures.

The main feature for this forecast period is the increasing cloud cover this afternoon, the possibility for rain overnight, and a cold frontal passage for Friday morning.

The calm weather that the Mid-Mississippi Valley region is experiencing today is due to the flow at 250mb being zonal. This begins to change some this evening as clouds will start to move into the area which will usher in the possibility of cloudy skies and possible light rain overnight. The confidence in the potential for rain looks low. This is because there is a lack of UVM at 500mb. The values for UVM are less that 2 ubar/s, so we lack lift in the atmosphere. The 700-mb RH values of upwards of 100% look promising, yet there is also a lack of moisture in the column to work with as PWAT values struggle to reach 1 inch. Lastly, the 06z GFS soundings show the column being saturated from 300mb down to 700mb, yet there is a dry column of air from 700mb to the surface. This indicates that there will just be cloud cover. The main feature though is that the surface low looks to track to the south in central and southern Arkansas. With all those factors, any rainfall received will be light and scattered in nature. What is for certain is that there will be a frontal passage late tonight into tomorrow morning. This will switch our winds to out of the North giving us a backing wind profile leading to CAA occurring overnight as well. The CAA will drop high temperatures for tomorrow ten to twelve degrees colder than today. Cloud cover will also remain in place for a majority of tomorrow. The low level clouds will begin to move out tomorrow afternoon, but the high level cirrus will remain into tomorrow night. The sky will begin to clear out after 9pm tomorrow night which will give us sunny skies Saturday and high temperatures back to near seasonal average.

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