Monday - Sunny. High: 74-78
Monday Night - Becoming mostly cloudy. Low: 54-58
Tuesday - Mostly Cloudy. High: 72-76
Tuesday Night - Becoming overcast. Low: 54-58
Discussion: Coming off of a refreshingly beautiful weekend, similar weather can be expected today. Sunny skies and near-normal temperatures will go far in brightening this Monday. Beginning tonight, however, we will begin to experience increasing cloud cover as the remnants of Tropical Storm Beta draw near. Expect high clouds to build in tonight and persist through Tuesday night. By Wednesday, the cloud cover should thicken as Beta's remnant low pressure center makes its closest pass to mid-Missouri. We may even see some isolated showers out of this, although it appears at this time that if there were to be rain, it would be of short duration and light intensity. Because of increasing clouds early this week, temperatures will be slightly cooler each day, but they still will be pleasant.
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Forecaster: Ritter
Issued: 10 AM CDT 21 September 2020
Technical Discussion (The nerdy stuff we are discussing in class)
Welcome back, everyone!
The main issue in forecasting for this period is the behavior of the remnants of T.S. Beta and their potential impacts on
mid-Missouri. The GFS was used for this forecast as it has done well in handling Beta.
Currently, there is very little to speak of occurring over central Missouri. Upper-level flow has been zonal and quite weak
over the past couple of days, and there has been no moisture or moisture advection at the lower levels of the atmosphere.
Additionally, the winds at the lower levels of the atmosphere have been weak and significantly varied in direction, so
there has been no clear thermal advection in the past couple of days either. This resulted in mostly clear skies throughout
the weekend, with nearly the same afternoon high temperatures both Saturday and Sunday. Per WPC surface analysis, a
weak cold front stretches from central Colorado up through the eastern Dakotas, but this front has hardly moved in the
past 24 hours, and it will have no bearing on this forecast. T.S. Beta is also currently positioned off the coast of Texas.
This storm is expected to move inland by tonight, and this feature will have some influence on our weather as it moves
into the south-Central US this week.
Looking ahead to the period Monday through Wednesday, the overall weather will become a bit more active in response to
the remnants of T.S. Beta. Flow at 300 hPa will remain weak and zonal, but an offshoot disturbance from Beta will create a
shortwave trough and generate a vorticity maximum at 500 hPa over southern Missouri Tuesday, which will deepen and
move east Wednesday. Per GFS Skew-T's, the initial development of this shortwave trough should cause high clouds to build
in as early as overnight tonight. As the trough deepens into Wednesday, this should introduce better low level moisture into
the region by Wednesday, as evidenced by increasing 700-hPa and 850-hPa moisture forecasted by the GFS during this time
frame. This will result in lowering clouds Tuesday night into Wednesday. By Wednesday, low level moisture looks healthy
enough to support some drizzle/light rain showers during the day. The better chances for widespread rain and higher rainfall
totals look to be confined to southern Missouri at this time.
As for temperatures, due to abundant sunshine and southerly surface winds, today should be the warmest day of the period,
with a high temperature in the upper 70s. As cloud cover generally increases each day this week, each day will be a couple
degrees cooler than the previous. Given both nights during this period will have similar cloud cover, similar low temperatures
in the mid- to upper-50s can be expected both nights.
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