Friday Night - Cloudy becoming clear. Low: 28-32
Saturday - Sunny. High: 54-58
Saturday Night- Few Clouds. Low: 42-46
Sunday - Becoming cloudy. Possible late evening rain. High: 62-66
Monday - Scattered Clouds. Possibility of rain. High: 46-52
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Discussion:We warm up this weekend as a low pressure system moves away from us and we become under the influence of a ridge. However, this is short lived as we expect precipitation from Sunday night into Monday as another low pressure system comes into from the west of us.
Forecasters: Balkissoon, Munley
Issued: 5:00pm: February 28, 2020
Technical Discussion (The nerdy stuff we are discussing in class)
The WPC Model Diagnostics indicate that a general model blend is preferred with an above average confidence. As such, this briefing we will look at the GFS model in the top down approach and will focus in on the SREF for the accumulative precipitation amounts and temperature trends.
From the 250-hPa map of winds, heights, wind divergence and wind speeds. Today we note that there do not exist any significant upper level divergence over Missouri. We also observe that we sit on a base of a positively tilted trough. This is indicative that the low has not fully developed or matured. However, from Saturday to Sunday we become under the influence of a ridge which can account for the warm up this weekend. There is no significant upper level divergence over us until Monday at 9Z. This divergence aloft can be associated with the low pressure system which, from the model, is located at the SW of us at this time.
From the 500-hPa map of Heights and Vorticity, we observe regions of circulation over Missouri on Saturday at 0Z. This positive vorticity noted is associated with the low pressure to the east of us. As this system moves, we do not see significant disturbance in the atmosphere until Sunday at 18Z. It is around this time, 21Z, after consulting the SREF we observe that rainfall is expected.
From the 700-hPa Height and Omega map, even though we observe moisture Friday night over our domain, we do not see the required lift to support precipitation. This is not the case on Sunday night into Monday where we see moisture but some lift. This is also supported by the GFS skew-T in which there is non-zero CAPE value indicative that there is some upward vertical velocity.
From the 1000-500 hPa thickness and pressure map, we note that we are under the 540 line which indicates that we are above freezing. This line moves to the north of us as we toggle through the weekend. This is also indicative of our warm up. Also, WAA is noted observing the solenoids, as the pressure is seen to increase to the west of us. From the skew-T, we do note our winds backing with height which indicates again, WAA.