Friday Night - Mostly clear. Low: 30-34
Thanks to IconArchive.com for the icons!
Discussion:We expect warm temperatures this weekend, keeping in trend with what we got this week. This is because we will be under the influence of a ridging pattern. However, a low pressure system coming in from our west will bring with it the ingredients necessary for rainfall, which we are expected to receive throughout our Monday.
Issued: 5:00pm: March 6, 2020
Technical Discussion (The nerdy stuff we are discussing in class)
For this analysis the GFS model was used in the top down approach and for the skew-T runs. For the average temperatures and the precipitation amounts the SREF was consulted. This was chosen as the WPC model diagnostics placed a general model blend with slightly above average confidence within our forecast period (through Sunday 12Z).
From 250-hPa height, wind divergence and wind speed map, it is observed that on Friday at 21Z, there is a trough to the east of us. We however, sit on a ridge on Saturday at 21Z and are located south of the jet which will account for our warmer temperatures. On Monday at 3Z, we do get divergence aloft which is associated with a positively tilted trough coming in from the Pacific. This indicates that this low pressure system is still in its developmental stage. This system is expected to affect us throughout Monday.
Similarly, when we look at the 500-hPa height and vorticity map, we observe on Friday at 21Z, circulation over Illinois, Indiana and Kentucky which is associated with the low pressure system east of us. In our region though, maximum circulation is noted from Monday at 3Z throughout the entire day.
The 700-hPa height and omega map yields no moisture over Missouri throughout the weekend as we are under the effects of the ridging patterns. On Sunday at 15Z, the model projects moisture over us however, there is no lift to support precipitation at that time. Monday at 9Z, though, have both moisture and a significant omega value of 12. This combination of moisture and lift will persist throughout Monday. Consulting the skew-Ts at the aforementioned times, gave similar conclusions where 051 hours out or Sunday at 9am had no lift, saturated layer nor CAPE. However, Monday 3am or 069 hours outwards was pinpointed as the time we are expecting the start of precipitation.
From the 850-hPa height, wind and temperature, we stay above freezing for the entire forecast period. From the 1000-500-hP thickness and MSLP map, we observe that for Monday, in particular, we stay below the 540 line which indicates that we are above freezing and as such the precipitation we are expecting will be in the form of rain. The SREF QPF places that total amount less than three-quarters of an inch.