Thanks to IconArchive.com for the icons!
Forecasters: Heaven, Travis, Fox, Balkissoon
Issued: 4:00 p.m. ; October 18, 2019
This weekend we expect to have partly cloudy to cloudy skies. The average temperature ranges from the models outputs, puts us in the upper 40s for the lows of tonight as well as Saturday night. The high temperatures for Saturday and Sunday are 60-64 and 63-67 degrees respectively. Monday's high is below the average temperature over the weekend due to the passage of a cold front associated with a low pressure system north of Missouri. We expect on Sunday night, under 0.5 inches of rain.
Technical Discussion (The nerdy stuff we are discussing in class!)
From the GFS 250mb Wind Divergence map, there is a formation of a low pressure system north-east of Missouri Sun 18z. The max upper air divergence occurs on Monday 12z. Around this period, this coincides with the maximum range of vorticity for our forecast period. There is an area of positive vorticity representative of the circulation associated with this cyclonic development. A comma cloud is noted in the GFS 700mb map of RH in which around 15z on Monday, Missouri is in the dry conveyor belt region of the system. The strong thickness (delta z) is also noted in the vicinity of the low pressure system on Monday when viewing the GFS 1000-500mb thickness map.
From GFS Skew-T analysis, we see that unlike Friday night, the atmosphere shows conditions conducive to rain as Saturday around 9am, areas of saturation is noted in the mid to upper levels (600hPa to 400hPa) and the same on Sunday but in the lower levels (850hPa to 1000hPa). However, from the NAM total precipitation product, rain is expected in the North-Eastern parts of Missouri on Saturday 18z. The maximum range of precipitation occurs on Monday at 7am throughout Missouri with values ranging from 0.26 to 0.90 inches. The NAM is however, over aggressive in its model precip output as both the GREF and SREF mean precipitation amounts from the various model run, saw rainfall value of approximately 0.3 inches.