Current Conditions at Sanborn Field
Thursday Night - Rain stopping around 10pm staying mostly cloudy. Low: 36-40
Friday Night - Overcast with light showers. Low: 48-52
Saturday - Isolated showers beginning in the evening. High: 70-74
Sunday - Mostly clear. High: 56-60
Rain will continue throughout the evening on Thursday with the exodus of the low pressure system currently over the area. Lingering moisture in the area will result in widespread cloud cover over the area for most of the day on Friday. Strong southerly flow of winds will contribute to the rising temperatures we will experience on Saturday. Due to a cold front passage on Saturday night, temperatures will start to decrease as well as increased chances for light rain scattered over Missouri. The moisture and rising air associated with the cold front will further help the chances for isolated showers and storms on Saturday evening into Sunday. Finally on Sunday, due to the cold frontal passage mentioned above, the direction of wind will switch back to northerly early Sunday morning along with a much drier atmosphere resulting in a more cool and calm end to the weekend.
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The GFS was used in this forecast because it produced sea level pressures and temperatures closer to the observed analysis. The focus of this forecast is the longwave trough moving east across Central Missouri and the WAA causing unseasonably warm temperatures on Saturday.
According to the GFS, in the upper atmosphere, there is a jet streak identified at the 250-mb level over Missouri, oriented southwest to northeast. This helped give rise to the storm system that dominated the area on Thursday. By late Thursday night, a shortwave trough from the western United States will push the remaining divergence out of Missouri, forcing the rain out along with it. This shortwave is followed by a more significant long-wave trough that is going to have the most significant impact on the forecast area.
Into the 500-mb level, the short-wave trough is still present, but moves northeast out of the region. The long-wave trough follows in its wake, creating a strong southwesterly flow aloft. Around 00Z Saturday, another short-wave trough passes over Central Missouri. Circulations that accompany this trough, will support rain showers into Friday night. However, due to little moisture in the atmosphere, severe weather will not be likely. As the trough axis approaches from the southwest, strong circulations and upward motion enter the area on Saturday evening. This increases the likelihood of isolated showers and thunderstorms. Sunday experiences pleasant conditions as northwest zonal flow dominates the area.
At 700 mb, there is still a dominant southwesterly flow. Relative humidity plots at this level shows most of the moisture leaving the area Thursday night, as the low-pressure system moves northeast. After the low passes, Central Missouri stays relatively dry until the trough axis travels over the area on Saturday evening. This will give a chance for some precipitation and isolated storms.
At the surface, the low-pressure system continues to move to the Northeast leaving a strong southwesterly flow. In combination with the solenoids seen at the 500-1000-mb thickness and MSLP plot, strong WAA is expected to bring unseasonably warm temperatures on Saturday. A surface low starts to develop to the west of Missouri early Saturday and pushes northeast. Branching off from this low, is cold front that will move through Columbia on Saturday evening. Isolated showers and thunderstorms are possible for the region as the cold front pushes east. Sunday is expected to be cooler after the passage of the cold front, as the winds turn northwesterly initiating CAA.
The future forecast period should focus on the zonal flow that dominates the Midwest.
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