Current Conditions at Sanborn Field
Tuesday Night - Mostly cloudy and windy.
Wednesday - Cloudy with a small possibility for showers. Windy. High: 68-72
Wednesday Night - Cloudy. Rain with possible thunderstorms. Low: 54-58
The consistent sunshine we have been seeing for the past couple of days here in mid-Missouri will sadly be leaving us in just a few hours. Temperatures throughout most of the week will still be comfortable, but it's a good idea to bring your umbrella or rain jacket with you if you plan to head outside. Hold onto those umbrellas though, as it will be windy Tuesday night and into Wednesday. The possibility for showers also begins on Wednesday, with increasing chances for thunderstorms to begin on Wednesday night. A cold front will make it's way over Missouri later in the morning on Thursday, bringing with it the possibility for severe thunderstorms and plenty of rain showers. On Friday, the high temperature will be much cooler than seen throughout the earlier part of this week due to the cold front that will pass through the area on Thursday, and the possibility for rain showers will continue into the weekend.
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This forecast was assembled using the 18Z GFS, SREF and GEFS plumes, and GFS soundings. The GFS was chosen because of its initial condition accuracy. While no models have been perfect with the high temperatures in the past few days, the GFS has handled them the best.
The GFS 250-mb plots of heights, winds, and divergence shows that there is plenty of divergence scattered around the central CONUS Tuesday and into Wednesday night. Thursday through the remainder of the forecast period has Missouri entering the right entrance region of the jet streak, soon falling under the influence of a positively tilted upper level trough.
Plots of vorticity and heights at the 500-mb level depict abundant vorticity moving into Mid-Missouri Wednesday night around 03Z, helping spur the increasing cloud cover overnight. The forecast region then lacks any significant vorticity until Thursday morning around 15Z when the passage of a cold front brings more into the area. This vorticity helps contribute to Thursday's rain and potential for severe storms.
700-mb plots of relative humidity depicts why the chances for rain continually increase and decrease throughout the forecast. Abundant moisture is continually in and out of the Mid-Missouri area on Wednesday, which contributes to the cloudy skies but low rain chances. The passage of the cold front Thursday morning finally brings abundant moisture into the area, where it will remain for the remainder of the forecast period. 850-mb temperature and wind plots continue to tell the same frontal passage story. South-easterly winds lead to warm temperatures up until Thursday morning with the passage of the cold front. Due to this, Thursday will see its high temperatures in the morning rather than the afternoon. By the time when high temperatures are usually seen, highs will be in the low to mid 40s.
GFS surface plots of SLP and thickness and soundings tell the best story of this upcoming rain event. Tuesday and Wednesday will be dominated by WAA, leading to the unseasonably warm temperatures. There is also a tight isobar gradient at this time, leading to high winds these days as well. This changes when the passage of a cold front is visible in the plot of MSLP 15Z Thursday. The cold front reaches southeast Missouri, becomes an occluded front, and stalls by 21Z Thursday. The occluded front stays in SE MO until around 15Z Friday, and with the abundant moisture will bring heavy rainfall. If this front were to occlude and stall sooner than predicted, it would increase rainfall potential and alter temperatures significantly, so it is something that future forecasters should watch for.
Soundings were used to determine timing of rainfall, amount of cloud cover, and the potential for severe weather. The highest potential for severe weather comes Thursday with the passage of the cold front. Soundings at this time depict significant omega values, low LI values, and MUCAPE ranging anywhere from 400-600 J/kg. These values create the possibility of hail and, while it is slight, the opportunity for weak tornadic events on the leading edge of the predicted QLCS. It is too soon to be decisive about this event, so future forecasters should definitely keep an eye on it.
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