Current Conditions at Sanborn Field
Freeze Warning in effect April 22 12:00AM CDT until 09:00AM CDT
Wednesday Night- Partly cloudy with a hard freeze. Low: 28-32
Thursday- Partly cloudy. High: 50-54
Thursday Night - Overcast with rain beginning late. Low: 42-46
Friday - Overcast with rain. High: 54-58
Saturday - Overcast with rain. High: 56-60
Once
again, Central Missouri is under a freeze warning as we can expect
another chilly night tonight. Though it will remain on the cooler side
for this time of the year, we will receive some periodic sunshine on
Thursday in advance of yet another low pressure system bringing rain in
time for the weekend. Once the rain begins late Thursday night, it will
persist until Saturday. While unlikely, thunderstorms are a
possibility during the overnight hours of Friday into Saturday. The
Columbia area should receive between 0.25 - 1.15 inches of rain between
Thursday night and the end of the rain on Saturday.
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This forecast was assembled using the 12Z GFS model due to its consistency with the location of current low pressure systems and the current temperatures. SREF and GEFS were included for QPF and temperature forecasts. There are a couple of rain producing systems that will effect the region over this forecast period.
At the 250-mb level, there are currently two jet streaks that are going to help induce divergence aloft over the forecast period. The entrance region of the northern streak is place over Kansas and stretches to the east coast. The entrance region of the southern streak is placed over the west coast of Mexico with the exit region over the Texas Gulf coast. As time goes on into Thursday evening, the two jet streaks will progress until the southern jet's left exit region couples with the northern jet's right entrance region, encouraging the production of divergence aloft. Friday at 00Z, values of divergence aloft reach about 15/1e5S. As the jets progress eastward through the day Friday, Missouri becomes placed in the entrance region of these jets where abundance of divergence aloft is forecast Friday night and into Saturday Morning.
Looking at the 500-mb chart of heights and vorticity, Mid-Mo is currently located upstream of a trough axis over Ohio. Thursday, a weak amplitude and short lived ridge moves across the area before a short wave trough moves in Thursday evening, which has circulation associated with it. The main low pressure associated with the shortwave will remain well to the north into Minnesota, but will advect vorticity into our region. A deeper trough will move into the region for Friday evening and Saturday, advecting vorticity as well from the southwest with most of the higher values of vorticity staying south of Mid-Mo.
At the lower levels in the atmosphere, there is defined CAA that is currently in place with Northwesterly winds. CAA will continue through today and tomorrow until southerly flow returns by Friday. The trough seen at the 500-mb chart will bring moisture into the region overnight Thursday and the moisture looks to stick around through Saturday afternoon.
At the surface, Mid-Mo will see the effect of the CAA through Thursday afternoon. Given the moisture and lift mentioned above, Columbia could expect rain overnight Thursday into Friday morning. Looking at GFS soundings, this moisture stays through Saturday afternoon, giving the region precipitation through much of this time period. The area could see rain amounts of up to 1.25 inches through this time period. Due to the return of southerly flow, the region will see warmer temperatures than what has been observed the past couple days.
Future forecasters need to watch the progressed of the jet streaks and the low pressure systems bringing the chances of rain. Both GEFS and SREF plumes have a great amount of uncertainty for QPF and CAPE as well. Therefore, watch for the potential for convection overnight Friday.
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