Monday Night: Partly Cloudy/Cloudy Low: 66°F   

Tuesday: Partly Cloudy. High: 71°F   

Tuesday Night: Chance of Rain. Low: 59°F   

Wednesday: Rain. High: 73°F   

Wednesday Night: Rain slowing later in the night. Low: 60°F   

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General Discussion:   

The atmosphere is in between stability and instability as a split flow pattern begins to take hold of the region bringing with it chance for (although unlikely) severe weather tonight, and rain to the region Wednesday.

Iffrig

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Forecasters: Carrier, Iffrig

Date Issued: 04 Apr 25 5:00 PM CST   

Technical Discussion: 

Key Messages:   

• Split flow in the upper levels of the atmosphere will drive conditions favorable for severe weather but timing will keep that chance low 
• Stay weather aware during the overnight hours of Monday and evening hours of Tuesday.
  

The story of the early half of the week begins in the upper levels. A negatively tilted trough is currently situated over the central plains and will begin to dig into the desert southwest. A jet streak will eventually propagate on the eastern flank of the trough, which in normal conditions will cause it to de-amplify. However in the current atmospheric setup, split flow evident at 500mb and aloft will allow this trough to continue to dig and advance eastward toward Missouri and the Ohio River Valley. This split flow coupled with Missouri being situated in the divergence region of the upper level jet stream will allow for conversion at the surface to begin creating partially cloudy sky conditions as of 4:00 PM Monday and throughout the overnight hours. The surface convergence, in tandem with mid-level vorticity will increase the chance for severe weather tonight and keep the sky conditions mostly the same throughout Tuesday into Wednesday when the probability of rain will increase.

The middle levels of the atmosphere will be the primary mechanism for weather experienced in mid-Missouri for this week. What is not exactly clear at 250mb is more evident at 500mb; a partially cutoff low is creating the aforementioned split flow and will remain in place for the duration. A series of shortwave troughs will begin to impact the region late Tuesday into the evening and overnight hours. These will advect elevated levels of vorticity to the region, although the impact of such will remain negligible at best for severe weather. Models are struggling to maintain a grasp of moisture in the mid-levels as current sky conditions are cloudy while the NAM and GFS would suggest otherwise. However moisture return cannot be ruled out as the trough and low begin to creep East and start to settle and weaken into Wednesday.

850mb and subsequently the surface will help lay out what could be an isolated severe weather event for tonight and the weather for Wednesday. At 850mb a story similar to the mid-levels is unfolding with moisture return taking place in the evening to overnight hours of Tuesday carrying over into Wednesday where the primary weather event will be stratiform rain. The shortwave events evident in the mid-levels of the atmosphere will also usher in omega in the lower levels increasing the likelihood of rain for Wednesday. That being said however, conditions in the evening to overnight hours of Monday are favorable for a severe weather setup. The only concern is the timing and situation of features aloft, namely the low-level and 500mb jet as well as boundaries. Current model runs indicate the two jets streams entering the region split by only a few hours, reducing the chance of severe weather significantly, but, if further runs have these jets impacting more directly then those chances realign. A dry line and cold front situated to the East over central Kansas, provided current conditions and timing stay the same/improve, will act as the forcing mechanisms for storms to fire over Western Missouri that could propagate to the East. Sufficient shear (both directional and speed) in the low levels combined with sufficient 3CAPE, DCAPE, and SRH provide conditions favorable for tornadogenesis.

All that being said, the current atmospheric setup does not favor that outcome, rather potentially some periods of stronger rain. Future forecast shifts should monitor the split flow currently in place along with the cold front advancing through for any storms to fire.

Iffrig