Wednesday Night: Heavy rain. Low: 38
Thursday: Morning rain, clearing up for a sunny afternoon. High: 51
Thursday Night: Cloudy. Low: 32
Friday: Decreasing clouds, sunny afternoon. High: 37
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Discussion:
A low-pressure system is moving through central Missouri Wednesday during the day. Mid-Missouri will be seeing the backside of this low bringing rain during the day on Wednesday, ramping up during the night Wednesday. Expect more than an inch of rain between the day and night Wednesday. In addition, colder temperatures will be moving in Thursday night into Friday morning.
Ritsema
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Forecasters: Clark, Ritsema
Date Issued: 2/8/2023 10:30 AM CST
Technical Discussion:
Problem of the day:
A low-pressure system moving through the central United States. Elevated levels of divergence, vorticity, moisture, and vertical velocities will lead to heavy rain in Missouri Wednesday into Thursday morning.
Both the GFS and the NAM were used in the creation of this forecast due to the similarities throughout the forecast period. Temperatures line up evenly, with a small cold bias on the NAM. The position and the path of the low throughout the forecast period is remarkably similar between the two models which gives confidence on the track.
Wednesday, a shortwave in the tropical jet stream will be traversing its way northeast across the central United Stated before being absorbed into the jet stream. Along this shortwave, elevated levels of divergence and elevated levels of vorticity will be great forcing mechanisms for lift. With clouds already in place Wednesday at 15z, this forcing will be key in precipitation production in the upper and mid-levels.
Lower in the atmosphere, at 700mb, moisture moves in at 15z and persists throughout the day and night Wednesday. In addition to the moisture present, there are also raised vertical velocities across the region. At 850mb, moisture and warm air advection can be seen in mid-Missouri throughout the day and night Wednesday. In addition to the other forcing mechanisms in place, this will only benefit rain production in the lower levels.
Soundings suggest PWat values greater than an inch and complete saturation of all levels of the atmosphere between Wednesday 21z and Thursday 09z. More than an inch of rain is expected throughout this rainfall event with the heaviest precipitation occurring between Wednesday 21z and Thursday 09z.
As the low-pressure system begins to move out of the area on Thursday around 18z, all the moisture, vertical velocity, and divergence will also be moving out at the same time. This will lead to a break in cloud cover in the afternoon Thursday before a longwave trough and cloud cover moves in Friday 00z. Moisture continues to build in at the lower levels overnight Thursday, possibly building enough to precipitate early Friday around 09z. The precipitation that could fall would be light snow, melting on impact with the ground.
This longwave trough is fast-moving and will pass through mid-Missouri during the day Friday. The backside of the trough will bring stronger northerly winds at all levels, cooling down Missouri to have high temperatures in the upper 30s.
-Ritsema
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