Tuesday, September 10th – Afternoon Forecast

Tuesday Night: Mostly Clear. Low: 59°F

Wednesday: Mostly Sunny. High: 87°F

Wednesday Night: Clear. Low: 64°F

Thursday: Partly Cloudy. High: 85°F

Thursday Night: Overnight Rain Possible: 64°F

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General Discussion:

Current conditions will persist with warmer temperatures and southerly winds until Thursday, when cloud cover and moisture move into the area. Chances for rain increase by Thursday night into Friday morning.

-Hayes, Schifferdecker

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Forecasters: Hayes, Schifferdecker, Jackson

Date Issued: 09/10/2024 5:00 PM CDT

Technical Discussion:

Key Messages: 

• High pressure will be keeping us warm and calm with a southerly flow for the next couple of days.
• The current tropical storm Francine will be making landfall by 9:00Z-12:00Z Wednesday, and will be bringing cloud coverage and possible rainfall to the area by 0:00Z – 6:00Z Friday morning. 

The NAM and GFS were used in this forecasting process as they were in general agreement for the trends noted. 

At 250 MB, a high pressure system and western zonal flow resides over the Midwest area, bringing in a slightly warmer trend for temperatures. This trend is consistent throughout the different levels of the atmosphere, as it siphons off moisture and vorticity until after 12:00Z on Thursday.

 General flow across Missouri stemming from the west transitions into a southerly flow by this time Thursday. Despite southerly flow, we will still experience limited upper level moisture. Small amounts of divergence at 500 MB may usher in mid-level clouds Thursday, as increasing vorticity moves through southern Missouri. Differences in the NAM versus GFS bring slight uncertainty to this situation, as the NAM Predicts both an increased level of vorticity as well as more 850 MB level moisture content than the GFS model. However, both agree on the general trend of the high pressure system persisting until Thursday. 

Throughout Thursday, we will be seeing upper level cloud cover increasing throughout the day, and this will be due to the remnants of Francine moving in from the south. Francine will fully move into Missouri by Friday at 0:00Z. Vorticity at 500MB increases along the ridge, impacting areas by Thursday 15:00Z- 18:00z. Omega follows closely behind the low, remaining southeast of the area. This will increase the chances for rainfall, though amounts are predicted to reach less than 0.05 inches. This is because the system is expected to pass slightly east of us, and so better rainfall will be held off to the east as well. 

-Hayes, Schifferdecker