With today's tempertures topping out around the mid-70s, the rest of the week looks to be a few degrees cooler. A low pressure system over Arkansas will be the driving force for our weather over the next few days. Cloud cover is expected to increase through the overnight hours with temperatures reaching the upper 50s. Tuesday, the chance for isolated showers will return, skies will remain overcast thoughout the day with high temperatures near 70 degrees. Tuesday night, temperatures will drop into the low 60s with winds coming from the northeast at 5-10mph. Wednesday, temperatures will climb back into the high 60s with a chance of isolated storms during afternoon/evening hours. Overnight temperatures are expected to fall back to the low-mid 60s with lingering showers until daybreak.
- Gromada, Alexander
Forecasters: Gromada, Alexander, Gotsch
Date Issued: 10/4/21 05:00 PM CST
This forecast was generated using the NAM 12Z from 4 October. Its handling of the current low pressure system over the midwest and ridge near the Rockies is more accurate than the GFS in this forecast period.The main focus of this forecast is the low pressure system and the scattered showers it will bring to the region.
250mb: Monday night, the open low in southern Missouri will move farther south and slightly strengthen in the overnight hours. Columbia is under the left entrance region and will be under the center line by morning. A ridge over the CO and KS boarders will push farther northeast. Tuesday will see the low stall out over southern Arkansas and become cutoff. The ridge then pushes into Upper-Midwest area. Moving into Wednesday, upper level winds begin pushing the cutoff low to the northeast. The cutoff low moves over the southeast quarter of Missouri in the overnight hours of Wednesday.
500 mb: Increased positive vorticy from the closed low will be present overnight Monday. During Tuesday evening and night, the vorticty will lessen and become negitive. Wednesday afternoon/evening, strong, but isolated, PVA will become present due to the return of the closed low. after the initial passing of storms on Wednesday evening, the PVA will weaken.
700 mb: Monday overnight, moisture pushes in from NE creating cloudcover overnight. Early Tuesday morning, a line of dry air will cause a break in the clouds. As the day progresses, increased moisture will begin piling into the region. This will continue until Wednesday night as the rain will begin removing moisture from the air and taking it to the ground. Rainfall totals on Tuesday are expected to be no more than .25 inch. For Wednesday, precipitation totals could reach up an inch.
850 mb: The Low Level Jet (LLJ) is currently coming from the northeast, maxing out around 30 kt. Tuesday night will see the LLJ weaken until Wednesday where it picks back up. The LLJ at that time will be coming from the east, wrapping around the low pressure system pulling moisture from the Gulf of Mexico.This will be the main source of moisture for the Wednesday precipitation.
Surface: Throughout the forecast period, surface winds will remain calm. Temperatures will be decreasing tonight, overnight into Wednesday. Tempertures on Wednesday will be hovering around the 70s with winds coming from the northeast.
The main area of concern for the next forecastors will be the stalling upper level low stalling to the southeast of Central Missouri leading to increased chances of scattered showers Thursday afternoon.