textproduct: Kansas City/Pleasant Hill

KEY MESSAGES

- Dense fog will continue across the region through this morning. Conditions should improve during the afternoon.

- Very warm and dry conditions continue through Saturday. Record highs may be approached, but the extent of cloudiness increases uncertainty in the temperature forecast, especially today and Saturday.

- Much colder and windy on Sunday. There are increasing signs of precipitation chances on Sunday as well. Wind chills in the single digits above and below zero are forecast Sunday night and Monday morning.

DISCUSSION

Issued at 236 PM CST Wed Dec 24 2025

Broad ridge is still prominent across the Central CONUS this afternoon and will continue to be through Friday. PV anomaly over the Pacific has shifted further eastward, and H5 trough is starting to approach the coast of California. This is sending several localized vort maxima across the Intermountain West and into the Front Range. The persistent nudges and shots of dCVA has been enough to maintain a surface low over the Central Plains and keeping lower tropospheric flow southerly, along with plenty of moisture transport from the Gulf. Fog and stratus over the past couple of days resulted in stronger differential heating across the forecast area, so along with periods of weak and strong WAA, have placed a boundary which so far today has moved northward as warm front to around Interstate 70. It took a while but finally started to see some breaks in the cloud cover. However, after sunset tonight, the low over the Plains stalls and eastward surface trough does as well, resulting in weaker pressure gradient in the Lower Missouri River Valley. With plenty of moisture still in place and perhaps some pooling along the thermal boundary, this is setting up another favorable scenario for fog, that could start as early as 03z-04z this evening and continue into Thursday morning. HREF probabilities have been fairly high for dense fog between Hwy. 50 and Hwy. 36, especially during the pre-dawn hours of Thursday. Given this strong signal in the probabilistic fields amongst ensemble members, persistence, and little actual change to the pattern, have issued a Dense Fog Advisory this evening for most of the area. Counties further south of Hwy. 50 are currently not included, and counties that border the Iowa state line have also been excluded. However if the warm front does move further north and results in better moisture transport through the evening, dense fog may find its way into far northern Missouri. There is also potential for drizzle along the warm front where there may be a little extra lift for a few hours late tonight, and the first kilometer from the surface upward completely saturated. Drizzle occurrence may delay the onset of fog in some locations, but by Thursday morning should come to an end to allow fog to develop.

Unsure how long the fog will last into Thursday afternoon, as these past few fog events have been a hybrid of both advection, and radiational cooling, processes. The amount of upper-level cloud cover may also play in role in how efficient mixing can start to erode the fog and low-level stratus. This will also have important implications for high temperatures on Thursday. WAA will still keep conditions well above normal for this time of year, but an increasing signal for lingering cloud cover especially along the Interstate 70 corridor and northward may keep things below daily records. This may largely depend on the movement of the boundary. Areas south of Hwy. 50 perhaps could see some clearing if the front pushes well northward, and if the low deepens could help increase wind. This is likely the area to reach the 70 degree mark if any points in our forecast area are able to achieve it. But compared to what model guidance was projecting before this pattern setup here, it is notably cooler. Friday morning, the ridge axis deamplifies as more vorticity advection occurs over the Intermountain West, and works to deepen the surface cyclone. Southerly flow strengthens again and pushes the warm front toward the Iowa state line, or, perhaps even further into Iowa. This will provide another warm day. This continues into Saturday. The main H85 thermal ridge axis will pass through Saturday, maintaining temperatures into the mid 60s, though far northern Missouri may only see the upper 50s. A dry airmass will likely move through early Saturday morning, but cooler temperatures are not progged to occur with a subtle boundary moving through. Clearing skies and returning southerly flow with another wave moving through will keep conditions warm.

Sunday, deeper H5 trough travels into the Front Rockies, and pushes the the low pressure toward the Great Lakes Region, with stronger lobe of vorticity moving toward the upper Midwest. A strong surface anticyclone trails this feature dropping southeastward from Canada, bringing a strong polar airmass into the CONUS. This strong cold front moves through the lat afternoon hours, and will drop temperatures to below late December normal values. Ensemble guidance has pulled some low end probabilities for rain and rain-snow mix into our eastern counties, but currently does not depict much in the way of accumulation. The main story on Sunday will be the gusty northwesterly winds, along with major temperature swing. This will lead to cooler conditions through next week. We will need to monitor this system, if that H5 trough digs further south, we could see more surface convergence that could bring more precipitation late Sunday.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1126 PM CST Wed Dec 24 2025

Dense fog has overspread the terminals this evening, and is expected to continue through 15z or so. Conditions are expected to improve in the 15z to 18z time window, but there is substantial uncertainty in timing. Lingering MVFR/IFR ceilings may last through 20z to 22z (especially at STJ; 30 to 60 percent chance), but confidence is low. When improvement occurs, conditions may go from VLIFR to VFR in very little time. With this in mind, expect several TAF amendments on Thursday given the high uncertainty. Regarding winds, light and variable through the morning, becoming southeast or south around 10 kt after 18z Thursday, switching to a southwest direction around/after 00z. There may be a window of deteriorating conditions again Thursday evening, but confidence is very low owing to the passage of a system to the north of the area. Once its passage occurs (around 06z Thursday), chances for restrictions diminish markedly.

CLIMATE

Issued at 157 AM CST Tue Dec 23 2025

Record High Temperatures:

December 25: KMCI: 67/1922 KSTJ: 65/2019

December 26: KMCI: 66/2008 KSTJ: 65/2008

EAX WATCHES/WARNINGS/ADVISORIES

MO...Dense Fog Advisory until 10 AM CST Thursday for MOZ001>008- 011>017-020>025-028>033-037>040-043>046. KS...Dense Fog Advisory until 10 AM CST Thursday for KSZ025-057- 102>105.