textproduct: Kansas City/Pleasant Hill

KEY MESSAGES

- Accumulating Snowfall Today

- Widespread 1-2 Inches, Areas of 2-4 Inches

- Cold Airmass This Week

DISCUSSION

Issued at 240 AM CST Mon Dec 1 2025

Happy first day of meteorological Winter! We've got snow in the forecast for you!

Modest H5 ridge axis has passed through the area, and has deamplified into a brisk zonal flow regime. Broad surface anticyclone is still in place across the region, allowing a cold airmass to settle as temperatures are hanging around in the teens during the early morning hours. The surface high will actually stick around while the approaching trough moves through the area. The calm surface winds with this anticyclone will actually help snowfall accumulations.

As of 08z positively tilted trough axis is moving across the Rockies this morning, with H3 jet streak extending into Central Kansas, while H5 jet streak currently sits just west of the TX/OK Panhandle Region. There is a surface cyclone attempting to develop in the lee of the Rockies with the stronger dCVA ahead of the trough axis, but is still progged to become disconnected later this morning, which is not unusual for troughs exhibiting a positive tilt like this. The vort max will eject will eastward into the Central Plains and become dislocated from the surface low. Ahead of this trough, flow above 900mb has allowed moisture transport for the past several hours. While the immediate boundary layer remains dry due the polar airmass that moved in, the troposphere between 800mb to 500mb is starting to saturate. At far distances from WSR-88Ds across the Plains, you see some returns. Not much is occurring at the surface though. Some light snow has occurred in Concordia KS, and then a few reports near Colby and Goodland KS. Between 10z-13z this morning, main vorticity maxima moves across Central Kansas, and modest mid-level height falls will start over eastern Kansas and western Missouri. Some weak lift may begin to develop, allowing for initial flurry development in northeast Kansas and northwest Missouri early this morning. It will still take several hours for the entire column to fully saturate. 00z HREF has slowed down the initial timing of potential snow by a few hours. However, synoptic scale models still indicate some potential for initial snowfall. Accumulating snowfall though may hold off until after 12z for even our western counties. Most model soundings show full saturation by 13z-14z. This is also when the 00z HREF 1-hr mean snowfall begins to show a signal for accumulating snow, then slowly moves this eastward through the afternoon and into the evening hours. Late morning through early afternoon is when the primary mid-level vort maximum will also move through. Strong 700-500mb Q-vector convergence is still depicted along the leading edge of this, and this will be the primary forcing for precipitation for this snowfall event. This is also roughly where the DGZ will be located, and both synoptic scale models and CAMs show an uptick in omega through the DGZ along this feature, which explains the favorable timing for accumulating precipitation as the afternoon and evening progresses. Most of the forecast area is still looking at a widespread 1-2 inches of snowfall, with a band of 2-4 inches primarily just north of the Missouri River. Model consensus for the location of this heavier band has become better over the past 12-18 hours, especially compared to the model cycles last night that had a difference of nearly 100 miles. The most notable change to the forecast this morning, is increased snowfall to the south-southeast of the heaviest snowfall axis. While the past few CAM cycles have slightly decreased snowfall totals, there had been an upward trend from yesterday afternoon's model cycles. NBM, GEFS, and other ensemble suites probabilities for at least 2" of snow along and south of Interstate 70 east of the Kansas City Metro increased to around 50 percent. With a stronger signal for convergence along the short-wave further south-southeast, the Winter Weather Advisory has been expanded with this forecast update to now include Johnson [MO], Pettis, Cooper, and Howard Counties from this afternoon through late Monday night. This is mainly driven by the increased probabilities for 2 inches of snow. The past few days, the probabilities for exceeding 1 inch were fairly low, but confidence has increased enough to warrant expansion of the Winter Weather Advisory. Further, afternoon commute along I-70 may be impacted by hourly snowfall rates of 0.50 to 0.75 inches.

Let's take a deeper dive into this 2-4 inch band we are seeing a signal for north of the Missouri River. As mentioned before, HREF and GEFS both show this area between the Missouri River to just south of Hwy. 36 for a few runs now. Looking at cross section analysis of the RAP, GFS and NAM, this is where the greatest magnitude of omega is showing lift through a large portion of the DGZ, allowing for healthy dendritic growth that will push snow ratios in this cold column upwards of 14:1. Yesterday's model cycles were showing the potential for stronger FGEN processes, which is usually a positive enhancement of snow to liquid ratios resulting in higher snowfall accumulation. However, those FGEN signals have actually gone down. Within this same region, EPV values show a few pockets that dip down to zero or just slightly below it, but generally speaking are not screaming strong conditional symmetric instability (CSI) release, with may limit the ability for a robust mesoscale band to develop. The heavier snowfall is largely being driven by the healthy lift through the DGZ. Will point out that the probability matched mean field in the 00z HREF, does depict and area of 4-6 to inches north of the Missouri River to around Hwy. 36. These PMM values are likely showing a reasonable outcome for very localized pockets of heavier snow within the area we are anticipating 2-4 inches for. If there was a clearer signal for a strong FGEN band or some kind of CSI release, would have more confidence to call for 4-6 inches in the forecast. However, with the current data analyzed, this is not the case. As this event unfolds, this will probably be the mesoscale analysis challenge of the day, tracking to see if a localized FGEN band is able to develop or some kind CSI release. That is likely the condition needed to get that 4- 6 inch measurement somewhere. Some CAM guidance attempt to place this elevated snowfall range in northern Platte and Clay Counties, while another takes that pocket but places it in Ray and Carroll Counties. Therefore, due the lack of a clear FGEN or CSI signal, along with inconsistent placement amongst high resolution guidance, have kept the Winter Weather Advisory as is for the area of likely 2- 4 inches. At this time, there is not enough confidence to warrant a need for a winter storm warning.

The main trough axis and vorticity maxima exits the forecast area between 00z-01z this evening, and moves east of the Mississippi River after 03z. Accumulating snowfall should end for our eastern counties in central Missouri between 02z-03z. A few flurries may still be ongoing.

Very modest mid-level ridge moves across the area on Tuesday, and surface anticyclone gradually shifts eastward toward the Ohio River Valley. While low-level flow will attempt to turn southerly, the appreciable WAA will stay far south in the southern Plains. We may see temperatures Tuesday and Wednesday climb back above 30F. Another trough moves across the western CONUS Wednesday into Thursday which will provide northwesterly flow across the northern Plains. Stronger cyclone attempts to develop in the southern Plains. Across the northern Plains strong anticyclone reinforces an Arctic Airmass toward the area. Depending on where forcing sets up, we may see some convergence toward the end of the week that brings additional precipitation potential. Ensemble suites are showing low-end probabilities for detectable precipitation late Thursday into Friday.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1123 AM CST Mon Dec 1 2025

Poor overall conditions remain blanketed across the TAF sites, with visibilities often less than 1 mile due to falling snow and ceilings often around 1kft at the moment. Conditions will gradually improve over the next few hours, but too will remain well below VFR until around 00z as back edge of snowfall drifts eastward. Winds, fortunately, light to variable throughout. VFR conditions attempt to return overnight, but depending on how the cloud deck behaves, there is some uncertainty on that exact time overnight into Tuesday morning.

EAX WATCHES/WARNINGS/ADVISORIES

MO...Winter Weather Advisory until 6 PM CST this evening for MOZ001>005-011>014-020>022-028>030-037-043-053. Winter Weather Advisory until 9 PM CST this evening for MOZ006>008-015>017-023>025-031>033-038>040-044>046-054. KS...Winter Weather Advisory until 6 PM CST this evening for KSZ025- 057-060-102>105.