textproduct: Kansas City/Pleasant Hill

KEY MESSAGES

- Very warm temperatures are expected by the middle of the week, with record highs in jeopardy on Thursday.

- Dry weather is expected to continue through the upcoming weekend.

- Fog is expected to develop tonight, particularly in river valleys and cooler rural locations.

DISCUSSION

Issued at 203 AM CST Mon Dec 22 2025

We are on the cusp of a weather pattern I like to call ridge city -- a broad, high-amplitude ridge controlling much of the CONUS weather for a streak of days. This will bring exceptional warmth to the central U.S. during the midweek period, which has long been advertised. However, as the event draws nearer, there are a couple of finer-scale details that require some fleshing out, and one of them will be transpiring in the next 24 hours. Models have been projecting a low-amplitude perturbation moving through the northern U.S. early this week, and over time there have been increasing hints of its influence farther and farther south. We are seeing this come to fruition this morning, with return flow well-established and a stratus deck developing to our south and southwest. This has already moved into southwestern portions of our forecast area this morning, and will likely persist through much of the day, particularly in southern portions of the area. However, dewpoint depressions are around 30 degrees early this morning, and models appear much too aggressive in saturating the near-surface layer. Thus, a cloud deck is about all I expect from the weak ascent glancing our region in advance of the perturbation today. However, this may curtail the strength of the warming forecast by a majority of the model suite today, and I am wondering if highs in the upper 50s to lower 60s may be a little too optimistic. Will have to keep an eye on this today, as it may turn out this will be a day where temperatures end up a few degrees below consensus, despite the persistent warm advection in advance of the vort max.

The synoptic front will approach the region tonight, with the steady south breeze diminishing and veering to a more easterly direction by tomorrow. With the warm advection today followed by rather weak/nebulous surface flow tonight, lows tonight should be warmer than what we saw early this morning. As the warm advection ceases, skies should begin to improve as well (which may occur as early as mid-afternoon today). This will set the stage for some fog potential. HREF probabilities of visibility below a half mile are very high for almost 24 hours in advance (60-80 percent) in much of the CWA. Other guidance is less enthused (NBM has probabilities generally lower than 20 percent for <1 mi visibility). My experience with these types of scenarios is that it is entirely dependent on the passage of the vort max. If the vort max is in the vicinity of the region, fog tends to be very unlikely to materialize extensively. In tonight's scenario, the southern extent of the perturbation is expected to be well east of the area, and given the surface saddle point of pressure that develops (corresponding to a weak or nearly nonexistent pressure gradient), this looks pretty favorable for fog. Have included mention in the forecast with this update, and I suspect the forecast will need to get more aggressive with coverage/extent wording later today.

The forecast for Wednesday and Thursday continues to look anomalously warm for our region, but there are some question marks remaining with just how warm, especially on Wednesday. Guidance appears to develop another extensive cloud deck Tuesday night into Wednesday across the central Plains. This appears to be tied to a region of strong warm advection in advance of another weak perturbation ejecting from the western U.S. during this period. These cloud decks tend to be rather stubborn, so it is quite possible diurnal heating is muted considerably on Wednesday, and the warming will almost entirely be a result of the warm advection. Highs in the 60s are assured for much of the area, but it may be rather challenging to hit 70 if overcast conditions refuse to give way.

However, Thursday's warmth looks more and more impressive, as the pattern is more favorable for more sunshine, and the ridge axis will be in close proximity to the region. Record highs look to be in serious jeopardy for Christmas Day.

The forecast after Thursday continues to pose some challenges. Models have wobbled rather substantially in the past 24 hours with the vort max moving through the northern U.S. Most models have trended toward less cooling following its passage through the region for Friday and Saturday (with highs returning to the 60s versus the cooler 50s that consensus was depicting from yesterday's runs), but confidence seems low given the lack of run-to-run continuity observed for this period. It does appear that the upstream system moving into the northern U.S. this coming weekend will be strong but very progressive, which means we might expect more of a wind event than a precipitation event in this portion of the country. Indeed, the pressure gradient that becomes established by Saturday afternoon may be quite strong given the strength of the upstream high. By Sunday, the 70s of Christmas Day may be a long-distant memory as highs return to reasonable...that is to say seasonal. However, upper ridging to our immediate west and southwest never really goes away, so the pattern continues to look mostly warmer than average through the rest of the year. As mentioned in yesterday morning's discussion, the overall pattern in the U.S. also does continue to look more active on New Year's week.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 503 AM CST Mon Dec 22 2025

MVFR stratus deck has moved in from the southwest this morning and is expected to persist for the next couple of hours before lifting to VFR and eventually dissipating this afternoon. Confidence is not high on timing of improvement, and ceilings may bounce from VFR to MVFR often this morning. A steady south wind around 10 to 15 kt with occasional gusts 20 to 25 kt is expected through early afternoon before diminishing to 5 to 10 kt after 21z. VFR and light winds should be prevalent from 00z to 06z, but some fog may develop after 06z (especially STJ and IXD). Probabilities of IFR fog are fairly high (50-75%) after 09z, but was conservative with the forecast at this point since confidence with timing and coverage is still low at this point.

CLIMATE

Issued at 220 AM CST Sun Dec 21 2025

Record High Temperatures:

December 24: KMCI: 72/2021 KSTJ: 69/2021

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

Record High Minimum Temperatures:

December 25: KMCI: 53/1936 KSTJ: 51/1936

EAX WATCHES/WARNINGS/ADVISORIES

MO...None. KS...None.