Area Forecast Discussion
Issued by NWS St. Louis, MO
Issued by NWS St. Louis, MO
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
588 FXUS63 KLSX 300447 AFDLSX Area Forecast Discussion...Updated Aviation National Weather Service Saint Louis MO 1047 PM CST Thu Jan 29 2026 .KEY MESSAGES... - Snow remains likely across parts of east central Missouri into southwest and south central Illinois this evening. Little or no accumulation is expected in most locations, however a narrow band of 0.5 to 1 inch is possible. - Another round of very cold weather is expected this weekend. Wind chill values of -10 to -15 degrees are possible Saturday morning. - There will be a chance for snow on Sunday. Accumulations, if any, are expected to be light. Another round of precipitation is possible Tuesday and Wednesday. && .SHORT TERM... (Through Late Friday Night) Issued at 258 PM CST Thu Jan 29 2026 The primary concern in the short term remains accumulating snow this afternoon and tonight. A band of precipitation is drifting across northeast Missouri and west central and south central Illinois at this time. The vast majority of this precipitation is not reaching the ground at this time, although a webcam in La Plata showed a few flurries, and there was one mPING report of snow from western Ralls county. ACARS soundings from KSTL are showing a dry layer from the surface to around 7000 feet which is evaporating the snow before it can reach the ground, and the layer is represented pretty well in model soundings this afternoon. While the dry layer is being reinforced through a northeast wind, model soundings show it gradually moistening late this afternoon into the evening, primarily along and south of I-70 in east central and southeast Missouri into southwest and south central Illinois. Still seeing a good deal of mid-level frontogenesis in the models from 850-700mb this evening to keep generating precip, so have kept likely PoPs in the forecast this evening in the aforementioned areas of Missouri and Illinois. There is less QPF in the guidance than there was yesterday, most likely due to more evaporation in the dry low levels, so have lowered snow amounts marginally. The overarching message remains, most areas will see little or no accumulation, but localized accumulations of 0.5 to an inch will be possible. Any snow that falls should be largely out of the area before 09Z. A strong short wave will move through the Midwest on Friday and Friday night. Strong PVA ahead of the wave will produce a great deal of synoptic scale lift, model soundings show steep low level lapse rates and a saturated layer around 3000 feet. This looks like a classic cold advection stratocumulus set up for Friday afternoon. Clouds linger into the evening and deterministic guidance spits out spotty QPF as the wave passes...mainly outside of our forecast area. Could see spotty snow showers or flurries. However ensemble guidance snows basically 0 chance for snowfall >0.1 inch so will keep mention of snow out of Saturday/Saturday night`s forecast for now. Lastly, the short wave will be dragging another strong Arctic high pressure system behind it through the Midwest and Great Plains. This will bring us another round of bitterly cold air. Friday`s highs will only be in the mid teens to low 20s and Saturday morning`s lows are still looking like 0 to 5 above with wind chill values between 5 and 15 below zero. Carney && .LONG TERM... (Saturday through Next Thursday) Issued at 258 PM CST Thu Jan 29 2026 Little change to the forecast for Saturday night into next week. The Arctic high moves southeast of the area Sunday allowing some milder air to return to the Mid Mississippi Valley with highs approaching freezing. There`s still a chance for some light snow on Sunday, mainly across northern Missouri into central Illinois as another wave passes over the region. The GFS and ECMWF are dry, and have very light QPF respectively. LREF probabilities for measurable snow are 20-40 percent, so the NBM`s 20-30% look reasonable. Monday through next Thursday`s temperatures continue to warm up, although another cold high pressure system will be lurking over southern Canada and the Upper Midwest. This will try to continually funnel colder air south into the Mid Mississippi Valley. Temperature IQRs next week are as wide as 15 degrees in some locations due to uncertainty in the position of the high. Another short wave will roll through the Midwest Tuesday into Wednesday with another chance for precipitation. The GFS and ECMWF vary widely on how much QPF they produce, and the LREF 24 hour QPF ranges from 0 to nearly 0.3 inches at the 25th and 75th percentiles. The wide variance in solutions obviously lends little confidence in the forecast into midweek. Carney && .AVIATION... (For the 06z TAFs through 06z Friday Night) Issued at 1046 PM CST Thu Jan 29 2026 Currently, a 4-7kft stratus deck with very isolated pockets of flurries and light snow showers is still draped from west to east over the area and is now over the St. Louis metro and points south. This band of stratus and light snow is forecasted to continue moving slowly to the south tonight with light northerly surface flow in place. Surface winds will back slightly becoming north-northwesterly by tomorrow with MVFR ceilings still forecasted to move in from the north tomorrow afternoon lasting into the late evening. Confidence remains low (20%) in the occurrence of light snow late tomorrow evening with the current expectation being scattered pockets of flurries resulting in little impact to aviation. As a result, the mention of any snow has been left out for now. Peine/Elmore && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX