Hidden Valley Ski Area Snow Report

442 FXUS63 KLSX 150742 AFDLSX Area Forecast Discussion National Weather Service St Louis MO 242 AM CDT Sat Aug 15 2026 .KEY MESSAGES... - Localized flash flooding remains a threat through mid-morning across northeast MO and west-central Illinois, due to ongoing thunderstorms producing heavy rain rates (1-2+ inches per hour). Another round of locally heavy rain is possible (40-60%) in these same areas overnight tonight, although confidence is relatively low. - Dangerous heat is expected again today and tomorrow, particularly along and south of I-70. More widespread heat relief is expected Monday and Tuesday. && .SHORT TERM /THROUGH SUNDAY/... Issued at 236 AM CDT Sat Aug 15 2026 The most pressing item of concern is the ongoing development of thunderstorms across northern Missouri and central Illinois, and the threat of flash flooding that they pose overnight through tomorrow morning. In these areas, numerous thunderstorms have developed and expanded over the past few hours, producing exceptionally high rain rates (2+ inches per hour) within their convective cores. These storms are being forced by a moderate low level jet (25-30kt) interacting with a stalled front, within a regime of extremely high moisture (precipitable water of 2.2-2.5 inches per mesoanalysis). This is very close to observed all-time maximums from the historical sounding database at Lincoln, IL, and is no doubt contributing to very efficient precipitation rates. So far though, the most persistent and strongest showers have remained just north of our area, with only a few showers grazing our portion of northeast Missouri, and we have not seen any substantial "training" as has been observed just to our north and northeast. This activity is expected to continue to develop in these areas, and while we expect the most significant impacts to remain just to our north, we will need to keep a close eye out for a southward outflow surge that could carry heavier rain into our area over the next few hours. These storms are expected to continue to develop for several hours in the same areas, and gradually wind down from mid to late morning as the nocturnal low level jet wanes. For the remainder of the day, the focus shifts to the continuation of extreme heat in many areas, particularly along and south of the I-70 corridor where thunderstorm outflow winds are not expected to provide any meaningful relief. In these areas, yet another day of 105-115 degree heat index values can be expected. However, we did opt to shave a row of counties out of the Heat Advisory in northeast MO and west central IL (Shelby/Marion, MO and Pike, IL), as these areas are not likely to see heat index values above 100 degrees today thanks to outflow winds and cloud cover. This was the case yesterday, and it is more likely than not that we will see something similar today, followed by a surging cold front tomorrow. As such, we felt it was time to pull some of those northern areas from the ongoing Advisory. Otherwise, while we may see a few showers this afternoon, most areas will be dry once this morning`s activity winds down. Overnight tonight, a very similar pattern is expected to unfold across northern Missouri and central Illinois, with a strengthening nocturnal low level jet overriding a stalled surface front, and pooled moisture once again reaching nearly 2.2 inches of precipitable water. Current high resolution model guidance suggests that tonight`s LLJ may be slightly weaker and veered compared to this morning`s iteration, and we suspect that this is the main reason that modeled precipitation amounts are slightly lower. Still, considering the persistence of extremely high moisture and locally saturated soils from recent rain, we will need to monitor this closely for renewed Flash Flooding concerns tonight and tomorrow morning. During the day Sunday, at long last a passing Great Lakes shortwave is expected to both suppress the upper ridge and nudge the stalled frontal boundary southward, although the timing of this feature remains somewhat uncertain. While we do have at least some confidence that this will provide a bit of extra heat relief along the northern fringes of our current heat headlines, this front is likely to be weakening and slowing down as it arrives, and the Ozarks and southwest Illinois are still in line for one more day of similar heat and humidity Sunday. We will also need to keep an eye on the potential for scattered showers and thunderstorms along the front throughout the day Sunday, but especially late afternoon and evening as the low level jet starts to ramp up. Forcing along this boundary is not expected to be very strong, but with such ample moisture in place, it likely won`t take much to force a few showers and thunderstorms with a little added boost from the LLJ. Bursts of heavy rain and occasional strong wind gusts would be the main hazards with this activity, although weak wind shear should limit the overall severe weather threat. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Issued at 236 AM CDT Sat Aug 15 2026 By Monday, the cold front is expected to stall somewhere across southern Missouri, ushering in a relatively mild and dry airmass into most of the area. Confidence is still relatively high that this should provide enough cooling to allow for all of our current heat headlines to expire Sunday evening, although this may not be a slam- dunk in our southernmost Ozark counties depending on where exactly the front stalls. There is still a reasonable potential for a weaker/slower front to stall before it completely exits the area, and if this materializes, places like Reynolds/Iron/Madison counties in southeast Missouri may hover near Advisory levels of heat (100- 105 degree heat index) Monday and Tuesday, before heat returns back north slightly ahead of another cold front Wednesday. In any case, Monday and Tuesday should, for the most part, feature more comfortable temperatures/humidity, and low chances (~20%) for additional showers in the vicinity of the stalled front. On Wednesday, confidence continues to increase that a deeper, stronger shortwave will dig into the Great Lakes, further suppress the central CONUS upper ridge, and send a reinforcing cold front into the area sometime during the day. There remains a high degree of timing variability among members, with LREF cluster analysis unsurprisingly suggesting that a weaker shortwave would lead to a slower/weaker front and warmer Wednesday temperatures. This is also evident in much wider temperature spreads Wednesday, as some areas may actually see another day of Advisory-level heat and humidity Wednesday, while other areas stay relatively mild. The distribution of such will all depend on how quickly this front passes through our area. Meanwhile, confidence is also increasing that this front will bring another round of showers and thunderstorms between late Tuesday and late Wednesday, with at least a modest potential for strong or severe storms. Confidence remains low regarding this potential though, due to both the aforementioned timing uncertainty and limited wind shear. Behind the cold front though, trends continue to drift towards further temperature moderation, although we do note that ensemble spreads remain relatively high, and likewise forecast confidence in the current deterministic NBM temperatures is relatively low. && .AVIATION /00Z TAFS THROUGH 06Z SUNDAY/... Issued at 1043 PM CDT Fri Aug 14 2026 Showers and thunderstorms will continue to move across northeast Missouri and west central Illinois through 15Z on Saturday morning. Have added a TEMPO group with IFR visibilities in heavy rain between 06-10Z. These conditions may need to extended past 10Z. Elsewhere and past 15Z at UIN, mainly dry and VFR conditions are expected. Winds are expected to be less than 10 knots outside of thunderstorms. && .LSX WATCHES/WARNINGS/ADVISORIES... MO...Heat Advisory until 9 PM CDT Sunday for MOZ035-036-042-052. Extreme Heat Warning until 9 PM CDT Sunday for MOZ041-047>051- 059>065-072>075-084-085-099. Flood Watch until 10 AM CDT this morning for MOZ018-019-026- 027. Heat Advisory until 9 PM CDT this evening for MOZ034. IL...Heat Advisory until 9 PM CDT Sunday for ILZ058>060-064-065-098- 099. Extreme Heat Warning until 9 PM CDT Sunday for ILZ069-070-074- 079-100>102. Flood Watch until 10 AM CDT this morning for ILZ095-096. && $$ SHORT TERM...BRC LONG TERM...BRC AVIATION...