Marine Weather and Tide Forecast for Winchester, MO

SHORT TERM
(Through Late Thursday Night)
Issued at 251 PM CDT Wed Mar 11 2026

This morning's cold front has brought an end to our record warm, muggy weather and is ushering in much cooler conditions on gusty northwest winds this afternoon. These winds will die down overnight and clouds disperse allowing temperatures area wide to fall to near or below freezing for the first time in about a week and a half for most of us. Despite plenty of sun and winds turning southwesterly on Thursday, we only warm up into the 50s. That's right about normal for mid March, but it will be some 25-30 degrees colder than yesterday.

Kimble

LONG TERM
(Friday through Next Wednesday)
Issued at 251 PM CDT Wed Mar 11 2026

Late Thursday into Friday, a trough tracks east across the Upper Midwest moving into the Great Lakes Friday morning. The bulk of the precipitation with this trough will be closer to the track of the Upper Low through the Great Lakes, and it's cold enough for snow up there. For our area, though, our brief warm up on southwesterly flow comes to an end as a cold front trailing from behind this system shifts winds back to the north briefly. Southern areas will be warmer than northern areas on Friday as the front arrives quicker up north. All uncertainty on highs Friday (NBM IQR of about 6 degrees)
relates to the timing of the front. We're confident it will be a dry frontal passage for our area. Today's cold front shuts off access to Gulf moisture for a while, so this front arriving so quickly on its heals won't have enough time to pull Gulf moisture northward ahead of it.

The cool air behind this front is not very intense and doesn't last long at all. By Saturday zonal flow aloft across the Rockies and Plains will already begin to initiate return southerly flow over the Southern Plains and Mississippi Valley, pushing the front back north as a warm front. How quickly that warm front lifts north will play a big role in temperatures on Saturday. Clouds along and north of the front keep things cooler, in the 40s, but once the front lifts north and the sun comes out temperatures soar through the 60s to near 70.
So there's considerably more uncertainty on high temperatures Saturday, with NBM IQR as high as 10 degrees in spots. Northern areas are likely to stay in the cool, cloudy weather longer while southern locales are more likely to see the front lift north and feel the full warmth of the day.

The next trough makes its way onshore in the Pacific Northwest Friday and across the Northern Rockies on Saturday. It then digs a broader trough over the Plains on Saturday as the core of the low moves east into the Great Lakes. This time there's more time for the Gulf moisture to recharge ahead of it, developing a broad moist sector. While confidence is high that the surface low tracks to our north, keeping the bulk of the synoptic scale precipitation (wintry)
to our north, there is the potential for instability in the moist sector to produce thunderstorms in the vicinity of the advancing cold front. At the moment, guidance is indicating dewpoints rising into the 50s with weak instability developing (less than 10 percent of GEFS members produce 500 CAPE). For comparison, ahead of yesterdays front dewpoints were in the mid 60s with well over 2000 CAPE. Considering how strong this system is and the wind field associated with it, we can't rule out a severe weather potential developing. But the more limited moisture available is what keeps our expectations low at this time.

Behind the front Sunday, temperatures take another tumble. This time we have access to some truly winter-like temperatures. In fact, there's potential for some of the synoptically driven precipitation wrapping around the back side of the low to bring a period of snow Sunday night as the system exits. It's clear that the primary area under threat for significant snowfall is to the north across Iowa into the Great Lakes, but depending on how the system evolves there could be a brief period of snow down here as well. Currently about 20 to 50 percent of low resolution ensemble guidance produces snow across our region, roughly on par with recent model runs. However, less than 15 percent of members produce enough snow to pose a threat for ground accumulation (0.1 liquid equivalent falling as snow).

The surface high associated with this cold air mass plunges straight south through the Plains, with the core of the cold air pushing through the central US and into our area early next week. While there is the usual amount of uncertainty on just how cold it will be 5 to 6 days out (NBM IQR of 8 to 10 degrees), we are quite confident that it will be cold. In fact, almost winter-like. Mondays highs only in the 30s are even colder than normal high temperatures in mid January. The coldest temperatures are likely Monday night when the surface high is more likely to be overhead leading to calm winds and potentially a clear sky. Current NBM low temperature forecasts bring the entire area down into the teens, but if a clear sky and calm winds develop, sheltered areas could be even colder. Dewpoints in the single digits suggest an even lower floor if those ideal conditions develop. A gradual warm up begins Tuesday, so this late brush with winter only lasts about 36 to 48 hours.

Kimble

AVIATION
(For the 06z TAFs through 06z Thursday Night)
Issued at 1034 PM CDT Wed Mar 11 2026

Dry, VFR conditions will continue through the end of the TAF period. Winds will be variable overnight as a surface high passes over the area, before picking up from the southwest tomorrow afternoon. Winds will become gusty tomorrow afternoon and remain gusty through the end of the TAF period, increasing in speed overnight. Gusts will be driven both by a tightening surface pressure gradient from a strong low across the Great lakes as well as from higher winds 3,000-5,000 ft AGL mixing to the surface.

SPECIFICS FOR KSTL: Strong and gusty winds will prevail from the southwest (190-230 degrees) Thursday afternoon and evening. Confidence in winds sustaining from 210 for more than brief moments over the period in question is low.

Delia

LSX WATCHES/WARNINGS/ADVISORIES
MO...None.
IL...None.