Marine Weather and Tide Forecast for Hettick, IL

SHORT TERM
(Through Late Monday Night)
Issued at 205 PM CST Sun Jan 18 2026

A weak northern stream system will move southeast from the Upper Midwest through west-central and central Illinois this evening.
While mid-level saturation (750-500mb) and ascent are present, dry air below 750mb will prevent much more than isolated flurries, if that. Aside from flurries, thicker cloud cover will be the end result from northeast Missouri through southwest Illinois. Even drier air over central and southeast Missouri trend toward mostly clear skies tonight.

A cold front trailing this system will bring a reinforcing shot of cold air and increasing winds late this evening. The front's southward progression is expected to stall, keeping the core of the coldest air to the north. Lows tonight will be similar to last night. However, winds will be the difference with HRRR probabilistic guidance showing speeds exceeding 15 mph (>60% probability) from Kirksville, MO, through Alton and Mt. Vernon, IL. These factors will result in wind chills between -10 and -15 degrees. Recent HRRR ensemble guidance shows 50-60% probabilities for -10 wind chills now extend just south of I-70 in Illinois.
Therefore, I've added Madison, Bond, Fayette, and Marion Counties to the cold weather advisory, which will go into effect at 3AM-10AM Monday morning.

High pressure moves southeastward, centered near the OK/AR border Monday, with winds gradually subsiding and backing from the northwest to the west-southwest to southwest in the pre-dawn hours Tuesday. While warm air advection will begin to pull milder air in from the southern Plains, it will not arrive in time to prevent another cold night with lows in the upper single digits to low teens early Tuesday morning.

Maples

LONG TERM
(Tuesday through Next Sunday)
Issued at 205 PM CST Sun Jan 18 2026

On Tuesday, the surface high will broaden and center over the western Gulf as a shortwave trough moves into the central Plains.
This will enhance warm air advection, with west and southwest flow drawing on milder mid-level temperatures. While air will be seasonably milder (5C at the Front Range vs. -5C Locally), the approaching trough drags another cold front through the region, which stymies the northward advancement of warmer air, maintaining a more westerly flow component. Temperatures return to near normal on Tuesday, ranging from the low 30s to low 40s.

Wednesday is expected to be the warmest day of the week, with temperatures rising into the upper 30s and mid-40s. Parts of southeast Missouri and southwest Illinois may flirt with 50 degrees as the warm mid-level air mass extends along and south of I-70. As the shortwave tracks east into the Ohio Valley by Wednesday night, it will reinforce colder air, dropping high temperatures by 5 to 10 degrees for Thursday.

The forecast becomes more complex late in the week as a stalled front creates a sharp temperature gradient, ranging from the mid-20s near the MO/IA border to the low 40s in southeast Missouri. Long- range guidance remains inconsistent due to uncertainty regarding boundary placement and the organization of impending disturbances.
Currently, deterministic ECM and GFS models show a cutoff southwestern upper trough off the Baja Peninsula, while northern stream disturbances continue to affect the northern U.S.

The late-week pattern is not conducive to deep, organized systems, but it may eject multiple fragments of vorticity eastward from the southwestern upper trough/low. These disturbances tend to track along and over top the stalled boundaries. Key limiting factors include the position of the Gulf high, which restricts moisture return, and southward reinforcements of cold air with each successive shortwave. The weak La Niña pattern suggests systems often become better organized as they reach the eastern trough and take advantage of strong baroclinicity. That being said, while a stark, north-south temperature gradient exists in this timeframe, there are no strong signals supportive of intensification, more specifically over the mid-Mississippi Valley. One area of higher confidence is in temperature trends. The strong cold front that arrives late Friday brings a significant cooling trend toward the end of the week into next weekend. Despite wide IQR spreads as much as 15 degrees, IQR plots show a distinctive drop in temperatures through next weekend with highs in the 20s and lows in the single digits.

Maples

AVIATION
(For the 00z TAFs through 00z Monday Evening)
Issued at 530 PM CST Sun Jan 18 2026

Th primary concern during the 00Z TAF period is wind, as a reinforcing cold front will push through the area this evening/overnight and bring a round of gusty northwest wind. Wind speeds are expected to be strongest prior to sunrise, but will remain breezy through much of the day tomorrow. Wind speeds are expected to diminish considerably by late afternoon tomorrow.

Otherwise, some patches of VFR stratocumulus will move through terminals this evening and overnight, but flight category reductions are not anticipated.

BRC

LSX WATCHES/WARNINGS/ADVISORIES
MO...Cold Weather Advisory from 3 AM to 10 AM CST Monday for Knox MO- Lewis MO-Marion MO.

IL...Cold Weather Advisory from 3 AM to 10 AM CST Monday for Adams IL- Bond IL-Brown IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL- Jersey IL-Macoupin IL-Madison IL-Marion IL-Montgomery IL- Pike IL.