Marine Weather and Tide Forecast for Apple River, IL

SHORT TERM /THROUGH FRIDAY NIGHT/
Issued at 300 AM CDT Thu Apr 16 2026

Today

A shortwave trough and attendant surface low will shift east of the area today into the Lower Great Lakes. Mid- level height rises and a weak area of surface high pressure will build in through the day, setting up quiet conditions for a change with mainly dry weather expected. Temperatures will remain above normal due to plenty of sun pushing highs into the lower 70s north to mid 70s along I-80 and low 80s in the far southwest.
Today will be a much needed break from the repeated rounds of showers and thunderstorms this week, especially for areas north of I-80 that have been hit the hardest with bouts of flooding.

Friday

Unfortunately, only a short reprieve from the active weather is expected as a deep upper trough and strong cold front move through the Midwest on Friday into Friday night. This system will set the stage for another round of severe storms across the Upper Mississippi Valley region with southerly flow ahead of the cold front advecting an anomalously warm and moist air mass northward. Forecast highs are in the mid 70s NW to mid 80s far south with dewpoints in the ~mid 60s on average, making it feel more like an early summer day than mid April.

The atmosphere will become increasingly unstable into Friday afternoon/evening with SBCAPE building to 2000-3000 J/kg (per the HRRR) which will coincide with notable 500mb height falls/large scale ascent. With the ample instability and sufficient deep layer shear (0-6 km between 35-45 kts), conditions will be favorable for organized convection and severe weather which may come in two rounds. The first round may be the development of isolated to scattered supercells or multicell clusters during the mid/late afternoon along a subtle pre- frontal trough axis, out ahead of the approaching strong cold front. Then the subsequent round looks to come in the form of a robust squall line/QLCS during the evening to early nighttime, bringing with it potential for significant straight-line winds and mesovortices/QLCS tornadoes. Friday could bring some significant severe weather to portions of the area with all severe weather hazards possible; the primary threats being damaging winds (possibly 70+ mph) and isolated tornadoes.
Another potential hazard, given the wet antecedent conditions, is localized flash flooding for areas that get hit by repeated rounds of storms with locations north of I-80 most susceptible.

SPC's latest severe outlook for Friday has an Enhanced Risk (level 3 of 5) area-wide and WPC has a Slight Risk for flash flooding (level 2 of 4). Continue to keep up with the forecast for Friday as we will be able to provide more details on timing, location, and specific hazards.

LONG TERM /SATURDAY THROUGH WEDNESDAY/
Issued at 300 AM CDT Thu Apr 16 2026

This weekend, upper level flow becomes northwesterly behind the aforementioned shortwave. Modest cold advection will kick in, bringing much cooler air to the area. Daytime temperatures are set to be in the upper 40s to 50s through the weekend, which is quite the change to the 70s and 80s we have been seeing. Overnight lows will be in the 30s, with counties roughly along and north of I-80 seeing lows approaching freezing. Thus, our north half or so will have the chance to see a frost/freeze during this timeframe. Dry conditions are expected through the weekend, with mostly clear skies. Breezy NW winds will make it feel rather chilly, especially on Saturday.

Going into next week, it looks like the upper level pattern becomes active again. There remains many differences amongst guidance, but precipitation chances return to the area by midweek, along with increasing temperatures.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
Issued at 1143 PM CDT Wed Apr 15 2026

The widespread thunderstorm activity has moved east and south of the region, though a small area of storms will be near DBQ in northeast Iowa just before 06Z, and a couple isolated showers / possible storms will dot areas south into the night. Thus, a very widely scattered shower could impact terminals, but the majority of time will be dry. Some MVFR cigs are possible in northeast Iowa overnight, as low pressure moves into Wisconsin, otherwise VFR conditions will persist through Thursday into Thursday evening, as very pleasant weather moves in, for just one day before more storms arrive Friday.

DVN WATCHES/WARNINGS/ADVISORIES
IA...None.
IL...None.
MO...None.