Coggon, IA Weather

This Hazardous Weather Outlook is for portions of north central Illinois: northwest Illinois: west central Illinois: east central Iowa: northeast Iowa: southeast Iowa and northeast Missouri.

Day one: TODAY AND TONIGHT

Isolated thunderstorms are possible today in far southeast Iowa and far northeast Missouri. There is also a slight chance of thunderstorms tonight across the entire outlook area. Strong to severe storms are not expected today and tonight.

Days two through seven: SATURDAY THROUGH THURSDAY

The probability for widespread hazardous weather is low.

Spotter information statement

Spotter activation will not be needed today or tonight.

Key messages

- Rain chances return today (peaking at 60-90% coverage tonight) and linger into Halloween morning. Isolated thunderstorms are possible today and tonight.

- An active weather pattern early next week will bring rain and breezy conditions to the region, including on Election Day.

Short term

Issued at 103 AM CDT Fri Oct 30 2026

A cloudy and potentially rainy day for much of the area as a warm front over central Missouri lifts northward. Isentropic upglide on the 295-305 K layer along with WAA around 850 mb will support scattered showers (30-50% coverage) and isolated thunderstorms this morning. By the early afternoon, these showers and storms try to move northeastward but dry air in the low levels is expected to limit coverage (10-20%) north of Highway 30. No severe weather is expected, but mostly cloudy skies will keep highs cooler in the mid-50s to low 60s.

After a brief dry period for much of the area, the warm front finally advances northward this evening into our CWA, prompting another round of more widespread showers (60-90% coverage) and isolated storms. Again, no severe weather is expected with this round with the only hazards being periods of heavy rain and a few rumbles of thunder. With dew points climbing back into the mid-40s and low-50s, lows should only drop to those temperatures.

Heading into Halloween, the mid-level remnants of Tropical Depression Vance reaches the Central Plains and Mid-Mississippi River Valley, keeping scattered showers (30-60% coverage) around through midday. Continued cloud cover will cool highs again in the upper-50s to mid-60s. Once the subtropical trough passes Saturday night, shortwave ridging sets in for Sunday. Rainfall totals of 0.25-0.75 of an inch are likely (60-80% chance) through Saturday.

Long term

Issued at 103 AM CDT Fri Oct 30 2026

A mostly dry Sunday is in the cards with highs climbing into the 60s areawide, but some may call this the calm before the storm. Moving into Sunday night, a longwave trough over the western CONUS propagates into the Rockies, deepening low pressure along the Front Range of Colorado and Wyoming. As this mid-latitude cyclone moves into the Central Plains, it will begin to turn to the northeast, but disagreements among the global ensembles still exist on whether the system tracks through the Dakotas/Minnesota or through Iowa. This will have major implications on the location of the warm sector, our rainfall potential, and even severe weather chances. Latest LREF guidance has PWATs across the CWA climbing near or above 1.5 inches (50-70% chance), close to the maximum of climatological values for the first week of November! Regardless of track though, PoPs start to increase on Monday afternoon and stick around into Wednesday night. General consensus among the ensembles favor a cold frontal passage between Tuesday night into Wednesday with northwesterly flow pumping in some cooler, more seasonable air for the end of next week.

Overall, there is great uncertainty in rainfall totals with this system. The latest LREF guidance shows a 1-inch spread between the 25th and 75th percentiles with the 01z NBM having a 60-80% chance of 1+ inches of rainfall through Wednesday morning. One thing is more certain: the winds. Prior to the cold frontal passage, southerly wind gusts of 20-30 mph are likely (70-90% chance) Monday afternoon into Wednesday. Gusts after Wednesday will be dependent on the track of the low pressure. Regardless of solution though, a more active pattern compared the last few weeks is in store.

Aviation

Issued at 1239 PM CDT Fri Oct 30 2026

VFR conditions were observed as of TAF issuance, with some mid- to high-clouds in place and isolated showers. There may be some MVFR visibility reductions at DBQ for the first few hours of the TAF period due to an approaching light shower. Outside of this, we're not seeing much in terms of flight category impacts through this evening area-wide. As we go into overnight tonight, an approaching mid-level trough should result in increasing chances of showers over the area (40-70% coverage), along with lowering ceilings. Confidence in flight impacts remains low overnight, especially for visibility as they will be variable depending on where the showers develop. On the flip side, NBM probabilities of MVFR ceilings is quite low (less than 20%), so decided to keep 2kft clouds as SCT instead of BKN overnight despite the signal in the RRFS guidance for thicker ceilings.

Watches, warnings and advisories

IA: None. IL: None. MO: None.