Part III: Several rivers went into flood as heavy rainfall, heavy snow and resultant melting snow all led to higher streamflows in the latter half of April across portions of central and northern Iowa. Flooding at 3 locations including the West Fork of the Des Moines River at Estherville, Emmetsburg and Humboldt remained above flood stage into May 2018.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS DMX wrote it up.
Part III: Several rivers went into flood as heavy rainfall, heavy snow and resultant melting snow all led to higher streamflows in the latter half of April across portions of central and northern Iowa. Flooding at 3 locations including the West Fork of the Des Moines River at Estherville, Emmetsburg and Humboldt remained above flood stage into May 2018. Some of the rivers went in and out of flood a few times during the period. There are 2 parts to this event.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Des Moines, IA wrote its last area forecast discussion before the first event at Apr 24, 10:51 PM CST, 3 hours 54 minutes earlier.
Area Forecast Discussion National Weather Service Des Moines IA 1151 PM CDT Tue Apr 24 2018 ...Updated for 06z Aviation Discussion... .SHORT TERM.../Tonight through Wednesday/ Issued at 336 PM CDT Tue Apr 24 2018 Confidence: Medium to High Main concern this period will be chances for showers overnight. Approaching wave still expected to dive southeast with weakening support over northern Iowa while western/southwest areas still may see enough mechanical forcing to induce some light showers this evening into Wednesday morning. Not expecting much precipitation due to overall lack of forcing and the fact that airmass is rather dry in lower/mid levels right now over the area which will result in some virga in some cases. Hires models suggest a few light showers or sprinkles north this evening but for now will leave mention out due to overall lack of confidence. Trough accompanying this system will track southeast and as expected...slightly cooler air will arrive later tonight into Wednesday over much of the area. Lows tonight will remain mild with lower to mid 30s far north...then into the mid to upper 40s over the south. Highs Wednesday should recover in the lower 60s over most of the region. Clouds overnight will exit from north to south during the morning on Wednesday with a fair amount of sunshine most of the day north and more sunshine after noon over the remainder of the region. .LONG TERM.../Wednesday night through Tuesday/ Issued at 336 PM CDT Tue Apr 24 2018 Confidence: Medium to High There remains some uncertainty with regard to precipitation on Thursday. The Euro and GFS continue to show the northern and southern stream waves diverging within the northwest flow stream with weakening support for showers. The NAM is also much less bullish on precipitation as the front tracks across the region. For now will continue with a blend with slight chances for showers with the frontal passage and monitor trends moving forward. Again today the convective potential looks muted over the region for Thursday. After mins in the 30s to lower 40s Wednesday night afternoon highs Thursday should recover to the upper 50s north to the upper 60s southeast. Beyond Thursday dry weather will again return with warming temperatures through the weekend. Highs by Saturday will warm to the lower to mid 60s northeast to the upper 60s to lower 70s southwest. As a stronger shortwave deepens over the western CONUS H850 temperatures will moderate into the upper single digits to lower teens from Sunday through Tuesday. This should push highs well into the 60s/70s over the area. Also the strength and expansive nature of the western trough should easily tap into both Pacific and Gulf moisture by early next week. Thus a period of more active weather with showers and thunderstorms is expected especially near and beyond Tuesday. Lows will also moderate into the 50s for a few days with 40s and 50s more common from the weekend into early next week. && .AVIATION.../For the 06Z TAFS through 06Z Wednesday night/ Issued at 1151 PM CDT Tue Apr 24 2018 Fairly high confidence that VFR conditions will prevail at the forecast terminals through this period. There may still be sub-VFR restrictions in rain showers that will stay primarily west of a SPW-CIN-LWD line the rest of tonight into Wednesday morning. Skies will begin to clear over northern Iowa tonight with clearing reaching southern Iowa by late afternoon Wednesday. Winds from the north or northeast will generally be light through late Wednesday. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...REV LONG TERM...REV AVIATION...Ansorge
Hazardous Weather Outlook National Weather Service Des Moines IA 337 PM CDT Tue Apr 24 2018 IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075- 081>086-092>097-252045- Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo- Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun- Webster-Hamilton-Hardin-Grundy-Black Hawk-Crawford-Carroll-Greene- Boone-Story-Marshall-Tama-Audubon-Guthrie-Dallas-Polk-Jasper- Poweshiek-Cass-Adair-Madison-Warren-Marion-Mahaska-Adams-Union- Clarke-Lucas-Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne- Appanoose-Davis- 337 PM CDT Tue Apr 24 2018 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...This afternoon and tonight No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Wednesday through Monday River flooding due to snow melt is expected to continue or develop along the upper reaches of the Des Moines River Basin, as well as the Cedar River near Cedar Falls. Flood Warnings remain in effect for these areas. Please refer to the National Weather Service website at weather.gov/desmoines for further details. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be necessary. REV
The national radar mosaic for the moment the first event began.
2 flood. Local standard time, as filed.
The West Fork of the Des Moines River at Emmetsburg crested at 11.39 feet on 27 April 2018 at 3:00 UTC.
The West Fork of the Des Moines River at Emmetsburg crested at 11.17 feet on 30 April 2018 at 11:00 UTC.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2018Every state in 2018This day in weather historyWarnings in Iowa, April 2018
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 751722, 751723.