What in the Weather?

This one's for you if you want to understand weather better! Join Dan Fillius, Iowa State University Extension Horticulture Field Specialist, Madelynn Wuestenberg, ISU Extension Ag. Climatology Specialist, and Dr. Justin Glisan, Iowa’s State Climatologist, as they discuss what is happening in the world of Iowa weather. Every week during the main growing season we'll discuss recent weather, its impacts on fruits and vegetables, and provide a climate outlook for the coming week in Iowa. Let us know what you think, though as Mark Twain once said, "If you don't like the weather, wait a few minutes."

11/6/25 - Killing Frost this weekend...then warmer again 11/06/2025

10/23/25 - So...about that frost that just happened 10/23/2025

10/16/25 - Widespread frost not likely until November 10/16/2025

10/9/25 - Maybe no frost 'til last week of October? 10/09/2025

9/25/25 - Frost before Oct. 11 not likely 09/25/2025

9/17/25 - How bad was the summer this year? 09/17/2025

9/11/25 - Summery Weather Ahead 09/11/2025

9/4/25 - Summer Season Recap 09/04/2025

9/4/25 - Summer Season Recap Weather History & Forecasts Iowa Weather History (1989): Large thunderstorms brought heavy rain to western Iowa with severe weather and brief tornadoes, causing wind damage, roof damage, and trees falling on cars 7-Day Forecast: Cool autumn weather with clear skies and below-average temperatures; best rain chances on days 4-6 due to Atlantic activity and shifted Bermuda high Climate Outlook: September 9-13 shows slightly warmer temperatures and higher precipitation chances in western Iowa; monthly outlook suggests equal temperature chances and wetter conditions statewide Weather Summary & Notable Events Past Week: Most of Iowa received below-normal rainfall (0.5" below average), except western/southwestern Iowa which saw above-average amounts Cold Snap: Some locations hit around 40°F, causing potential localized damage to sensitive plants like basil but not widespread frost damage Summer 2025 Overview: 10th wettest summer in 153 years with 18.5" total precipitation (5" above average); July was 2nd wettest on record; August was drier at 3.4" (0.75" below average) Heavy Dews Explanation Seasonal Pattern: Heavy dews occur in late August/early September due to shorter daylight hours and cooling surface temperatures Science: Earth radiates heat overnight while warm air masses remain overhead, reaching dew point and creating heavy condensation Crop Impact: Wet leaves from heavy dews can promote foliar pathogens and crop decline Specialty Crop Topics Foxtail Grass Seeds: Grower concerned about viability of mowed green foxtail; recommended germination testing with moist paper towel method Compost Management: While beneficial, compost can raise soil pH and create phosphorus excess due to 1:1:1 N-P-K ratio; rule of thumb: 1% organic matter = 20 lbs nitrogen per season Nitrogen in Rainfall: Addressed grower question about delayed flower blooming; rainfall contains minimal nitrogen (0.5-3 mg/L) compared to irrigation water nitrate levels (10+ mg/L); plant greening after rain is primarily due to improved nutrient availability from soil moisture, not atmospheric nitrogen Cover Crops: Good timing now for oats and peas establishment; winter rye timing approaching; recommend seeding when rainfall is expected Episode Summary created by Claude.ai /episode/index/show/b33ba467-a72c-459a-a3c9-d09e013cb51c/id/38089925

8/28/25 - Continuing Cool and Drier..."Worst Season Ever?" 08/28/2025

8/21/25 - Cooler and Drier on the way...Warm fall? 08/21/2025

8/14/25 - New podcast preview: Pivot Points 08/14/2025

8/7/25 - Iowa's top 10 rainfalls of all time 08/07/2025

7/31/25 - Corn Sweat with Dr. Justin "Soybean Glistens" 07/31/2025

7/24/25 - Temperatures moderating, Wetness continues 07/24/2025

7/24/25 - Temperatures moderating, Wetness continues Historical Weather (This Day in History - 1993) Severe thunderstorms moved from Nebraska to western Iowa at 60 mph Wind gusts exceeded 70 mph, with 75 mph winds in Pottawattamie County destroying barns Council Bluffs received 2 inches of rain in 30 minutes causing urban flooding Des Moines recorded 83 mph wind gust 1993 was record wet year for Ames (20 inches of rain in July alone vs. 8 inches in July 2025) Current Weather Forecast Short-term (Justin Glisan) Rainfall chances continue through Friday night Cold front broke heat dome, bringing dew points down Temperatures: mid-80s through weekend, then back to 90s Minor rainfall chances early next week Northern Iowa has less rain chance as storm track moves south Expected rainfall: 3/4 inch statewide (below normal), 1.5-2 inches in southwestern Iowa Extended Outlook (Madelynn Wuestenberg) 6-10 day outlook (July 29-Aug 2): Slightly below normal temperatures in north, near normal in south; 33-40% chance above normal precipitation 8-14 day outlook (July 31-Aug 6): Continued slight chances of below normal temperatures; western Iowa slightly wetter, eastern Iowa near normal Normal temperatures: Daily highs mid-80s, lows in 60s Recent Weather Events Heat and Humidity Yesterday and prior day were hot, with cloud cover mitigating worst conditions in central Iowa Eastern Iowa experienced "dew point pooling" with dew points in upper 70s-low 80s Hottest reading: Dubuque Lock and Dam hit 95°F with heat index of 110°F Severe Weather 6 AM tornado warnings in central Iowa Tornado warnings near Maxwell and eastern Iowa Caused by remnants of mesoscale convective vortex from Kansas moving along warm boundary Rainfall Totals (Past 7 Days) Northeast Iowa: 4-4.5 inches (highest) Central Iowa: 3-3.5 inches Southwest Iowa: Trace to 0.25 inches (lowest, drought conditions persist) Specialty Crop Impacts Garlic Disease Investigation Farm in Chariton, Iowa had garlic crop with yellowing (suspected aster yellows) Testing revealed it was a virus, not aster yellows phytoplasma Cannot save seed for next year due to virus Comparison with aunt's clean stock showed dramatic difference At a different farm, possible Embellisia skin blotch observed on garlic wrappers Brassica Issues Black rot & alternaria affecting collards, broccoli, and kale Wet conditions exacerbating disease problems Nutritional Concerns Nitrogen leaching due to excessive moisture Fertilization may be necessary to supplement leached nutrients Crop Performance Issues Onions in Central Minnesota: Unexpectedly bolting across all varieties (planted from seed this spring) Zucchini: Poor fruit set, currently "worst crop of the year" candidate Tomatoes: Slow growth, fruit remaining green General pollination: Poor across multiple crops due to hot, wet conditions Heat may be affecting fruit set in tomatoes and peppers (flower abortion) Upcoming Events July 30: Cut flower field walk at River Root Farm (Decorah) July 31-Aug 1: Plant Peddler educator field day and variety day (Cresco) August 2: Grow Johnson County field day and food safety workshop August 5: Iowa State fruit and vegetable Field Day August 20: Midwest mechanical weed control field day Show Notes Hiatus announcement: No new episodes for 3 weeks (pre-recorded content only) Return date: August 21st, 2025 summary generated using Claude.ai /episode/index/show/b33ba467-a72c-459a-a3c9-d09e013cb51c/id/37537210

7/17/25 - Hot next week; Wet conditions continue 07/17/2025

7/17/25 - Hot next week; Wet conditions continue Weather History On July 17, 1972, slow-moving morning thunderstorms dropped 5.5 inches of rain at Sioux City, setting the all-time daily rainfall record there (still standing). Other highlights: 4.63 inches at Sac City, 3.45 inches at Humboldt. Short-Term Weather Outlook Cool air has returned after a recent frontal passage, but temperatures are forecast to increase again heading into next week. There are chances for showers and thunderstorms through the weekend. A “Ring of Fire” storm pattern will set up as a heat dome builds south over Missouri, leading to more storms along its northern edge (ridge riders/squall lines), likely north of Iowa, affecting the Upper Midwest (ND, SD, MN, WI). Medium-Range Weather Setup The bullseye of the heat dome appears over Missouri July 22–26; during this time, Iowa will see a precipitation gradient, with most rain favored in northeast Iowa. Precipitation forecast is variable, and storm placement will become clearer closer to each event. Southeast Iowa (and previously drier northern counties) have recently received significant rainfall, shifting them from "have-nots" to "haves." Ottumwa remains in moderate drought ("D1") as a stubborn dry spot. Climate Outlook 6–10 and 8–14 day forecasts show high probabilities for above-normal warmth (especially south), then continued wetness through late July. The 3–4 week outlook through August 8 gives no clear signal on temperatures, with a slight lean toward dryness in southwestern Iowa. Initial August outlooks show “equal chances” for temperature and precipitation over southern and central Iowa, a result of persistent widespread soil moisture which helps moderate heat. Atmospheric Impacts Recent wetness tamps down temperature extremes due to moist soils and increased cloud cover. The area’s high dew points indicate low atmospheric demand, reducing drought risk but potentially increasing plant disease issues. Past Week's Weather Severe weather last Friday produced two weak tornadoes in southern and eastern Iowa, with no widespread damage. Wildfire smoke from Canada arrived over the weekend after a strong cold front and wind shift to northwesterly flow. Wet conditions continued across much of the state. Specialty Crop Impacts Foliar Disease Risk Prolonged wet conditions are increasing foliar disease risks in specialty crops. Preventive fungicide programs are recommended for conventional growers, especially on brassicas (cabbage, broccoli, cauliflower). Summary of biopesticide efficacy for brassica diseases (per Meg McGrath, Cornell University): For black rot: Oxidate worked in 1 of 1 trial, Regalia in 1 of 2, copper in 4 of 5, Double Nickel in 1 of 1. For alternaria: copper is most effective. Over-use of copper risks resistance and soil accumulation; organic certification requires soil copper testing before use. For basil downy mildew: Only resistant varieties (notably the Prospera series) provide reliable control—fungicides are not effective. For powdery mildew on pumpkins and squash: Use potassium bicarbonate products like Kaligreen or Milstop (these are safer than baking soda due to plant salt sensitivity). Disease and Cost Monitoring Meg McGrath's cost-per-acre chart helps growers compare costs of biopesticides and fungicides Beet and Swiss Chard Disease Cercospora leaf spot is appearing on beet and Swiss chard leaves, making chard unmarketable. Resistant varieties like Char Bell are advised for chard. Japanese Beetle Management Listener asked about Milky Spore for Japanese beetle grub control. Dan cautions little evidence supports its effectiveness and prefers pest exclusion over soil treatments, since beetles migrate from other areas. Pheromone traps may attract more beetles than they catch—sometimes best given to neighbors to ward beetles away from your crops. Colorado Potato Beetle Resistance The second generation of Colorado potato beetle larvae has emerged. Rotate insecticide chemistries to avoid resistance (e.g., use Azera in the second generation if spinosad was used in the first). Non-chemical methods, like knocking beetles into a soapy water bucket, remain effective—plants tolerate up to ~33% defoliation before yield loss. Announcements and Events The Fruit and Vegetable Field Day at Iowa State University’s Horticulture Research Station will be held August 5th, 2:00–5:30 PM (free, with supper and registration link provided). The Plant Peddler "Educate the Educators" Day is July 31st in Cresco, with a feast and entertainment; the next day is Variety Day showcasing mature bedding plants (trade show only, not for sale). Practical Farmers of Iowa opened applications for the horticulture program coordinator position. Podcast summary generated using perplexity.ai /episode/index/show/b33ba467-a72c-459a-a3c9-d09e013cb51c/id/37444055

7/11/25 - More rain to come, cooling a bit next week 07/11/2025

7/11/25 - More rain to come, cooling a bit next week Recent Iowa Weather Highlights Heavy Rainfall: Rain gauges in the Des Moines area report 1–2.2 inches; some areas in western/central Iowa received up to 6 inches in the past week. Southeast Iowa remains much drier, with some locations getting less than 0.1 inch. Historical Context: July 11, 1993: Major flooding in Des Moines, with 250,000 residents losing water after levee breaches. 1993 marked 20 out of 37 consecutive days of measurable rain somewhere in Iowa. Current Wet Stretch: Statewide rainfall is 137% of normal for July so far. Several stations have received half a month’s rainfall in just the last 10 days. Dew points remain high (60s–70s), signaling ongoing Gulf moisture. Weather Outlook Short-Term Forecast: Active weather continues for the next two days, with a chance of severe storms (supercells transitioning to linear systems). Flood warnings and flash flood watches remain in effect. After the weekend, temperatures return to the 90s, then cool down. Medium & Long-Term Outlook: July 16–20: Likely below-normal temperatures, leaning wet. July 18–24: Continued cool and wet trend. End of July: Warmer temperatures expected, with equal chances for precipitation. Southeast Iowa may remain drier than other regions. Regional Details: The "blue bullseye" for cooler weather covers eastern Nebraska, most of Iowa, Minnesota, and Wisconsin. Weather Patterns & Impacts Storm Dynamics: Stationary fronts and ample Gulf moisture are causing repeated thunderstorms. Linear wind profiles have led to more squall lines and fewer tornadoes. "Training" thunderstorms have produced localized heavy rain. Precipitation Trends: 40% of Iowa’s annual precipitation typically falls on just 10 days. High-intensity, short-duration rain events are becoming more common, often leading to localized flooding and drought in different parts of the state. National Weather Note: Texas Flooding Recent Event: Two Texas locations received 11 inches of rain in just over 24 hours. Catastrophic flooding on the Guadalupe River, with water rising 20–30 feet in under an hour. Factors: Gulf and monsoonal moisture, remnants of Tropical Storm Barry, and stalled weather systems. Similar patterns have caused flash flooding in Iowa (e.g., Clive in 2018, Des Moines metro in 2019). Specialty Crop & Pest Updates Disease Risks: Continued wetness raises concerns about foliar diseases (e.g., black rot in brassicas and cabbage). Wet conditions and heavy dews may increase disease pressure as the season progresses. Pest Observations & Management: Japanese Beetles: Active on crops like zinnias, basil, and sweet corn (can affect pollination if silk is heavily clipped). Control options: Conventional sprays (e.g., Mustang Maxx), manual removal, and using trap crops. Colorado Potato Beetle: Reports of spinosad resistance. Alternative controls: Physical removal (bucket method), azadirachtin, or biological products (though some, like certain BT strains, are hard to find). Potatoes can tolerate 33% defoliation before yield loss. Onion Thrips: High populations observed in some fields, causing silvery-white damage. Economic thresholds vary (1–3 thrips/leaf per Cornell/UMass; up to 30 per UC). Control: Multiple modes of action, increased spray volume, horticultural oils, azadirachtin, and soil treatments with fungi or nematodes. Other Notes & Events Field Days & Workshops: August 2: Field day at Grow Johnson County’s Poor Farm, covering no-till vegetable research and a short food safety workshop (counts as an annual update for PSA-trained growers). Agrivoltaic field days in Ames: Ongoing research on crops grown under solar panels, with field days every other week through September. Podcast summary generated using perplexity.ai /episode/index/show/b33ba467-a72c-459a-a3c9-d09e013cb51c/id/37377740

7/3/25 - Average summer weather 07/03/2025

7/3/25 - Average summer weather Iowa Weather History: On July 3, 2001, severe thunderstorms in southern Iowa produced very large hail: 2.5-inch stones at Osceola, 3-inch at Otley, and 4-inch at Truro, causing widespread and extensive damage. Recent Severe Weather Trends: Hail has been infrequent this year, with the most recent notable event in north central/northwestern Iowa a few weeks ago. The primary severe weather mode this season has been wind, with only a few pockets of hail and very few tornadoes (no tornadoes in May, five reports in June, including a landspout). Despite fewer severe storms, thunderstorms have provided good rainfall, especially in northern and western Iowa, aiding drought improvement. 7-Day Weather Forecast: Expect average summer weather: several chances for thunderstorms over the next week. Temperatures will be typical for the season, with daytime highs in the mid-80s and overnight lows in the mid to upper 60s. Rainfall (QPF) is forecast at 0.5 to 1 inch, mostly thunderstorm-driven and variable. The best chance for statewide rain is Saturday night into Sunday, with additional chances late Tuesday into Wednesday. Climate Outlook: The July outlook initially showed a large dry area from the High Plains to the Gulf, but recent wet weather reduced this to a small bullseye over Nebraska, Kansas, Missouri, and Iowa. The last ten years of Julys in Iowa have been 5–10% drier than average, influencing the forecast. The first half of July still leans wet for most of Iowa; models suggest the second half could turn drier. Past Week’s Weather: The past week was about 2°F above average for temperatures and below average for rainfall. The state is transitioning to a quieter storm track, and soil moisture has improved thanks to late June rains. Eastern Iowa, especially around Waterloo, Cedar Rapids, Washington, Wapello, Linn, and Black Hawk counties, remains drier and needs more rain. Specialty Crop Impacts: Zucchini: Squash vine borer is active and affecting small plantings; some growers report a lull in fruit set, possibly due to poor pollination (weather or varietal timing). Squash bugs: Adults are mating; now is the time to scout for eggs and treat nymphs with insecticidal soap or oils. Adults are hard to control; many growers opt to replant rather than spray. Japanese beetles: Now appearing, mostly affecting basil (culinary and cut flower types), zinnias, and grape leaves. Basil downy mildew: 'Cardinal' basil (popular for cut flowers) lacks resistance and is vulnerable. 'Thai Prospera' basil offers downy mildew resistance and may be a better filler for bouquets. Garlic: Harvest is beginning. Use the "five green leaves, sixth browning" rule to time harvest for optimal bulb quality and storage. Tomato spotted wilt virus: A grower in Kalona who lost most of his tomato crop to this virus in previous years now sees minimal infection, likely due to reduced thrips pressure. Onion thrips can also vector the virus, so monitor onions for thrips damage. Upcoming Resources and Events: Dan will share links in the newsletter on strawberry plug planting, spring broccoli variety trials, root maggot information, and upcoming field days (flower field day in Decorah, urban ag field day in Waterloo, and a native plant propagation survey). summary generated using Perplexity.ai /episode/index/show/b33ba467-a72c-459a-a3c9-d09e013cb51c/id/37275235

6/26/25 - Sweet Corn Soon; More wet for now, dry next week 06/26/2025

6/26/25 - Sweet Corn Soon; More wet for now, dry next week Weather History & Current Conditions Historical reference: June 26, 1993 - Severe hailstorms in western Iowa with golf ball to softball-sized hail caused extensive damage to crops, trees, cars, and buildings Recent weather: 150-400% of normal rainfall across southern Iowa with some areas receiving 3-8 inches (equivalent to a month's worth of rain) Heat wave anomaly: Unusual combination of high 90s temperatures, high humidity, and sustained strong southerly winds for 24-36 hours - described as a "black swan event" Record temperatures: Many stations recorded daily record warm overnight low temperatures that didn't allow for cooling Weather Forecasts Short-term: Continued unsettled pattern with thunderstorms and slight severe weather risk in north-central to northeastern Iowa Coming week: Heavy rain potential (1-2 inches), cooler 80s tomorrow, then back to low 90s with Sunday thunderstorms followed by quieter conditions Extended outlook: 6-10 and 8-14 day forecasts show near normal temperatures with continued wet signal; July outlook leans warm statewide with slight dry tendency in western Iowa Sweet Corn Season & Pest Management Sweet corn timing: First harvest expected within days - Roger VanDonselaarr (Prairie Produce, Grinnell) and Hilltop Farm (Dallas Center) Production methods: Early growers use clear plastic mulch and row covers to accelerate growth Corn earworm challenge: Moths present requiring spray applications every 2-3 days, but wet conditions prevent field access Quality standards: Zero tolerance for worms in commercial sweet corn due to consumer expectations and processing requirements Drone spraying: Some growers adopting drone technology to overcome wet soil limitations, though wind conditions still restrict applications Disease Management & Crop Care Disease scouting tips: Stay out of wet fields to prevent disease spread Start with youngest, healthiest plants before moving to diseased areas Use clean clothes, tools, and boots daily Disinfect pruners between plants Current diseases observed: Bacterial leaf spot in parsley/cilantro and black rot in brassicas Garlic Production Scape removal timing: Research shows removing scapes as early as possible (when just emerged) produces largest bulbs Manual vs. mechanical removal: Hand removal preferred as mowing can remove leaves and reduce bulb size by 15% Market considerations: If selling scapes, wait for full curl; if maximizing bulb size, remove immediately Upcoming Events July 1: Plant diagnostic clinic at Twin County Produce Auction, Kalona (9-11 AM) July 8: Rodale Field Day at Midwest Organic Center near Cedar Rapids - featuring autonomous robotic ag tools July 31: Educate the Educators Day at Plant Peddler, Cresco August 1: Variety Day trade show at Plant Peddler End of July: Cut flower field day at River Root Farm, Decorah End of August: Midwest Mechanical Weed Control Field Day, Ames summary generated using claude.ai /episode/index/show/b33ba467-a72c-459a-a3c9-d09e013cb51c/id/37164430

6/19/25 - Two words: "Blast Furnace" 06/19/2025

6/19/25 - Two words: "Blast Furnace" Iowa Weather History: On June 19, 1996, severe thunderstorms produced very large hail in northwest Iowa, with a 3.5-inch stone near Hinton (Plymouth County) and a 4.5-inch stone at Cushing (Woodbury County), causing $200,000 in damage to vehicles and buildings. 7-Day Weather Forecast: Iowa is entering a "blast furnace" pattern: temperatures will soar 15–20°F above average, with highs in the 90s to upper 90s and overnight lows in the mid to upper 70s. Persistent high overnight lows will make it difficult for people and plants to recover. Strong southwesterly winds will continue, bringing high dew points and Gulf moisture. By days 4–6 (early next week), the northwestern two-thirds of Iowa could see 2–5 inches of rain, especially in western Iowa, which needs relief from drought. Climate Outlook: The 6–10 day forecast shows the heat shifting east, with a tighter temperature gradient and continued potential for heavy rainfall, especially in northern Iowa. The 8–14 day outlook keeps a warm and wet signal, which is positive for the wettest month of the year after recent dryness. The 3–4 week outlook still leans warm, with no clear signal on rainfall. The initial July outlook (issued June 19) leans slightly warm statewide, with a slight lean dry in the western third of Iowa. Recent Weather and Notables: The past week was slightly warmer than average with an unsettled pattern of pulse and “popcorn” thunderstorms across the state. Severe weather ingredients did not come together for widespread severe storms, but there was a landspout tornado in eastern Iowa. Landspouts are weaker, photogenic tornadoes (a step above dust devils), typically anticyclonic, and distinct from stronger tornadoes. Specialty Crop Impacts: Hot weather is negatively affecting broccoli development, leading to issues like “brown bead” (brown florets) and heat-delayed buds. Brown bead can be caused by hot, humid nights; broccolini is less susceptible and can regrow after harvest. Hollow stem in broccoli may result from fast growth due to excess nitrogen and water, not just boron deficiency. Tighter in-row spacing and careful nitrogen management can reduce hollow stem. Boron deficiency causes brown, dead cells lining the hollow stem, while fast growth causes uniformly green or white hollows. Boron should be mixed with other powders for uniform soil application to avoid toxicity. Some broccoli varieties (e.g., Green Magic) are more prone to hollow stem than newer ones (e.g., Eastern Crown). Heat can also cause uneven, lighter green patches in broccoli heads (heat-delayed buds). Brown bead does not grow out, but heat-delayed buds sometimes do Cabbage White butterflies and their caterpillars are active. BT (Bacillus thuringiensis) sprays are effective when caterpillars are first seen, especially on new growth and broccoli heads. Rotate BT with other organic insecticides if resistance is suspected. Cabbage moth caterpillars can hide inside broccoli heads, making washing difficult. Summary created using Perplexity.ai /episode/index/show/b33ba467-a72c-459a-a3c9-d09e013cb51c/id/37079210

6/13/25 - Continued Warmth Ahead; Watch for Aster Yellows, Squash Vine Borer 06/13/2025

6/13/25 - Continued Warmth Ahead; Watch for Aster Yellows, Squash Vine Borer Iowa Weather History June 13, 1976: an F5 tornado near Luther, Iowa, was one of the largest in state history. The tornado, nearly a mile wide, spawned multiple satellite tornadoes and caused widespread destruction between Boone and Ames, demolishing over 60 homes and 300 farm buildings. Charles Barthold’s iconic photographs of the event contributed to tornado science and earned him a Peabody Award. 7-Day Weather Forecast Expect continued warmth with a risk of extreme heat in the coming week. An active precipitation pattern is forecast, with widespread rain likely. Most of Iowa should receive at least an inch of rain between June 12–19; northern areas may get up to 2 inches, especially with thunderstorms. The Climate Prediction Center’s outlooks (6–10 day, 8–14 day, and 3–4 week) all lean toward above-normal temperatures and slightly above-normal precipitation. There is a slight risk for extreme heat (June 19–21) and heavy precipitation (June 19–22, especially in northern Iowa). Recent Weather The past two weeks were cooler than normal, averaging 65°F (2–4° below normal). On June 11, hailstorms hit northern Iowa (Palo Alto, Kossuth, Hancock Counties), causing severe crop damage and total losses in some corn and soybean fields. Specialty Crops Impacts Aster Yellows in Garlic and Other Crops: Aster leafhopper infectivity for aster yellows has jumped from near zero to 15–20% in Michigan, exceeding last year’s rates. Growers should watch for symptoms in garlic, flowers, and lettuce. One Iowa garlic grower observed premature yellowing and is testing for the disease; comparison with seed garlic from another location suggests possible infection. Squash Yellowing (B Gene): Yellow leaves in squash during cool weather may be due to the B gene, which breeders retain for its positive effects (fruit color, yield, virus resistance). The B gene can be identified by a yellow stem on yellow squash. Onion Thrips: High thrips numbers reported in onions and mulberries. Thrips are tough to control; Dan recommends using azadirachtin (from neem), horticultural oil, a spreader-sticker, soil-drench nematodes, and mycopesticides (Beauveria bassiana). Control is important because thrips damage increases storage rots. Aphids: Aphids can multiply rapidly, especially under row covers. Dan suggests treating transplants with insecticidal soap (e.g., M-Pede) before planting and repeating the spray after five days. In the field, use water sprays, insecticidal soap, oils, and azadirachtin. Tank-mix treatments after jar testing. Attract beneficial insects with sweet alyssum and other flowers, especially in tunnels or greenhouses. Squash Vine Borer: The pest is now active in central Iowa. Remove row covers from flowering squash, scout for eggs at the stem base, and use BT sprays or manual removal of larvae. Large fields are less affected; small plantings are at greater risk. Tomato Yellow Shoulder Disorder: This disorder is more common in hot weather and is linked to potassium deficiency and high fruit temperatures. Dan recommends ensuring adequate potassium and using shade cloth in high tunnels to keep fruit shoulders cool. Some cultivars are more susceptible. Podcast summary generated using Perplexity.ai /episode/index/show/b33ba467-a72c-459a-a3c9-d09e013cb51c/id/36998770

6/4/25 - Meteorological Spring Recap 2025 06/04/2025

6/4/25 - Meteorological Spring Recap 2025 Iowa Weather History On June 4, 1998, sleet and trace ice were reported in Rock Rapids, northwestern Iowa—the only official winter precipitation recorded in Iowa in June; none in July or August. 1997–1998 was a strong El Niño year, noted for heavy precipitation events. Recent and Upcoming Weather Unsettled weather with rain and severe storms in eastern Iowa over the past week. Statewide air quality alert due to wildfire smoke from Canada, reducing solar radiation and lowering temperatures by 1–2°F. Transitioning to a warmer, drier pattern with scattered rain chances. Three- to four-week outlook: warmer than normal, but precipitation outlook is uncertain (equal chances of above, below, or normal rainfall). 8–14 day hazards outlook: slight risk of high temperatures (June 12–17) and heavy precipitation (June 11–14). Storm and Precipitation Recap Severe weather affected Texas, Oklahoma, Missouri, and southeast Iowa. Tornado reported in Kansas City; unconfirmed tornado in Fort Madison, Iowa, possibly derailing a train. Widespread rainfall: up to 2 inches in southeast Iowa, 2–2.5 inches in north-central and northwest Iowa, at least a trace in central Iowa. 80% of Iowa received at least half an inch of rain. Temperature Trends Last week: statewide average temperature 2.4°F below normal. Earlier in May: above normal temperatures, then a cool period. Meteorological Spring Recap (March–May) Precipitation: North-central Iowa: 114% of normal (1.4 inches above average). Southwest Iowa: 66% of normal (3.5 inches below average). Statewide: 92% of normal (about 1 inch below average). South-central and southwest Iowa: 5–6 inches below average, with ongoing drought. Temperature: Central to eastern and southern Iowa: top 20 warmest springs on record (since 1895), 1.5–2.4°F above normal. Statewide: 1.7°F above average. Severe Weather: March: 1 tornado (average is 2). April: 10 tornadoes (average is 6). May: 0 tornadoes (first time since 2010 with no May tornadoes). 2024 had 59 tornadoes in April and 47 in May—much more active than 2025. Daytime vs. Nighttime Warming: March: daytime highs 9.5°F above average, overnight lows 3.1°F above average. April: daytime highs 1.5°F above average, overnight lows 1.1°F above average. May: first half 4–6°F above average, second half cooler. Specialty Crop Impacts Wind and Erosion: Sandy soils in southeast Iowa caused sandblasting of young melons, requiring replanting. Cover crops helped reduce erosion. Pests: Moist conditions favored slugs and roly-polies (pill bugs), which damaged pepper leaves. Earwigs were problematic for dahlias. Sluggo Plus (iron phosphate with spinosad) is labeled for these pests, but efficacy is uncertain. Hay Harvest and Pests: Hay harvest displaces potato leaf hoppers, which then move to green beans and potatoes. Leaf hoppers are difficult to manage due to large populations. Garlic: Garlic scapes are emerging. Removing scapes increases yield by about 15%. Garlic scape anthracnose (a disease) can occur—remove affected scapes to prevent spread. Aster leaf hoppers and aster yellows disease: this year, no positive disease tests in Michigan (last year, 4–11% positive). Flowers: Campanula and feverfew recently bloomed. Dara and volunteer rudbeckia expected to bloom soon. Summary generated by Perplexity.ai and edited by Dan Fillius /episode/index/show/b33ba467-a72c-459a-a3c9-d09e013cb51c/id/36852920

5/28/25 - Summer is right around the corner 05/28/2025

5/28/25 - Summer is right around the corner Iowa Weather History 1906 Historical Frost: Late season statewide frost on May 28th with temperatures dropping to 30-32°F across multiple Iowa cities, though crop damage was minimal due to brief duration 2021 Comparison: Similar late freeze event occurred on May 29th with 37°F statewide average (13° below normal) Recent Frost Data: Last frost dates varied by location - Sibley (April 21st), Ames (April 12th), Keokuk (April 9th), though Mason City hit 32°F as recently as May 20th Weather Forecast & Climate Trends Short-term: Nice weekend weather with 70s-80s temperatures, some scattered showers and thunderstorms Long-term outlook: Moving toward more active storm pattern with warmer and wetter conditions expected Growing season: Expanding by 10-15 days due to climate trends, with later fall freezes and earlier spring thaws Moisture transport: Southern states' wet conditions could benefit Iowa through Gulf moisture transport mechanisms Recent Weather Conditions Memorial Day weekend: Quieter weather with temperatures 6-8°F below average Soil conditions: Persistently moist and cool, excellent for plant establishment Spring assessment: Very comfortable conditions, though not quite as ideal as 2024 when no irrigation was needed Specialty Crop Impacts & Pest Management Positive Conditions Excellent plant establishment due to consistent moisture No irrigation concerns for getting crops started Good conditions for transplant survival Potential Issues Blossom end rot risk: Persistent wetness reduces water movement and calcium transport in tomatoes Weed pressure: Moist conditions favor rapid weed growth Active Pests to Monitor Colorado Potato Beetle: Now active based on degree day models, targeting potatoes and eggplants Seed Corn Maggot: Second generation emerging, threatens direct-seeded crops like beans, corn, cucumbers Slugs: Increased activity in moist conditions, causing characteristic rasping damage Roly-polies: Higher populations in high organic matter soils may damage plant stems Management Recommendations Use row covers for newly planted eggplants and direct-seeded crops to protect from Colorado Potato Beetle, flea beetles, and seed corn maggot. Scout for Colorado potato beetle eggs and larvae Hand removal and soapy water treatments for organic pest control Monitor for slug damage patterns (round holes with scraped areas) Stay vigilant about weed management during optimal growing conditions Episode Summary generated by Claude.ai and edited by Dan Fillius /episode/index/show/b33ba467-a72c-459a-a3c9-d09e013cb51c/id/36753135

5/22/25 - Cool and wet now, stay tuned for warmer and drier 05/22/2025

5/22/25 - Cool and wet now, stay tuned for warmer and drier Weather History: In 1873, a deadly tornado tore through southeastern Iowa, affecting Keokuk, Washington, and Louisa counties before moving into Illinois. The storm produced very large hail (up to 4.5 inches in diameter), killed 8 people, and injured at least a dozen others. This event prompted the first detailed tornado damage survey in Iowa, conducted by the U.S. Army Signal Corps. 7-Day Weather Forecast: Temperatures are expected to remain cool for the next week. Rain chances increase as the weekend approaches, with the best chance for precipitation Sunday night into Monday. The following week will be less active Climate Forecast: 6–10 Day Outlook (May 27–31): Cooler temperatures expected in the south, near normal in the north, and likely below-average rainfall statewide. 8–14 Day Outlook (May 29–June 4): The drier signal is enhanced, and temperatures are expected to be warmer than normal. 3–4 Week Outlook (mid-June): The outlook leans warm and wetter, suggesting a shift to a more active weather pattern as summer approaches. Past Week of Weather: The past week was notably cooler and wetter than usual, with 3–4 inches of rain along the I-35 corridor and surrounding counties. Des Moines International Airport recorded 4.84 inches, the highest in the state. Temperatures were about 5°F below normal. Overnight lows dipped into the 40s, which is chilly for late May Other Weather/Climate Discussion Topics: Wind and Hail: Northern Iowa experienced strong sustained winds (37–39 mph) and gusts up to 52 mph. Hail up to 2 inches was reported in Grand River (Decatur County) and Osceola. Wind Damage: Growers in northern Iowa reported significant losses of plastic mulch beds due to high winds. Wind erosion was also noted in sandy soils in southeastern Iowa. Weather Impacts on Crops: High winds caused physical damage to plants (broken leaf petioles, windblown soil particles), and some farms reported unusual leaf spotting, possibly from wind or chemical drift. Drift investigations are ongoing in affected areas. Precipitation and Irrigation: The recent rains improved abnormally dry conditions, but growers are reminded to water in new transplants as their roots are not yet established. Weeds are expected to germinate rapidly, so timely cultivation is encouraged. Specialty Crops Impacts: Wind Damage: Growers lost plastic mulch beds and experienced wind erosion, especially in northern and southeastern Iowa. Leaf Spotting: Multiple crops (potatoes, radishes, tomatoes, cabbage, Swiss chard, cucumbers) showed inter-veinal necrosis, likely due to wind or desiccation, not herbicide drift. Weed Management: Recent rains will trigger weed germination, so growers are advised to cultivate early at the white thread stage. Cold Weather Effects: Cool temperatures can increase cat-facing in tomatoes and blossom end rot in susceptible crops. Growers are reminded to monitor for these issues if crops are flowering. Irrigation: Irrigation is less necessary after recent rains, but new plantings still require watering. Flower Crops: Rain can damage open blooms, but many flowers are harvested in the bud stage. Peony growers are drying blooms before cold storage to prevent moisture issues. Listener Engagement: Listeners should share their experiences and the impact of the podcast on their growing decisions, especially if they can quantify the financial benefit of advice received Summary provided by perplexity.ai /episode/index/show/b33ba467-a72c-459a-a3c9-d09e013cb51c/id/36679500

5/15/25 - Let my irrigation flow 05/15/2025

5/8/25 - Cut Flowers for Mothers Day 05/08/2025

5/8/25 - Cut Flowers for Mothers Day Weather Update and Forecast Current conditions feature stable, pleasant weather A localized rain event occurred the previous night (May 7th) across central Iowa, with amounts around 0.21 inches in some areas Weather pattern is currently dictated by an "Omega block" high pressure system creating stable air Forecast shows temperatures warming into the 80s with relatively dry conditions 6-10 and 8-14 day outlooks indicate: Above normal temperatures for Iowa, though this pattern is moving eastward Above normal precipitation chances in the coming weeks Western US expected to have below normal temperatures Historical Weather Note On May 8, 1964, Iowa experienced very strong winds (60-75 mph, up to 85 mph in Des Moines) This created widespread dust storms described as the worst since the 1930s Climate Patterns Discussion A temperature gradient between western and eastern US suggests potential for a more active storm track Possible thunderstorm conditions developing May 15-21 Recent precipitation has been below normal over the past week Temperature gradient with southern Iowa cooler than normal and northern Iowa warmer than normal Specialty Crop Focus: Cut Flowers for Mother's Day Dan discussed preparing cut flowers for Mother's Day sales Highlighted benefits of overwintering certain flowers in low tunnels: Earlier blooming than spring-planted flowers Longer stems on cool-weather flowers Currently blooming: Iceland poppy, bachelor's button Nearly ready: foxglove Other successful overwintered varieties: dianthus, campanula, larkspur, delphinium, Nigella, bupleurum, bells of Ireland Shared an alternative low tunnel design using carabiners, hose clamps, and bungee cords Addressed a flower disease issue: blue mold affecting tulips Disease infects bulbs during harvest Shows variety-specific impacts Management includes identifying infected bulbs before planting Episode Summary generated by Claude.ai /episode/index/show/b33ba467-a72c-459a-a3c9-d09e013cb51c/id/36490985

5/1/25 - Weather like San Diego ahead?! 05/01/2025

5/1/25 - Weather like San Diego ahead?! This Day in Iowa Weather History In 1911, unseasonably cold air brought rain mixed with snow across northwestern Iowa. Most snow melted on contact, but some locations reported accumulations: 1 inch at Denison, 1.5 inches at Alta and Lamars, 2 inches at Algona, Mason City, New Hampton, Onawa, and Rockwell City, 2.5 inches at Rock Rapids, and 4 inches at Elma in Howard County. 7-Day Weather Forecast Showers and thunderstorms are possible today, but the weekend will bring pleasant, San Diego-like weather: sunny skies and highs in the 70s. A quieter weather pattern is expected to settle in. Climate Outlook 8–14 Days (May 8–14): Strong likelihood of above-normal temperatures. The eastern half of Iowa leans slightly below normal for precipitation, while the western half is near normal-overall, a little dry and definitely warm. 3–4 Weeks (May 10–23): The outlook leans warm with equal chances for precipitation. Precipitation remains difficult to forecast due to the spring transition. May Monthly Outlook: Most of Iowa is likely to be warmer than normal. Precipitation is split: the northeast leans slightly drier, while the southwest has equal chances for above, below, or normal precipitation. Recent Weather Impacts On Monday, Iowa experienced very windy conditions (gusts up to 70 mph in Ames) but no tornadoes. The severe weather event was well forecasted in terms of risk areas, but many Iowans did not experience significant storms, leading to a perception of overhype. The lack of severe storms in Iowa was attributed to a strong atmospheric cap, cloud cover, dust, and wind alignment that prevented updrafts, despite all other ingredients for severe weather being present. Specialty Crop Impacts Winter Rye: Beginning to flower across Iowa. Growers can terminate rye reliably by mowing and tilling at anthesis (pollen shed). One grower plans to mow and bale rye for weed-free straw mulch. Overwintered Flowers: Iceland poppies are starting to open; dianthus are looking good. More flower updates are expected next week, ahead of Mother’s Day. Greenhouse Tomatoes: Ripe tomatoes are being harvested in greenhouses in Grinnell and likely at some auction houses. Garlic & Aster Yellows: Growers are on watch for aster yellows phytoplasma, which devastated garlic crops last year, especially in northeast Iowa and neighboring states. Recent lab tests found rotted garlic cloves infected with pythium and rhizoctonia, not aster yellows. The likely cause was winterkill due to low snow cover, not disease. Spring-planted garlic had much higher survival. Management Advice: Rogue out yellow, weak garlic plants now to prevent potential spread of aster yellows by leafhoppers. Mulch and snow cover help protect overwintered garlic. Soil Testing: New online and spreadsheet tools are available for interpreting soil test results and generating fertilizer recommendations. MASC Payments: A new round of Market Assistance for Specialty Crops (MASC) payments has been announced. Growers should check with their FSA office for eligibility. Podcast summary generated using Perplexity.ai /episode/index/show/b33ba467-a72c-459a-a3c9-d09e013cb51c/id/36397310

4/25/25 - Still warm, severe weather chance on Monday 04/25/2025

4/17/25 - Warmer and wetter; How much would you bet that we've seen our last frost? 04/17/2025

4/17/25 - Warmer and wetter; How much would you bet that we've seen our last frost? In summary: The episode covers current severe storm risk, a warm/wet outlook, lingering (but mostly localized) frost potential, and advice for growers on weather impacts, pest and seedling management, and fieldwork timing. There’s a focus on using sound data (not just forecasts) for planting decisions, and corrections on frost hardiness for strawberry crops. Weather Recap & Outlook The hosts recall a historic severe weather event: an F3 tornado in Van Buren County on April 16th, 1967. For the current day (April 17, 2025), the main severe weather threat is large hail (1–2+ inches), especially from Omaha through Des Moines and Ames; tornado risk is low due to low dew points. Forecast: Severe storms possible overnight. Friday and Saturday expected to be pleasant, with more rain chances from Saturday night into Sunday. Rainfall of 0.75–1.25 inches possible across the state. Eastern Iowa, especially between Waterloo and Cedar Rapids (D1 drought area), is currently receiving needed rain. The 6–10 and 8–14 day forecasts show a warm and wet signal, especially in southwestern Iowa. The month-ahead and seasonal outlooks are less certain, with possible slightly increased warmth and dryness moving into early summer. Frost & Soil Temperature Despite a strong signal for above-normal temperatures, the last frost of the season may not have occurred yet, especially in central and northern Iowa. Widespread frost is unlikely, but localized events could still occur, especially in valleys or low-lying, dry areas. Soil temperatures are fluctuating widely due to dry soils, with values expected mostly in the low/mid 60s to mid 40s over coming weeks. Some forecasts show soil temps as low as 42°F in northern Iowa by early May. Growers are advised not to rush warm-season crops like tomatoes and peppers into the field before mid-May or early June, due to risk of cold soil and air temperatures. Recent Weather, Climate Notables & Grower Reports It’s been windier than usual, which is notable particularly in northwest Iowa. Cloud cover and cooler temps have persisted in eastern Iowa, verified by grower feedback. Accumulation of growing degree days is ahead of normal, prompting early alfalfa weevil egg hatch in southern Iowa. Some growers are experimenting with blackening cover crops to encourage warmer soils for earlier sweet corn, but cloudy weather has limited the benefits. Pest & Seedling Updates Problems with bean germination in greenhouse trays may be linked to seed maggots and/or sensitive response to high nutrient salt levels in potting media. Microclimate and possible ammonia burn are additional considerations. Growers are advised to bioassay suspect potting media using sensitive crops like beans and peas. Strawberry Correction & Field Work The host corrects a previous statement: Strawberry flower buds are hardy to 20°F; open blossoms are damaged in the high 20s. With wetter weather on the horizon, growers are encouraged to finish field prep and tillage now, before rain delays field access and results in transplants outgrowing their cells. *Podcast transcript and summary provided using AI /episode/index/show/b33ba467-a72c-459a-a3c9-d09e013cb51c/id/36209280

Warmer than average temps, but windy 04/10/2025

Warmer than average temps, but windy 7-day Weather Forecast - Dr. Justin Glisan Temperature: Above average temperatures in the 50s and 60s Temperature gradient across the state Precipitation: Quieter weather pattern after an active March Windy conditions expected Climate Forecast - Madelynn Wuestenberg 6-10 day (April 15-19): Temperature: Leaning below normal temperatures along the eastern part of the state Near normal temperatures for the rest of the state Precipitation: Southeast edge of the state leaning slightly above normal The rest of the state near normal precipitation 8-14 day (April 17-23): Temperature: Eastern part of the state: near normal temperature conditions Western half of the state: 33-40% chance of leaning above normal temperatures Precipitation: Most of the state near normal precipitation 3-4 week (April 19-May 2): Temperature: Equal chances for above, below, or near normal temperatures Precipitation: Equal chances for above, below, or near normal precipitation Normal Weather Context for This Time of Year: Temperature: Low 60s for daytime highs, upper 30s for overnight lows Precipitation: About 1/10 of an inch per day (doubling by the end of the month) Recent Weather Events - Madelynn Wuestenberg Temperature: March was the 9th warmest on record (based on 153 years of records) Recent cold snap with temperatures as low as 18°F in Audubon Precipitation/Severe Weather: First tornado of the year near Wilton, IA (EF0, traveled almost 2 miles) Localized heavy snowfall in March (band from north of Omaha through Mason City) More snow from March 20th event than the entire December-February winter period Specialty Crops Impacts Strawberry blossoms likely damaged if left uncovered during recent cold snap (temperatures reached 18-25°F) Magnolia trees in Des Moines showing brown flowers from frost damage Some growers reporting issues with greenhouse transplants showing death to cotyledons or stunting Soil conditions have been dry enough for field work preparation Innovative approach: A grower in Louisa County burned down terminated cover crop to create a blackened field that would absorb more solar radiation, potentially keeping the soil warmer for sweet corn seeds Other Weather/Climate Discussion Topics ENSO Status: Last La Niña advisory with significant chances for ENSO neutral conditions developing Spring Barrier: Transition period where global teleconnections (like ENSO) have less influence on local weather Windiness: Iowa experiencing second windiest spring on record due to three strong low-pressure systems in March April is climatologically the windiest month for Iowa This Day in Iowa Weather History - Dr. Justin Glisan: On April 10, 1930, very warm weather pushed temperatures to 96°F at Clarinda, making it the earliest date of the year on which such a temperature has ever been recorded in Iowa. Other high temperatures included 95°F at Thurman, 94°F at Atlantic, 93°F at Burlington, Cedar Rapids and Iowa City, and 92°F in Des Moines, Dubuque and Keokuk. At many locations, this remains the earliest date on record of temperatures in the 90s. /episode/index/show/b33ba467-a72c-459a-a3c9-d09e013cb51c/id/36087445

2/26/25 - Staying warm-ish with chance for precip. next week + Recap of Meteorological Winter 02/26/2025

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