What in the Weather?

00:00:25 — Iowa weather history: two violent 1974 tornadoes caused F4 damage in eastern Iowa.

00:01:31 — Weather trivia asks listeners to identify the leading cause of weather-related fatalities in the United States.

00:01:51 — Near-term forecast: an active "ring of fire" pattern brings widespread thunderstorm chances for the next four to five days, followed by a quieter, seasonable start to next week.

00:02:29 — Rainfall outlook and forecasting explained: model ensembles suggest broad totals of at least 1.5 inches, with isolated 3–4 inch amounts possible from central to eastern Iowa; local thunderstorm totals will remain highly variable.

00:05:18 — Extended outlook: Aug. 19–25 is favored to be warmer than normal in Iowa, with near-normal precipitation; the late-August/early-September outlook leans slightly drier.

00:06:44 — The team explains how Pacific monsoon moisture, the jet stream, and emerging El Niño conditions may contribute to Iowa's humidity and heavy-rain potential.

00:09:08 — El Niño update: European model projections show a potential very strong event later this year, though the hosts emphasize uncertainty and promise a fuller winter-focused discussion.

00:13:37 — Derecho and severe-weather recap: a damaging line of storms crossed eastern Iowa and continued through the Ohio Valley, with wind gusts up to 75 mph near Independence and two reported tornadoes in Delaware County.

00:15:19 — Past-week Iowa conditions: eastern Iowa saw tornado, hail, wind, crop, tree, and building damage; Nashua recorded 3.04 inches of rain, while Rock Rapids had only a trace.

00:16:52 — Recent temperature and humidity context: highs reached 94°F, Spencer fell to 47°F overnight, and the hosts compare this summer's heat and dew points with 2025.

00:18:46 — Specialty-crop update: growers seeking heat-tolerant broccoli varieties are directed to Cornell's Eastern Broccoli Project research.

00:20:14 — Corn rootworm beetles are replacing Japanese beetles as a concern for flowers, pumpkins, and sweet corn; exclusion netting or bags are the most pollinator-safe control options for cut-flower growers.

00:22:51 — Watermelon harvest challenges after heavy rain: excessive moisture can cause splitting, while growers must balance harvest timing, maturity, rind development, and variety-specific traits.

00:25:18 — Hail damage report from Algona: penny-size, likely wind-driven hail damaged zucchini and pumpkins; photos will be included in the show notes.

00:26:32 — Upcoming events: Midwest Mechanical Weed Control Field Day in Michigan (Sept. 16), Appropriate Technology Field Day in Kentucky (Aug. 25), Great Lakes Tek Flex in Michigan (Sept. 10–11), and the 40th-anniversary Hort Friday field day in Ames (Sept. 26).

00:29:25 — Additional event reminders: High Tunnel Short Course on Nov. 11 and the Southeast Research Farm Field Day in Crawfordsville on Sept. 10.

00:29:44 — Trivia answer

podcast summary generated using Perplexity.ai

[00:00:08] August 5 Iowa weather history segment, including a severe 1989 thunderstorm complex and derecho discussion.

[00:01:35] Madelynn shares the weather trivia question: Does Iowa get more than 40% of its annual precipitation in its 10 wettest days?

[00:02:03] Justin gives the upcoming forecast headline: rain chances easing, then a return to mid- to upper-80s temperatures.

[00:05:03] Madelynn reviews the 8-to-14-day and one-month Climate Prediction Center outlooks, which lean warmer and wetter for parts of Iowa.

[00:06:14] The team discusses heavy precipitation risk in eastern Iowa, wet soils, flash flooding concerns, and ridge-rider storm potential.

[00:07:56] Madelynn summarizes the past week's weather shift from hot and humid to cooler, pleasant conditions with soft rains across much of the state.

[00:10:23] Justin shares recent weather extremes, including the hottest location, coolest overnight lows, and top precipitation totals.

[00:11:21] The hosts talk about heavy rain and training lines in southern and central Iowa, plus flash flood concerns and rainfall extremes.

[00:12:51] Dan moves into specialty crop impacts, covering watermelon harvest progress and melon ripening in Iowa.

[00:13:57] Dan discusses broad mites in peppers, including symptoms, scouting, and management challenges.

[00:15:16] The conversation shifts to thrips damage in gladiolus, possible species involved, and treatment considerations.

[00:18:29] Dan explains the difference between truss tomatoes and standard tomato varieties, using a grower example and seed sources.

[00:20:30] Dan notes the first Wisconsin report of beet rhizomania and explains why it matters for beet production.

[00:21:15] The episode includes a listener question about Japanese beetles, their life cycle, and when they should disappear.

[00:23:20] Madelynn answers the trivia question

00:00:08–00:02:00: Dan and Justin discuss the first recorded tornado damage in Iowa history from 1804.

00:02:00–00:04:05: The team previews the coming week's forecast, including heat, muggy conditions, wildfire smoke, and a rain system that could bring widespread rainfall.

00:02:41–00:03:55: Madelynn introduces the weekly trivia question about which RAGBRAI year had the most hours with a heat index above 85 degrees, with a note that Des Moines data is being used as a proxy.

00:04:05–00:08:24: Madelynn walks through the 8–14 day Climate Prediction Center outlook, the hazard outlook, and the three-to-four-week outlook, highlighting above-normal temperatures, near-normal precipitation, and some drought concern.

00:07:39–00:08:24: Dan adds harvest timing advice for potatoes, onions, and garlic ahead of potential rain, and mentions the upcoming final August monthly outlook.

00:08:25–00:10:12: Madelynn summarizes the past week as "moist and on fire," describing heat, humidity, dense fog, and a fire at the Agristar meat processing plant in Postville.

00:10:12–00:11:20: The hosts review extreme heat statistics for Des Moines, including a 1936 record and the near-record heat index from July 27, 2026.

00:11:21–00:13:13: Justin shares weekly weather superlatives, including the statewide high, low, and wettest location, and the hosts correct a questionable Spencer low-temperature reading.

00:13:14–00:16:06: Dan discusses tomato botrytis issues in a high tunnel, possible management options, and whether removing infected plants could spread spores.

00:16:06–00:18:10: Dan shares that he tested positive for Cyclospora, explains the infection route, and talks about antibiotics and sun sensitivity.

00:18:10–00:20:38: The conversation turns to garlic viruses, clean seed production, and how virus-free seed can improve yields.

00:20:46–00:22:24: Dan discusses farm decision-making and labor tracking using the "Know Your Cost to Grow" approach to evaluate equipment investments.

00:22:45–00:23:31: Dan plugs Farm to Table for All, a local produce-purchasing and food-distribution effort in the Des Moines area, and mentions an upcoming event.

00:23:35–00:24:14: Madelynn reveals the trivia answer

00:24:25–00:25:18: Dan closes with thoughts on tailwinds and headwinds during RAGBRAI, congratulates riders, and signs off for the week.

summary generated using Perplexity.ai

00:00:31 Iowa weather history: July 23, 2010 flooding and Delhi dam failure

00:02:03 Trivia question on severe weather warnings in Iowa

00:02:39 Weekly forecast: hot, humid conditions with highs in the mid to upper 90s

00:03:02 Rain outlook: scattered storms, potential for localized heavy rain, low severe risk

00:04:31 Climate Prediction Center outlook: above-normal temps, below-normal precipitation trends

00:05:55 Extended outlooks: limited signals; slight precipitation increase for August

00:06:48 Recent weather recap: storms, uneven rainfall

00:07:58 Wildfire smoke impacts across the Midwest and Iowa

00:10:33 Discussion on repeated heavy rainfall in central Iowa and storm patterns

00:13:44 Temperature extremes: recent highs above 100°F and questionable low temperature readings

00:16:30 Precipitation totals: Osage leading rainfall; continued dryness in northwest Iowa

00:18:51 Home weather station experiment: large discrepancies in rainfall measurements

00:21:50 Specialty crop segment begins

00:22:06 Horticulture Field Day announcement (July 29 in Ames)

00:22:54 Purslane weed management: growth habits and control strategies

00:25:09 Bacterial canker in tomatoes: symptoms and prevention

00:26:17 Rapid crop development due to heat and degree day accumulation

00:26:40 Cyclospora outbreak: food safety considerations and transmission

00:30:12 Trivia answer revealed

Summary generated by Perplexity.ai

It's Swass season, y'all.

00:00:49 – This Day in Iowa Weather History: the 1984 temperature swing from 35°F frost at Elkader to 100°F at Shenandoah in 24 hours

01:19 – Weekly trivia question introduced: what's Iowa's record 24-hour precipitation total?

03:15 – Weather forecast headline: slight severe storm risk overnight, hot and mostly dry week ahead with highs in the low-to-mid 90s

04:12 – Extended climate outlook: hot and dry pattern dominates 6-10 day, and 8-14 day outlooks, with a Level 3 heat risk for northwest/western Iowa July 10-14

08:41 – Past week's weather recap: multiple tornado reports, wind/hail damage, and significant flash flooding over the July 4th weekend

11:09 – Breakdown of extreme rainfall totals from the holiday weekend, including a 12+ inch radar-estimated total near Elkhart and a 10.99" official CoCoRaHS reading in Polk City

11:16 – Guidance on food safety for flooded fields, including National Organic Program waiting periods (90/120 days) and FSMA considerations

15:16 – Why CoCoRaHS gauge density matters, plus a call for listeners to join the network

18:49 – Discussion of why the storm's rainfall was under-forecasted, tied to an upper-level disturbance disrupting the priorheat dome

22:04 – Revisiting "100-year" and "1,000-year" flood terminology and annual exceedance probability

24:23 – Specialty crop impacts: Phytophthora risk in wet cucurbit/pepper fields, growth-regulator herbicide drift symptoms in tomatoes/peppers, and distinguishing drift damage from broad mite infestation

27:03 – Tip on sanitizing surfaces efficiently using a hose-end sprayer

episode summary generated using claude.ai

Resources:

• VDIFN Tool
• Ari's tutorial on YouTube for visual aids
• VDIFN User's Manual
• Crop Risk Tool

[00:00:08] Dan introduces the episode, recorded in advance while he's away, featuring guest Ari Abbrescia, Organic and Sustainable Agricultural Outreach Specialist with UW-Madison Extension.

[00:00:48] Ari provides an overview of the VDIFN (Vegetable Disease and Insect Forecasting Network), including its creators — Dr. Amanda Gevens, Dr. Russ Groves, and Ben Bradford — and its role in supporting integrated pest management across the upper Midwest.

[00:02:06] Dan and Ari dig into a real-world example: why VDIFN appears to show flea beetles absent in Iowa when growers in southern Minnesota are already seeing them.

[00:03:36] Explaining the difference between Fahrenheit degree days (FDD) and growing degree days (GDD), and what those values mean within the flea beetle model.

[00:04:50] Ari clarifies that the VDIFN flea beetle model tracks the first hatched generation — not overwintering adults — which explains the apparent gap between model output and field observations.

[00:07:08] Key takeaway: VDIFN measures risk for damage, not pest presence — an especially important distinction when interpreting disease models like late blight.

[00:07:28] Dan shares how he wants to use VDIFN as a scouting lead-time tool for growers, and discusses Spinosad as a management option against adult flea beetles.

[00:08:42] Ari walks through the seed corn maggot model as a strong example of how VDIFN can directly inform planting timing decisions based on Fahrenheit degree day thresholds.

[00:10:18] Discussion of the early blight model for tomato, including how to use the biofix date and P-day accumulation to time preventative fungicide applications.

[00:11:14] Ari explains what P-days (physiological days) are and how they relate to degree days and disease severity tracking.

[00:14:31] Introduction of the Crop Risk Tool — a newer, still-developing tool built by Ben Bradford that allows users to save named locations, upload CSV field lists, and view risk across multiple models for specific sites.

[00:15:59] A key advantage of the Crop Risk Tool: it includes a 14-day NOAA-based forecast, allowing growers to look ahead and plan management decisions proactively.

[00:17:37] Comparing the two tools — VDIFN excels at visualizing spatial patterns and the movement of pest risk across the landscape; the Crop Risk Tool excels at site-specific, forward-looking risk assessment.

[00:19:23] Dan and Ari share a common wish-list feature: the ability for growers to select and view only their key pests and diseases for a saved location, rather than toggling through categories. Ari adds that text alerts are also a dream feature in early development.

[00:20:10] Dan notes that squash bugs and cucumber beetles are absent from VDIFN, sparking a discussion about overwintering adult pests and the diseases they vector, including bacterial wilt and squash mosaic virus.

[00:21:05] Conversation turns to Western flower thrips and onion thrips — including uncertainty about whether VDIFN's thrips model covers one, the other, or both — and whether the distinction matters for tomato spotted wilt virus management.

Episode summary generated using claude.ai

Welcome & Iowa Weather History: The 1952 F4 Tornado and the Train that raced to outrun it [00:00:07]

7-Day Weather Forecast: Quieter Pattern, QPF Totals, and Warming Trend [00:01:15]

Ring of Fire & Ridge Riders: How the Setup Affects Iowa Rain Chances [00:02:13]

8–14 Day & Monthly Climate Outlooks: Warm Signal, Near-Normal Precip, and El Niño Influence [00:02:39]

8–14 Day Hazards: Slight Risk for High Temps and Heavy Precip in Southern Iowa [00:04:45]

Northwest Iowa Dryness vs. Southeast Wetness: Farmer Reports and Crop Conditions [00:06:56]

Past Week Weather Notables: EF2 Tornado, Tornado Climatology, and Illinois' Record Year [00:07:38]

Temperature Trends: Cooler-than-Normal Stretch Easing Stress from Low Rain [00:11:01]

Weekly Superlatives: Warmest, Coolest, and Wettest/Driest Gauges [00:11:51]

Specialty Crop Impacts: Cabbage Black Rot, Kale Leaf Spots, and Squash Vine Borer Alerts [00:12:48]

Overwintered Onion Success and Weed Management Benefits [00:15:23]

Upcoming Events: Controlled Environment Ag Short Course, ISCGA Field Day, Choose Iowa Farm Crawl [00:16:17]

Special Forecast for Farm Crawl and Next Week's Episode Preview: Pest Forecasting with Degree-Day Models [00:17:57]

Episode summary generated using perplexity.ai

Episode Summary

00:00:32 – Iowa weather history: a severe 1978 thunderstorm with softball-sized hail and damaging winds from Sioux City to Webster City

00:01:09 – Follow-up on the latest recorded frost in Iowa history (June 22, 1902, in Columbus Junction) and the cooler global climate trends of that era

00:02:21 – Weekly forecast: continued active weather, more rain Saturday night into Sunday, near-normal temperatures trending slightly cooler next week, and comfortable dew points

00:03:34 – Breakdown of the storm system moving through Iowa, including a 94 mph wind gust in Marshalltown and discussion of squall lines, the low-level jet, and derecho criteria

00:07:37 – Whether last week's 8-to-14-day hazard outlook predicted this week's severe weather event

00:09:14 – New 8-to-14-day outlook (June 24–30): slightly cooler and wetter than normal, no hazards expected

00:10:06 – Three-to-four-week outlook (June 27–July 10): equal chances for above/below/near normal temperature and precipitation

00:10:35 – Discussion of June running about 4°F above the 30-year average so far

00:11:51 – Past week's weather recap: the June 10 derecho, a tornado in Washington County, and severe wind/hail damage on June 11 in southwest Iowa

00:14:37 – Verification of last week's rainfall forecast (heavy in the southeast, minimal in the northwest) and impacts on weed cultivation

00:15:34 – Weekly weather data: highs, lows, and rainfall totals across the state

00:16:14 – Recap of a windier-than-normal meteorological spring (March–May)

00:17:38 – Outlook for a wetter Gulf/southern US and its connection to a possible cooler July-August-September signal for Iowa

00:20:46 – Drought risk specifically for northwest Iowa given drier conditions there

00:21:32 – Specialty crop pest and disease update: cucumber beetles, squash vine borer, aster leafhopper/aster yellows, Japanese beetles, and halo blight on green beans

00:25:40 – Cool temperatures expected to delay heat-loving crops like tomatoes, peppers, and sweet corn

00:26:29 – Weed control strategy: understanding the "critical weed-free period" for different crops

00:27:39 – Reminder to report suspected herbicide spray drift (2,4-D/dicamba) to IDALS

00:28:52 – Upcoming Controlled Environment Ag Short Course in Ames

summary generated using claude.ai

• [00:00:42] This day in Iowa weather history: a late freeze in 1928 brought 32°F lows to Decorah and frost across the state
• [00:01:22] Weekend forecast: a break from the heat is coming, but severe weather is likely — enhanced risk (3 of 5) for much of Iowa, with 3–5 inches of rain possible in the southern third of the state
• [00:03:15] Climate outlook 6–10 days (June 15–19): 60–70% chance of below-normal temperatures for northern Iowa
• [00:04:24] Climate outlook 8–14 days (June 17–23): continued slight chance of below-normal temps; slightly wetter conditions expected; slight risk of heavy precipitation for eastern Iowa, Illinois, and Missouri
• [00:06:22] Past week recap: eastern Iowa saw 3½ inches above-normal rainfall; statewide temperatures ran 4–10 degrees above normal
• [00:07:49] Extreme data points of the week: high of 95°F at Sioux City; 5.9 inches of rain in Russell (Lucas County); dew points hitting 79°F at Osceola
• [00:09:57] Weather explainer: what is the boundary layer, and why doesn't the overnight low always drop to the dew point?
• [00:11:00] Specialty crop update: tomato trellising, weed control, and irrigation underway; poor strawberry yields reported statewide
• [00:12:31] Pest and disease alerts: growth regulator spray drift reports continue (report to IDALS if you see it); bacterial canker detected in a Kalona greenhouse tomato high tunnel; spider mites active in high tunnels
• [00:14:28] Meteorological spring recap: 7th warmest spring on record at 52°F average; near-normal precipitation; 51 tornadoes reported vs. a climatological average of 38

Summary generated by Claude.ai

[00:00:30] This day in Iowa weather history: the devastating 1860 tornado outbreak across central and eastern Iowa that killed at least 134 people and left 2,500 homeless

[00:02:44] Weekly weather forecast: rain chances Thursday and Friday, ¾"–1.5" possible; highs in the 80s, lows in the 60s

[00:03:35] 8–14 day outlook (June 10–16): above-normal temperatures, slightly wetter conditions; slight risk of hazardous temperatures June 10–11

[00:04:08] One-month outlook for June: leaning slightly above-normal temps; equal chances for precipitation

[00:05:57] Last week's weather recap: generally dry across Iowa with spotty pop-up showers; a downburst near Jefferson caused local damage; Missouri Valley led the state with 4.1" of rain

[00:08:53] Rapid onset drought risk warning for parts of eastern and northeastern Iowa

[00:09:37] Last week's temperature extremes: high of 95°F at Sioux City; lows of 47°F at multiple stations

[00:09:56] Data quality spotlight: investigating a suspicious 25°F low temperature reading

[00:11:15] Specialty crop update: leafhopper and hopper burn emerging in potatoes; Colorado potato beetle populations ramping up

[00:13:11] Managing thrips in flowers and onions; overview of organic and conventional control options including Captiva Prime as a novel tank mix

[00:15:48] Pesticide rotation strategies to prevent resistance in thrips and Colorado potato beetles

[00:17:59] Aster leafhopper and aster yellows: MSU infectivity alert now at 4%; crops to watch include garlic, flowers, and lettuce

[00:18:50] Strawberry pests: thrips damage and tarnished plant bug as the primary cause of cat-faced fruit

[00:19:22] Garlic scape management: timing of removal, yield impacts, and research exploring mowing as an option for large scale removal

[00:22:01] Upcoming event: Controlled Environments Short Course in Ames, Iowa in three weeks

summary generated using Claude.ai