Storm Updates: Ohio Valley Marginal, Arizona Flood Moderate — Wednesday, September 16, 2026

This is a live Wednesday afternoon snapshot of U.S. local-storm activity as of Wednesday, September 16, 2026. The Storm Prediction Center 2000 UTC Day 1 Convective Outlook still holds a Marginal Risk of isolated strong to severe thunderstorms over parts of northern Utah and parts of Ohio and vicinity. No convective watches are valid. Two mesoscale discussions are out this afternoon — MD 2302 for east-central Indiana into central Ohio and MD 2303 for northeastern Utah — both tagged severe potential, watch unlikely. The Weather Prediction Center Day 1 Excessive Rainfall Outlook still holds a Moderate Risk over portions of southern and central Arizona and the Sacramento Mountains of New Mexico. There is no named tropical cyclone threatening U.S. land.

What is organized this afternoon is water in the Southwest, not a Midwest derecho. Restoration exposure is isolated damaging wind or hail if a cell or small cluster holds together in Ohio or Utah, plus flash flood and burn-scar runoff where the monsoon plume sits over Arizona, New Mexico, southern Utah, and the San Juans. Conditions change by county. Verify with the National Weather Service before you roll.

What is live this afternoon

SPC issued the 2000 UTC Day 1 Convective Outlook at 0232 PM CDT, valid 162000Z–171200Z. Headline: isolated strong to severe thunderstorms appear possible today across parts of the Midwest/Ohio Valley and Utah/far northwest Colorado. The 20Z update said the forecast remains generally on track with only minor changes. Risk-area population centers listed by SPC include Columbus, Pittsburgh, Fort Wayne, Akron, and Salt Lake City. Categorical risk is Marginal only. No Slight Risk. No tornado probabilities.

Current convective watches: none. Most recently issued watch was Severe Thunderstorm Watch 669, already expired. Do not treat 669 as a live product.

MD 2302, issued 0246 PM CDT for east-central Indiana into central Ohio, valid through 162145Z: isolated thunderstorms near the Indiana/Ohio state line ahead of a stalled front. Temperatures in the 80s to near 90 F with mid-70s dewpoints. Effective shear 20–30 kt. Most probable peak gust up to 60 mph. Watch issuance probability 5 percent.

MD 2303, issued 0353 PM CDT for portions of northeastern Utah, valid through 162300Z: a developing supercell in a 500–1000 J/kg MLCAPE environment with 40–50 kt effective shear. Primary risk large hail (most probable 1.00–1.75 inches) plus isolated damaging gusts up to 60 mph. Watch issuance probability 20 percent. Watch still unlikely.

WPC Day 1 excessive rainfall, valid 12Z Wednesday through 12Z Thursday, keeps the organized water story in the Southwest. Moderate Risk over southern and central Arizona, including the Phoenix metro and the Mogollon Rim, and over the Sacramento Mountains of New Mexico around the Ruidoso burn-scar country. High-end Slight Risk covers much of Arizona into southern Utah, southwestern Colorado, and much of New Mexico. Isolated to widely scattered flash-flood prospects remain possible later across parts of Illinois, Indiana, and Ohio if cells train on the residual front, and again tonight along the I-80 corridor from Iowa into northern Illinois.

SPC preliminary storm reports for the current 16/1200Z–17/1159Z window show no tornado, hail, or wind reports as of this afternoon desk. Yesterday’s 15/1200Z–16/1159Z window is the just-hit file.

Hotspot 1 — East-central Indiana into central and eastern Ohio

SPC’s 1630 and 2000 UTC discussions keep the Ohio Valley on precip-loaded downdrafts, not supercells. PWAT values approaching 2 inches and steep low-level lapse rates can still produce strong or occasionally damaging winds. MD 2302 is the afternoon confirmation that cells are already firing near the state line. Coverage is widely scattered. Poor mid-level lapse rates should limit how long any one core lasts.

Overnight flash-flood warnings from Wilmington, Ohio, and Northern Indiana for Mercer County, Ohio, and Grant, Blackford, Adams, and Wells counties, Indiana, have expired. Those counties already took 1.5 to 3 inches before dawn. That water is still on the ground even if the warning product is dead.

Restoration read: wind first if a cluster organizes through early evening, then trees and lines. Water first in the counties that already flooded overnight. Stage tarps and tree crews in the Fort Wayne–Dayton–Columbus–Pittsburgh belt before the first new warning, not after it.

Hotspot 2 — Southern and central Arizona, Sacramento Mountains of New Mexico

This remains today’s organized flood ticket. WPC language still prints 2–3 inches, locally higher, where storms focus on the south-central Arizona desert including Phoenix and surrounds, the Mogollon Rim, southern Utah slot-canyon country from Zion toward Moab, the San Juans of Colorado, and the Sacramentos. Rates above 1 inch per hour for multiple hours are in the discussion. Burn-scar debris flow remains the life-safety language around Ruidoso and similar terrain.

SPC did not hang severe probabilities over Arizona and New Mexico on the 2000 UTC outlook. Water is the story. Gusty outflow is possible. Do not invent a severe-thunderstorm watch here.

Restoration read: extraction and drying on a 24–48 hour mold clock if cells stall over the same ZIP. Photograph interiors only when it is safe. Do not drive flooded washes. Turn around, don’t drown.

Hotspot 3 — Northeastern Utah into far northwest Colorado

Moisture has increased across Utah over the past 24 hours, with dewpoints in the low-to-mid 50s and PWAT over 1 inch. A band of 35–45 kt southwesterly mid-level flow is enough for a few rotating storms. MD 2303 is the live product on that cell: hail first, isolated wind second, watch unlikely. Grand Junction’s overnight flash-flood warning for the Lee Burn Scar in central Rio Blanco County expired before dawn. That scar can still run if another core sits on it.

Restoration read: isolated hail and wind tickets around the Wasatch Front and northeastern Utah valleys if the supercell holds. Burn-scar runoff is a separate life-safety problem from a roof-survey call in Salt Lake, West Valley, Provo, or Orem.

Just hit

SPC preliminary storm reports for 15/1200Z–16/1159Z show no tornadoes. Hail included 2.00 inches at Edgerton, Johnson County, Kansas; 1.75 inches west of Cairo, Randolph County, Missouri; 1.50 inches near Alta, Peoria County, Illinois; and 1.00-inch stones at Smyer, Texas, and Richmond, Missouri. Wind included 75 mph at McConnell Air Force Base in Sedgwick County, Kansas, with wall panels ripped at a nearby plant; 71 mph at Alva, Oklahoma, and railroad cars overturned east of Avard; 70 mph near Morton, Texas, and southeast of Hazelton, Kansas; an RV flipped west of Smyer, Texas; 67 mph south of Junction, Utah; trees and lines in Richmond and the Kansas City suburbs (Greenwood, Pleasant Hill, Lake Winnebago, west of Raytown); trees and lines in Congerville and Brimfield, Illinois; 65 mph near Wallen, Allen County, Indiana; numerous trees down near Lake Wawasee, Kosciusko County, Indiana; and power lines down near Humble City and Eunice, New Mexico.

Kansas City/Pleasant Hill still has river flood warnings on the Grand River near Chillicothe, Sumner, and Brunswick with crests later this week. That is channel water from Tuesday night, not a new convective watch. Tuesday afternoon’s Storm Tracker covered the Kansas–Missouri Moderate flood risk while it was live. This afternoon treats that corridor as aftermath plus river follow-through.

Pulse table

What this means for restoration teams

Wind at 60 mph is trees, lines, gutters, and isolated roof work — not a regional CAT. Two-inch hail from last night is already a roof-survey ticket in Johnson County, Kansas. Flash flooding on the Arizona–New Mexico Moderate Risk is wet drywall and a same-night extraction clock if water is inside. Grand River crests later this week are a separate staffing problem from today’s monsoon cells. Do not send one crew to both stories without checking which county has a warning now.

For teams near the Ohio Valley Marginal: the afternoon window is now, not tonight. Property owners should photograph damage in daylight if it is safe, call the carrier, and start extraction the same night if water is inside.

What this is not

This is not a Slight Risk day, not a live watch, and not a U.S. mainland hurricane landfall. NHC reports no tropical cyclones in the Atlantic, eastern Pacific, or central Pacific as of this afternoon. Two MCDs with watch-unlikely tags are not watches. The work, if it verifies, will be scattered: a wind swath through an Indiana or Ohio county, a hail core in northeastern Utah, a flooded wash in Arizona or New Mexico, leftover river water in north-central Missouri.

Looking ahead

SPC Day 2 (Thursday, valid 171200Z–181200Z) currently carries no severe thunderstorm areas. The 1730 UTC Day 2 discussion leaves room for later low-end wind probabilities near the Appalachians and Ohio Valley but kept the threat too marginal for an outlook area in this update. WPC still has a nocturnal Slight flood overlay from Iowa into northern Illinois late tonight, plus lingering Southwest water. The next Storm Tracker update should re-check the 0100 UTC Day 1 outlook and any new watches rather than assuming this afternoon’s Marginal stays the last word.

Sources and how to verify

Primary sources: NOAA Storm Prediction Center Sep 16, 2026 2000 UTC Day 1 Convective Outlook (Chalmers/Weinman, previous Hart/Chalmers); 1730 UTC Day 2 Convective Outlook; current convective watches (none valid; last issued Watch 669); Mesoscale Discussion 2302; Mesoscale Discussion 2303; SPC preliminary storm reports for 20260916 and 20260915; Weather Prediction Center Day 1 Excessive Rainfall Outlook (Kleebauer, 352 AM EDT); National Hurricane Center Tropical Weather Outlooks, September 16, 2026 (no tropical cyclones in Atlantic, eastern Pacific, or central Pacific).

Morning desk: Wednesday, September 16 morning Storm Updates. Prior afternoon: Tuesday, September 15 afternoon Storm Updates.

Check weather.gov for the county warning, spc.noaa.gov for the outlook, watch, MD, and LSRs, and WPC excessive rainfall for the flood overlay.

Informational only — not an official weather warning. Follow local authorities and the National Weather Service. Turn around, don’t drown.