This is a live Friday morning snapshot of U.S. local-storm activity as of early Friday, September 18, 2026. Overnight convection dumped tennis-ball hail on Bingham County, Idaho, knocked power lines down near Lewisville, and forced National Weather Service flash-flood warnings for the Idaho Falls and Rexburg areas that expired before dawn. The Storm Prediction Center 1300 UTC Day 1 outlook holds a Marginal Risk of isolated severe thunderstorms from the Carolinas into northern Georgia, across Iowa, over parts of the central High Plains, and again in the Intermountain West. No convective watches are valid. The Weather Prediction Center Day 1 Excessive Rainfall Outlook holds Slight Risks over the Upper Mississippi Valley and southwest Montana. There is no named tropical cyclone threatening U.S. land.
These are county- and ZIP-scale thunderstorms and flash-flood pulses, not a mainland hurricane landfall. Restoration exposure today is leftover hail and interior water in eastern Idaho, isolated damaging gusts on the Carolina Piedmont and in Iowa this afternoon, and training rain from southern Minnesota into Wisconsin tonight. Conditions change fast. Verify with the National Weather Service for the specific county or ZIP before you roll.
What is live this morning
SPC issued the 1300 UTC Day 1 Convective Outlook at 0719 AM CDT. Valid 181300Z–191200Z. Headline: an isolated severe risk later today into the evening for the Carolinas into northern Georgia, Iowa, parts of the central High Plains, and parts of the Intermountain West. Categorical risk is Marginal over about 171,000 square miles and roughly 21 million people. Wind is the shared 5 percent contour. A 2 percent tornado contour sits over north-central Iowa (Ames, Ankeny, Mason City, Fort Dodge, Marshalltown). A 5 percent hail contour remains over the Salt Lake City–Provo corridor.
No Severe Thunderstorm Watch or Tornado Watch is in effect. The most recently issued watch on the SPC board is Watch 669, already expired. Today’s 1200 UTC–onward local storm report page is empty as of this desk: no tornado, hail, or wind reports on the new cycle yet. Last night’s work is on the September 17 cycle.
WPC’s 1034 UTC Day 1 Excessive Rainfall Outlook, valid 12Z Friday through 12Z Saturday, holds a Slight Risk of rainfall exceeding flash-flood guidance over the Upper Mississippi Valley (southern Minnesota into Wisconsin and adjacent Iowa/Illinois) and a separate Slight over southwest Montana. Marginal flood pockets cover leftover Southwest terrain, the northern High Plains, South Florida and the Keys, a Midwest/Great Lakes corridor, and the Ohio Valley into the central Appalachians. Guidance still supports 2 to 4 inches in the better Upper Midwest swath.
The National Hurricane Center 800 AM EDT Atlantic outlook and companion eastern and central Pacific outlooks list no tropical cyclones. That sentence stays off the restoration board unless NHC names something that threatens U.S. land.
Overnight into this morning
Thursday’s SPC report cycle (1200 UTC September 17 through 1159 UTC September 18) is the just-hit file. One brief tornado was reported 11 miles north-northeast of Chappell in Garden County, Nebraska, around 0034 UTC. Hail clustered on eastern Idaho: 1.00 to 1.75 inches around Blackfoot, Shelley, Firth, Moreland, and Menan; 2.50 inches (tennis ball) one mile north-northeast of Rose in Bingham County; 1.25 inches at Gannett in Blaine County; 1.00 inch east of Alton in Bear Lake County. Utah added 1.50 inches at Midway in Wasatch County. Nebraska High Plains added 1.50 inches east-southeast of Broadwater. Missouri picked up 1.00 inch near Saint Paul in St. Charles County.
Wind: power lines down in Lewisville, Jefferson County, Idaho; 61 mph at the INL rover south-southwest of Mud Lake; trees and shingles near Saint Paul, Missouri; a 59 mph gust at Truth or Consequences, New Mexico; trees down in Tippecanoe and Carroll counties, Indiana; a large tree on Yalta Drive in Beavercreek, Ohio; several large trees in Ashland, Kentucky, with one person injured and transported when a tree fell. Overnight flash-flood warnings for the Idaho Falls area (until 2:00 AM MDT) and the Rexburg area (until 2:45 AM MDT) have expired. Those were water jobs on eastern Idaho drainages after the same hail cores, not a new watch this morning.
Hotspot 1 — Carolinas into northern Georgia
A cluster of weak thunderstorms this morning over Kentucky and West Virginia rides south on northerly flow around a mid-level high over the Ark-La-Tex. SPC expects rejuvenation near convective outflow along the Virginia–North Carolina border, then scattered storms over the Piedmont into northern Georgia as the boundary layer heats. Isolated 50–60 mph gusts are the advertised threat. Cities inside the Marginal contour include Charlotte, Raleigh, Greensboro, and Atlanta.
Restoration read: wind first, not a tornado outbreak. Stage tarps and tree crews for late afternoon into evening. Photograph roofs in remaining daylight only if it is safe. This is a scatter of cores, not a watch-boxed line.
Hotspot 2 — Iowa and the Upper Mississippi Valley
A front lies from the lower Ohio Valley west into the mid Missouri Valley, with a weak surface low over western Nebraska. Lower-70s dewpoints sit south of the boundary. SPC favors thunderstorms over Iowa into far southern Minnesota where heating and low-level forcing erode inhibition. Primary hazard is marginally severe gusts. Enlarged hodographs near the warm front leave a localized chance of a couple of weak, short-lived supercells — that is the 2 percent tornado contour, not a Slight Risk upgrade. Upscale growth late evening would drift toward the southwest Great Lakes and lose buoyancy.
WPC’s Slight Risk is the organized water ticket. A disturbance tracking out of the Dakotas across southern Minnesota into Wisconsin can support 2–4 inches where the low-level jet blossoms the rain shield. That is wet drywall and a 24–48 hour mold clock in the better swaths, not a river-flood headline yet.
Restoration read: Iowa wind this afternoon, Minnesota–Wisconsin water tonight. Do not staff both with the same crew without checking which county has a warning now.
Hotspot 3 — Intermountain West and central High Plains
A mid-level trough crosses the Intermountain West. Dewpoints in the 50s from northern Utah into western Wyoming valleys, MLCAPE 1000–1200 J/kg, and moderate shear support isolated severe gusts and hail again late afternoon and evening — the same corridor that just put tennis-ball hail on Bingham County. On the High Plains, a vorticity maximum over New Mexico may help isolated storms grow into a small eastward cluster over eastern Colorado into southwest Nebraska and northwest Kansas, with isolated severe gusts on outflow.
Southwest Montana sits under WPC’s second Slight Risk after Thursday’s cell behavior and ensemble 2-inch QPF. Rates can still beat flash-flood guidance even if storms stay progressive. Residual Marginal flood language covers New Mexico and Arizona terrain for one more diurnal cycle.
Just hit
Eastern Idaho hail, the expired Idaho Falls and Rexburg flash-flood warnings, the Garden County brief tornado, and the Ashland, Kentucky tree injury are yesterday’s tickets. Thursday afternoon’s Storm Tracker already carried the Idaho–Utah Marginal and Dakotas flood Slight on the prior Day 1 package. This morning desk moves the live outlook east onto the Carolinas and Iowa and slides the flood Slight onto the Upper Mississippi Valley and southwest Montana.
Pulse table
| Region | Main threats | SPC / NWS / WPC level | Status this morning |
|---|---|---|---|
| Carolinas / northern GA | Isolated 50–60 mph gusts | SPC Marginal | Afternoon–evening cells |
| Iowa / southern MN | Gusts; localized brief tornado | SPC Marginal; 2% tornado | Afternoon into evening |
| Southern MN / WI / adjacent IA–IL | Flash flood, 2–4″ swaths | WPC Slight | Today’s organized water ticket |
| Northern UT / ID / WY valleys | Isolated hail and severe gusts | SPC Marginal (5% hail UT) | Late afternoon–evening |
| E CO / SW NE / NW KS | Isolated severe gusts | SPC Marginal | Evening cluster possible |
| Southwest Montana | Flash flood on progressive cells | WPC Slight | Afternoon–evening |
| Bingham / Jefferson / Madison ID | Hail, wires, expired FFWs | Aftermath | Just-hit desk |
| Atlantic / Gulf vs. U.S. mainland | No landfalling cyclone | NHC quiet | Quiet |
What this means for restoration teams
Idaho hail is already on cars, windows, and roofs in Bingham County. That is same-day emergency board-up and a multi-day supplement fight, not a forecast. Carolina and Iowa wind at 50–60 mph is roof, siding, gutter, and tree-on-structure work if cores verify. Upper Mississippi Valley rain is extraction and drying if 2–4 inch swaths land on saturated ground. A 2 percent tornado contour is a narrow, short-lived threat — staff it as a local damage survey if a warning verifies, not as a regional event.
For teams near Charlotte, Raleigh, Atlanta, Des Moines, Ames, or the Salt Lake valley: stage before peak heating, not after the first warning. 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 convective day, not a live watch, and not a U.S. mainland hurricane landfall. The work today, if it comes, will be scattered: a wind-damaged street on the Piedmont, a brief spin-up near an Iowa warm front, another hail core in a Utah or Idaho valley, a flooded underpass in southern Minnesota or Wisconsin. That is the local-storm pattern this desk should staff.
Looking ahead
Saturday’s Day 2 outlook is already a Slight Risk of scattered severe wind and hail over portions of the central Plains, with isolated severe storms possible from the High Plains and central Rockies into the Midwest and Southeast. Sunday is Marginal. Day 4–8 has no 15 percent areas. Watch the afternoon Storm Tracker for the 1630 UTC Day 1 update rather than assuming this morning’s Marginal is the last line of the weekend.
Sources and how to verify
Primary sources: NOAA Storm Prediction Center Sep 18, 2026 1300 UTC Day 1 Convective Outlook (Smith/Mead); SPC current watches page (none valid; last watch 669); SPC local storm reports for 20260917 and 20260918; Weather Prediction Center Day 1 Excessive Rainfall Outlook issued 1034 UTC Friday; National Hurricane Center 800 AM EDT Friday Tropical Weather Outlook; National Weather Service Pocatello flash-flood warning text for Idaho Falls and Rexburg, now expired.
Check weather.gov for the county warning, spc.noaa.gov for the outlook, watch, and LSRs, and WPC excessive rainfall for the flood overlay. Prior desk: Thursday afternoon Storm Updates: Idaho–Utah Marginal, Dakotas Flood Slight. Related overnight posts: Idaho Falls flash-flood warning and Rexburg flash-flood warning.
Informational only — not an official weather warning. Follow local authorities and the National Weather Service. Turn around, don’t drown.