Storm Updates: Carolinas Wind Pulse + Upper Mississippi Flood Slight — Friday, September 18, 2026

This is a live Friday afternoon snapshot of U.S. local-storm activity as of Friday, September 18, 2026. The Storm Prediction Center 2000 UTC Day 1 Convective Outlook holds a Marginal Risk of isolated severe thunderstorms from the Carolina Piedmont into northern Georgia, northern Iowa, parts of the central High Plains, and parts of the Intermountain West. No convective watches are valid. Mesoscale discussions referenced in the 2000 UTC package (MCDs 2306 and 2307) are no longer in effect. The Weather Prediction Center Day 1 Excessive Rainfall Outlook is the organized ticket: Slight Risk over portions of the Upper Mississippi Valley and a second Slight Risk over southwest Montana. There is no named tropical cyclone in the Atlantic, eastern Pacific, or central Pacific.

These are county- and ZIP-scale thunderstorms and flash-flood pulses, not a mainland hurricane landfall. Restoration exposure this afternoon is wind and trees already verifying across central North Carolina, isolated hail leftover from Intermountain cells, and water tonight from southeast Minnesota into west-central Wisconsin. Conditions change fast. Verify with the National Weather Service for the specific county or ZIP before you roll.

What is live this afternoon

SPC issued the 2000 UTC Day 1 Convective Outlook at 0241 PM CDT, valid 182000Z–191200Z. Forecasters Chalmers and Wendt made only minor adjustments from the midday package. Headline: an isolated severe risk continues for portions of the Carolinas into northern Georgia and parts of the Intermountain West. Isolated severe storms are also forecast later today across portions of northern Iowa and parts of the central High Plains. Risk-area population centers listed by SPC include Charlotte, Atlanta, Raleigh, Greensboro, and Durham. Categorical risk is Marginal only. No Slight Risk on Day 1. No tornado probabilities in the 2000 UTC categorical headline. Risk-area size on the 2000 UTC graphic is about 179,316 square miles covering roughly 19.6 million people.

Current convective watches: none. SPC watch page last updated 1805 UTC Friday: no watches currently valid. Most recently issued watch remains Severe Thunderstorm Watch 669, already expired. Do not treat 669 as a live product.

The 2000 UTC discussion points to MCDs 2306 and 2307 for additional information. By late afternoon the live MD list showed no mesoscale discussions currently in effect. Most recently issued discussion on the current-MD page was 2305. Treat those numbers as the latest issued discussions, not standing watches.

WPC Day 1 excessive-rainfall language valid 16Z Friday through 12Z Saturday holds Slight Risk for portions of the Upper Mississippi Valley and southwest Montana. The 16Z update expanded the eastern edge of the Slight and high-end Slight about one to two counties into southeast Wisconsin and northeast Illinois, where recent heavy rain left the ground sensitive. Highest amounts still focus over southeast Minnesota and west-central Wisconsin, with model-consensus QPF in the 2 to 4 inch range. A separate Slight Risk covers southwest Montana. Marginal Risk remains over South Florida and the Keys, a remnant Intermountain/Southwest terrain corridor, a Northern Plains strip, and a thin Ohio Valley pocket. WPC’s short-range discussion already flags a Moderate Risk of excessive rainfall Saturday over parts of the Upper Great Lakes into the Middle Mississippi Valley. That is tomorrow’s water upgrade, not today’s Day 1 map.

Hotspot 1 — Carolina Piedmont into northern Georgia

A wavy stationary front this morning ran from southern Illinois through southern Indiana and southern Ohio into southwest Pennsylvania. Decaying showers preceded it from southern Illinois into northern Kentucky. The boundary is shifting south as cooler air follows a shortwave through southern Quebec and the Canadian Maritimes. The front is relatively weak, but it is interacting with a warm, moist, diurnally destabilized airmass across the Carolina Piedmont and northern Georgia. Precipitable water is over 2 inches. Vertical shear is weak. Storm mode is outflow-dominant. The risk is occasionally strong downbursts, not a long-lived supercell corridor.

That language already verified this afternoon. Preliminary LSRs on the 18/1200Z cycle include a 69 mph gust at KGSO (5 ESE Colfax, Guilford County), a 66 mph gust at KFAY (4 ENE Hope Mills, Cumberland County), trees down on I-85 near Route 68, trees blocking roads in Randolph, Davie, Iredell, Rowan, Chatham, and Moore counties, and a power-company outage from downed trees northwest of Craven in Rowan County. Those are trees-on-pavement and trees-on-wires tickets in the Charlotte–Greensboro–Fayetteville corridor, not a watch-scale outbreak.

Restoration read: wind first. Stage tree, tarp, and board-up capacity for the Piedmont counties that already have LSRs. Hail is not the lead threat on this corridor. Water is secondary unless a cell trains over the same ZIP that already took a 2-inch precipitable-water plume.

Hotspot 2 — Upper Mississippi Valley water

A Northern Plains disturbance continues east from the Dakotas across southern Minnesota into Wisconsin tonight. WPC keeps the Slight Risk and high-end Slight focused on southeast Minnesota and west-central Wisconsin, with the eastern edge nudged into southeast Wisconsin and northeast Illinois because those counties already took rain. Local NWS language from La Crosse this afternoon still has 1–3 inches likely and 4–6 inches possible in pockets, with a Flood Watch south of I-94 and rivers such as the Kickapoo at Gays Mills and Viola and the Cedar at Charles City expected to reach minor flood stage if the heavier corridor verifies.

SPC’s northern Iowa Marginal is a separate overlay: elevated storms tonight on warm-air advection and a moderate low-level jet, with isolated hail the primary severe hazard and a strong gust or two if any linear structures develop. That is hail and wind on the southern edge of the water corridor, not a Slight Risk severe day.

Restoration read: water first from southeast Minnesota through west-central Wisconsin into northeast Iowa tonight. Extraction and wet-drywall clocks start the same night if water is inside. Do not send the same crew to a Piedmont tree job and a Kickapoo basement without checking which county has a warning now.

Hotspot 3 — Intermountain West and central High Plains

A shortwave trough continues east into southern Idaho and northern Utah. Highs stay relatively cool — upper 60s in southern Idaho, low to mid 70s in northern Utah — but cold temperatures aloft plus strong deep-layer shear still support organized updrafts. Isolated severe gusts and small hail remain the SPC language. That already verified on today’s LSR cycle: 1.50-inch hail 2 W of Kaysville in Davis County, Utah, and quarter-size hail near Farmington in San Juan County, New Mexico.

On the High Plains, a mid-level vorticity maximum lifting north-northeast later this evening may support isolated severe gusts and a conditional, less-than-5-percent hail risk if a more cellular mode holds into better low-level moisture near the Colorado–Nebraska–Kansas border. Storms may grow upscale into a small eastward-moving cluster this evening. Isolated outflow surges, not a derecho.

Restoration read: hail first if cells verify over the Wasatch Front or the Four Corners. Wind second if High Plains clusters organize. Flash-flood risk on this corridor is Marginal to isolated except for the separate southwest Montana Slight Risk, where WPC introduced Slight coverage after Thursday’s cell behavior and 0.5–1.5 inch guidance.

Just hit

SPC preliminary storm reports for the current 18/1200Z–19/1159Z cycle already include one brief landspout at Lighthouse Point in Broward County, Florida (palm fronds lofted; no damage path described as a supercell tornado), quarter to 1.50-inch hail in San Juan County, New Mexico, and Davis County, Utah, and a long list of North Carolina wind reports from Davie, Guilford, Randolph, Cumberland, Iredell, Rowan, Chatham, and Moore counties, including measured 69 mph at Greensboro and 66 mph at Fayetteville.

The last 24-hour ticket pile on the prior cycle (17/1200Z–18/1159Z) is the Idaho hail outbreak the morning desk already logged: tennis-ball hail (2.50 inches) near Rose in Bingham County, golf-ball hail in Blackfoot and Shelley, quarter to 1.25-inch hail across Bingham, Blaine, Jefferson, and Bear Lake counties, plus 1.50-inch hail at Midway, Wasatch County, Utah, and 1.50-inch hail near Broadwater, Morrill County, Nebraska. Wind on that cycle included power lines down at Lewisville, Jefferson County, Idaho; a 61 mph gust south-southwest of Mud Lake; trees in Beavercreek, Greene County, Ohio; a tree-fall injury in Ashland, Boyd County, Kentucky; and trees in Tippecanoe and Carroll counties, Indiana. A brief tornado touchdown was reported 11 NNE of Chappell in Garden County, Nebraska. Those products are expired. The roofs and cars in Bingham County are still the ticket.

This morning’s Storm Tracker already covered the 1300 UTC outlook family. This afternoon desk updates to the 2000 UTC package, confirms still-zero watches, and adds the live North Carolina LSR cluster and the WPC 16Z flood-edge nudge into southeast Wisconsin and northeast Illinois.

Pulse table

What this means for restoration teams

The live ticket this afternoon is wind on the Carolina Piedmont: trees, wires, and a measured 66–69 mph pair at Greensboro and Fayetteville. Isolated Intermountain hail is a roof and auto-glass survey if cells keep firing over the Wasatch Front or Farmington, New Mexico. The organized ticket tonight is still water from southeast Minnesota through west-central Wisconsin. Idaho’s overnight tennis-ball hail around Blackfoot, Rose, and Shelley is a separate just-hit staffing problem from this afternoon’s Piedmont wind.

For teams near the Carolina Marginal: the warnings and LSRs are already out. Photograph damage in daylight if it is safe, call the carrier, and start extraction the same night if water is inside. Turn around, don’t drown on Upper Mississippi and Montana washes.

What this is not

This is not a Slight Risk severe day, not a live convective watch, and not a U.S. mainland hurricane landfall. MCDs 2306 and 2307 are not watches. The Broward landspout is a brief landspout LSR, not a tornado outbreak. NHC reports no tropical cyclones in the Atlantic, eastern Pacific, or central Pacific as of this afternoon. The work, if it keeps verifying, will be scattered: a tree swath through a Piedmont county, a hail report on the Wasatch Front, and heavier rain over southeast Minnesota and west-central Wisconsin tonight.

Looking ahead

SPC Day 2 (Saturday) holds a Slight Risk of severe thunderstorms late Saturday afternoon and evening from northwest Oklahoma into eastern Kansas, with more isolated severe storms possible across the central High Plains, central Rockies, and the Midwest to Southeast. The 1730 UTC Day 2 summary calls for scattered severe wind and hail-producing storms on the central Plains. WPC already has a Moderate Risk of excessive rainfall Saturday over parts of the Upper Great Lakes into the Middle Mississippi Valley. The next Storm Tracker update should re-check the 0100 UTC Day 1 outlook, any new watches, and whether that Moderate flood risk is the morning headline rather than assuming today’s Marginal stays the last word.

Sources and how to verify

Primary sources: NOAA Storm Prediction Center Sep 18, 2026 2000 UTC Day 1 Convective Outlook (Chalmers/Wendt); Day 2 Convective Outlook; current convective watches (none valid; last issued Watch 669); current mesoscale discussions (none in effect); SPC preliminary storm reports for the 20260918 cycle and 20260917 cycle; Weather Prediction Center Day 1 Excessive Rainfall Outlook (Campbell, 332 PM EDT Fri Sep 18, 2026); National Hurricane Center Tropical Weather Outlook, September 18, 2026 (no tropical cyclones in the Atlantic, eastern Pacific, or central Pacific).

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. Morning desk for this calendar day: Storm Updates: Carolinas–Georgia + Iowa Marginal, Upper Mississippi Flood Slight — Friday, September 18, 2026 (Morning).

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