Tuesday afternoon desk. Water still owns the Southwest. A Marginal severe corridor is open from southeast Arizona across southern and eastern New Mexico into west Texas. Not an NWS warning. This is a live Tuesday afternoon snapshot of U.S. local-storm activity as of Tuesday, September 29, 2026. The Storm Prediction Center 2000 UTC Day 1 Convective Outlook, issued 2:45 PM CDT, holds a Marginal Risk of severe thunderstorms from southern Arizona across southern and eastern New Mexico into west Texas. Isolated severe gusts and possibly a tornado or two remain the official language for this afternoon into tonight. No Severe Thunderstorm Watch or Tornado Watch is valid. Mesoscale Discussion 2333, issued 3:06 PM CDT for south-central into southeastern New Mexico, flags a sparse isolated gust or brief tornado and says a watch is unlikely.
The Weather Prediction Center still carries a Moderate Risk of excessive rainfall on portions of the Southwest and Four Corners after a late-Monday special Day 1 update trimmed the outline over western and northern Arizona into southern Utah. Restoration exposure this afternoon is interior water on already-saturated soils, wash and burn-scar flooding, trees and service drops on isolated severe gusts, and a narrow tornado swath if a cell organizes over southeastern New Mexico or west Texas. Conditions change fast. Verify with the National Weather Service for the specific county or ZIP before you roll.
What is live this afternoon
No convective watches are in effect as of the SPC watch page update at 21:04 UTC on Tuesday, September 29, 2026. The last issued watch number on that page is 0674 and it is not valid now. Today’s official Local Storm Report board covering 12Z Tuesday through 12Z Wednesday shows no tornado, hail, or wind reports as of this desk.
The 20Z update left severe probabilities unchanged. SPC expects thunderstorm coverage to increase this afternoon and evening as the remnant core of Polo moves northeast into the southern High Plains, likely in a complex or linear mode. Locally greater potential sits over southeastern New Mexico into West Texas, where less cloud cover allowed stronger heating through mid-afternoon. Population centers inside the Day 1 Marginal include El Paso, Tucson, Lubbock, Amarillo, and Midland.
National Hurricane Center Tropical Storm Polo Advisory 37, 2:00 PM MST Tuesday, September 29, 2026: the center was near 29.0°N, 109.7°W, about 275 miles southwest of El Paso, moving northeast at 21 mph with 65 mph maximum sustained winds and 992 mb pressure. Coastal watches and warnings for Mexico have been discontinued. Interests in northwestern Mexico, southern New Mexico, and far western Texas should keep watching the remnant. Polo is not a U.S. mainland hurricane landfall. NHC notes a Wind Advisory is in effect for portions of southern New Mexico and far western Texas for gusty remnant winds late today and tonight.
Hotspot 1 — Four Corners / Southwest flood pulse
This is still the water desk. WPC language supports a Moderate Risk of 1-to-6-hour rainfall exceeding flash-flood guidance over parts of the Southwest. The late-Monday 2200 UTC special update cut back Moderate coverage over western and northern Arizona into southern Utah after convection there stayed more scattered and instability stayed limited. Intense rates were then focused along a compact warm-conveyor axis over far southeastern California, the Arizona–Nevada border, and southwest Utah, plus a smaller pocket over southeast Arizona and southwest New Mexico downstream of Polo. Outside those pockets much of the rain over Arizona and New Mexico had been stratiform. Wet soils, burn scars, slot canyons, and south- and west-facing slopes along the Mogollon Rim and the San Juans still favor flooding even if the Moderate category is on the low end of that contour.
Cities and counties to watch: Kingman, Bullhead City, Laughlin, Colorado City, Hildale, Flagstaff and Mogollon Rim drainages, Lordsburg country and the Sacramento Mountains in New Mexico, and flashy drainages in southern Utah. Overnight Flash Flood Warnings on that corridor — Hildale and Short Creek, Colorado City and northern Mohave, the Laughlin–Kingman–Bullhead line, and pieces of San Bernardino and Clark counties — are yesterday-into-this-morning water, not a new afternoon watch.
Restoration read: extraction and drying first. Treat burn-scar and wash flooding as a same-night water job if rain is still falling on the same ZIP. Photograph only if it is safe. Do not drive flooded washes.
Hotspot 2 — Southeastern New Mexico into West Texas
This is the afternoon severe window inside the SPC Marginal. MD 2333 covers south-central into southeastern New Mexico, valid 2006–2130 UTC Tuesday. A small QLCS segment was intensifying on KHDX and MRMS as it approached a destabilizing airmass with surface temperatures in the 70s F, dewpoints in the 60s F, and more than 500 J/kg MLCAPE. Effective bulk shear over 40 kt, much of it in the lowest 3 km, leaves room for embedded mesovortices. Official MD language: an isolated severe gust or a brief tornado is possible through the remainder of the afternoon; the threat should stay sparse; watch issuance probability 5 percent. Most probable peak gust in that discussion is up to 60 mph; most probable peak tornado intensity is listed as up to 90 mph if one occurs.
Farther east, west Texas is the part of the Marginal that had more heating. Storm mode should trend complex or linear as Polo’s remnant and the low-level jet interact after 00Z. A brief tornado and strong gusts can ride any organized, persistent structure. That is still isolated, not a Slight Risk.
Restoration read: wind and water on the same ticket. Stage tarps and extractors for the South Plains and Permian Basin before late afternoon. A brief tornado, if one occurs, is a narrow swath — staff it as a local damage survey, not a regional event.
Hotspot 3 — Southeast Arizona and the Tucson–Phoenix moisture axis
Southern Arizona stays inside the same Day 1 Marginal. Mid-to-upper-60s dewpoints were analyzed from the international border into the Phoenix vicinity this morning, with long hodographs and 30 to 40 kt of low- and mid-level southwesterly flow. Widespread showers and thunderstorms continue under limited heating and weak tropical lapse rates. Weak or transient supercells and later convective bands can still produce strong gusts. This is not the higher-end part of the corridor compared with southeastern New Mexico and West Texas this afternoon, but Tucson sits inside the official risk area.
Restoration read: water first, wind second. Urban street flooding and isolated tree damage are the likely tickets, not a metro-wide wind event.
Just hit
Today’s 12Z-cycle LSR board is empty. The last 24 hours that already look like tickets sit on Monday’s 12Z-to-12Z page: 77 mph near Kenel and 71 mph near Pollock in Campbell County, South Dakota; 1.00-inch hail and a 60 mph gust 10 miles north of Belle Fourche in Butte County, South Dakota; power lines down near New Kingman-Butler in Mohave County, Arizona. Overnight Flash Flood Warnings on the Arizona–Utah–Nevada border country and a separate Fargo–Moorhead warning with up to two inches already down are water aftermath, not this afternoon’s new severe reports.
Tropical Storm Rachel remains offshore of southwestern Mexico and is not a U.S. land threat this afternoon. Hurricane Nolo is a Central Pacific / Hawaii desk. Neither is this Storm Tracker’s mainland corridor.
Pulse table
| Region | Main threats | SPC / NWS / WPC level | Status this afternoon |
|---|---|---|---|
| Four Corners / SW AZ–UT–NM | Flash flood, burn-scar and wash flooding | WPC Moderate excessive rainfall | Live flood pulse; Moderate trimmed on the northwest edge |
| SE New Mexico / West Texas | Isolated severe gust, brief tornado possible, heavy rain | SPC Marginal + MD 2333 | Afternoon–tonight window; watch unlikely |
| Southeast Arizona / Tucson corridor | Strong gusts, heavy rain | SPC Marginal | Ongoing showers; limited heating |
| Eastern Dakotas / NW Minnesota | Training heavy rain | WPC Slight / Marginal ERO (prior discussion) | Fargo–Moorhead just-hit water |
| Western/central Dakotas (Monday) | Severe gusts, small hail | Expired Marginal + LSRs | Aftermath |
| U.S. mainland coast vs. tropics | No landfalling hurricane | Polo a TS inland over Sonora | Quiet on the mainland coast |
What this means for restoration teams
The Southwest Moderate Risk is wet drywall, silt near washes, and a 24–48 hour mold clock on buildings that took water overnight. Southeastern New Mexico and west Texas are a wind-first desk if the QLCS or a discrete cell organizes, with water on the same ZIPs if cells train. Monday night’s Campbell County gusts are already a roof-and-siding ticket. Mohave County lines-down is already a tree-and-drop ticket.
For teams near the SPC Marginal: stage before late afternoon local, 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. Turn around, don’t drown remains the flood rule on every wash in the Moderate Risk.
What this is not
This is not a regional derecho and not a U.S. mainland hurricane landfall. Polo is a Mexico inland tropical storm whose remnant moisture and shear are already inside the Southwest and southern High Plains forecast. MD 2333 is explicit that the New Mexico severe threat should stay sparse and that a watch is unlikely. The work today, if it comes, will be scattered: a flooded wash in Mohave or Washington County, a wind swath through a southeastern New Mexico or west Texas county, leftover urban water in Fargo. That is the local-storm pattern this desk should staff.
Looking ahead
Wednesday’s SPC Day 2 Convective Outlook already draws a Slight Risk of severe thunderstorms across parts of the southern Plains, with damaging wind, hail, and perhaps a tornado or two from west-central Texas into southwest Oklahoma as an upper low and dryline organize. Isolated severe gusts and hail may also occur from western and central Kansas into far southern Nebraska. Thursday stays Marginal over parts of the southern Plains. Watch the next Storm Tracker update rather than assuming today’s Marginal is the last line of the week.
Sources and how to verify
Primary sources dated Tuesday, September 29, 2026: NOAA Storm Prediction Center 2000 UTC Day 1 Convective Outlook (Chalmers/Thornton; prior Guyer/Bentley discussion); Mesoscale Discussion 2333 (Squitieri/Mosier); SPC current watches page (no watches valid; last issued 0674); SPC today and 28 September preliminary local storm reports; Weather Prediction Center Day 1 Excessive Rainfall Outlook (Hurley/Wegman 2200 UTC update and prior Campbell/Pereira discussion); National Hurricane Center Tropical Storm Polo Advisory 37, 2:00 PM MST; National Weather Service warning text via the national watches/warnings feed.
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: Southwest Flood Moderate, West Texas Marginal — Tuesday, September 29, 2026 (Morning).
Informational only — not an official weather warning. Follow local authorities and the National Weather Service. Turn around, don’t drown.