textproduct: Norman

KEY MESSAGES

Updated at 507 AM CDT Sat Sep 12 2026

- Strong to severe thunderstorms are possible this afternoon and evening, especially across northern Oklahoma.

- Hot and humid conditions through at least midweek next week.

- Elevated to near-critical fire weather conditions possible Monday afternoon across the west.

NEAR TERM

(Through Saturday night) Issued at 210 AM CDT Sat Sep 12 2026

A line of thunderstorms is developing along a cold front across Nebraska early this morning. As this line of thunderstorms continues to move the southeast, the remnants may impact north central Oklahoma later this morning (after sunrise). There is an ~30 to 40% chance of storms across north central Oklahoma this morning. If the thunderstorms survive, the risk for severe weather is low as the activity should generally be weakening with southeast extent as the low-level jet will be subsiding after 12Z.

Another hot and humid afternoon is expected with high temperatures ranging from the mid 90s to mid 100s deg F. A Heat Advisory is in effect for this afternoon for locations along and south of I-40. For locations north of I-40, uncertainty is a bit higher as temperatures will be highly dependent on the evolution of any morning thunderstorms and associated cloud debris/ convective outflow.

Scattered showers and thunderstorms are expected to redevelop late this afternoon into the evening with two potential areas for development. The first zone is ahead of a cold front in northern Oklahoma. The second zone is the location of any remnant outflow boundary from the morning convection. There is greater confidence for development in the first zone given there is uncertainty on the evolution of the morning storms and location of any outflow boundary. If the remnants of the storms make it into north central Oklahoma this morning, the outflow boundary could be located somewhere across central/east central Oklahoma.

Strong to severe thunderstorms are possible with a threat for both damaging wind gusts and large hail given MLCAPE ~3000 to 4000 J/kg, effective bulk shear ~30 to 35 knots, and downdraft CAPE >1000 J/kg. There will also be a threat for heavy rainfall given the high precipitable water values (>1.5). For example, the HREF ensemble max indicates the potential for locally heavy rainfall up to 2 to 3" in northern Oklahoma. Most locations will not receive that much rainfall, but that gives an idea of a reasonable maximum amount of rainfall. If these amounts were to occur in an an area susceptible to flooding (e.g., an urban area), there would be some flooding risk. Thunderstorms may organize into a cluster that would move east-southeast across the northern half of Oklahoma late evening through the overnight.

Mahale

SHORT TERM

(Sunday through Monday night) Issued at 210 AM CDT Sat Sep 12 2026

The ~594 dam subtropical ridge will be centered across the Southern Plains on Sunday, which significantly decreases the chance for showers and thunderstorms. Hot and humid conditions are expected with widespread triple digit heat indices and dry conditions. A Heat Advisory will likely be needed for parts of the area on Sunday.

The subtropical ridge will begin to move eastward on Monday. Even so, the heat will continue with a strong low-level thermal ridge across the western/northwestern side of the ridge. Lee cyclogenesis east of the Rocky Mountains will cause a deepening surface low and attendant trough across the Central Plains. Elevated to near-critical fire weather conditions are possible across the west on Monday afternoon with a strengthening surface pressure gradient resulting in breezy southerly winds.

Mahale

LONG TERM

(Tuesday through Friday) Issued at 210 AM CDT Sat Sep 12 2026

The subtropical ridge will remain centered across the southeast United States through at least the middle part of next week. Oklahoma and north Texas will be on the western periphery of the ridge with a strong low-level thermal ridge. Above-normal temperatures are likely to continue with high temperatures in the 90s to mid 100s deg F. Bias-corrected probabilistic guidance indicates little temperature spread through Wednesday (e.g., the 10th percentile is above-normal), which indicates high confidence of above-normal temperatures.

Northern and western Oklahoma will be close enough to stronger flow aloft (on the periphery of the ridge known as the ring of fire), where there will be occasional chances of showers and thunderstorms from remnant convection or nearby fronts.

Ensemble spread does increase by late next week into the following weekend (September 18-20), which indicates the potential for a pattern change with the subtropical ridge breaking down and a stronger cold front advancing southward into the area. It's not a guarantee, but there is a 40 to 70% chance of high temperatures below 90 deg F on Sunday, September 20 (40% south; 70% north). The coldest end of guidance even indicates a low to medium chance (10 to 40%) of high temperatures below 80 deg F.

Mahale

AVIATION

(12Z TAFS) Issued at 507 AM CDT Sat Sep 12 2026

Morning showers and thunderstorms are possible near KPNC and KSWO. However, given the trajectory of the storm complex currently tracking southeastwards across eastern Kansas chances appear to be diminishing for this round of precipitation.

Scattered strong to severe thunderstorms are possible by late afternoon and into the evening hours across northern, central and into southern Oklahoma. Given the varied modeled output for this round, probabilities are on the low-side with PROB30's for many terminals. Severe storms will have the potential to yield large hail up to the size of golf-balls and wind gusts to 70 mph.

PRELIMINARY POINT TEMPS/POPS

Oklahoma City OK 99 75 99 76 / 20 20 0 0 Hobart OK 104 76 102 77 / 20 10 0 0 Wichita Falls TX 105 76 103 76 / 0 0 0 0 Gage OK 101 71 101 75 / 30 30 10 0 Ponca City OK 94 70 97 73 / 40 30 10 0 Durant OK 102 76 101 76 / 20 10 0 0

OUN WATCHES/WARNINGS/ADVISORIES

OK...Heat Advisory from 1 PM this afternoon to 7 PM CDT this evening for OKZ021>025-027>048-050>052.

TX...Heat Advisory from 1 PM this afternoon to 7 PM CDT this evening for TXZ083>090.