textproduct: Norman

KEY MESSAGES

Updated at 205 AM CDT Sun Sep 13 2026

- Hot and humid conditions through at least midweek.

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

- Chance of showers and thunderstorms across western and northern Oklahoma by Tuesday into Wednesday.

NEAR TERM

(Through Sunday) Issued at 205 AM CDT Sun Sep 13 2026

Scattered showers and thunderstorms are ongoing this morning across the northern and western Oklahoma. This convection is occurring along and north of the effective, convectively- reinforced cold front/out flow boundary that is being intersected by the low-level jet. The expectation is this activity will continue to move east-southeast and gradually decrease in intensity and coverage with time through the morning. No severe weather is expected.

The aforementioned outflow boundary/effective cold front will lift to the north and dissipate during the daytime hours as southerly winds increase. The ~594 dam subtropical ridge will be in close proximity, which significantly decreases the chance for showers and thunderstorms today (especially with no evident mesoscale features like yesterday). Nevertheless, forecast soundings do indicate a weakly capped, relatively moist environment. Therefore, there is a low chance (10% or less) of isolated thunderstorms across the northern half of Oklahoma this afternoon.

Hot and humid conditions are expected with widespread triple digit heat indices. A Heat Advisory was issued for the entire area. Northwest Oklahoma will be on the edge of criteria; however, since it will be quite hot for mid-September, opted to keep it simple and include that area in the advisory given it will be hot either way. High temperatures today will be ~15 deg F above normal.

Mahale

SHORT TERM

(Sunday night through Tuesday night) Issued at 205 AM CDT Sun Sep 13 2026

The subtropical ridge will begin to move eastward on Monday with increasing lee cyclogenesis east of the Rocky Mountains. Lee cyclogenesis will cause a deepening surface low and attendant trough across the Central Plains. The strengthening surface pressure gradient will result in breezy southerly winds Monday afternoon. 30 to 35 knots of 925 to 850 mb flow indicate the potential for wind gusts between 30 to 40 mph across northwest Oklahoma. While minimum relative humidity will not be overly low (~20 to 25%), these wind speeds will likely result in elevated to near-critical fire weather conditions across western Oklahoma Monday afternoon. The heat will continue with a strong low-level thermal ridge across the western/northwestern side of the subtropical ridge. High temperatures will be in the upper 90s to mid 100s deg F.

By Tuesday into Tuesday night, northern and western Oklahoma will be close enough to stronger flow aloft (on the periphery of the ridge), where there will be a chance of showers and thunderstorms associated with a cold front. Temperatures across northwest Oklahoma Tuesday afternoon will be highly dependent on how far southeast the front progresses (i.e., theres a chance it could end up being cooler than forecast). Elsewhere, the heat will continue on Tuesday. Lighter winds and more moisture compared to Monday should limit the fire weather risk Tuesday afternoon.

Mahale

LONG TERM

(Wednesday through Saturday) Issued at 205 AM CDT Sun Sep 13 2026

Above-normal temperatures will likely continue through at least Thursday as bias-corrected probabilistic guidance indicates little temperature spread with even the 10th percentile above-normal through that period. High temperatures will range from the mid 90s to the low 100s deg F.

Ensemble spread increases among the global models by late in the week into next weekend (September 18-20), which indicates the potential for a pattern change. There is a chance the subtropical ridge will break down as a mid-level trough digs across the Plains. This would drive a cold front southward into the Southern Plains. There is a 30 to 70% chance of high temperatures below 90 deg F by Saturday (30% southeast; 70% north). The coldest end of guidance indicates a low to medium chance (5% southeast; 50% north) of high temperatures below 80 deg F. These probabilities increase by 10 to 20% by Sunday (i.e., the chance of cooler weather increases later in the weekend).

Mahale

AVIATION

(06Z TAFS) Issued at 1240 AM CDT Sun Sep 13 2026

Thunderstorm activity is trending downward, with showers and a few storms possible over the next few hours across portions of north, west, and central Oklahoma. Gusts to 30 mph are possible with this activity. Expect dry conditions on Sunday with VFR conditions.

PRELIMINARY POINT TEMPS/POPS

Oklahoma City OK 100 76 99 77 / 0 0 0 0 Hobart OK 103 77 102 77 / 0 0 0 0 Wichita Falls TX 103 77 102 77 / 0 0 0 0 Gage OK 102 76 101 77 / 10 0 0 0 Ponca City OK 97 74 98 75 / 10 0 0 0 Durant OK 102 76 101 76 / 0 0 0 0

OUN WATCHES/WARNINGS/ADVISORIES

OK...Heat Advisory from noon today to 7 PM CDT this evening for OKZ004>048-050>052.

TX...Heat Advisory from noon today to 7 PM CDT this evening for TXZ083>090.