textproduct: Norman

KEY MESSAGES

Updated at 548 AM CDT Tue Sep 29 2026

- Periods of heavy rain are expected from Tuesday afternoon through Thursday afternoon, with flooding possible in parts of western north Texas and southern Oklahoma.

- Chance of severe storms Wednesday afternoon and Wednesday night.

- Significant cooldown expected from Thursday through the weekend.

NEAR TERM

(Through Tuesday) Issued at 158 AM CDT Tue Sep 29 2026

We'll feel the opening salvos of the upcoming rain event this afternoon and evening. Chances for rain and thunderstorms today will primarily be across the northern and western parts of Oklahoma that have been favored for rain over the last week or so. The primary impacts will be pockets of heavy rain and lightning. For the rest of us, one final day of summer heat awaits.

Shortwave ridging remains in place early this morning across the Southern Plains, but by midafternoon a lead wave will be ejecting into Kansas from the southwest. This will push us into a broad zone of southwest flow that corresponds to the tropical moisture plume. About 1,000 J/kg of MLCAPE will exist by early afternoon, so scattered to widespread small showers and thunderstorms are expected to develop with the lead wave. Deep-layer shear will be quite weak, so organization of individual storm cells into multicell clusters or supercells is unlikely. PWATs will already be pushing/exceeding 2.00 inches with this activity, so potential for brief very heavy rain rates will exist. The primary zone for this activity will be along and north of a line from Sayre to Perry.

The lead wave will depart by late in the afternoon. The primary trough and Polo's remnants will still be well to our west. That means that much of tonight looks dry across our area, potentially excepting far western or northern Oklahoma closer to the moisture conveyor. Temperatures continue to be quite warm with dewpoints sitting as high as they are.

Meister

SHORT TERM

(Tuesday night through Thursday night) Issued at 158 AM CDT Tue Sep 29 2026

The primary window for active weather looks to be in the short-term forecast period from Wednesday - Thursday. Heavy rainfall and attendant flooding as well as severe weather are possible. The end of the short-term period will see us making a transition into something a little closer to fall.

0Z guidance tonight is surprisingly united in showing a period of relatively dry weather Wednesday morning. This is potentially due to the passage of the 700 mb warm front earlier in the morning. Either way, this will allow classic cyclogenesis to occur in the lee of the New Mexico Rockies. As the surface low sweeps northeast ahead of the trough, the dryline will sharpen near the OK/TX panhandle border by Wednesday afternoon. With height falls overspreading the dryline late in the afternoon, this would look like a classic transition- season severe weather event - if there was any semblance of an EML whatsoever. As it is, warm advection during the daytime will lead to the development of isolated showers in a 1,000 MLCAPE environment, but the chances of discrete dryline convection seem rather slim.

The more robust opportunity for thunderstorms will occur in the evening to overnight near and southeast of I-44. With the trough's approach continuing to lower heights, continued low-level theta-E advection, and a 40 knot veered LLJ across the warm sector, there are more than a few similarities synoptically between this event and others that have produced prolifically rainy squall lines (and those event did so with lower PWATS than we will see). How much rain falls will largely be a question of the location and progressiveness of the MCS. There is some reason to believe it won't translate eastward all that rapidly with meridional flow aloft and such a powerful LLJ. In that case, parts of southern Oklahoma and western north Texas are likely to see multiple inches of rain. NBM 90th percentile rainfall totals are near 6 inches of rain by Thursday afternoon in a portion of southern Oklahoma centered on Pauls Valley. While it is unlikely that many locations receive up to 6 inches of rain, that benchmark serves as a reasonable anchor to a mental model of what localized flash flooding may look like Wednesday night. Severe weather is possible with this MCS. The lack of EML will reduce instability overall, but favorable theta-E advection regimes could increase low- level instability. If so, hodographs Wednesday night would be favorable for QLCS-embedded tornadoes.

It also needs to be said that the majority of 0Z guidance members are bifurcating rain totals. In effect, the Tuesday/early Wednesday wave of rain in northern/western Oklahoma and the stripe of heavier rain from the Wednesday night MCS may not overlap, with a "Reverse Goldilocks zone" of low-to-nil rainfall totals in between them through Thursday. This is an extremely complex forecast and we are not encouraging anyone to give up on their chance for a good, soaking rain. But right now, a best estimate of where that reverse Goldilocks zone might end up being would highlight west central Oklahoma, southwest Oklahoma, and central Oklahoma as far southeast as the western OKC metro.

The upper-level trough will approach and move overhead/through Kansas during the day on Thursday. With the deeply saturated airmass in place, redevelopment of storms in the warm sector remains a possibility, particularly southeast of I-44. The backside of the system will bring a robust cold front by Thursday night.

Meister

LONG TERM

(Friday through Monday) Issued at 158 AM CDT Tue Sep 29 2026

The story of the long-term forecast is one of a long-awaited pattern change. Cooler temperatures are expected. Much drier weather will occur in northern/western Oklahoma, while rain chances will linger in southeast Oklahoma and parts of western north Texas.

As the trough responsible for this week's system approaches the polar jet, it will degenerate into an open wave. However, the remnant weakness in the subtropical ridge (still kicking to our west and east) will allow our weather to behave more like early October should. The robust cold front on Thursday will keep sweeping through on Friday, and a reinforcing front is expected early next week as a 1026 mb high dominates the central US. This will keep temperatures at or below seasonal normals as late as next Monday before lee troughing potentially returns.

Showers do linger in the forecast, particularly Friday and Saturday in southeast/central Oklahoma where remnant moisture may be stronger. The reinforcing front will do the job to dry us all the way out: our forecast calls for no mentionable rain chances next Monday.

Meister

AVIATION

(12Z TAFS) Issued at 548 AM CDT Tue Sep 29 2026

Starting to see some precip across western parts of Oklahoma early this morning and expect this to continue and expand across much of western into northern Oklahoma today. This will impact mainly CSM/WWR/PNC through the day. Still anticipate mostly VFR conditions, but some MVFR ceilings possible, especially at WWR.

Otherwise, should see a break this evening before another round of rain/storms move back into western Oklahoma overnight. Winds will pick up from the south after by mid-morning with some gusts over 20kts.

PRELIMINARY POINT TEMPS/POPS

Oklahoma City OK 73 85 69 80 / 0 60 100 80 Hobart OK 72 85 69 84 / 30 50 70 40 Wichita Falls TX 73 90 69 85 / 10 60 100 70 Gage OK 67 83 63 77 / 60 50 50 50 Ponca City OK 70 85 66 76 / 10 60 100 90 Durant OK 72 91 70 84 / 0 30 80 100

OUN WATCHES/WARNINGS/ADVISORIES

OK...Flood Watch from Wednesday afternoon through Thursday afternoon for OKZ031-032-040>043-045>048-050>052.

TX...Flood Watch from Wednesday afternoon through Thursday afternoon for TXZ086-088>090.