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KEY MESSAGES

Updated at 220 AM CDT Tue Aug 18 2026

- Dangerous heating returns across our entire area with triple digit high temperatures between 105-110 degrees

- Fire weather conditions increase to an Elevated Risk across western Oklahoma & western north Texas for Today & Wednesday.

- Weak summer cold front on Wednesday may restrict the dangerous heating to southern Oklahoma & western north Texas on Thursday.

- Dangerous heating becoming more widespread on Friday and hotter into the weekend.

NEAR TERM

(Through Tuesday) Issued at 220 AM CDT Tue Aug 18 2026

The main headlines for today will be the return of both extreme heating and fire weather.

Our stalled "summer" cold front near the Red River is expected to wash out or lift as a warm front with a return of southerly low- level flow and increasing pressure heights as upper ridging builds to our north & east. A surface low lee of the Colorado Rockies is expected to deepen increasing our surface winds out of the southwest by this afternoon. This will start advecting slightly drier "west Texas-based" air already in place across western north Texas and southwest Oklahoma further northward into central & northern Oklahoma. Although this may keep the heat index spread more narrow and closer to the air temperatures, much of our excessive heating of 105 to 110 degrees will be more "air temperature" than "heat index" driven. We may see a few to scattered CU develop this afternoon especially in central through southeast Oklahoma but not expecting that to abate solar heating. The hot but driest air across our western forecast area will result in very low afternoon RHs between 15-20% increasing fire danger there especially with dry vegetation due to the persisting extreme drought conditions there. Not expecting southwest winds to be very strong but breezy for fire spread (10-20 mph) or gusty due to the lack of a low-level jet to mix into. However, high fuel loading and very dry air with an ignition source will at least Elevate the risk for fire weather during the afternoon hours till sundown across western Oklahoma and adjacent western north Texas.

As far as the dangerous heating, will maintain an Extreme Heat Warning across the eastern half of our forecast area where air temperatures may exceed 105 degrees to a Heat Advisory across the remaining western half of our area which including our Texas counties. Both warning and advisory will be in effect from 11 AM this morning until 8 PM near sundown.

SHORT TERM

(Tuesday night through Thursday night) Issued at 220 AM CDT Tue Aug 18 2026

Tonight will be our warmest night in the forecast period with many locations only falling to 80 degrees which could come close to tying or breaking daily warmest minimum temperature records. There will be a robust low-level jet develop overnight but expected to weaken by the afternoon keeping afternoon wind gusts down. Overnight south winds veer southwest by Wednesday afternoon just ahead of our next "summer" cold front coming down from the Central Plains. Models have speeded up timing of the front with the NAM & GFS pushing it into northern Oklahoma during the latter half of Wednesday morning with a slower ECMWF solution during the early half of the afternoon. Because of the model uncertainty would expect the surface boundary to be somewhere between the Kansas/Oklahoma state line to I-40 by late afternoon heating. A bit challenging with Wednesdays MaxT but did trend slightly cooler than NBM across northern Oklahoma using the CONSAll guidance. Not sure how far north it will go but will likely still see at least a Heat Advisory across the southern two- thirds of our forecast area to perhaps even an Extreme Heat Warning across southeast Oklahoma. The upper support pushing Wednesdays surface front will be shortwave digging through the upper ridging across Kansas with a second (main) wave of energy trailing it. Although some CAMs suggest rain developing along the front should it come through late Wednesday morning I would expect it to be more virga/high based with the lower-levels very dry and stable and capped in the afternoon. For now the best chances for rain/storm POPs would be toward Wednesday evening across far northern Oklahoma and more high-based with the 2nd trailing wave. For now expecting the severe risk to be just north in Kansas across the Central Plains where the strongest moisture & instability is in place. By Thursday expecting the surface boundary somewhere between I-40 to the Red River with decreasing pressure heights from the main upper trough coming through. Although still unseasonably hot this might break our heatwave at least north of I-40 with upper 90s highs but not much relief further south especially in southern Oklahoma and western north Texas where triple digit highs will persist staying in or near heat advisory criteria.

LONG TERM

(Friday through Monday) Issued at 220 AM CDT Tue Aug 18 2026

Upper ridging across much of the western U.S. continues to build eastward over the Southern High Plains with our heatwave returning across our entire forecast area with widespread triple digit highs across our area by Saturday. Sunday & Monday looking even hotter between 105-110 degrees all air temperature vs heat index values. Could see another "summer" cold front at least partially push through early next week.

AVIATION

(12Z TAFS) Issued at 544 AM CDT Tue Aug 18 2026

VFR conditions are expected with few to scattered mid and high level clouds. Non-convective low-level wind shear will likely develop across north central Oklahoma with southwesterly winds above the surface.

PRELIMINARY POINT TEMPS/POPS

Oklahoma City OK 105 80 109 76 / 0 0 0 0 Hobart OK 108 79 108 75 / 0 0 0 0 Wichita Falls TX 108 81 108 79 / 0 0 0 0 Gage OK 105 75 96 68 / 0 0 10 20 Ponca City OK 103 78 99 71 / 0 0 0 30 Durant OK 107 81 108 80 / 0 0 0 0

OUN WATCHES/WARNINGS/ADVISORIES

OK...Heat Advisory from 11 AM this morning to 8 PM CDT this evening for OKZ004>006-009>011-014>017-021>023-033>038-044.

Extreme Heat Warning from 11 AM this morning to 8 PM CDT this evening for OKZ007-008-012-013-018>020-024>032-039>043- 045>048-050>052.

TX...Heat Advisory from 11 AM this morning to 8 PM CDT this evening for TXZ083>090.