textproduct: Norman

KEY MESSAGES

Updated at 240 AM CDT Sun Jun 21 2026

- Hot and humid conditions are expected this afternoon with triple digit heat indices.

- An unsettled pattern with multiple rounds of rain/storms are expected over the next several days; severe storms and heavy rainfall are possible on tonight and Monday nights. - Below normal temperatures are forecast this upcoming work week.

NEAR TERM

(Through Sunday) Issued at 240 AM CDT Sun Jun 21 2026

A mesoscale convective complex (MCS) continues to move eastward across Kansas early this morning. The southern edge of this complex and its associated outflow boundary will result in a chance of showers and thunderstorms across far north central Oklahoma.

Hotter weather is expected this afternoon as the low-level thermal ridge expands eastward and strengthens ahead of an approaching cold front. High temperatures are forecast to range from the low 90s (southeast) to low 100s deg F (west) with triple digit heat indices.

By this afternoon, the cold front is forecast to advance into northern Oklahoma. The air mass ahead of the cold front is forecast to become highly unstable (~3000 to 4000 J/kg of MLCAPE) with modest vertical wind shear (~30 to 35 knots of effective bulk shear), which is an environment sufficient for strong to severe thunderstorms. Low-covergence along the cold front will likely be sufficient for convection initiation by late afternoon into the early evening.

Initial thunderstorms will likely be discrete with supercell characteristics that will have a threat for large hail (at least up to golf balls), damaging wind gusts (up to 70 mph), and a very low tornado risk. With time, upscale growth/consolidation into clusters of thunderstorms is expected. Heavy rainfall/flooding may become an increasing hazard overnight as a strengthening low- level jet will favor continued redevelopment of elevated, training thunderstorms.

Mahale

SHORT TERM

(Sunday night through Tuesday night) Issued at 240 AM CDT Sun Jun 21 2026

Monday's weather will be highly dependent on how far south the effective, convectively-reinforced cold front advances Sunday night into Monday morning. Currently, it appears the front will be somewhere between I-40 and the Red River--but forecast uncertainty is relatively high as it will depend on how widespread thunderstorm coverage is tonight.

There will be a north to south temperature gradient with much cooler weather north of the front Monday afternoon with highs in the low to mid 80s deg F. South of the front, temperatures will rise back into the 90s deg F.

Showers and thunderstorms will likely develop in close proximity to the front/remnant boundary during the day Monday. Increasing ascent from an approaching wave and a strengthening low-level jet Monday night will likely further increase shower/thunderstorm coverage near and even north of the front. Strong to severe thunderstorms are possible along with a threat for heavy rainfall/flooding.

Another round of showers and thunderstorms is possible late Tuesday into Tuesday night as another shortwave trough embedded in the northwest flow approaches the Southern Plains. There will be a risk of strong to severe thunderstorms, especially across northwest Oklahoma, and a threat for heavy rainfall/flooding.

Mahale

LONG TERM

(Wednesday through Saturday) Issued at 240 AM CDT Sun Jun 21 2026

Northwest to west-northwest flow will continue to persist across the Southern Plains through at least Friday with a mid-level ridge remaining quasi-stationary across the southwest U.S into northern Mexico.

With northwest flow aloft, an active weather pattern will continue as embedded shortwaves within the flow move across the Plains. As these waves pass by, there will be ongoing chances for showers and thunderstorms as MCSs and/or effective cold fronts advance southward. The highest chance for showers and thunderstorms will generally be in the overnight/early morning hours. With respect to location, the highest chances will be across northern Oklahoma with decreasing chances with southward extent. These complexes of thunderstorms and their effective, convectively-reinforced cold fronts should result in seasonable to slightly below normal temperatures.

By the late into the upcoming weekend into next week, deterministic and ensemble data indicate a mid-level ridge may strengthen to our east. This would result in hotter and drier weather across the Southern Plains.

Mahale

AVIATION

(06Z TAFS) Issued at 1032 PM CDT Sat Jun 20 2026

A thunderstorm complex coming down the Central High Plains could impact 3 of our terminals in northern Oklahoma through 12Z. As a result terminals KWWR, KPNC, and KSWO could briefly reduce down to an IFR category with a lowered ceiling and reduced visibility in rain although the latter two could stay in an IFR category due to stratus up to 15Z. Another storm system along a cold front passage will increase after 19Z across northern Oklahoma reaching the I-40 corridor by 01Z as 30% probabilities are in place at terminals KCSM and the Oklahoma City Metro (KOKC & KOUN).

Surface winds currently out of the southeast but expected to veer more southerly by 12Z at 15 kts gusting to 20 kts. By 16Z south- southwest winds increasing 15-20 kts will gusting up to 30 kts as we start mixing higher into a low-level jet. At current time the low-level jet is strengthening out of the south increasing to 35 kts flow which could produce low-level wind shear across our terminals. A cold front will start pushing into northern Oklahoma between 00-03Z shifting surface winds out of the northeast behind it.

PRELIMINARY POINT TEMPS/POPS

Oklahoma City OK 95 72 86 68 / 0 60 40 90 Hobart OK 97 72 90 68 / 0 40 40 70 Wichita Falls TX 95 75 94 72 / 0 30 30 50 Gage OK 102 66 84 64 / 10 40 50 60 Ponca City OK 95 67 80 65 / 30 60 20 70 Durant OK 92 78 92 76 / 0 40 50 50

OUN WATCHES/WARNINGS/ADVISORIES

OK...Heat Advisory from 1 PM this afternoon to 8 PM CDT this evening for OKZ005>008-011>013-015>027-033>039-044-045.

TX...Heat Advisory from 1 PM this afternoon to 8 PM CDT this evening for TXZ083>090.