textproduct: Norman

KEY MESSAGES

Updated at 1249 PM CDT Tue Apr 28 2026

- Severe thunderstorms expected this afternoon across southern Oklahoma and western north Texas, with very large hail and a low tornado risk.

- A widespread round of rain is expected Thursday into Friday, but could be limited to locations along and south of I-40.

NEAR TERM

(Rest of today and tonight) Issued at 1249 PM CDT Tue Apr 28 2026

The rather widespread convective activity this morning makes for a complex forecast this afternoon. Early indications were that we would see rather aggressive wiping of atmospheric moisture behind any morning convection. However, OK Mesonet observations show low- 70s dewpoints and at least weak surface southerlies back into Jefferson/Love/Carter Counties. With that in mind, and with skies clearing out behind the morning convection, surface-based convection initiation looks likely this afternoon along the frontal zone of southern Oklahoma/adjacent north Texas.

RAP forecast soundings suggest MLCAPE in excess of 3,000 J/kg along and just south of the frontal boundary by midafternoon. Combined with about 80 knots of cloud-layer shear, very large hail will be possible with any initial supercell-type structures. The tornado risk will be extant with any storms early and interacting with the boundary, particularly with the extreme boundary-layer moisture leading to 100-150 J/kg of 0-3 km instability. However, two factors should limit the tornado risk: generally weak low-level shear with no appreciable LLJ and veered surface winds, as well as a tendency for the front to sink southeast in the afternoon and undercut any convection immediately along it. A transition to more of a severe wind risk over far southeast Oklahoma looks probable as storm cold pools merge in the extremely unstable environment.

Convection will press south and east of our area by late evening as the cold front continues southward. For those of us well behind the front, it will be a cool day with low cloud cover struggling to thin out.

Meister

SHORT TERM

(Wednesday through Thursday night) Issued at 1249 PM CDT Tue Apr 28 2026

Large-scale troughing moves into the Great Lakes during the day tomorrow. Despite the continued activity of the subtropical jet, the large-scale troughing will dominate the surface pattern, promoting pressure rises and northerly surface winds. Because of that, it will feel like a beautiful spring day, especially across the northern half of the area where the sun is expected to come out in the afternoon. Highs will remain in the upper 60s to low 70s.

The active southern stream will last into Thursday and presage a return to southeasterly 850 mb winds. Given the suppression of the surface warm sector, this does not pose a risk of surface-based convection, but rather a chance for a widespread area of isentropic ascent to develop from Thursday into Friday. Some of the guidance this morning has continued the usual correction of northerly model biases during widespread precip shield, which means that at least through Thursday the best chance for measurable/appreciable rain could be limited to areas south of I-40. This would also lead to widespread cloudiness and cooler-than-normal temperatures struggling to make it much past 60.

Meister

LONG TERM

(Friday through Monday) Issued at 148 AM CDT Tue Apr 28 2026

Precipitation is expected to become more widespread on Friday, especially in the south, with showers and thunderstorm chances persisting into Friday evening before ending as the mid-level trough moves east of the forecast area. Temperatures will be seasonably cool again Saturday before a warming trend through Tuesday. After this system exits Friday evening, there are no significant precipitation chances through the remainder of the forecast period.

AVIATION

(18Z TAFS) Issued at 1226 PM CDT Tue Apr 28 2026

Many of our terminals will remain in a MVFR category through 00Z with most terminals likely in a VFR category after 00Z through the end of the forecast period. Most of our terminals are north of a warm front boundary with northerly surface winds at 10 kts gusting to 15 kts. Expecting the warm front currently stretched just east and south of the I-44 corridor to begin pushing as a cold front into southeast Oklahoma initiating a final round of thunderstorms. Our terminal with the highest probability for storms will be KDUA where TEMPOs are in place through 00Z for potential severe thunderstorms. There is a 30% probability for storms to impact terminal KSPS while probabilities are too low around 20% for storms impacting terminals in the OKC Metro (KOKC & KOUN) and KSWO to be in their respective TAFs but is worth mentioning in this discussion. Surface winds will shift northerly over terminal KDUA after the cold front passage and when potential convective activity there moves out.

PRELIMINARY POINT TEMPS/POPS

Oklahoma City OK 47 69 49 64 / 0 0 0 50 Hobart OK 45 73 49 62 / 0 0 10 60 Wichita Falls TX 52 73 54 66 / 0 0 10 60 Gage OK 38 70 44 60 / 0 0 20 70 Ponca City OK 44 69 46 66 / 0 0 0 20 Durant OK 55 70 56 67 / 40 10 10 50

OUN WATCHES/WARNINGS/ADVISORIES

OK...None. TX...None.