textproduct: Tulsa

KEY MESSAGES

Updated at 1230 PM CDT Thu May 21 2026

- Rain and thunder chances increase today and linger into Friday. There are rain chances forecast daily into the first half of next week with periods of heavy rain.

- Abnormally cool weather is expected Thursday, with a slow warming trend then developing into next week.

SHORT TERM

(Through Friday) Issued at 1230 PM CDT Thu May 21 2026

As of late morning Thursday, an area of increased vorticity was lifting northeast across central Oklahoma and interacting with an area of isentropic lift to create continued development of rain showers spreading northeast over northeast Oklahoma. Marginal elevated instability with this disturbance was aiding in some embedded thunder as well. Within the stronger showers/embedded thunder hourly rain rates were estimated up around 1 inch per hr. This activity has remained over the western half of the CWA thus far, as weak mid level high pressure was slow to exit western Arkansas.

Through this afternoon and into this evening, rain showers and slight to scattered embedded thunder are expected to spread across eastern Oklahoma and also northwest Arkansas. This is in response to the area of vorticity moving through, an approaching short wave lifting northeast through Texas, and the weak mid level high pressure finally exiting. At the same time, a low level moisture axis/moisture convergence sets up from southeast Oklahoma into northwest Arkansas/far northeast corner of Oklahoma, which can already be seen by the plume of mid/upper 60 dewpoints over this same area. Thus, the greater rain/thunder potential mid afternoon into the evening hours looks to be along and near this axis. Precipitable water values in excess of 1.5 inches will continue a heavy rain threat with locally flooding concerns.

Overnight tonight into Friday morning, the shortwave lifts into the CWA with the bulk of the rain showers residing over far eastern Oklahoma and western Arkansas. Will hold onto a slight chance of embedded thunder, though elevated instability weakens through the evening hours. Rain chances begin to taper off from west to east during the day Friday and then exit Friday evening once the backside of the shortwave clears the region. Again, a heavy rain threat continues to be main threat into Friday, as severe weather is not anticipated from the marginal instability. marginal mid level lapse rates, and weak shear aloft.

Rainfall amounts through Friday afternoon of a half inch to 1.5 inches remain forecast over much of eastern Oklahoma and northwest Arkansas, which could lead to locally increased flood concerns. Also, there remains a 10 percent chance of localized areas of around 3 inches of rainfall which could allow for a low potential of river flooding as well.

Temperatures Thursday afternoon could warm slightly from the increasing plume of low level moisture with highs in the 60s and 70s. Temperatures tonight should remain close to the dewpoint before trying to warm into the 70s Friday behind the exiting shortwave. Cloud cover over eastern Oklahoma could become more scattered Friday afternoon and create a few locations in southeast Oklahoma warming up around 80 deg.

LONG TERM

(Friday Night through Thursday) Issued at 1230 PM CDT Thu May 21 2026

Storm chances are forecast to develop out over the Oklahoma/Texas Panhandles Friday evening and spread eastward with another developing area of vorticity. Latest guidance has differed on the timing of the eastward movement of the vort max reaching the CWA. The GFS remains the faster solution while the NAM is on the slower side of solutions. Latest thinking is shower and thunderstorm chances return to eastern Oklahoma late Friday night/early Saturday morning, and then spread eastward over the CWA during the day Saturday with the movement of the vort max. A little warmer temperatures Saturday will help to create a little better instability compared to Thursday/Friday. Thus, scattered thunderstorm chances are forecast for the CWA Saturday. Marginal shear values should keep overall severe potentials isolated to limited.

Another shortwave quickly lifts into the region in the wake of the exiting vort max Saturday evening with additional shower and thunderstorm chances continuing into Sunday. There is potential for a brief lull in precip chances Sunday night into Monday morning before a more broad area of low pressure sets up over the southern Plains during the day Monday. This area of low pressure is progged to hold over the region into the middle part of next week ahead of another wave moving into the region for the second half of next week. Thus, daily shower and thunderstorm chances remain in the forecast for next week as well. Weak flow aloft interacting with the broad area of low pressure looks to limit overall severe potentials. However, with the multiple rounds of rain chances, a locally heavy rain threat which could lead to increased flood concerns exists into next week for the CWA.

AVIATION

(18Z TAFS) Issued at 1245 PM CDT Thu May 21 2026

The NE OK TAF sites still reside in the shallow cool air near the surface and will see at least periodic showers and storms through the period. Thus, the poorest flight conditions (IFR or blo for the most part) will be here for this forecast. To the south at the SE OK TAF site (KMLC), sky conditions have improved to VFR recently, but should deteriorate as the rain and increasing coverage of storms affects this area. Once conditions go down, they will stay down, with the possibility of some improvement toward the end of the forecast midday Friday. At the NW AR sites, satellite imagery shows potential for VFR conditions with clouds scattering out this out, but elected to keep an MVFR prevailing with lingering lower cloud over there. Aside from a few spotty showers, activity may hold off until late afternoon in the far NW, and could hold off until overnight or early Friday morning at KFSM. Expect a downward trend in cigs tonight back to IFR with a moist low level airmass in place that is not going anywhere.

Lacy

PRELIMINARY POINT TEMPS/POPS

TUL 62 78 62 78 / 90 60 20 50 FSM 66 79 63 83 / 80 70 10 50 MLC 64 80 63 81 / 80 30 40 50 BVO 59 78 58 78 / 80 60 20 40 FYV 62 75 60 79 / 80 70 10 50 BYV 62 72 59 79 / 60 70 10 50 MKO 63 78 62 79 / 90 60 20 50 MIO 61 75 59 79 / 90 70 10 50 F10 61 79 61 79 / 90 40 30 50 HHW 64 81 63 81 / 80 30 50 60

TSA WATCHES/WARNINGS/ADVISORIES

OK...None. AR...None.