FXUS64 KTSA 210446 AFDTSA Area Forecast Discussion National Weather Service Tulsa OK 1146 PM CDT Sat Jun 20 2026 ...New SHORT TERM, LONG TERM... .KEY MESSAGES... Updated at 1146 PM CDT Sat Jun 20 2026 - Advisory level heat and humidity is forecast this afternoon for portions of northeast Oklahoma and west central Arkansas. - Unsettled weather is expected to begin today/tonight and persist through much of the upcoming work week. There will be multiple opportunities for heavy rainfall and some severe weather during this time frame. - Below average temperatures are forecast this upcoming work week. && .SHORT TERM... (Through Sunday Night) Issued at 1146 PM CDT Sat Jun 20 2026 Imagery from GOES-19 shows a well defined, southeastward- advancing MCS beginning to push in south-central KS. Latest model guidance shows the mean mid-level flow becoming more zonal after midnight, helping propagate the MCS to more of a west-to-east motion. With that said, much of the moderate to heavy rainfall is anticipated to stay just north of the CWA, through a few isolated to scattered showers and thunderstorms may affect the northern- tier OK counties through the morning. Healthy storms that are able to cross the OK/KS border will be capable of producing marginally severe wind gusts up to 60 mph, though the overall severe potential is low at this time. The MCS should be in the process of weakening and/or exiting the area to the northeast by midday. Will need to monitor for remnant outflow boundaries caused by the MCS, where convection can re- initiate as diurnal heating gets going. Additionally, guidance continues to hold onto diurnally-driven convection forming off of a theta-e gradient that will setup across southeast OK and into northwest AR. Convection is expected to be isolated in nature and any activity should quickly dissipate with the loss of daytime heating late in the afternoon or early in the evening. Overall, Sunday looks mostly dry, hot, humid, and very breezy for much of the area. The surface pressure gradient will tighten as a cold front slowly work its way southeast across KS through the daytime, in addition to area of low pressure setting up across northwest OK. As a result, breezy and gust southerly winds will develop, with frequent gusts between 20 and 30 mph through the day. The strong winds and compression ahead of the front will draw up moisture and heat temperatures up, causing some dangerous heat index values across the district. Highest heat indices are forecast to occur across northeast OK and in the Arkansas River Valley, with values as high as 108 degrees. A Heat Advisory remains in effect for portions of northeast OK and west-central AR between 1 PM and 7 PM Sunday. The slow-moving cold front will be on the doorstep of the CWA, or near the OK/KS border, around sunset Sunday evening. High resolution models are in good agreement that storms will fire off the frontal boundary in southeast KS late in the afternoon, with storms pushing ahead of the frontal boundary as it shifts south. Guidance shows another MCS developing in far southeast KS or northeast OK from this activity, with movement towards the east- southeast, generally from late evening through sunrise Monday morning as the MCS pushes across far northeast OK and northwest AR. Though there are still a few questions regarding coverage and exact intensity of the storms, strong to severe thunderstorms appear likely with the storm complex, with mostly damaging wind gusts as the primary hazard with storms. However, a brief window for large and/or very large hail and a limited risk for a couple of tornadoes will exist early to mid evening, initially with storm development, before storms cluster and the MCS fully develops. On top of the severe potential, very heavy rainfall is anticipated with the MCS. Rainfall amounts through sunrise Monday of one to two inches will be common, with higher amounts possible, underneath the heaviest storms and where training occurs. Minor flooding is likely, with isolated flash flooding possible through daybreak Monday morning. Will hold off on a Flood Watch due to low confidence of widespread rainfall amounts reaching flash flood guidance. However, a Watch may be needed by the next forecast package for at least portions of the forecast area, especially for far northeast OK and northwest AR, through the next few days if QPF guidance trends higher. Mejia && .LONG TERM... (Monday through Saturday) Issued at 1146 PM CDT Sat Jun 20 2026 Storms should be ongoing at the start of the long-term period as a cold front continues to slowly advance south through the CWA on Monday. The main concern with the ongoing storms Monday morning will be the heavy rain/flooding threat, but instability, shear, and lift will all be sufficient enough for strong and marginally severe storms through the morning and perhaps early on into the afternoon. Storms should shift east and south of the area in the afternoon and things should stay mostly dry as the atmosphere becomes worked over. By Monday evening/night and into Tuesday morning, another mid-level shortwave trough becomes better defined and will move across the area. Heavy rain, flooding, and some severe potential will exist with this shortwave trough. The frontal boundary from Monday will remain in the region through at least midweek, perhaps even into late in the week. With a favorable upper-level pattern for storms remaining in place, chances for showers and thunderstorms will continue daily as the frontal boundary hangs out in the area, though chances and coverage may differ slightly each day. Mejia && .AVIATION... (00Z TAFS) Issued at 617 PM CDT Sat Jun 20 2026 Ongoing VFR conditions will continue into the overnight hours. Stratus may develop and expand quickly near sunrise through mid morning w/ periodic MVFR ceilings though confidence is not high regarding the overall coverage of lower ceilings. Gusty winds and a return to VFR conditions expected by late morning or early afternoon. Precip chances through early morning Sunday are highest near the OK / KS border and points northward. The next window of higher storm chances will occur just beyond this forecast period. && .PRELIMINARY POINT TEMPS/POPS... TUL 75 93 71 82 / 20 20 60 30 FSM 74 93 75 88 / 10 10 70 60 MLC 75 92 76 88 / 0 0 60 60 BVO 73 93 66 80 / 30 30 60 20 FYV 71 89 71 83 / 10 10 80 50 BYV 69 88 69 81 / 10 20 90 60 MKO 73 91 72 84 / 10 10 70 50 MIO 72 90 67 80 / 30 30 90 20 F10 73 91 72 84 / 0 10 70 50 HHW 73 91 76 89 / 10 10 40 60 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...Heat Advisory from 1 PM to 7 PM CDT Sunday for OKZ055-056- 059>061-064>067-070-071-074-154-176-254-272-354. AR...Heat Advisory from 1 PM to 7 PM CDT Sunday for ARZ129-219-220. && $$ SHORT TERM...67 LONG TERM....67 AVIATION...07