Area Forecast Discussion
Issued by NWS Oklahoma City, OK
Issued by NWS Oklahoma City, OK
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358 FXUS64 KOUN 221815 AFDOUN Area Forecast Discussion National Weather Service Norman OK 115 PM CDT Wed May 22 2024 ...New AVIATION... .SHORT TERM... (This evening through Thursday) Issued at 104 PM CDT Wed May 22 2024 Northerly winds will begin to weaken this evening as the upper trough ejects into the Great Lakes. Skies may be clear in the early part of the period prior to an expected switch to southerly surface winds as southwesterly flow builds back in aloft. The moist airmass will begin to filter back in prior to daybreak, especially in southern Oklahoma and western north Texas where 6-hour dewpoint rises may be as much as 5-10 degrees. Given this regime, the development of advection fog along and south of I-40 is possible late tonight and lingering into tomorrow morning. The surface low will deepen to 994 mb across the High Plains tomorrow afternoon, allowing for an impressive surface response. By all indications, even the overmixed models like the HRRR/FV3/ARW all show a pool of 70-73 dewpoints within our area by 22Z with the dryline hanging around the 100th meridian. Storm coverage is very much in question; the primary forcing mechanism will be a trough moving into the central/northern Plains, and secondary forcing from the STJ will pass through central Texas. On numerous occasions this year we have seen STJ "lead waves" throw a wrench in the forecast on Day 1. However, given the extremely rich boundary-layer moisture, a sufficient environment is in place along the dryline that only weak forcing will be necessary to trigger convection. If storms do develop, the environment is favorable for supercells with an initial risk for large-to-very-large hail. In the evening, the tornado risk with supercells will increase as the LLJ increases and hodographs take on a more streamwise shape. Overall, the risk for severe weather at any one place tomorrow is on the low-to-medium side due to questions about storm coverage, but interests in the path of any of those storms tomorrow evening will want to pay very close attention. As an aside: a flood watch remains in effect for southeast Oklahoma until late tomorrow evening. It doesn`t look like we`re going to end up verifying widespread flooding conditions, but given the potential for early-day CI in southeast Oklahoma with the STJ and maybe another round later on, will continue the watch for at least one more cycle. Meister && .LONG TERM... (Thursday night through next Tuesday) Issued at 104 PM CDT Wed May 22 2024 As the upper-level wave translates eastward across the northern Plains Thursday night into Friday morning, another cold front will crash southward. Right now, no members of the HREF suggest a signal for convection with this front at least through 12Z on Friday morning. Based on the 12km NAM, the front may begin to slow down in our southeast Oklahoma counties Friday afternoon and evening, so we may see some anafrontal convection develop with a low-end severe/flood risk in the region. Highs during the day look stratified across our area, with northern Oklahoma staying in the low 80s and western north Texas/southern Oklahoma approaching 90. Potentially the highest-ceiling day for severe weather in the current stretch will be on Saturday. More substantial (50+ knots at 500 mb) flow will be impinging on the dryline near the 100th meridian during peak heating, with plenty of instability and deep- layer shear forecasted. Supercells capable of all severe hazards will be possible in the afternoon and evening as it currently stands, although uncertainty remains high thanks to the multiple rounds of storms between now and then. The dryline looks like it will make an eastward push during the day on Sunday, keeping the storm risk lower and allowing highs to soar into the 90s across a large portion of our area. By Monday, a transition to western ridging looks likely across the US, which will increase the potential for northwest flow, cold fronts, and potentially MCSs across the northern half of our area. Meister && .AVIATION... (18Z TAFS) Issued at 106 PM CDT Wed May 22 2024 Thunderstorms will continue across southeast Oklahoma which will be affecting terminals KDUA through at least 03Z with PROB30 continuing through 08Z. Up the Red River from Durant, terminal KSPS will also remain under MVFR conditions but only through 21Z. All other terminals should remain under VFR conditions at least through 03Z, after which a stratus deck will lower with all terminals reducing to MVFR conditions with most terminals further reduced to IFR to LIFR conditions after 07Z. Dense advection fog may also spread into southeast Oklahoma further reducing visibilities at terminal KDUA to below 1/4 mile by 09Z. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 77 62 82 66 / 40 20 50 10 Hobart OK 79 60 89 64 / 10 10 30 0 Wichita Falls TX 80 66 88 69 / 40 40 40 0 Gage OK 80 55 91 57 / 0 10 20 0 Ponca City OK 78 58 81 65 / 20 10 40 30 Durant OK 84 66 84 68 / 90 70 50 30 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...Flood Watch through late Thursday night for OKZ032-041>043- 046>048-050>052. TX...None. && $$ SHORT TERM...04 LONG TERM....04 AVIATION...68