Area Forecast Discussion
Issued by NWS Oklahoma City, OK
Issued by NWS Oklahoma City, OK
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699 FXUS64 KOUN 221550 AFDOUN Area Forecast Discussion National Weather Service Norman OK 1050 AM CDT Wed May 22 2024 ...New UPDATE... .UPDATE... Issued at 1048 AM CDT Wed May 22 2024 This morning`s storms have generally pushed the outflow boundary further south than CAMS indicated (not a shock, as this is a persistent CAM bias). Around 10:30 am local time, the synoptic cold front can be found on satellite in an arc from the storms near Madill/Tishomingo back to the southwest to near Abilene. It`s still trucking to the south, and a secondary outflow boundary from today`s convection is currently running from Marietta to near Seymour and moving south on its own. Current indication via satellite analysis is that the area north of these boundaries is currently quite stable. However, the HRRR indicates a remaining reservoir of 2,000- 3,000 J/kg of MUCAPE north of the boundaries this afternoon. Convection initiation after this current round of storms is rather uncertain. Members of the 12Z HREF that failed to depict the magnitude of this morning`s storms generally showed early afternoon redevelopment occurring in southeast Oklahoma, which seems rather implausible in the face of the ongoing MCS. The latest few runs of the HRRR, which did a somewhat better job of depicting this MCS, shows redevelopment occurring early this afternoon along the outflow boundary just south of our area. The margin of error (and the suggestion of a continued reservoir of instability) are enough for us to want to keep our guard up for the potential for elevated strong to severe storms this afternoon, especially in the Clay-to- Bryan County corridor where the outflow hasn`t blasted as hard. However, the spatial and probabilistic window for severe weather this afternoon appears to be shrinking. Meister && .SHORT TERM... (Today and tonight) Issued at 237 AM CDT Wed May 22 2024 At least intermittent severe risk is expected, perhaps by as early as ~3-4 AM this morning, focusing primarily along/south of the Interstate 40 corridor. A weak frontal boundary has `washed out`/stalled across portions of west-central into southeast Oklahoma early this morning. As a second (stronger) surface front impinges on this feature, scattered to potentially widespread precipitation/storm development is expected to ensue. Current objective analysis and short-term guidance highlights a mesoscale environment favorable for severe weather. With sufficient to locally extreme (2000-4000 J/kg MUCAPE) instability and very strong deep/cloud-layer wind shear, large hail will be possible with robust storm cores. Evolution of individual/clusters of storms will determine whether surface-based hazards (damaging wind/very low tornado risk) can be realized this morning. Storms developing south of or having sustained motion (more southeasterly) along the front and consolidating cold pool will have the greatest opportunity to carry aforementioned risks. The most likely scenario is for dominant/quick transition towards elevated convection this morning, especially as convective reinforcement allows the boundary to surge quicker to the south/southeast. A second round of severe weather is expected by early this afternoon into this evening, focusing near the Red River Valley/southeast Oklahoma. Latest guidance is more bearish on potential/coverage for this round, likely the result of greater southward push (into north- central Texas) of the aforementioned boundary. Should this occur, `elevated` convection would be favored, posing a continued risk for large to potentially very large hail owing to favorable instability/organizing wind shear persisting north of the front. In a more unlikely scenario, should portions of the front remain draped across far southern zones into the afternoon, then a brief period of damaging wind and low tornado (along with hail) risk would develop with robust storms. In addition, concern for at least localized flash flooding will likely develop across southeastern Oklahoma today, perhaps by midday/early afternoon. This will be especially true if a heavy round of morning storms "primes" soil conditions for additional heavy bouts of precipitation later in the day. A Flash Flood Watch has been maintained, and continues into early Friday morning owing to potential for additional rounds of storms on Thursday. Ungar && .LONG TERM... (Thursday through Tuesday) Issued at 237 AM CDT Wed May 22 2024 Thursday: Potential exists for a notable severe weather episode from the afternoon into late evening, with at least limited potential for much/all of the forecast area. Broad southwesterly upper flow looks to be maintained into the late week, with both jet stream branches (i.e. polar/subtropical) in close proximity across the western/central CONUS. Low amplitude/compact upper features remain advertised to move out into the Plains on Thursday within each branch. As this occurs rather impressive mass response is forecast across our area. A combination of storm development originating along a dryline near the 100th meridian, and associated with warm air advection processes, is possible. Uncertainties in coverage/exact corridors of highest potential/hazards remains, owing to subtle synoptic/mesoscale forcing expected. However, at this point, all areas of the forecast area will harbor some risk for severe weather from the afternoon into evening on Thursday. All storm hazards (hail/winds/tornadoes) appear possible. Stay up to date on trends for Thursday, as signals concerning aforementioned factors will hopefully converge towards a most likely outcome. Friday-Holiday Weekend: Additional chances for storms/severe weather will exist, especially on Saturday afternoon into evening. Friday will likely feature the nadir of storm and severe weather potential through Sunday. Still with a front expected across central into eastern Oklahoma, limited diurnally-driven convection is possible across mentioned areas. By Saturday, attention will once again turn towards the possibility of another impactful severe weather episode. A majority of global model/grand ensemble guidance depicts a slightly stronger (when compared to Thursday) subtropical-based wave sliding out across the Southern Plains through the day. Once again, impressive mass response is expected ahead of an evolving dryline feature across western Oklahoma. At this point, development of a few organized storms would be favored, posing risks for large hail, damaging winds and tornadoes. This will be another period to monitor closely over coming forecast cycles. Sunday-Next Week: General consensus is for a transition towards drier weather. Expectation is for main upper support to shift towards the Mississippi Valley by Sunday. Should this occur, then a dry and warm (many areas seeing highs of 90+ degrees) Sunday can be expected. Into the next work week, grand ensemble guidance shows transition towards upper ridge development across the western US. This will favor mostly dry days. Frontal intrusion early in the week may help keep maximum daily temperatures near to slightly below average heading into the midweek period. Ungar && .AVIATION... (12Z TAFS) Issued at 638 AM CDT Wed May 22 2024 Scattered TSRA will progress slowly east and southeast this morning across central into southern Oklahoma. MVFR cigs will be widespread across central and southern portions of Oklahoma, with mainly VFR cigs farther north in drier low level air. Cigs should rise through the day, although MVFR and additional TSRA possible at KDUA this afternoon. Frontal boundary will lift north tonight and allow moisture return and lowering cigs into MVFR and possibly IFR by end of forecast. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 77 63 81 67 / 40 20 50 20 Hobart OK 79 61 87 64 / 10 10 30 20 Wichita Falls TX 80 66 86 69 / 40 30 40 20 Gage OK 80 55 88 58 / 0 10 20 10 Ponca City OK 78 59 81 65 / 20 10 50 30 Durant OK 84 66 82 69 / 90 60 60 30 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...Flood Watch until 5 PM CDT this afternoon for OKZ032-041>043- 046>048-050>052. TX...None. && $$ SHORT TERM...34 LONG TERM....34 AVIATION...11