Area Forecast Discussion
Issued by NWS Oklahoma City, OK
Issued by NWS Oklahoma City, OK
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974 FXUS64 KOUN 231757 AFDOUN Area Forecast Discussion National Weather Service Norman OK 1257 PM CDT Thu May 23 2024 ...New AVIATION... .UPDATE... Issued at 1209 PM CDT Thu May 23 2024 Watching a complex severe weather forecast this afternoon and evening. Boundary layer moisture return has been extremely robust this morning following the overnight round of convection. The outflow boundary from those previous storms could be seen in surface observations as a sharp warm front across central Oklahoma; surface wind fields on the Oklahoma Mesonet have shown a distinct diffusion of this front over the last 2 hours. With that said, dewpoints in northwest Oklahoma are in the mid-60s with a distinct gradient to dewpoints in the low-to-mid 70s across western north Texas and southern Oklahoma. A stratus deck is also shown on satellite across most of the area, particularly near the 100th meridian. Given the moisture advection ongoing, there are some questions about how long this takes to mix out. If stratus does linger into the afternoon, the severe risk would likely be reduced. Over the past hour, however, GOES satellite has shown some thinning of the stratus across the 100th meridian and corresponding eastern portions of the Texas panhandle, which coincides with an easterly push of the dryline off of the Caprock. The expectation is that the western fringe of the cloud cover will continue to downscale into cumulus over the next several hours, which will allow for partial insolation. The number of storms we receive is similarly in question and in part dependent on how much insolation we receive. Most members of the HREF/MPAS do try to cue up at least one or a few storms by late this afternoon in western Oklahoma, with a particular focus on the triple point between the effective warm front and the dryline. Meanwhile, another area will be watched in southern and central Oklahoma where some models have shown a signal for convection initiation within a warm advection regime. There appears to be a negative correlation between storm coverage in the two regimes; in other words, more WAA storms to the east could reduce or even remove storm coverage along the dryline later. The early storms, should they develop, will have access to 3,000- 4,000 J/kg of MLCAPE and sufficient bulk shear for the development of supercells. Low-level shear will be weak, so the main concern would be for severe hail and damaging winds, but a very low tornado risk would accompany these storms. Off to the west, any storms that develop along the dryline will initially be favored to become supercellular and produce large to very large hail. There is a noticeable uptick in the LLJ on model guidance beginning about 8:00 pm, so there will be a window for any established supercells to produce tornadoes this evening as they move eastward. Meister && .SHORT TERM... (Today and tonight) Issued at 348 AM CDT Thu May 23 2024 Severe weather potential will remain the main weather message on Thursday. For early this morning (through ~sunrise), widely scattered thunderstorm development is expected to continue across portions of southeast Oklahoma. This activity is likely being fostered in part by increasing warm air advection/mass response and cold pool effects with recent storms. Despite a stable boundary layer, objective analysis continues to show an environment favorable for at least limited strong to severe storm potential. Large hail and gusty winds will be the main concerns with activity this morning. Additionally, areas of fog may develop (along/south of Interstate 40) as aforementioned moisture transport spreads northward through the area. Couldn`t rule out localized dense fog, especially along and east of a Holdenville- to-Waurika line. Otherwise, attention will turn towards an additional (more impactful) round of severe thunderstorms late this afternoon into evening. In between, low clouds/drizzle and perhaps a few thunderstorms may develop as low-level moisture advection continues through much of the day, and as an effective warm front lifts through the area. Severe weather chances are generally low through 2-3 PM, though one or two severe storms cannot be ruled out (mainly across west-central into eastern Oklahoma). After ~4-5 PM, focus for severe weather will reside near a sharpening dryline in vicinity of the 100th meridian. While the main synoptic support will be associated with a wave emerging across the Northern/Central Plains, a branch of the subtropical jet (across portions of central Texas) looks to remain active through the day. Additionally, a combination of at least filtered insolation and rather unseasonable moisture (HREF mean ~68-72 degrees) will help erode residual elevated warm layers (the `cap`) into the mid- afternoon. The result will be the potential for scattered development of organized/severe storms near and east of the dryline, even amidst a weakly forced regime. The forecasted mesoscale environment will be quite favorable for organized (supercell) thunderstorms, posing a risk for all storm hazards. Initially, large to very large hail will be the favored hazard owing to steep lapse rates and strong cloud-bearing wind shear. Towards mid-evening/sunset, as a nocturnal low-level jet becomes established, concern for tornadic potential will likely increase with any ongoing supercell. The most established storms may take some time to fully meet their demise after sunset, especially when considering continued mass flux late this evening. For now, storm intensity and concern for severe weather is expected to wane towards ~11 PM-Midnight. In addition to severe weather concern, potential for at least limited heavy rainfall and flooding continues across portions of southeastern Oklahoma. While forecast confidence/signal is not as strong compared to previous cycles, enough potential remains to warranted continuation of ongoing Flash Flood Watch through early Friday morning. Ungar && .LONG TERM... (Friday through Wednesday) Issued at 348 AM CDT Thu May 23 2024 Friday: Low potential for storms and severe weather looks to develop across far southeastern Oklahoma during the afternoon/evening. As the aforementioned north-central CONUS wave lifts into portions of the western Great Lakes, a trailing front is expected to push through the area beginning early Friday morning. A few light rain showers may be noted during and just behind frontal passage on Friday morning. Otherwise, very low (~20%) potential for additional storm development is currently anticipated by Friday afternoon/evening across far southern/southeastern Oklahoma. How far the front ultimately advances (southward) through the day will determine the severe weather risk for counties near the Red River, as the mesoscale environment will support a hail/wind risk with sustained storms. Saturday: A potent severe weather event is possible across portions of the area/region. A strong upper wave ejection is expected across the Plains through the day. Strong mass response is again expected ahead of this feature. As forcing overspreads a dryline, expected to reside across western into west-central Oklahoma into the afternoon, scattered thunderstorm development is expected. The progged mesoscale environment will strongly favor strong supercells, posing a risk for large hail, damaging winds and tornadoes (including significant events of each). This is a day that bears close watching, as any storm will be capable of significant and impactful outcomes. Sunday-Next Week: Transition towards mostly dry and seasonable weather is expected. As the Saturday system departs to the east, a stretch of mostly dry weather is expected to ensure. Pending the strength of the frontal intrusion on Sunday, temperatures into the early-midweek may run near to slightly cooler than average for the last days of May. Ungar && .AVIATION... (18Z TAFS) Issued at 1237 PM CDT Thu May 23 2024 Current stratus deck will slowly scatter with increasing visibilities as all terminals should return to VFR conditions around 20-21Z. Isolated thunderstorms will be possible and could impact some of our terminals between 22-04Z with probabilities up to 50 percent. Although storm activity could reduce conditions below VFR conditions, expecting another stratus deck to lower ceilings to MVFR to IFR between 05Z-10Z with low confidence of reduced visibility`s in fog down to 2 miles at some terminals. A cold front will be pushing into northern Oklahoma after 12Z as surface winds will be shifting out of the north behind the front. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 82 67 83 62 / 50 50 0 0 Hobart OK 89 65 86 60 / 30 30 0 0 Wichita Falls TX 89 70 90 65 / 30 30 0 0 Gage OK 91 58 81 54 / 20 20 0 0 Ponca City OK 83 65 82 57 / 40 40 0 0 Durant OK 84 70 90 68 / 50 50 0 20 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...Flood Watch through late tonight for OKZ032-041>043-046>048- 050>052. TX...None. && $$ SHORT TERM...34 LONG TERM....34 AVIATION...68