####018005542#### ACUS01 KWNS 060556 SWODY1 SPC AC 060555 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Mon May 06 2024 Valid 061200Z - 071200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR PARTS OF WESTERN/CENTRAL/NORTHEAST OKLAHOMA INTO SOUTH-CENTRAL AND SOUTHEAST KANSAS... ...SUMMARY... Numerous severe thunderstorms are expected to develop and move eastward Monday afternoon through Monday night across parts of the southern/central Plains. Multiple intense, long-track tornadoes, very large to giant hail, and severe/damaging winds all appear likely. ...Synopsis... A potent shortwave trough is evident in water vapor imagery this evening within the Great Basin. This feature will continue eastward into the Four Corners by early this morning. An initial speed max is expected to eject into western Kansas. By late afternoon into the evening, another speed max will approach western Oklahoma. Deep low-level moisture is already being observed in the BRO 00Z sounding. Surface observations also show low 70s dewpoint as far north as the DFW Metroplex this evening. As the trough approaches, this moisture should stream northward. The overall synoptic setup indicates a severe weather outbreak occurring this afternoon and extending into the evening and parts of the overnight period. Multiple intense, long-track tornadoes are expected, especially in parts of southern Kansas into Oklahoma. Very-large hail of up 2-4 inches can also be expected with intense supercells. Severe gusts may initially be isolated, but storm coverage should increase with time as well as the mode becoming more linear. As this occurs, severe gusts, some up to 80 mph, will become more common. ...Oklahoma into southern Kansas... Intense storms are expected across these areas by late afternoon. Storm coverage is likely to initially be greatest in south-central Kansas given the greater and earlier upper-level forcing. Isolated storms will still be possible along the dryline in western Oklahoma as strong heating in the Texas Panhandle should support dryline circulations that should at least locally erode inhibition. By the evening, greater forcing for ascent will arrive in western Oklahoma. Flow aloft will be nearly perpendicular to the dryline, which will favor a discrete storm mode. Even as the weak Pacific front overtakes the dryline, low-level forcing is not expected to be strong enough to promote substantial upscale growth, especially when coupled with continued strong shear across the boundary. Overall, there appears to be prolonged opportunity for discrete storms to form across western Oklahoma into parts of southern Kansas. While the environment during the afternoon will certainly support intense, long-track tornadoes, concern only grows by early evening. Discrete storms are expected to move eastward into an intensifying low-level jet core in central and eastern Oklahoma into southeast Kansas. Surface-based activity will likely persist into the evening and even parts of the overnight, given continued influx of moisture and weak capping. The time frame of greatest concern for intense tornadoes is from 03-06Z across central into northeast Oklahoma. This is a high-end environment. An upgrade to a tornado-driven High Risk was considered. There remains some lingering uncertainty with regard to the number of intense tornadoes that will occur. An increase in tornado probabilities will certainly be warranted should confidence in coverage and preferred corridors increase. ...Western Kansas into Nebraska...Iowa...Missouri... Convection will likely initiate in western Kansas into southwest Nebraska earlier than elsewhere given the timing of the upper-level forcing. Furthermore, a linear mode should more quickly become established due to the deep layer shear being oriented much more parallel to the initiating boundary than farther south. Buoyancy will generally decrease with northward extent. That being said, moisture will continue to push northward through the day and into the evening. Mid 60s F dewpoints could reach southeast Nebraska. Strong deep-layer and low-level shear will promote an organized line of convection capable of wind damage and QLCS tornadoes (some potentially strong). There is some potential for discrete storms to form ahead of the anticipated line. These storms would pose a greater threat for significant tornadoes. Large to very large hail will likely be more likely in western and central Kansas and coverage of very large hail will be conditional on how long a discrete mode is maintained. ...South Dakota... Richer low-level moisture (upper 50s to perhaps near 60 F dewpoints) will reach portions of central into northwest South Dakota. A narrow zone of instability is expected to develop by the afternoon between the cold and warm front. Large hail and severe gusts will be the main threats, but low-level shear will be sufficient for a tornado or two. ...Edwards Plateau into Texas Rolling Plains... Storm coverage this far south should generally be much more isolated on account of weak and nebulous forcing. However, a strong enough dryline circulation could initiate convection within a strongly unstable and sheared environment. Should storms form, large hail and severe wind gusts would be possible. ..Wendt/Darrow.. 05/06/2024 $$ ####018004598#### ACUS02 KWNS 060600 SWODY2 SPC AC 060558 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Mon May 06 2024 Valid 071200Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID-SOUTH INTO THE OHIO VALLEY... ...SUMMARY... Scattered severe thunderstorms will be possible Tuesday from the Mid-South northeastward into the Ohio Valley. A few tornadoes, large to very large hail, and severe/damaging winds all appear possible. ...Synopsis... A large upper cyclone centered over the northern Plains should slowly occlude on Tuesday. A convectively augmented mid-level shortwave trough is forecast to move quickly northeastward across the Upper Midwest and Great Lakes through the day. The primary surface low over ND should weaken/occlude through the day, while a separate, weak low is forecast to develop northeastward across the Upper Midwest in tandem with the shortwave trough. A cold front will sweep eastward across the Midwest/OH Valley through the day before decelerating, while a warm front simultaneously lifts northward across the OH Valley and lower Great Lakes. ...Mid-South/Mid Mississippi Valley into the Ohio Valley... There is relatively high confidence that a band of strong to severe convection will be ongoing at the start of the period Tuesday morning over parts of the Midwest/mid MS Valley. This convection will probably weaken though the morning as it encounters a less unstable airmass into the OH Valley. But, it may still pose some threat for damaging winds. With somewhat steepened mid-level lapse rates overspreading a moist low-level airmass, moderate to locally strong instability should develop with diurnal heating across much of the warm sector in the OH/TN Valleys. The effect of the early-day convection complicates the potential for a greater severe threat. Still, eventual regeneration along the morning convection's outflow and/or leading edge seems probable into Tuesday afternoon. Strengthening mid-level flow on the nose of an enhanced (50-70 kt) mid-level jet will aid in the development of strong deep-layer shear, which will support organized updrafts/severe convection. Overall mode may be somewhat messy, with a mix of supercells and multicell clusters possible. Regardless, any persistent supercells should be capable of producing large to very large hail. Low-level shear associated with a 25-35 kt south-southwesterly low-level jet appears sufficient to support updraft rotation and a threat for a few tornadoes, mainly across the OH Valley. If thunderstorms can congeal into one or more clusters, then a greater threat for severe/damaging winds would be realized. This convection should spread into the western parts of the central Appalachians Tuesday evening before eventually weakening. ...Upper Midwest... Cold mid-level temperatures associated with the upper trough should foster the development of weak instability through Tuesday afternoon. Strong large-scale ascent will likely encourage the development of low-topped thunderstorms across parts of WI and vicinity. Isolated hail and gusty winds may occur with the more robust cores, and a brief tornado or two also appears possible. ...Virginia/North Carolina... Isolated to perhaps widely scattered thunderstorms may develop Tuesday afternoon across parts of VA/NC, generally along/east of a weak surface lee trough. Sufficient forecast instability and shear should be present to support some threat for hail and strong winds with any thunderstorms that form. The overall severe threat is expected to remain fairly isolated/marginal. ...Lower Mississippi Valley/Deep South... Weaker forcing with southward extent across the lower MS Valley/Deep South suggests a more conditional severe threat compared to locations farther north. But, at least isolated strong to severe thunderstorms appear possible Tuesday afternoon/evening, especially along a weak surface trough extending into parts of MS/AL. ...Central Texas... A highly conditional threat for thunderstorms is apparent across parts of central TX Tuesday afternoon along/near a low-level moisture gradient/sharpening dryline. While large-scale ascent aloft appears negligible, if any thunderstorms can form and persist, they could become severe given a strongly unstable airmass. This scenario appears too uncertain to add low severe probabilities at this time. ..Gleason.. 05/06/2024 $$