Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
582 ACUS02 KWNS 050555 SWODY2 SPC AC 050553 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1253 AM CDT Fri Jul 05 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF NORTHERN KANSAS INTO CENTRAL AND EASTERN NEBRASKA... ...SUMMARY... Severe thunderstorms are possible from southern South Dakota into the southern High Plains on Saturday, with the highest coverage expected in parts of the central Plains. Large hail (some greater than 2 inches) and severe winds are the expected hazards. ...Synopsis... Broad cyclonic flow will persist across much of the CONUS with the exception of the West Coast. A shortwave trough is expected to move into the central Plains by the afternoon. At the surface, a high pressure system will shift eastward into the Mid-South and lower Ohio Valley. Around the western flank of this anticyclone, moisture will return northward. A modest surface low will develop in the vicinity of the NE/CO/KS border, though models have some disagreement on how deep this low will become. The main focus for thunderstorm development will be near this surface low and farther east along a weak warm front/theta-e boundary. ...Central/eastern Nebraska...northwest/north-central Kansas... Thunderstorm development is expected during the mid/late afternoon. Upper 50s F dewpoints are expected to support 1000-1500 J/kg MLCAPE (with some areas perhaps near 2000 J/kg). Relatively cold temperatures aloft (around -12 C at 500 mb) and northwesterly mid/high-level flow with 35-40 kts of effective shear will promote some initial risk for supercells capable of large hail (some 2+ inches). Given the larger temperature-dewpoint spreads, upscale growth will likely occur later in the convective cycle. Severe wind gusts would become more common as this process unfolds. There is some uncertainty with regard to the most favorable area for potential MCS development. There is some signal in guidance that this could occur in western Kansas where slightly greater low-level moisture will be present, mid-level lapse rates will be steeper, and the low-level jet will be focused. Significant severe gusts are possible with an organized MCS, but confidence in placement remain quite low at this time. ...Southern High Plains... With the surface high helping to push moisture back into the southern Rockies and parts of West Texas, a few strong to severe storms are possible during the afternoon. Convection/outflow is possible prior to the D2/Saturday period on Friday afternoon/evening in the Texas Panhandle/South Plains. As a result, there is some uncertainty as to how far east the severe threat will reach. Shear will be weaker this far south, but steep low/mid-level lapse rates will promote a risk of severe winds and isolated large hail in the strongest storms. ...Mid-Atlantic... A weak cold front will move through the region during the afternoon/evening. While a richly moist (70+ F dewpoints) airmass will be in place, the stronger mid-level winds will generally be displaced farther to the northwest. Furthermore, mid-level heights will be near neutral and convergence along the front will be rather weak. Most model guidance continues to suggest limited storm coverage for those reasons. No highlights will be added, but a strong storm or two remains possible. ..Wendt.. 07/05/2024 $$