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Archives for the SPC Convective Outlook are updated daily (approximately) with a live map at the beginning of each article. Follow the link at the end of the article to check for current updates on the NOAA/NWS Storm Prediction Center website. Also, see Archives for Chicago's hourly weather data on CARDINAL NEWS Magazine.

Wednesday, April 27, 2022

SPC Apr 27, 2022 0730 UTC Day 3 Severe Thunderstorm Outlook

SPC 0730Z Day 3 Outlook Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0238 AM CDT Wed Apr 27 2022 Valid 291200Z - 301200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHEAST NEBRASKA INTO NORTHEAST KANSAS... ...SUMMARY... Severe thunderstorms capable of all hazards are possible Friday afternoon into Friday night across portions of the southern and central Plains into the lower Missouri Valley. ...Synopsis... A negative-tilt mid/upper trough will be centered from the northern Intermountain region to the southern Rockies Friday morning. This system is expected to shift east through the period, emerging over the Plains by evening. As this occurs, an upper low is expected to close over the central Plains. This will focus the strongest flow, forcing for ascent and upper divergence from far northern OK into KS and NE. At the surface, low pressure is forecast to deepen over western KS and shift east near the KS/NE border through evening before lifting northeast toward southeast SD overnight. A dryline will extend southward from the low across central KS into central OK/TX by mid-afternoon. Meanwhile, a warm front will lift northward through the period, extending from the low near central NE into southern IA during the afternoon/evening. Low to mid 60s F surface dewpoints (with some pockets of upper 60s F possible with southward extent) will reside within the warm sector. A surface cold front will surge southeast during the evening/overnight, eventually overtaking the dryline and becoming positioned from southwest IA into western MO, southeast OK and north-central TX by Saturday morning. ...NE/KS into the Lower MO Valley... Forecast guidance indicates a strong midlevel cap will erode by late afternoon amid increasing ascent and low-level moist advection. Backed low-level winds near the triple point will result in enlarged low-level hodographs with forecast effective shear magnitudes around 35-45 kt. Backed low-level flow will also enhance low-level shear, with SRH values increasing to greater than 250 m2/s2. This will be favorable for rotating supercells, and a few tornadoes are possible. Very steep midlevel lapse rates and MLCAPE as high as 2500 J/kg will support large to very large hail. Initial supercell activity may eventually grow into clusters as the cold front surges east during the evening, resulting in a potential transition toward damaging gusts and hail as convection spreads east/northeast into parts of the MO Valley. ...OK/TX... A somewhat more conditional threat will extend southward along the dryline into OK/TX. Forcing for ascent will be weaker across this area. Additionally, guidance suggest the stout capping inversion will remain intact across much of the area through peak heating. However, a narrow corridor along the dryline appears likely to become uncapped during the afternoon amid strong heating and increasing low-level moisture. If these cells develop, supercells capable of all severe hazards will be possible across parts of central OK into northwest TX. As the cold front develops southeast during the late evening/overnight, elevated storms are more likely to shift east across the area. This activity will mainly pose a risk for large hail. ..Leitman.. 04/27/2022 Read more CHECK UPDATE ZOOM GRAPHIC