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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.

Sunday, June 5, 2022

SPC Jun 5, 2022 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Sun Jun 05 2022 Valid 052000Z - 061200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF OKLAHOMA/KANSAS AND WESTERN NEBRASKA... ...SUMMARY... Significant severe thunderstorms producing very large hail, intense damaging winds, and a few tornadoes remain possible across parts of Nebraska, Kansas, and Oklahoma late this afternoon through tonight. ...20Z Update... No changes have been made to the Enhanced Risk extending from parts of NE across KS and into northern/central OK. A robust supercell producing large hail has recently developed over north-central KS on the eastern extent of persistent cloud cover in western KS. It remains somewhat unclear when/where additional intense thunderstorms will develop across northern/central KS this afternoon and evening. There will be some potential for convective initiation later this afternoon into the early evening along a dryline/outflow boundary intersection in the southwestern KS to northwestern OK vicinity. But, warm mid-level temperatures are still contributing to a substantial cap across this area based on recent mesoanalysis estimates. Isolated to scattered thunderstorms appear more probable to develop across parts of western into central NE, northwestern KS, and far eastern CO along a surface trough in the next few hours as modest upslope flow occurs and a weak mid-level disturbance ejects over the central Plains. This may already be occurring across parts of northwestern NE. Given the presence of steep mid-level lapse rates and adequate deep-layer shear, very large hail will be a possibility with any supercell that can be sustained. Otherwise, a southerly low-level jet that is forecast to strengthen this evening and tonight across the southern/central Plains should aid in upscale growth of convection across parts of central/southern KS and perhaps northern OK. Intense, severe wind gusts will be possible if this evolution into a bowing MCS occurs. But, there is still substantial uncertainty regarding the most favored corridor for this potentially significant MCS. Some expansion to the Marginal Risk has been made across parts of central/eastern OR into eastern WA based on recent observational and radar trends. Isolated hail and locally damaging winds remain possible with any of the stronger cores that can develop across the interior Pacific Northwest into the northern Rockies. See Mesoscale Discussion 1038 for more details on the short-term severe threat across this region. ..Gleason.. 06/05/2022 .PREV DISCUSSION... /ISSUED 1146 AM CDT Sun Jun 05 2022/ ...Kansas/Nebraska/Oklahoma... A semi-organized MCS continues southeastward at midday across eastern/southeast Oklahoma. Episodic pulse-type severe cores may persist on its western flank for a time this afternoon while it otherwise spreads toward the Ozark Plateau and ArkLaTex vicinity. Isolated severe hail on its western flank is the most probable risk, but some diurnally renewed damaging wind potential is also plausible downstream. To the west of this MCS and near/west of its related outflow, a very unstable environment will evolve this afternoon across the High Plains including western Nebraska and western/southern Kansas into Oklahoma. 12z upper-air data featured semi-cool mid-level thermal profiles for early June as noted from Dodge City/North Platte observed soundings with 500 mb temperatures around -12C to -13C, although a notable capping inversion was noted to the southwest (12z Amarillo sounding around 14C at 700 mb). Related High Plains elevated mixed layer plume will persist and modestly advect/recover eastward today on the western fringes of the late-night and early morning MCS now over eastern Oklahoma. This will be atop mid/upper 60s F surface dewpoints, which will contribute to ample buoyancy with upwards of 3000+ J/kg MLCAPE in the aforementioned corridor. Storms are most likely to initially develop near the front across Nebraska this afternoon, with deep convective initiation in/around peak heating a bit more uncertain (but still very plausible) across western/south-central Kansas and northwest Oklahoma in vicinity of the outflow boundary and lee trough/dryline vicinity. Multiple sub-regional corridors of several intense supercells can be expected with initial development. This includes potential for very large hail given the lapse rates/buoyancy reservoir and moderate deep-layer shear, which will be accentuated by relatively strong west/northwesterly high-level winds. A couple of tornadoes are possible as well. Consolidating cold pools will likely yield upscale growth into a maturing MCS towards south-central Nebraska and central Kansas during the evening. The overall intensity/coverage of the severe wind threat with this MCS will be modulated by whether a separate MCS will be simultaneously developing/ongoing in far southern Kansas and northern Oklahoma. Although there are timing/spatial uncertainties, aggregate meteorological scenario suggests a relatively high net potential/probability of large hail and widespread damaging winds this evening into the overnight across parts of southern Kansas and Oklahoma. A Moderate Risk upgrade could still be warranted later today pending greater confidence in a confined corridor of intense storm development including higher-end wind potential this evening into the overnight. ...Interior Northwest/northern Great Basin... Within the left exit region of an intense upper jet centered on northern California and southern Oregon, scattered thunderstorms are expected this afternoon from eastern Oregon across Idaho into a portion of western Montana, and in a more isolated sense across northern Nevada/Utah. Elongated, straight-line hodographs will encourage a few splitting supercells. However, buoyancy will likely remain weak with moderate mid-level lapse rates and below-normal surface temperatures. This suggests that isolated severe hail will be the primary hazard (especially across northern parts of the region), with locally strong wind gusts also a viable risk. Read more CHECK UPDATE ZOOM GRAPHIC