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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.

Saturday, June 12, 2021

SPC Jun 12, 2021 0600 UTC Day 2 Convective Outlook

SPC 0600Z Day 2 Outlook Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CDT Sat Jun 12 2021 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER THE SOUTHERN HIGH PLAINS...WEST VIRGINIA INTO PENNSYLVANIA...AND ACROSS NORTHERN WISCONSIN... ...SUMMARY... Isolated severe hail or wind is possible Sunday afternoon and evening over parts of eastern New Mexico and Colorado, northern Wisconsin, and over parts of West Virginia, Pennsylvania, and central New York. ...Synopsis... An upper ridge will build over the Rockies as a shortwave trough drops south across the upper MS Valley and Great Lakes. The stronger cyclonic flow aloft will spread into the Mid Atlantic late, with height falls beginning during the late afternoon. To the west, strong southwest flow aloft will exist across the Pacific Northwest as a strong jet max grazes the WA and OR Coasts. At the surface, high pressure will be centered over the central Plains, and over the Appalachians. The most robust moisture and instability will remain over the southern Plains and lower MS Valley, but plumes of instability will extend around the central Plains high into the High Plains, as well as across the OH Valley near a weak surface trough. Weak instability is also expected to develop over northern MN into WI, where a weak surface low and cold front will develop out of the northwest. ...Front Range into the southern High Plains... Low-level winds will increase out of the southeast late in the day, resulting in moisture advection. Favorable instability will develop during the peak heating hours, with isolated storms likely forming along the Front Range. Although winds aloft will be weak out of the west/northwest, veering winds with height will favor slow-moving cells capable of marginal hail or wind from late afternoon through evening. ...WV into PA and central New York... A broken line of storms is expected to develop by 18Z from western NY southwestward toward the OH River near a developing front. Strong heating and 60s F dewpoints will result in up to 1500-2000 J/kg MUCAPE, with modest deep-layer shear on the order of 40 kt. Weak low-level winds suggest forward-propagating line segments capable of strong wind gusts, but the stronger storms may produce marginal hail as well. ...Northern WI and MN Arrowhead... Strong heating will lead to deep mixed layers, beneath strong northwest flow aloft. While moisture will be limited with lower 50s F dewpoints, sufficient CAPE is expected to develop, supporting a few strong storms given increasing lift near the low. In addition, hodographs will become very long, favoring cellular activity. Marginal hail will be possible, along with a few strong wind gusts. ..Jewell.. 06/12/2021 Read more LIVE: