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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, September 25, 2022

SPC Sep 25, 2022 0600 UTC Day 1 Convective Outlook

SPC 1200Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1205 AM CDT Sun Sep 25 2022 Valid 251200Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN APPALACHIANS INTO PARTS OF THE MID ATLANTIC AND SOUTHERN NEW ENGLAND... ...SUMMARY... Scattered severe storms producing large hail and damaging winds are expected from mid to late afternoon across the northern Appalachians and parts of the Mid Atlantic and southern New England through evening. ...Portions of the Appalachians, Mid Atlantic and southern New England... Within a larger-scale upper trough, a lead wave will move from the OH Valley to the Mid Atlantic during the day, providing cooling aloft and midlevel winds of 60-70 kt, enhancing shear. At the surface, low pressure will slowly deepen from Lake Huron into NY, with a front trailing southwestward across PA, WV, eastern KY and Middle TN by late afternoon. Meanwhile, a warm front will develop over southern New England, resulting in destabilization toward evening. Dewpoints will rise into the lower 60s F there, with upper 50s to lower 60s F southwestward along the front where heating and mixing will be stronger. The warm sector will become uncapped by around 18Z from PA southward across WV, VA, KY and TN, with further destabilization 21-00Z from NJ into southern New England. MLCAPE of 1000 J/kg will be common, with locally higher values. Deep-layer shear will be strong beneath the upper jet, with values around 60 kt common from eastern TN to the DelMarVa. Precipitation may be ongoing from OH into PA and western NY early in the day, north of the midlevel jet where temperatures aloft will be cold, and as warm advection around 850 mb translates east. Given cold temperatures aloft, some of this activity could produce small hail. As the air mass destabilizes beneath the cold air aloft, some of these storms may expand and become severe across PA and NJ during the afternoon, producing hail and wind. Later in the evening, additional storms may interact with the warm front where low-level shear will be stronger, and a brief/weak tornado could occur, depending on whether surface temperatures are warm enough for surface-based parcels. Farther south, southwest winds will maintain a moist air mass along the Appalachian Front, and heating will aid development after 18Z. Long, straight hodographs should favor fast-moving storms producing hail and wind. Additional isolated activity may occur into northern GA and AL along the front, primarily late afternoon and evening. ..Jewell/Wendt.. 09/25/2022 Read more CHECK UPDATE ZOOM GRAPHIC
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