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Weather conditions on bar directly above are near Lakefront. Tabs under Moon Phases refer to O'Hare (official).

Archives for SPC Convective outlook are updated daily with a live map a the beginning of the article. Touch or click map to get possible update, and follow link at end of article for referral to NOAA/NWS Storm Prediction Center. Archives for Chicago's hourly weather data were updated 24-48 hours after end of each day prior to Dec. 2020.

Sunday, February 27, 2022

SPC Feb 27, 2022 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook Day 1 Convective Outlook RESENT 1 NWS Storm Prediction Center Norman OK 0145 PM CST Sun Feb 27 2022 Valid 272000Z - 281200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across much of the U.S. late today through tonight, but a few lightning flashes might be possible in heavy snow squalls spreading into northern New England and northern New York State late this afternoon. ...20Z Outlook Update... ...Upstate New York and northern New England... A deep mid-level trough emerging from the Arctic latitudes continues to dig toward the northern Atlantic coast, accompanied by strong lower/mid tropospheric cooling and intensifying cyclonic mid-level flow across much of the Northeast. One particular belt of stronger low-level cooling (centered around the 850 mb level) is currently spreading across and southeast of the St. Lawrence Valley through the Lake Ontario region, and appears to be providing the primary focus for weak boundary-layer based destabilization supportive of bands of developing convection. While some lightning has been observed across parts of southeastern Ontario into southern Quebec, convection is rooted within a mostly sub-freezing boundary layer, and low-topped, with equilibrium levels peaking around 10-11,000 feet AGL. This is not expected to change substantively while overspreading much of northern New England and northern New York State through early evening, so probabilities for thunderstorms still appear to remain less than the 10 percent minimum threshold for a categorical thunderstorm area. However, convection may still be impactful, accompanied by periods of heavy snow squalls with strong wind gusts and sharply reduced visibilities. ..Kerr.. 02/27/2022 .PREV DISCUSSION... /ISSUED 1014 AM CST Sun Feb 27 2022/ ...Synopsis... An expansive surface high will remain entrenched across the central CONUS today, limiting the potential for deep convection for most of the country. A weak cold front continues to push east/southeastward across the southeastern U.S., and will eventually move offshore later today. This may support a few offshore thunderstorms late this evening off the FL/GA/SC coast. Across the Pacific Northwest, onshore flow will continue to bring scattered precipitation to western OR/WA, but both observed and forecast thermodynamic profiles appear too marginal to support much lightning potential. Read more CHECK UPDATE ZOOM GRAPHIC