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Weather conditions on bar directly above are near Lakefront. Weather conditions with Moon are O'Hare (official).

Tuesday, July 20, 2021

SPC Jul 20, 2021 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Tue Jul 20 2021 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF NORTHERN NEW YORK AND PARTS OF VERMONT THIS AFTERNOON AND EVENING... ...SUMMARY... Severe storms capable of producing damaging winds and isolated large hail are possible over parts of New York and Vermont this afternoon into early tonight. ...20Z Update... The northern portion of the Marginal Risk in eastern MI has been trimmed in the wake of ongoing convection, but otherwise no major changes have been made to the outlook. The greatest severe risk is still expected later this afternoon into this evening across parts of NY and VT, primarily in association with a long-lived QLCS that is currently approaching portions of western and northern NY. See the previous discussion below for more information. ..Dean.. 07/20/2021 .PREV DISCUSSION... /ISSUED 1109 AM CDT Tue Jul 20 2021/ ...NY/VT... A large upper ridge remains centered over the western states today, with northwest flow aloft across New England and the lower Great Lakes region. Water vapor imagery shows a shortwave trough moving into southeast Ontario. A cluster of thunderstorms associated with this feature will approach northern NY after 19z, and eventually track into VT. Given the relatively fast motion and bowing structures evident with these storms, damaging winds will be possible. There is uncertainty how far east the activity can maintain severe intensity, due to persistent clouds and weaker instability over parts of northeast VT and NH. However, given recent CAM solutions will extend the SLGT risk a little farther eastward into VT. Strong instability should develop across western/central NY this afternoon, with the potential for thunderstorm development along the trailing outflow boundary from the aforementioned activity. A combination of 30-40 kt mid-level flow and cooling temperatures aloft may result in a few strong/severe storms capable of hail and gusty winds through the evening. Read more LIVE: spc.noaa.gov