SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1107 AM CST Tue Nov 17 2020 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Wednesday or Wednesday night. ...Synopsis... A progressive, but relatively low amplitude upper pattern is anticipated across the CONUS on Wednesday. A shortwave trough is forecast to begin the period just off the Northeast coast, before quickly progressing northeastward. In the wake of this shortwave, modest upper ridging is expected to move from the northern/central Plains through the Upper MS Valley and Upper Great Lakes. Farther west, a series of shortwave troughs will move across the Pacific Northwest and northern Intermountain West. The lead wave in this series will likely move through the northern Plains early Thursday morning as the most substantial wave in the series moves into the coastal Pacific Northwest. At the surface, expansive high pressure over much of the eastern CONUS early Wednesday is forecast to gradually shift eastward as troughing associated with lead Pacific Northwest shortwave deepens and shifts eastward across the northern/central Plains into the Upper Midwest. Short wavelength between shortwave troughs will limit the duration of southerly return flow, keeping areas across the central and eastern CONUS too stable for thunderstorms. Cold mid-level temperatures atop moist onshore flow will result in modest instability along the Pacific Northwest coast, supporting the potential for isolated lightning flashes, particularly early Wednesday morning and late Wednesday night/early Thursday morning as shortwave troughs move through the area. Given the cold mid-level temperatures, small, sub-severe hail is possible with some of the stronger, more persistent cells. Very isolated (i.e. less than 10% coverage) lightning flashes may also occur across eastern OR/WA into ID late Wednesday afternoon/evening as the initial shortwave trough moves through. ..Mosier.. 11/17/2020
There’s more click here.