SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0135 AM CST Sat Feb 20 2021 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across the U.S., Monday through Monday night. ...Discussion... Models indicate that mid-level ridging will be maintained along an east-west axis across the mid-latitude eastern Pacific through this period. Within the westerlies to the north-northwest of this feature, short wave ridging is forecast to build across the northeastern Pacific into southwestern Alaska. As this occurs, progressive downstream flow appears likely to take on an increasing northwesterly component near the British Columbia coast into the Pacific Northwest, while remaining west-northwesterly to westerly across the interior U.S. through the Atlantic Seaboard. Within this regime, significant mid-level troughing shifting east of the Mississippi Valley by 12Z Monday is forecast to continue eastward. As it overspreads the Atlantic Seaboard late Monday afternoon through Monday night, it may be accompanied by secondary cyclogenesis off the middle and northern Atlantic coast, and a strengthening cold front across the south Atlantic coast into the adjacent western Atlantic. Ahead of the front, an influx of moisture, off a moistening boundary layer over the northeastern Gulf of Mexico, may contribute to weak CAPE across the Florida Panhandle into parts of southern Georgia and the Carolinas during the day Monday. However, it appears that this instability will generally rooted above the boundary layer, and the extent to which this may contribute to convection capable of producing lightning remains unclear. Somewhat better potential for boundary-layer based, or near boundary-layer based, thunderstorm development appears to exist ahead of the front across northern portions of the Florida Peninsula and coastal North Carolina by Monday evening. Substantially higher thunderstorm probabilities, though, appear focused offshore Monday night, near the Gulf Stream, in association with more favorable phasing of low-level destabilization and forcing for ascent. ..Kerr.. 02/20/2021
There’s more click here.