SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1112 AM CST Thu Nov 19 2020 Valid 201200Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms currently appears negligible across much of the U.S. Friday through Friday night. ...Synopsis... Models indicate that the westerlies will remain split, roughly along 120-140W longitude, with broadly confluent downstream flow centered across the northern tier of the U.S. and adjacent southern Canada. As one of the more significant perturbations embedded within this regime continues accelerating eastward, from northwest Ontario and the upper Great Lakes region through the Canadian Maritimes by 12Z Saturday, the center of broad cold surface ridging is forecast to build southeastward across/east of the middle Missouri Valley. This will tend to contribute to the reinforcement of generally dry and stable conditions in the wake of a prior cold intrusion; however, it will be preceded by at least some further boundary-layer recovery and inland return flow around the southern/western periphery of remnant surface ridging centered over the Southeast. ...Florida... Models indicate increasing potential instability within moistening easterly low-level flow across the southwestern Atlantic/Bahamas vicinity into the Florida Peninsula. This could contribute to potential for deepening convective development and scattered showers Friday into Friday night, particularly along the Atlantic coastal areas. However, it appears that relatively warm mid-levels and generally weak forcing for ascent will preclude intensification of convection into thunderstorms. ...Ozark Plateau vicinity... Models indicate that weak to modest low-level moistening on southerly return flow will contribute to weak CAPE above the leading edge of the southward advancing reinforcing cold intrusion. It appears that this may become focused along the Interstate 44 corridor of southwestern through south central Missouri, where mid-level cooling may also weaken inhibition sufficiently to allow for deepening convective development by 12Z Saturday. While forecast soundings appear to suggest some risk for lightning with this activity, the extent of this potential remains unclear, and thunderstorm probabilities are being maintained at less than 10 percent for now. ...Southwest... Models also indicate weak destabilization will occur across the Four Corners region Friday night, in response to low-level moisture return and cooling aloft associated with a low-amplitude wave emerging from the subtropical eastern Pacific. While at least some output suggests that this could be accompanied by convection capable of producing lightning, it remains unclear whether the risk reaches the minimum 10 percent probability for a categorical thunderstorm delineation. ..Kerr.. 11/19/2020
There’s more click here.