SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0140 AM CDT Tue Oct 06 2020 Valid 081200Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across much of the nation Thursday through Thursday night. ...Discussion... A strong, zonal mid/upper jet appears likely to continue gradually propagating across the northern mid-latitude Pacific, with its exit region perhaps approaching British Columbia/Pacific Northwest coastal areas toward the end of the period. Within one belt of branching downstream flow, broad mid-level ridging is forecast to gradually shift eastward across the Canadian Prairies and adjacent international border area, while similar amplitude downstream troughing progresses across the northern Atlantic coast. In another branch, a short wave trough and compact embedded mid-level low may approach northern California coastal areas, with broad downstream ridging across the Great Basin and Rockies into Upper Midwest remaining largely in phase with the ridging to the north. In lower latitudes, mid/upper subtropical ridging likely will be maintained across the western Atlantic into the Gulf of Mexico and adjacent portions of the Southeast. While weak troughing may begin progressing around its northwestern periphery, across the Rio Grande Valley into Texas, a couple of tropical perturbations will continue progressing within the lower-level easterlies on its southern/southwestern periphery. This will include Hurricane Delta, which may gradually turn north/northeastward, toward the north central Gulf coast, ahead of the mid/upper troughing. At least some model output appears weaker with cold surface ridging initially encompassing most areas across and east of the Mississippi Valley, including much of the Gulf Coast states, at the outset of the period. However, this feature is forecast to be generally maintained through the period, though with its center shifting from the Middle Mississippi Valley vicinity into the Mid Atlantic. Easterly/northeasterly low-level flow likely will maintain relatively dry/potentially cool boundary-layer air across much of the Gulf Coast states. While there may be a substantive elevated moisture influx ahead of Delta, accompanied by increasing precipitation and embedded convection across much of Louisiana, Mississippi and Alabama Thursday through Thursday night, warm and moist mid-levels with weak lapse rates are expected to minimize the risk for lightning. ..Kerr.. 10/06/2020
There’s more click here.