SPC Nov 13, 2017 2000 UTC Day 1 Convective Outlook

By Newsroom America Feeds at 13 Nov 2017

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0158 PM CST Mon Nov 13 2017 Valid 132000Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms may continue through this evening across coastal Washington and Oregon, as well as south to east-central Florida. ...20Z Update... No changes have been made to the ongoing forecast. ..Gleason.. 11/13/2017 .PREV DISCUSSION... /ISSUED 1018 AM CST Mon Nov 13 2017/ ...WA/OR Coast... Isolated storms are ongoing in the wake of a cold front passage this morning. While the 12Z UIL sounding sampled an environment supportive of potential updraft rotation, low-level winds have weakened and veered slightly per time-series of ATX/RTX VWPs. Short-term guidance is also suggestive of modest warming temperatures aloft as the mid-level cold-core lags well to the southwest of the deep occluding cyclone that is just west of Vancouver Island. Low-level hodograph curvature will increase briefly over parts of coastal WA this afternoon as the cyclone moves onshore accompanied by a secondary mid-level vorticity lobe. However, the less favorable thermodynamic environment should mitigate the severe-storm risk and may limit convection to low-topped showers. Farther south along the OR coast, mid-level lapse rates will remain steep with approach of the thermal trough and maintain a sporadic thunder risk through this evening, but low/deep-layer shear will be decreasing. ...FL... Northeasterly low-level flow will maintain a feed of tropical moisture across south to east-central FL, with a risk for isolated thunderstorms mainly through this afternoon. Read more



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