SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0140 PM CST Mon Nov 16 2020 Valid 162000Z - 171200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected across the contiguous U.S. through tonight. ...20Z Outlook Update... ...Pacific Northwest... Convection associated with weak CAPE is evident within a warm frontal precipitation band overspreading the region. The southern edge of the heavier precipitation (west of the Cascades) is currently near the Columbia River and forecast to shift north of the Puget Sound vicinity by around 03-05Z, with substantive lower/mid tropospheric drying into its wake. Despite the presence of the convection, initially warm and saturated thermodynamic profiles appear to be inhibiting the development of lightning. Even near the leading edge of the mid-level drying, warm layers aloft still appear inhibitive, and an area of offshore lightning (roughly near 45N/126W) between 16-17Z appears to have been short lived. ...South Florida... Relatively warm and dry mid-levels, coupled with generally weak low-level convergence, continues to inhibit thunderstorm development. However, models indicate at least some increase in low-level convergence along coastal areas near/north of Palm Beach later this afternoon through tonight, which might still support the risk for an isolated weak thunderstorm or two, in the presence of weak instability. ..Kerr.. 11/16/2020 .PREV DISCUSSION... /ISSUED 1015 AM CST Mon Nov 16 2020/ ...South FL... Isolated showers currently east-southeast of the Space Coast should increase in coverage as they spread southwestward along/ahead of a weakly convergent cold front pushing south from central FL. Rather poor 700-500 mb lapse rates between 4-5 C/km as sampled by regional 12Z soundings will be a limiting factor to sustaining charge separation, but adequate buoyancy exists for a risk of isolated thunderstorms. ...Coastal WA... A pronounced low-level warm advection regime will shift north from the Columbia Valley today. Scant elevated buoyancy may develop as 850-mb dew points rise to around 9 C this afternoon. Very isolated lightning could accompany deeper showers through early evening.
There’s more click here.