Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CST Sat Jan 07 2017 Valid 081200Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few weak thunderstorms are possible Sunday across parts of central California, as well as late Sunday night along the Pacific Northwest Coast. ...Synopsis... A small change with the southern extent of the general thunderstorm area has been made across a portion of central CA, as guidance suggests destabilization does not become sufficient to support thunderstorm development on Sunday. Otherwise, no changes have been made to the rest of the Day 2 Outlook. The mid- to upper-level flow pattern across the contiguous U.S. today is expected to become less amplified Sunday through Sunday night as a large-scale trough moves off the East Coast. Meanwhile, 500-mb height falls are expected across the western states, as a large closed low, currently located west of the British Columbia and Pacific Northwest Coast per water-vapor imagery, and associated trough begin to move inland. A series of midlevel impulses will spread northeast into the western U.S., with one more prominent trough expected to move through CA into the Great Basin Sunday night. ...Central and northern CA... Elevated instability attendant to lower-tropospheric warm air advection regime will likely be ongoing at 12Z Sunday with continuation for these elevated thunderstorms to occur into Sunday morning and perhaps Sunday afternoon ahead of the approaching shortwave trough. Additional lightning strikes will be possible Sunday night, given forcing for ascent occurs with the inland-moving shortwave trough and cooling temperatures aloft steepen lapse rates. ...Portions of Pacific Northwest Coast... Cooling 500-mb temperatures attendant to the arrival of the leading portion of the closed low will steepen lapse rates to support sufficient destabilization for a few lightning strikes late Sunday night. ..Peters.. 01/07/2017Read more
from SPC Forecast Products http://ift.tt/ws9HZn
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