SPC Feb 20, 2018 0700 UTC Day 2 Convective Outlook

By Newsroom America Feeds at 20 Feb 2018

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 AM CST Tue Feb 20 2018 Valid 211200Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Showers and embedded thunderstorms are expected from Texas through the lower Mississippi valley to the central Appalachians Wednesday. ...Synopsis... A broad positive-tilt synoptic trough will persist over the western half of the U.S. Wednesday. Several embedded vorticity maxima will eject from the Southern Plains through the OH Valley. A cold front from the Great Lakes through south TX will continue southeast, but may begin to stall from a portion of the lower MS Valley to Deep south TX. ...Southern TX through the Lower Mississippi Valley... A moist boundary layer with upper 60s F dewpoints will reside in pre-frontal warm sector across south and southeast TX supporting moderate instability (1000-1500 J/kg MLCAPE). Tendency will be for low-level jet to shift northeast away from TX warm sector leaving modest flow in the near-surface to 800 mb layer. In south TX the east-west orientation of the cold front relative to southwesterly winds aloft will contribute to an anafrontal regime where storms initiating along the front will tend to become elevated as they cross into the cool side of the boundary. Nevertheless MUCAPE from 400-800 J/kg and 45+ kt effective bulk shear could support some threat for hail. Farther east from southeast TX through the lower MS valley, stronger winds aloft will reside in post frontal zone with modest deep layer and low-level shear in warm sector. Any storms developing along warm conveyor belt should remain in an environment marginally supportive of storm organization. Due to the potential limiting factors, will not introduce severe probabilities this update, but a marginal risk category might be needed for a portion of these areas in future outlooks. ..Dial.. 02/20/2018 Read more



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