Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1120 PM CST Sun Jan 15 2017 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST TX INTO THE LOWER TO MIDDLE MISSISSIPPI VALLEY REGION... ...SUMMARY... Thunderstorms may pose a marginal risk for mainly isolated strong wind gusts and small to marginally severe hail from northeast Texas into northwestern Louisiana, Arkansas, and southeastern Missouri this afternoon and early evening. ...Northeast TX through the lower and middle Mississippi Valley region... Surface low will develop northeast into the middle MS valley in association with an ejecting shortwave trough. By late afternoon, a warm front will extend from the surface low in MO southeast into the OH valley. A secondary warm front will reside from the gulf coastal area into the lower MS valley region. Pacific cold front should stretch from the surface low in MO through western AR and eastern TX. A narrow corridor of partially modified Gulf air will advect through warm sector with upper 50s F dewpoints as far north as southeast MO and generally 60s F farther south through AR and eastern TX. Showers and a few thunderstorms will likely be ongoing along warm conveyor belt from east TX through eastern OK and AR into a portion of MO. The early convection may decrease in coverage, but widespread clouds will persist over much of warm sector. Weak mid-level lapse rates will further limit instability with MLCAPE mostly at or below 500 J/kg expected, except slightly greater over northeast TX and southern AR where more diabatic warming is possible. Potential will exist for thunderstorms to redevelop and undergo some intensification in pre-frontal confluent flow regime, especially from northeast TX into AR where boundary layer destabilization will be somewhat greater. Stronger deep-layer winds accompanying the ejecting upper trough will maintain favorable vertical shear profiles for organized storms including a conditional risk for supercells and bowing segments. Tendency will be for the deeper forcing for ascent to shift northeast away from the more unstable portion of the warm sector. This in conjunction with the overall marginal thermodynamic environment should limit a more substantial severe threat. ..Dial/Dean.. 01/16/2017Read more
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