SPC May 19, 2017 0600 UTC Day 2 Convective Outlook

By Newsroom America Feeds at 19 May 2017

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1248 AM CDT Fri May 19 2017 Valid 201200Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE LOWER TO MIDDLE MISSISSIPPI VALLEY...WESTERN TENNESSEE AND OHIO VALLEYS... ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM A PORTION OF THE SOUTHERN PLAINS TO THE GREAT LAKES... ...SUMMARY... Strong to severe thunderstorms will be possible ahead of a cold front from eastern Texas into the lower-to-middle Mississippi and lower Ohio Valleys Saturday and Saturday evening. Isolated strong wind gusts and hail will be the main concern. ...Synopsis... Primary feature of interest will be an upper trough initially over the central plains early in the period. This trough will advance northeast through the middle and upper MS Valley and Great Lakes during the day. Attendant surface low will occlude across IA/WI with trailing cold front continuing through the middle MS Valley into central and southwestern TX where it will likely stall. A warm front will extend east from the low and advance north into the Great Lakes. ...Lower to middle Mississippi, western Tennessee and lower Ohio Valleys... A moist airmass with upper 60s F dewpoints will reside in the pre-frontal warm sector, and the atmosphere will likely become moderately unstable with 1500-2000 J/kg possible as the boundary layer destabilizes during the day. It is likely that showers and thunderstorms will be ongoing along warm conveyor belt just ahead of the cold front from north central TX through eastern OK into a portion of the middle to upper MS valley region. This activity will probably weaken during the morning, but renewed development is likely by early afternoon as the atmosphere destabilizes. A mid-level jet will rotate through the eastern periphery of the upper low circulation, but it appears this feature will remain west of the more unstable portion of the warm sector. Nevertheless, 30-40 kt effective bulk shear will be sufficient for a few organized multicells with damaging wind and hail the main threats. Winds in the lowest 3 km will weaken over the lower MS valley as the primary low-level jet develops toward the OH Valley where some supercell structures will be possible near warm front if sufficient destabilization can occur. ...Eastern and southeast Texas... Winds in the 0-6 km layer and vertical shear will remain modest over the TX warm sector during the day as the upper low shifts northeast away from this region. While forcing along the outflow boundary and front may contribute to a few thunderstorms during the afternoon, weak vertical shear and modest lapse rates should limit storm organization and overall severe potential. However, a few of the stronger storms might produce gusty winds and hail. Overnight a few storms may develop north of the stalled front across southwest to central TX. These storms will be elevated but might become capable of producing hail. ..Dial.. 05/19/2017 Read more



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