Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0102 AM CDT Fri Aug 28 2020 Valid 291200Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTHERN KANSAS INTO NORTHERN OKLAHOMA AND NORTHERN ARKANSAS AND FROM THE CAROLINAS THROUGH THE MIDDLE ATLANTIC... ...SUMMARY... Strong to severe storms are possible from southern Kansas into northern Oklahoma and Arkansas Saturday afternoon and evening with damaging wind and large hail the main threats. A modest risk for a few strong to severe storms will exist from the Carolinas into the Middle Atlantic during the day with damaging wind gusts and a few tornadoes possible. ...Southern Kansas, Northern Oklahoma into northern Arkansas... A cold front will advance southward into OK and the TX Panhandle Saturday where the atmosphere will likely become moderately to strongly unstable in warm sector. Current indications are that elevated storms will probably be in progress north of the boundary across KS Saturday morning. Several CAMs as well as NAM and ECWMF depict an MCS and associated MCV across southern KS early in the period, and this activity will shift east southeast over top of a low-amplitude synoptic ridge during the day. Potential will exist for additional storms to develop across southern KS into northern OK as the shortwave trough advances east and interacts with the front and destabilizing boundary layer. Stronger flow/vertical shear will accompany the shortwave trough, and storms will have the potential to organize. A low-level jet will likely strengthen during the evening in association with this mesoscale system and help to sustain an organized MCS into the lower MS Valley region into the overnight. Damaging wind and hail will be the main threats. Other more isolated strong to severe storms may develop farther west in the post-frontal upslope region across the higher terrain of CO and spread east into High Plains during the late afternoon and evening. A few instances of large hail and damaging wind will be the main threats. ...Carolinas through the Middle Atlantic... Remnants of Laura are forecast to accelerate through the southern Appalachians and Carolinas to southern Middle Atlantic regions on Saturday as the system becomes absorbed within belt of westerlies. Laura should become loosely phased with a progressive northern-stream trough that will move through the Great Lakes and Northeast States. The accompanying cold front should extend from a surface low over the lower Great Lakes southwestward into the Ohio Valley early in the day. The front will continue into the Northeast States and Middle Atlantic during the mid to late afternoon. Rich tropical moisture will reside in pre-frontal warm sector, but weak lapse rates and potential for widespread clouds will likely result in marginal instability. The stronger low-level wind fields and largest hodographs accompanying Laura should spread through NC and southern VA based on latest guidance, but the system will continue to undergo a weakening trend. Latest satellite imagery show Laura is transitioning to a hybrid system and is entraining dry air in the mid-upper levels. This transition might allow for greater diabatic heating and destabilization of the boundary layer across parts of NC and VA where tornado threat will be greatest, but conditional upon sufficient low-level destabilization. Farther north into the Mid Atlantic and Northeast States, low-level hodographs will be smaller, but the kinematic environment might be sufficient for a threat of locally strong wind gusts with storms developing along and ahead of the advancing cold front. Threat in this region is also conditional upon sufficient boundary layer destabilization, which remains uncertain given potential for widespread clouds and areas of ongoing precipitation. ..Dial.. 08/28/2020Read more
from SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day2otlk_0600.html
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