MD 0268 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR PORTIONS OF SOUTH-CENTRAL VA…CENTRAL NC INTO NORTH-CENTRAL SC
Mesoscale Discussion 0268 NWS Storm Prediction Center Norman OK 0129 PM CDT Sun Apr 15 2018 Areas affected...portions of south-central VA...central NC into north-central SC Concerning...Severe potential...Watch likely Valid 151829Z - 152000Z Probability of Watch Issuance...80 percent SUMMARY...The severe threat will spread eastward into the NC/VA Piedmont vicinity this afternoon and evening. A threat of damaging wind and a few tornadoes will ensue as a line of convection across western NC/VA continues to track east-northeast across the region. A new tornado watch will be needed downstream of WW 52. DISCUSSION...Strong heating beneath thin cirrus has allowed temperatures to warm into the upper 70s to low 80s across the NC/VA Piedmont vicinity this afternoon. This is a bit warmer than forecast guidance previously has suggested, resulting in modestly improved thermodynamic profiles. Regardless, surface based instability is expected to top out around 1000-1500 J/kg at most across the region. While midlevel lapse rates will remain lackluster, warmer boundary layer temperatures should result in steeper surface to 3km lapse rates. 18z Mesoanalysis indicates low level lapse rates have increased to around 7 deg C/km. Furthermore, low level kinematics should continue to improve as the surface low continues to push east-northeast across the central Appalachians. On the whole, this will maintain severe threat into the Piedmont vicinity as QLCS across western VA/NC/SC continues northeastward. Strong deep layer shear with fast storm motion and previously mentioned steepened low level lapse rates will support damaging potential. Furthermore, backed low level flow and 0-1km SRH greater than 200 m2/s2 will support rotation in embedded supercell structures/mesovorticies along the line. More recently, showers have developed across the warm sector ahead of the eastward advancing line. At this time these showers remain rather shallow and weak. While some intensification is possible as forcing for ascent increases, severe potential remains uncertain and the main focus for severe threat remains the eastward advancing line. ..Leitman/Guyer.. 04/15/2018 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...AKQ...LWX...RAH...ILM...RNK...CAE...GSP... LAT...LON 34467898 34387943 34477985 34588021 34818034 35198045 35948045 36698050 37128045 37438033 37917979 38107950 38077905 37957874 37587839 37177831 36387826 34717853 34467898
from SPC Mesoscale Discussions http://bit.ly/2H3ckdh
Be First to Comment