MD 1649 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR PORTIONS OF CENTRAL AND EASTERN KS
Mesoscale Discussion 1649 NWS Storm Prediction Center Norman OK 0347 PM CDT Sat Sep 16 2017 Areas affected...Portions of central and eastern KS Concerning...Severe potential...Watch possible Valid 162047Z - 162315Z Probability of Watch Issuance...40 percent SUMMARY...A risk for severe thunderstorms may increase across parts of central and eastern KS through the late afternoon hours and continue into the evening. There is some possibility that Severe Thunderstorm Watch issuance could become necessary during the next few hours. DISCUSSION...Visible satellite imagery indicates a shallow, dense, swelling field of boundary-layer cumulus within the general apex region of a pre-frontal thermal ridge permeating the western flank of Gulf return moisture -- i.e. from Stafford and Rice Counties to Ottawa County. The front enters northeast KS near Nemaha County and extends southwestward, and mesoscale ascent is being bolstered near a diffuse triple point in proximity to Comanche County. Deeper convection may initiate from these zones of ascent in the 2130-2300Z time frame -- initially being delayed by ample antecedent capping associated within a moist-boundary-layer-overlying EML. Steep lapse rates of 8.5-9 C/km in the mid levels, accompanying the EML, are supporting 1500-2500 J/kg of MLCAPE in the warm/moist air mass. This may yield a few robust updrafts, probably following the repeated development and decay shallow convective plumes amidst only modest frontal ascent. A few sustained convective elements should be more likely by early evening, with 25-30 kt of effective shear supporting small forward-propagating clusters with isolated to widely scattered severe wind/hail. This activity will spread eastward/northeastward, reaching a corridor from Topeka and Lawrence toward Wichita by evening. This activity will eventually ingest convectively processed air from ongoing convection from the KC area to northeast OK. The anticipated severe storm coverage is presently questionable with stronger deep shear/ascent lagging behind the surface front, though environmental and convective trends will be monitored for possible Severe Thunderstorm Watch issuance. ..Cohen/Guyer.. 09/16/2017 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...EAX...TOP...ICT... LAT...LON 38219826 39149754 39579681 39789588 39399539 37639672 37309790 37469838 38219826
from SPC Mesoscale Discussions http://bit.ly/1nNM9pY
Be First to Comment