MD 1546 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR PORTIONS OF NORTHEASTERN KS INTO NORTHERN/CENTRAL MO
Mesoscale Discussion 1546 NWS Storm Prediction Center Norman OK 0636 PM CDT Mon Aug 21 2017 Areas affected...Portions of northeastern KS into northern/central MO Concerning...Severe potential...Watch possible Valid 212336Z - 220130Z Probability of Watch Issuance...40 percent SUMMARY...An isolated severe threat, with large hail, damaging winds, and perhaps a tornado or two, may be realized over the next several hours. While a watch is not immediately imminent, convective trends will be closely monitored for signs of increasing severe potential which may increase watch issuance probabilities. DISCUSSION...23Z surface observations and visible satellite imagery show an outflow boundary from earlier convection draped generally east-west across northeastern KS into parts of northern/central MO. The airmass along and south of this boundary has become strongly unstable owing to strong diurnal heating and a very moist low-level airmass, with 23Z RAP Mesoanalysis depicting generally 2000-3000 J/kg of MLCAPE across this region. Although stronger mid-level winds remain mostly displaced to the north of the surface boundary, there is enough veering/strengthening of the wind field through 6-7 km AGL to support 30 to locally 40 kt of effective bulk shear. This should be sufficient to support multicell to marginal supercell structures, with an isolated large hail/damaging wind threat. A tornado or two may also not be out of the question with any supercell given locally backed 0-1 km AGL winds near the outflow boundary enhancing effective SRH. Convective coverage has recently increased in northeastern KS, probably related to large-scale ascent associated with a weak impulse moving eastward across central NE/KS. There may be some potential for one or more small clusters of surface-based thunderstorms to congeal along the surface boundary and move east-southeastward this evening as a southwesterly low-level jet strengthens across this region. While not immediately likely, radar trends will closely monitored for possible watch issuance. ..Gleason/Goss.. 08/21/2017 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LSX...SGF...EAX...TOP... LAT...LON 39949634 39889480 39289188 38249193 38229340 38289517 38539634 39219691 39949634
from SPC Mesoscale Discussions http://bit.ly/2wsdSvK
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