Severe storm risk Wed/Thu
0 responses | 0 likes
Started by metmike - May 2, 2018, 1 p.m.

Severe storms and possibly a few tornadoes possible today and tomorrow.  Highest risk will be from OK to IL today, then shift a bit eastward Thursday.

Severe storm center just updated statement:

Day 1 Convective Outlook     NWS Storm Prediction Center Norman OK   1130 AM CDT Wed May 02 2018    Valid 021630Z - 031200Z    ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS NORTHWEST   OK...SOUTHERN TO NORTHEAST KS...NORTHWEST MO...    ...SUMMARY...   Severe thunderstorms are expected across parts of the southern and   central Plains into the middle Mississippi Valley this afternoon   into tonight. Swaths of damaging winds, large to very large hail,   and several tornadoes are anticipated, especially from   western/central Oklahoma across southern to eastern KS and northern   to central MO.    ...Synopsis...   A complex overall forecast with significant severe potential for all   hazards evident across a large swath of the central/southern Great   Plains this afternoon and evening. As such, have expanded Enhanced   and Moderate risks with this update.    ...KS/MO...   The surface front is stalling from southwest KS to southern IA. A   lead mid-upper speed max will eject northeast from NM/far west TX to   central KS by this evening.  This speed max will interact with the   front and warm sector starting by early afternoon in southwest KS,   where convective initiation is expected. Surface dewpoints in the   mid to upper 60s, beneath mid-level lapse rates in excess of 8 C/km,   will combine with daytime heating to support MLCAPE of 2500-3500   J/kg along and south of the stalled front. Effective bulk shear   around 50 kt will be sufficient for supercells, though low-level   shear/hodograph curvature will not be particularly large for most of   the afternoon. The expectation is for initial supercells with very   large hail to grow upscale into clusters and potentially bowing   segments through the afternoon and evening while surging northeast   along the front, with an increasing threat for widespread damaging   winds by late afternoon, persisting into the evening across MO. The   tornado threat is uncertain given the expected messy convective   modes and relatively weak low-level shear through most of the   afternoon. However, towards 00Z, increasing low-level shear in   conjunction with the strongly unstable air mass may support   semi-discrete tornadic supercells just ahead of/southeast of the   emerging clusters/bows, where a couple strong tornadoes are   possible.    ...Western/central OK...   A strongly unstable warm sector is expected into western OK this   afternoon, with upper 60s surface dew points beneath very steep   mid-level lapse rates. The dryline will mix east of the thicker high   cloud band in west TX as surface temperatures warm into the mid 90s.   Convergence along the dryline should strengthen beneath the   mid-level speed max ejecting towards KS. This scenario should   support discrete supercell development at least as far south as the   Red River near the southwest OK/northwest TX border. MLCAPE of   3000-4000 J/kg and 50-60 kt effective shear will support at least   very large hail. Forecast wind profiles will have some weakness near   700 mb this afternoon, though low-level shear will increase and   become more favorable for tornadic supercells in the evening. The   main uncertainty is whether discrete storm mode will persist into   this time frame with most CAMs suggesting it will not. While this   volatile setup has some potential to yield long-track supercells   with a few strong tornadoes, will only expand but not upgrade   probabilities with this outlook.    ...West to central and north TX...   Guidance appears to be trending faster with convection forming near   the Permian Basin this evening along the retreating portion of the   dryline. Very large hail will be the main initial threat with these   storms given a highly favorable CAPE/shear combination. Upscale   growth into clusters with both severe wind gusts and large hail will   be possible tonight, with this activity eventually weakening   overnight.    ...Southern IA to northern/central IL...   Clusters of strong to severe storms will probably develop this   afternoon along the stalling to slow-moving cold front. While the   overall intensity/coverage is not anticipated to be as large as   farther southwest, all hazards appear possible with clusters/bows   and a few embedded supercells. The late evening/overnight portion of   the MO MCS may also affect parts of central IL with a wind threat as   well.
No replies yet. Be the first!