Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1253 AM CDT Wed Aug 05 2020 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS REGION... ...SUMMARY... Strong to severe storms capable of strong wind gusts and large hail are possible this afternoon and evening over portions of the central High Plains. ...Synopsis... A weakly progressive upper pattern will exist over the U.S. today, with troughing expanding over the West, ridging moving across the Intermountain region toward the Plains, and a second trough crossing the Great Lakes/Midwest/Lower Mississippi Valley. At the surface, a generally weak/nondescript pattern will prevail, with high pressure over much of the eastern half of the country. A weak baroclinic zone will linger from the southern Appalachians across the Gulf Coast states, and then extending northwestward across Texas, while lee troughing persists over the High Plains through the period. ...Central High Plains... Daytime heating of the modestly moist (50s dewpoints) boundary layer across the central High Plains region will once again support moderate destabilization from southeast Wyoming and the Nebraska Panhandle south to northeastern New Mexico. Weak/subtle short-wave troughing within moderate west-northwesterly flow is expected to reach the High Plains during the afternoon, supporting isolated/robust convective development. With low-level southeasterlies across the region, veering/increasing flow with height will result in shear sufficient to augment convective intensity locally -- with large hail and locally damaging winds expected. With time, storms are forecast to merge into one or more east-southeastward-moving clusters, and cross eastern Colorado and portions of the Nebraska Panhandle. Risk for damaging winds may persist locally, before diurnal convective weakening commences. ...Eastern SD and southwestern MN into the mid MO valley... An upper perturbation now crossing North Dakota will continue moving southeastward across the eastern Dakotas through the afternoon, possibly accompanied by weak/remnant convection. Some regeneration of convection may occur over eastern South Dakota and southwestern Minnesota during the afternoon, as moderate destabilization occurs, with isolated storms possibly spreading into northeastern Nebraska and northwestern Iowa with time. With moderate northwesterly flow aloft atop this region, a stronger storm or two may be capable of producing gusty/damaging winds and marginal hail, before convection diminishes during the evening. ...Portions of eastern/southeastern TX into southwestern LA... Remnants of overnight convection -- and possibly an MCV -- should continue moving southeastward into/across East Texas into the afternoon. Lingering/weak convection may then reintensify during the afternoon, spreading into southeast Texas and southwestern Louisiana, as diurnal heating contributes to moderate destabilization. With moderate (25 to 35 kt) northwesterly flow at mid levels spreading into the area, atop low-level southerlies, shear may prove strong enough for a few storms to organize/become severe. If some upscale/linear growth can occur, attendant risk for gusty/damaging winds and marginal hail may spread as far southeastward as the western Gulf coastal waters by early evening, before storms dissipate. ..Goss/Wendt.. 08/05/2020Read more
from SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_1200.html
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