Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Tue May 16 2017 Valid 161630Z - 171200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER PARTS OF WESTERN OKLAHOMA AND THE EASTERN TEXAS PANHANDLE... ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM WEST TEXAS INTO PARTS OF NEBRASKA AND IOWA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE PLAINS STATES... ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE PLAINS STATES... ...SUMMARY... Multiple clusters of severe thunderstorms are expected this afternoon and tonight within a swath from west Texas across the central Plains to the western Corn Belt and mid Missouri Valley. Tornadoes, severe gusts, and large, damaging hail are expected within this corridor. The greatest threat of a strong tornado or two appears to be focused over parts of western Oklahoma and the eastern Texas Panhandle. ...KS/NEB/IA/MO... Morning water vapor loop shows a deep trough over the western states, with a leading shortwave impulse rotating across NM. 12z model solutions remain consistent that a cluster of intense thunderstorms will develop by mid afternoon over parts of southwest KS as this shortwave trough approaches. Strong heating is occurring in this region, with afternoon MLCAPE values over 3000 J/kg and minimal cap. Initial storms will likely be capable of very large hail and isolated tornadoes, but it seems likely that rapid upscale growth into a fast-moving squall line will occur. This will enhance the risk of damaging winds as storms spread northeastward across central/eastern KS and into parts of NE/IA/MO. If storm-scale trends dictate, this area may be considered for an upgrade to MDT risk in later updates. ...Western OK/TX Panhandle... Low level moisture continues to stream rapidly northward into the TX Panhandle and western OK, with dewpoints now in the mid 60s across the region. Model forecast soundings by mid-late afternoon suggest strong instability will be present with MLCAPE values over 3500 J/kg and 8 C/km lapse rates. Isolated and discrete convection is expected to form along the dryline in the TX Panhandle and track northeastward through the mid-evening. A pocket of strong low-level shear is forecast to develop in this region, resulting in favorable hodograph structures for supercells capable of very large hail and strong tornadoes. Therefore have upgraded this area to MDT risk. ...West TX... Later this evening, thunderstorms will likely develop southward along the dryline/cold front across parts of west TX. Large hail and damaging winds are expected with these storms. However, this activity is not expected to develop until well after dark when the capping inversion will be strengthening. This may tend to somewhat limit the coverage of severe storms. The line of storms will spread eastward and into west-central TX overnight. ...MN/WI/Upper MI... A shortwave trough over the eastern Dakotas will track eastward and help to maintain scattered thunderstorms over parts of the western Great Lakes region. Breaks in the clouds will help to destabilize this area, and may lead to a few strong/severe storms later this afternoon and evening. Forecast soundings suggest sufficient vertical shear and CAPE to pose a risk of hail and damaging winds in the strongest cells. An isolated tornado is also possible. ..Hart/Dean.. 05/16/2017Read more
from SPC Forecast Products http://ift.tt/wWCv9s
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