SPC AC 180730 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sat May 18 2019 Valid 201200Z - 211200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS THE EASTERN TX PANHANDLE...NORTHWEST TX...WESTERN/CENTRAL OK...AND FAR SOUTH-CENTRAL KS... ...SUMMARY... Severe thunderstorms capable of all severe hazards, including strong tornadoes, are expected across portions of the southern Plains on Monday. ...SIGNIFICANT SEVERE WEATHER EVENT POSSIBLE ACROSS THE SOUTHERN PLAINS ON MONDAY... ...Synopsis... Active upper pattern will continue on Monday as one shortwave trough progresses through the Northeast while another ejects through the base of the deep upper trough over the western CONUS late in the period. Subtropical ridging will remain in place over the Gulf of Mexico and Southeast, resulting in the development of strong southwesterly flow aloft ahead of the western CONUS shortwave. This strong flow will remain in place throughout the day, likely increasing to near 100 kt at 500 mb early Tuesday morning. Surface pattern will feature a deepening lee cyclone over the central High Plains with a dryline extending southward across the eastern TX Panhandle and a warm front quickly moving northward through OK. ...Southern Plains... Guidance is in good agreement that the ingredients are in place for a potentially significant severe weather event on Monday. A sharp warm front is expected to move northward throughout the day, starting from an early day position near the River Red and reaching the OK/KS border by 00Z. Air mass south of this warm front will be very moist (i.e. dewpoints in the upper 60s/low 70s) and unstable. Consequently, moderate to strong instability will likely to develop across the eastern TX Panhandle, northwest TX and much of OK, even if strong diurnal heating does not occur. Current expectation is for temperatures in this region to reach the low/mid 70s by late morning/early afternoon with some areas farther east reaching mid/upper 70s. Kinematic environment is even more impressive than the thermodynamic environment. 60-70 kt of southwesterly 500 mb flow will gradually spread eastward/northward across the TX Panhandle and into OK and KS. At same time, a strong and persistent low-level jet will be in place, with 40+ kt at 850 mb throughout the period. Surface winds within the warm sector will likely be southeasterly at 15 to 20 kt. All of these factors result in wind profiles very favorable for discrete supercells capable of all severe hazards, including significant tornadoes. Given that overall large-scale forcing for ascent is minimal throughout much of the day, much of the afternoon and evening activity is currently expected to initiate along the dryline and within the warm sector, with a discrete storm mode favored. As the shortwave ejects out later in the period, a more linear MCS may develop, resulting in a second round of severe thunderstorms Monday night into Tuesday morning. ...Northeast... Thunderstorms are expected to develop along and ahead of a cold front progressing across the region. Favorable low-level moisture ahead of this front as well as strong unidirectional wind fields will result in the potential for a few strong to severe storms. Damaging wind gusts are the primary severe threat. Uncertainty regarding coverage precludes higher severe probabilities with this forecast. ..Mosier.. 05/18/2019 CLICK TO GET WUUS03 PTSDY3 PRODUCT NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z