


Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
242 ACUS48 KWNS 180901 SWOD48 SPC AC 180859 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CDT Sat Oct 18 2025 Valid 211200Z - 261200Z ...DISCUSSION... In the wake of the strong eastern US trough and cold front moving offshore D3/Monday, a second upper low will deepen over the eastern US through the first half of next week. As the low deepens, persistent northwesterly flow aloft and surface high pressure will build over the central US. Post-frontal offshore flow should limit surface moisture/instability and resulting thunderstorm chances for much of the CONUS through Wednesday. Some thunderstorm potential may return D6/Thursday and D7/Friday as a southern stream shortwave trough moves from the Southwest into the southern Plains. Cooling temperatures aloft overspreading modest moisture return over TX/OK could support some thunderstorm activity. However, uncertainty on destabilization and stronger vertical shear remains very high, thereby limiting severe predictability. Additional thunderstorm chances may develop over the central US next weekend as another Pacific trough approaches. But, model guidance remains quite varied on the intensity/evolution as well as available moisture ahead of this system. Thus, predictability remains too low for severe probabilities through the extended forecast period. ..Lyons.. 10/18/2025