Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
950 ACUS02 KWNS 071720 SWODY2 SPC AC 071719 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1119 AM CST Fri Feb 07 2025 Valid 081200Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Scattered thunderstorm development is possible across parts of the Ohio Valley Saturday into Saturday night, but the risk for severe weather appears negligible. ...Discussion... Mid/upper flow is in the process of amplifying across the northern mid-latitudes of the eastern Pacific into western North America, and models continue to indicate further amplification into and through this period. This includes building mid-level ridging across the northeastern Pacific through Alaska, and subsequent digging downstream troughing across and to the lee of the Canadian and northern U.S. Rockies. Otherwise, the confluent downstream westerlies are forecast to remain generally zonal across the interior U.S. through offshore western Atlantic, between broad ridging, centered over the subtropic latitudes of northern Mexico into the western Atlantic, and a broad vortex, centered near the northeastern Canadian Arctic latitudes. At mid/upper levels, the subtropical ridging may maintain considerable influence as far north as the southern into central tier of the United States. Within the confluent regime across the northern tier of the U.S., it still appears that at least a couple of short wave perturbations might loosely consolidate into larger-scale, but still low-amplitude, troughing across the Great Lakes into Northeast by late Saturday through Saturday night. This is forecast to be trailed by a similar perturbation accelerating from the Great Basin into north central Great Plains. Beneath and just to the south of this regime, another cold surface ridge is likely to be in the process of building to the lee of the northern Rockies by early Saturday, reinforcing cold air already entrenched to the east of the Rockies. It still appears that the shallow southern periphery of this cold air will initially be in the process of eroding beneath a continuing south to southwesterly return flow across the Ozark Plateau into Ohio Valley. However, models indicate that associated low-level warming and moistening will largely remain confined beneath dry, warming layers farther aloft, as the reinforcing cold intrusion progresses south (and reaches the Gulf Coast state by 12Z Sunday). ...Ohio Valley... A pre-frontal corridor of boundary-layer warming and moistening near a developing frontal wave may contribute to weak potential instability, coincident with strengthening lower/mid-tropospheric wind fields, across the southern/eastern Kentucky vicinity by late Saturday afternoon. However, based on latest model output, it remains unlikely that forcing for ascent within the warm sector will be sufficient to overcome inhibition. Weak elevated thunderstorm development still appears possible Saturday through Saturday night, within an initial lower/mid-tropospheric warm advection regime near/north of the Ohio River into Allegheny Plateau and, later, near/south of the Ohio River along the undercutting southward advancing cold front. ..Kerr.. 02/07/2025 $$