← Previous March 31, 2023 4:07 AM
ACUS48 KWNS 310909 SWOD48 SPC AC 310907 Day 4-8 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 0407 AM CDT Fri Mar 31 2023 Valid 031200Z - 081200Z CORRECTED TYPOS IN TEXT ...DISCUSSION... Medium-range models indicate that mid/upper flow will undergo substantial amplification across the northern and middle latitudes of the Pacific during this period. This appears likely to include the evolution of a broad, deep mid-level trough which will support strong cyclogenesis to the southeast of the Aleutians by the end of next week. Downstream flow is then forecast to split near the North American Pacific coast, with ridging building across the far western Canadian provinces and troughing across the U.S. Great Basin and Southwest, before converging into broad troughing across the northwestern Atlantic. Prior to these developments, a significant mid-level short wave trough is forecast to emerge from the Intermountain West Monday into early Tuesday, before contributing to strong cyclogenesis across the central Great Plains into the Upper Midwest Tuesday through Tuesday night. The mid-level perturbation may be accompanied by a 100 kt cyclonically curved 500 mb jet, contributing to strong deep-layer shear across the warm sector of the surface cyclone, where intensifying southerly 850 mb flow may contribute to large, clockwise curved low-level hodographs. The GFS, ECMWF and their respective ensembles seem to be coming in better agreement with the late afternoon and early evening track of the surface cyclone across the northeastern Kansas into southeastern Nebraska vicinity, with a warm front extending across southern Iowa and the dryline trailing from the surface low southward near the Missouri/Kansas border. The dryline may become the focus for the initiation of strongest storms, which will tend to propagate northeastward before being overtaken by a surging cold front. There is some concern that a more subtle mid-level impulse may contribute to thunderstorm initiation within the open warm sector, across parts of the Ozark Plateau early in the day, and negatively impact destabilization across that area, and perhaps areas to the north. However, if this does not become a mitigating factor, a substantive organized severe weather event may evolve, including potential for strong tornadoes, large hail and damaging wind gusts Tuesday afternoon into Tuesday night across the lower Missouri Valley vicinity. ..Kerr.. 03/31/2023