Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 337 AM EDT Sat Sep 30 2023 Valid 12Z Sat Sep 30 2023 - 12Z Mon Oct 02 2023 ...Moderate snow over parts of the Sierra Nevada Mountains above 9000ft on Saturday... ...Temperatures will be 15 to 20 degrees above normal over parts of the Middle Mississippi Valley and Central Plains... ...Temperatures will be 10 to 20 degrees below average over parts of California, the Great Basin, and the Pacific Northwest on Saturday... On Saturday, low-pressure southeast of Southern New England will slowly move eastward out over the Western Atlantic by Sunday. The low will stream moisture air off the Atlantic, producing rain over parts of the northern Mid-Atlantic and Southern New England through Saturday evening. Meanwhile, tropical moisture over Florida, upper-level energy, and a weak front will create showers and thunderstorms over parts of Florida through Monday morning. Additionally, a weak front over parts of the Upper Midwest will slowly dissipate by Saturday night. The system will produce showers and thunderstorms over parts of the Upper Midwest through Sunday afternoon. Furthermore, upper-level ridging over the Middle/Lower Mississippi Valley and the Ohio/Tennessee Valleys will aid in allowing temperatures to be 15 to 20 degrees above normal over parts of the Middle Mississippi Valley and Central Plains on Saturday. Moreover, a deep upper-level trough over California and the Pacific Northwest will develop an upper-level low over the Great Basin by Sunday and begin to weaken on Monday. Rain will develop over parts of the Pacific Northwest into the Northern Intermountain Region and California/the Great Basin on Saturday. As the upper-level trough deepens, snow levels will drop over parts of the Sierra Nevada Mountains, producing moderate snow at elevations above 9000ft, with rain at lower elevations. The precipitation will continue through Sunday evening. Moreover, the upper-level troughing will allow temperatures to be 10 to 20 degrees below average over parts of California, the Great Basin, and the Pacific Northwest on Saturday. As the deep trough develops over the country s western half, moisture from the Gulf of Mexico will move northwestward over the Southern High Plains. The moisture and upper-level energy will aid in creating showers and thunderstorms over parts of the Southern Rockies/Southern High Plains on Saturday and by Saturday night, showers and thunderstorms will develop over parts of the Southern High Plains into parts of the Central High Plains. Additionally, moisture flowing off the Western Gulf of Mexico will create showers and thunderstorms over parts of the Western Gulf Coast through Monday. Ziegenfelder Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php