Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
Versions:
1
2
658 FXUS01 KWBC 180755 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 254 AM EST Tue Nov 18 2025 Valid 12Z Tue Nov 18 2025 - 12Z Thu Nov 20 2025 ...There is a Slight Risk of excessive rainfall over parts of the Southwest/southeastern California on Tuesday... ...Light snow over parts of the Upper Mississippi Valley and Great Lakes on Tuesday... ...Moderate to heavy snow over parts of the southern Utah Mountains and Sierra Nevada Mountains... A front over Southeastern California will move eastward to the Southern Rockies by Thursday. The system will produce heavy rain with embedded thunderstorms over parts of Southern California and the Southwest. Therefore, the WPC has issued a Slight Risk (level 2/4) of excessive rainfall over parts of the Southwest/southeastern California through Wednesday morning. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, small streams, and burn scars being the most vulnerable. In addition, moderate to heavy snow will develop over parts of the Sierra Nevada Mountains on Tuesday and the southern Utah Mountains on Tuesday and Wednesday. Furthermore, the system will produce rain with embedded thunderstorms over parts of the Southern Rockies/Southern High Plains on Wednesday into Thursday. Moreover, a weak front over the Pacific Northwest will move eastward to the Northern Rockies/Northern Intermountain Region before dissipating on Wednesday. The storm will produce rain and snow at the highest elevations over parts of the Pacific Northwest and the Northern Intermountain Region on Tuesday into Wednesday morning. Meanwhile, low pressure over the Middle Mississippi Valley will advance eastward to off the Mid-Atlantic Coast by Wednesday. Light snow will develop along the northern edge of the precipitation shield over parts of the Upper Mississippi Valley/Great Lakes, extending into parts of the Ohio Valley, on Tuesday. Rain and a few embedded thunderstorms will develop over parts of the Ohio Valley on Tuesday, tapering off by Wednesday. In addition, rain will move into the Central Appalachians and Mid-Atlantic on Tuesday afternoon, continuing into Wednesday morning before tapering off. A second area of low pressure will develop along the western edge of the front over the Southern Plains on Wednesday morning. The low will move northeastward to the Central Plains/Middle Mississippi Valley by Thursday. Showers and thunderstorms will develop along the boundary over the Southern Plains on Wednesday, expanding into parts of the Middle/Lower Mississippi Valley by Thursday. On Wednesday afternoon, a front over South-Central Canada will move into the Upper Mississippi Valley, producing light rain over parts of the Upper Mississippi Valley/Upper Great Lakes on Wednesday evening into Thursday. Additionally, on Wednesday, another front will approach the West Coast, producing light rain over parts of the Pacific Northwest and Northern California by Wednesday afternoon and expanding into parts of Southern California by early Thursday morning. Ziegenfelder Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$