475 FXUS21 KWNC 042007 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EST November 04 2025 SYNOPSIS: Mid-level low pressure forecast over the northeastern Pacific favors an increased risk of heavy precipitation, high elevation snowfall, and high winds over portions of the western contiguous U.S. (CONUS) during week-2. An early taste of winter is predicted from the end of week-1 into the beginning of week-2 across the East, extending as far south as Florida, as a departing mid-level low brings in some of the coldest air of the season thus far. This will likely signal the end of the growing season across the Mid-Atlantic Coastal Plain. HAZARDS Moderate risk of heavy snow across parts of the Sierra Nevada, Wed-Fri, Nov 12-14. Slight risk of heavy snow across portions of the Cascades, Sierra Nevada, and Klamath Mountains, Tue-Mon, Wed-Tue, Nov 12-18. Slight risk of heavy snow across portions of the Northern and Central Rockies and Wasatch Range, Wed-Tue, Nov 12-18. Slight risk of heavy precipitation across portions of the Pacific Northwest and northern and central California, Wed-Tue, Nov 12-18. Slight risk of heavy precipitation across coastal portions of central and southern California, Wed-Fri, Nov 12-14. Slight risk of heavy precipitation across parts of Arizona, Fri-Sun, Nov 14-16. Slight risk of heavy snow across parts of Arizona, Fri-Sun, Nov 14-16. Slight risk of high winds across along the West Coast of the CONUS, Wed-Tue, Nov 12-18. Slight risk of high winds across the Interior West, Wed-Fri, Nov 12-14. Moderate risk of much below normal temperatures for the southern Mid-Atlantic and Southeast U.S., Wed, Nov 12. Slight risk of much below normal temperatures across the Eastern Seaboard, Tennessee Valley, and Mississippi, Wed, Nov 12. DETAILED SUMMARY FOR FRIDAY NOVEMBER 07 - TUESDAY NOVEMBER 11: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR WEDNESDAY NOVEMBER 12 - TUESDAY NOVEMBER 18: Multiple model ensemble means indicate a more amplified pattern compared to yesterday. An amplified mid-level trough across the North Pacific and western CONUS is anticipated to bring enhanced moist flow to western portions of the CONUS. Amplified mid-level troughing over the eastern CONUS is predicted to bring much below normal temperatures from the end of week-1 into the onset of week-2, with temperatures anticipated to moderate fairly early in the period. The GEFS and ECENS Integrated Vapor Transport (IVT) shows greater signals for values > 250 kg/ms with a southward shift, compared to yesterday. This translates to extension and expansion of multiple hazards in today's outlook. A slight risk for heavy precipitation is added in today's outlook across coastal portions of central and southern California, Nov 12-14, associated with increased heavy precipitation signals in multiple tools associated with the southward shift in enhanced IVT. There are some tools that could suggest inclusion of a moderate risk, but due to some uncertainty, this area will be monitored tomorrow for possible increase in risk (likelihood). A slight risk of heavy precipitation is continued across the Pacific Northwest and northern and central California throughout the period, where the GEFS and ECENS Probabilistic Extremes Tools (PETs) depict at least a 20 percent chance of 3-day precipitation totals exceeding the 85th climatological percentile and 1.5-inches. A slight risk of heavy snow is maintained across portions of the Cascades, Sierra Nevada, and Klamath Mountains throughout the period. A moderate risk of heavy snow is added in today's outlook for parts of the Sierra Nevada, Nov 12-14, supported by increased chances of heavy snow indicated by the GEFS PET and uncalibrated ensemble guidance. A slight risk of high winds is also maintained throughout week-2 across the West Coast of the CONUS. The amplified trough is anticipated to support multiple surface lows over the Interior West, supporting the addition of a slight risk of high winds across the Interior West, Nov 12-14. The PETs indicate at least a 20% chance of wind speeds exceeding the 85th percentile and 20 mph. This stormy pattern across the West could support landslides and urban small stream flooding. The amplified mid-level trough is predicted to shift east by the middle of week-2, which may support increased risk of heavy precipitation and high elevation snow to parts of Arizona. Slight risks for heavy precipitation and high elevation snow is posted for Nov 14-16, where the GEFS and ECENS PETs show at least a 20% chance of 3-day accumulated liquid equivalent totals exceeding the 85th percentile and half an inch. Across the eastern CONUS, amplified mid-level troughing from the end of week-1 is anticipated to linger into the beginning of week-2, bringing cold air to parts of the East. There are increasing probabilities in the PETs indicating minimum temperatures falling to the lowest 15th percentile and 40 deg F further south into central Florida. The moderate risk for much below normal temperatures is shifted further south compared to yesterday, to include the southern Mid-Atlantic and Southeast U.S. A broader area of slight risk is highlighted for the Eastern Seaboard, Tennessee Valley, and Mississippi, also for day 8 (Nov 12). Temperatures are anticipated to moderate as the ridge over the central CONUS shifts to the East. Across Alaska the week-2 mean pattern favors weak mid-level troughing across western portions of the state and near zonal flow eastward. This pattern favors a fairly quiet hazards period. FORECASTER: Melissa Ou $$