US Day 3-7 Hazards Outlook NWS Weather Prediction Center College Park MD 155 PM EST Wed Nov 04 2020 Valid Saturday November 07 2020 - Wednesday November 11 2020 Hazards: - Heavy precipitation across portions of the Central Plains, the Middle Mississippi Valley, the Great Lakes, the Upper Mississippi Valley, and the Northern Plains, Tue-Wed, Nov 10-Nov 11. - Heavy rain across portions of the Central Plains, the Middle Mississippi Valley, the Great Lakes, the Ohio Valley, and the Upper Mississippi Valley, Tue-Wed, Nov 10-Nov 11. - Heavy rain across portions of the Southeast, Sat-Tue, Nov 7-Nov 10. - Heavy snow across portions of the Central Rockies, the Central Great Basin, the Northern Rockies, the Northern Great Basin, and the Northern Plains, Sat-Mon, Nov 7-Nov 9. - High winds across portions of the Central Plains, the Central Rockies, the Central Great Basin, the Southern Rockies, the Southern Plains, and the Southwest, Sat, Nov 7. - High winds across portions of the Northern Plains, Sun-Mon, Nov 8-Nov 9. - Much below normal temperatures across portions of the Central Plains, the Central Great Basin, the Northern Plains, the Northern Rockies, the Central Rockies, California, the Northern Great Basin, the Pacific Northwest, and the Southwest, Mon-Wed, Nov 9-Nov 11. - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Sun-Mon, Nov 8-Nov 9. Detailed Summary: The medium range period (Saturday, November 7th - Wednesday, November 11th) will feature a deep upper-level trough moving slowly through the western U.S. toward the central U.S. by next Tuesday, bringing anomalously cold air and precipitation potential. Heavy snowfall amounts greater than 6 inches and locally higher than a foot is possible from the Northern Rockies Saturday toward much of Montana into far western North Dakota through early Monday. High winds will also be possible across central and eastern Montana as a low pressure system rapidly strengthens, leading to possible blizzard conditions. Farther south, a potent cold front is expected to move west to east across the Great Basin, Four Corners, and into the Plains early next week ahead of the upper trough. Gusty winds could be a threat both ahead of and after the front (as the winds shift direction). Winds look to be highest in parts of the the Four Corners states Saturday, but some borderline high winds could make it into the Plains as well. Fire danger could be a threat, but may be limited due to cooler temperatures (causing higher relative humidities) and the potential for the West to see precipitation with the trough. Widespread and much-needed light to moderate precipitation can be expected across much of the West, while particularly high snowfall totals are possible in higher elevations of the San Juan Mountains in Colorado. The cold air associated with this system will be quite cold--high temperatures of 15 to 30 degrees below normal are expected in the West starting over the weekend, while low temperatures will become especially cold by Monday and Tuesday from parts of the West into the Northern High Plains. Single digit lows are forecast even in lower elevations of Montana, and in higher elevations of the Intermountain West. By Tuesday, the frontal system is forecast to track slowly through the Plains and Mississippi Valley, providing a focus for heavy precipitation both on Tuesday and Wednesday. On the warm side of the front, heavy rain is likely, but rain is expected to change over to snow in many areas on the western side from about eastern Nebraska to the Upper Great Lakes. At this point, it was decided to use "heavy precipitation" instead of "heavy snow" for this area as precipitation types are likely to change and uncertainties still remain as to where exactly the rain/snow line will set up. The heavy rain threat will shift eastward to the southern/central Appalachians and Mid-Atlantic by Wednesday, but high uncertainties prevented a hazard area from being added today. Meanwhile, ahead of the upper trough and frontal system, high pressure is generally expected, causing warmer than normal conditions to shift away from the Plains/Midwest after a warm end of the week and develop in the eastern U.S., with high temperature anomalies in the Great Lakes and Ohio Valley toward the Northeast 10 to 20 degrees above normal. Record warm minimum and maximum temperatures could be set through parts of the central and eastern CONUS. The active weather pattern also includes tropical trouble associated with Tropical Storm Eta. There is still plenty of uncertainty regarding what happens with Eta as it currently meanders in Central America. It still appears that at least energy (and maybe the same low pressure system) from Eta may reemerge over the northwestern Caribbean and could track northward toward Cuba and Florida early next week. See the National Hurricane Center for updated forecasts on this system. Regardless, rain is forecast to persist across southern and eastern Florida over the weekend and early next week thanks to easterly flow with tropical moisture. If a tropical system does end up approaching the state next week, additional heavy rainfall is likely. Across Alaska, the most certain potential hazard during the period is heavy precipitation spreading from west to east across the Gulf of Alaska Coast/Southcentral region into the Panhandle late this weekend into Monday as a surface low pressure system tracks along the coast. Localized areas of high winds are possible given the depth of the low, leading to the potential for some isolated areas of blizzard conditions in Southcentral Alaska, but the placement of these conditions is uncertain. Gusty winds, along with rain and snow will be possible across western portions of the state early next week as a strong low pressure system swings into the Bering Sea. However, the conditions at the moment don't appear to meet hazardous threshold and uncertainties also still remain. Snell