US Day 3-7 Hazards Outlook NWS Weather Prediction Center College Park MD 259 PM EST Fri Nov 06 2020 Valid Monday November 09 2020 - Friday November 13 2020 Hazards: - Heavy precipitation across portions of California, the Pacific Northwest, and the Northern Great Basin, Thu-Fri, Nov 12-Nov 13. - Heavy precipitation across portions of the Northern/Central Plains, the Upper/Middle Mississippi Valley, and the Great Lakes, Tue, Nov 10. - Heavy rain across portions of the Central Plains, the Upper/Middle Mississippi Valley, the Great Lakes, and the Southeast, Mon-Tue, Nov 9-Nov 10. - Heavy rain across portions of the Tennessee Valley, the Ohio Valley, the Central/Southern Appalachians, and the Eastern Seaboard, Tue-Fri, Nov 10-Nov 13. - Heavy snow across portions of the Central Rockies, Mon, Nov 9. - High winds across portions of the Southeast, Mon-Tue, Nov 9-Nov 10. - Much below normal temperatures across portions of the Pacific Northwest, California, the Great Basin, the Southwest, the Northern/Central Rockies, and the Northern Plains, Mon-Thu, Nov 9-Nov 12. - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Tue-Wed, Nov 10-Nov 11. - High winds across portions of mainland Alaska and the Aleutians, Mon-Wed, Nov 9-Nov 11. - High significant wave heights for coastal portions of mainland Alaska, Mon-Tue, Nov 9-Nov 10. Detailed Summary: The medium range period (Monday, November 9th - Friday, November 13th) will feature a slow-moving upper-level trough over the western U.S. pressing toward the central U.S. through the period, as shortwave troughs/upper lows come through to reinforce the broad trough. Upper-level ridging is likely over the East through the first half of the week, with the exception of what is currently Tropical Depression Eta. The medium range forecast for Eta remains uncertain as of Friday. Tropical Depression Eta has emerged from Central America into the Caribbean, and is still forecast to track northeastward toward Cuba in the short range. Then, current forecasts show Eta tracking toward southern Florida early next week as a tropical storm. Thus high winds and heavy rain hazards are in place for southern Florida on Monday/Tuesday, but its exact track is yet to be determined, especially past that point as it emerges into the Gulf of Mexico closer to midweek. A landfall along the Gulf Coast later in the week bringing additional high winds and heavy rain is not out of the question, but is highly uncertain at this point. Please see the National Hurricane Center for updates on Eta. With the western U.S. trough, periods of mainly light to moderate much-needed precipitation are possible across much of the West, with higher elevations generally seeing higher precipitation amounts due to upslope flow. One area in particular that could see heavy snow totals through Monday is the San Juan Mountains of Colorado. A round of heavier precipitation is possible in the Pacific Northwest and possibly the Northern Rockies late next week as moisture increases there. Another impact of the trough will be rather cold air across the West to the Rockies and High Plains. Low temperatures should drop to 10 to 20 degrees below normal from California toward the Northern High Plains, with single digit lows forecast even in lower elevations of Montana as well as higher elevations of the Intermountain West. High temperatures of 15 to 25 degrees below normal are forecast for much of the West through Thursday. Cooler than normal temperatures may continue into Friday in the West, but may be moderating nearer to normal. Meanwhile ahead of the trough, record-setting warm high temperatures into the 60s and 70s are likely as far north as the Great Lakes region Monday and Tuesday, before the trough encroaches and pushes the warmer than normal temperatures east toward the Eastern Seaboard. In fact, given the warm and moist conditions, hundreds of record warm temperatures could be set next week in the central to eastern U.S., with some record highs but particularly with record warm minimum temperatures. One shortwave trough/upper low within the main trough is forecast to move through the north-central U.S. Monday into Wednesday and push a cold front across the Plains, Mississippi Valley, and Great Lakes. Moisture inflow along and ahead of the front could lead to heavy rain over portions of those areas. With cold air filtering in behind the front, a changeover to mixed precipitation or snow is possible early Tuesday from around eastern Nebraska to the Upper Midwest, on the backside of a surface low developing along the front. Farther south, there could be some localized gusty winds behind the cold front in the Southern High Plains on Monday. As the front progresses eastward toward the Eastern Seaboard, the heavy rain threat will shift with it as tropical moisture flows northward from Eta into the vicinity of the front. Heavy rain may begin in portions of the East on Tuesday, but is currently expected to peak on Wednesday and Thursday across the Appalachians, Mid-Atlantic, and possibly parts of the Northeast. Some rain could linger into Friday in the southern Mid-Atlantic. While the exact axis, timing, and amounts of the rainfall are uncertain, the ingredients for heavy rainfall should be in place. Across Alaska, an active pattern is forecast to continue as a deep surface low pressure system should be located over the Bering Sea Monday, with another forming along the front around Tuesday, which should track eastward near the southern part of the state. This pattern creating tight pressure gradients could lead to high winds for the Aleutians toward the southwest mainland Monday through Wednesday, with significant waves possible as well. Some precipitation is forecast to spread into the western mainland with these systems, but the higher precipitation amounts are expected for the Gulf Coast/Southcentral region Tuesday toward the Panhandle Wednesday. Warmer than normal temperatures should persist across the mainland through at least midweek. Tate