US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
319 PM EST Tue Nov 03 2020
 
Valid Friday November 06 2020 - Tuesday November 10 2020
 
Hazards:
- Heavy precipitation across portions of the Plains, the Mississippi Valley, the Great Lakes, and 
the Ohio Valley, Mon-Tue, Nov 9-Nov 10.
- Heavy rain across portions of the Southeast, Sat-Tue, Nov 7-Nov 10.
- Heavy snow across portions of the Northern Plains, the Northern Rockies, and the Northern Great 
Basin, Fri-Sun, Nov 6-Nov 8.
- Heavy snow across portions of the Central Rockies and the Central Great Basin, Sat-Mon, Nov 7-Nov 
9.
- Flooding possible across portions of the Pacific Northwest.
- Flooding likely across portions of the Pacific Northwest and the Northern Great Basin.
- High winds across portions of the Central Great Basin, the Southwest, the Central/Southern 
Rockies, and the Central/Southern Plains, Fri-Sat, Nov 6-Nov 7.
- Much below normal temperatures across portions of the Pacific Northwest, California, the Great 
Basin, the Northern/Central Rockies, and the Northern/Central Plains, Mon-Tue, Nov 9-Nov 10.
- Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Sat-Mon, Nov 
7-Nov 9.
 
Detailed Summary:

The medium range period (Friday, November 6th - Tuesday, November 10th) will feature a deep 
upper-level trough moving slowly through the western U.S. toward the central U.S. by next Tuesday, 
bringing cold air and precipitation potential. Heavy snow is forecast to spread from the Northern 
Rockies Friday toward much of Montana into western North Dakota over the weekend, as a cold high 
pressure system comes in to the north of a cold front. Farther south, another 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 behind the front 
(as the winds shift direction). Winds look to be highest in parts of the Central Great Basin Friday 
into 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. 
While much of the West can expect light to moderate precipitation, one area that could see 
particularly high snowfall totals in higher elevations is the San Juan Mountains in Colorado. Then, 
the frontal system is forecast to track slowly through the Plains and Mississippi Valley, providing 
a focus for heavy precipitation by the beginning of the workweek. 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. At this point, did not want to delineate a rain/snow line given uncertainty in the timing of 
the precipitation and the arrival of the cold air. And it 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.

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.

Meanwhile, there is still plenty of uncertainty regarding what happens with what is currently 
Hurricane Eta nearing 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 in easterly flow with tropical moisture. Then if a tropical system does 
end up approaching the state next week, additional heavy rainfall is likely.

Over Alaska, warmer than normal temperatures are forecast to spread across much of the mainland. 
While most temperatures should stay below freezing in expected areas, temperatures flirting with 
the freezing mark above the surface could lead to mixed precipitation/freezing rain in areas of 
southwestern Alaska on Friday, but there is low confidence on this for now. The more 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 for the weekend into Monday as a 
surface low pressure system tracks across. 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, but the placement of these conditions is uncertain.

Tate