US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
345 PM EST Thu Nov 12 2020
 
Valid Sunday November 15 2020 - Thursday November 19 2020
 
Hazards:
- Heavy precipitation across portions of the Cascades, Sun-Mon, Nov 15-Nov 16.
- Heavy precipitation across the northern Sierra Nevada, Tue-Wed, Nov 17-Nov 18.
- Heavy snow across portions of the northern Cascades, Sun-Mon, Nov 15-Nov 16.
- Heavy snow across portions of the northern Rockies, Sun, Nov 15.
- Heavy rain across the Pacific Northwest to the west of the Cascades, Sun-Mon, Nov 15-Nov 16.
- Heavy rain across northwestern California into western Oregon, Tue-Wed, Nov 17-Nov 18.
- Much above normal temperatures across the central to southern High Plains, Tue-Thu, Nov 17-Nov 19.
- Flooding possible across portions of the Southeast, the southern Appalachians, the Mid-Atlantic, 
and the central Appalachians.
- Flooding occurring or imminent across portions of interior North Carolina and interior Virginia.
- Flooding likely across portions of the Carolinas and Virginia.
- Much below normal temperatures across portions of interior Alaska, Sun-Mon, Nov 15-Nov 16.
 
Detailed Summary:

Much of the hazardous weather during the medium-range period will be focused across the Pacific 
Northwest into northern California.  An active synoptic pattern across the northeastern Pacific 
will continue to direct energetic low pressure systems and high amounts of moisture from subtropics 
toward the Pacific Northwest.  Some of the moisture will initially be in the form of heavy mountain 
snow across northwestern Wyoming and northern Idaho on Sunday before tapering off.  The Cascades 
should expected heavy wintry precipitation on Sunday and Monday with snow likely across the 
northern portion of the mountain range.  Meanwhile, rain will likely be heavy across the lower 
elevations to the west of the Cascades.  By Tuesday into Wednesday, the focus of heavy rain should 
shift farther south across northwestern California into western Oregon as the next Pacific cyclone, 
potentially rather intense, edges closer toward the Pacific Northwest from the southwest.  Wintry 
precipitation will be likely across the northern Sierra Nevada.  Weather conditions should improve 
by next Thursday as the cyclone is forecast to weaken and lift further north toward the Alaska 
Panhandle.

Elsewhere across the country, a low pressure system is expected the bring blustery winds widespread 
precipitation across the Great Lakes on Sunday followed by the Northeast on Monday.  Although no 
high wind areas are indicated, wind gusts reaching gale force will be likely for these areas 
especially following the passage of the low center.  In addition to the blustery winds, parts of 
eastern Maine could be seeing heavy rain in the process of tapering off early on Sunday before a 
cold front pushes the rain away into the Canadian Maritimes.

A dry northwesterly flow aloft will promote subsidence across the mid section of the country 
through the medium-range period.  Surface temperatures will remain well above normal across the 
central to southern High Plains.  Combining these warm temperatures with the dry and breezy 
downslope winds from the Rockies could raise the threat of fire weather conditions across the High 
Plains.

Over Alaska, a cold surface high pressure area should support much colder than normal conditions 
for interior Alaska from Sunday into Monday before moderating on Tuesday.  The next notable low 
pressure system should be moving into the Aleutians by midweek next week. Conditions appear below 
hazards level at this time.  Another low pressure system should be weakening as it lifts northward 
toward the Alaska Panhandle by next Thursday although the models are indicating greater than normal 
uncertainty regarding its intensity at this time.

Kong