US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
315 PM EST Thu Dec 13 2018
 
Valid Sunday December 16 2018 - Thursday December 20 2018
 
Hazards:
Heavy precipitation across portions of California, the Pacific Northwest, and the Northern Great 
Basin, Sun-Thu, Dec 16-Dec 20.
Flooding possible across portions of the Southeast and the Mid-Atlantic.
Flooding occurring or imminent across portions of the Southeast, the Mid-Atlantic, and the Southern 
Plains.
Flooding likely across portions of the Southeast.
High winds across portions of California, the Pacific Northwest, and the Northern Great Basin, 
Mon-Tue, Dec 17-Dec 18.
High winds across portions of coastal southern New England, Sun, Dec 16.
High significant wave heights for coastal portions of California and the Pacific Northwest, 
Sun-Wed, Dec 16-Dec 19.
High significant wave heights for coastal portions of California, Mon, Dec 17.
High winds across portions of mainland Alaska, Sun, Dec 16.
High significant wave heights for coastal portions of the Alaska Panhandle and mainland Alaska, 
Sun, Dec 16.
 
Detailed Summary:

A series of fast-moving low pressure systems and associated fronts are forecast to impact Pacific 
Northwest into northern California through much of the medium range hazards period.  Periods of 
organized moderate to locally heavy precipitation along with high winds can be expected from 
coastal Pacific Northwest into the Cascades and down into northern California through the weekend, 
with significant waves along the coast and near offshore waters.  Models show 5-day totals of 
multiple inches of rainfall possible along the coast and snow measured in feet in the highest 
terrain, particularly in the Washington Cascades.  By early next week, the main activities should 
mostly depart northern California but will continue across the Pacific Northwest.
 
A complex low pressure system should be in the process of moving off the East Coast during the 
weekend.  As a secondary low pressure center forecast to deepen off the Mid-Atlantic region, winds 
along the southern New England coast could reach gale force Sunday and Sunday night.  A strong high 
pressure system building in behind the departing low should result in blustery northwesterly winds 
across New England next Tuesday and Wednesday.  It is possible that sustained winds reach gale 
force over parts of southeastern New England.

Flooding will be a lingering concern for a few more days across certain locations of Texas Gulf 
Coast, the Southeast and especially across central North Carolina into southern Virginia where a 
significant snowfall event has occurred recently.

The most significant temperature anomalies are expected across the northern tier where temperatures 
are forecast to be more than 20 degrees above normal through next Thursday.  Watch out for 
refreezing of surfaces overnight as temperatures are forecast to dip below freezing each night.

Over Alaska, a large-scale cyclone moving into the Gulf of Alaska on Sunday will bring high winds, 
significant waves, and possibly heavy snow in the higher elevations of southern and southeastern 
Alaska.  Another cyclone could bring increasing waves, winds and precipitation to similar locations 
by next Wednesday.  Temperatures will be much colder than normal over southwest Alaska through the 
period.

Kong