US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
215 PM EST Mon Jan 20 2020
 
Valid Thursday January 23 2020 - Monday January 27 2020
 
Hazards:
- Heavy precipitation across portions of the Pacific Northwest, Thu, Jan 23.
- Heavy precipitation across portions of Northern California and portions of the Central 
Appalachians to the Northeast, Sat-Sun, Jan 25-Jan 26.
- Heavy rain across portions of the Central Gulf Coast, Thu, Jan 23.
- Heavy rain across portions of the Southern Appalachians to the Mid-Atlantic, Jan 24-Jan 26.
- Heavy snow across portions of the Sierra Nevada, Sat-Sun, Jan 25-Jan 26.
- Flooding possible across portions of the Pacific Northwest.
- Flooding occurring or imminent across portions of the Mississippi Valley and the Northern Plains.
- Much below normal temperatures across portions of mainland Alaska, Fri-Mon, Jan 24-Jan 27.
 
Detailed Summary:

The weather across the CONUS during the medium range period (Thursday to Monday) will remain active 
for the East and West Coasts, but quiet in between. In the West, expect multiple rounds of 
potentially heavy precipitation (lower elevation rain and mountain snow) as a series of cold fronts 
move inland. The first batch should affect western portions of Washington and Oregon (including the 
Cascades) on Thursday. Precipitation may continue into Friday for parts of the region, though 
doesn't appear to be heavy or warrant an area on the hazards outlook. A second front nears the 
coast next weekend, bringing heavy precipitation to parts of Northern California, and heavy snows 
to much of the Sierra Nevada in California. 

In the East, an organizing low pressure system will track northeastward through the Lower 
Mississippi Valley into the Midwest Thursday and Friday. Widespread rainfall is likely across the 
Lower Mississippi Valley into the Tennessee Valley and parts of the Southeast, though the best 
chance for heavy rainfall looks to be across portions of the Central Gulf Coast and the Southern 
Appalachians which is where heavy rainfall areas are depicted today. Parts of the Midwest may see 
some snow with this system though amounts remain quite uncertain and so a heavy snow area was left 
off the chart at this time. This low will weaken next weekend in favor of a new developing low 
across the Southern Mid-Atlantic on Saturday, which tracks up the Northeast Coast Sunday-Monday. 
This will spread the potential for heavy rainfall along the I-95 corridor from DC to NYC. Depending 
on proximity of the low to the coast, heavy rain or snow is possible farther north into the 
northern Mid-Atlantic and portions of the Northeast, though both precipitation type and exact 
amounts remain in question. For now, this area was best represented by a general heavy 
precipitation area.

In Alaska, much below normal temperatures are likely through much of the period across western and 
central portions of the Mainland. Minimum and maximum temperature anomalies could be 20 to 30+ 
degrees below normal. A surface low across the Gulf of Alaska could bring a period of high winds to 
parts of the central coast, and moderate to locally heavy precipitation to the Panhandle region. 
The magnitude of both hazards looks marginal for inclusion of an area on the chart, though the 
potential exists.

Santorelli