US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
508 PM EDT Wed Oct 20 2021
 
Valid Saturday October 23 2021 - Wednesday October 27 2021
 
Hazards:
- Heavy precipitation across portions of California, the Great Basin, the Pacific Northwest, and 
the Southwest, Sat-Tue, Oct 23-Oct 26.
- Heavy precipitation across portions of the Central Rockies, the Great Basin, and the Northern 
Rockies, Mon, Oct 25.
- Heavy rain across portions of the Central Plains, the Upper/Middle Mississippi Valley, the Great 
Lakes, and the Ohio Valley, Sun, Oct 24.
- Flooding occurring or imminent across portions of the Southern Plains.
 
Detailed Summary:

On Saturday, moisture from the Pacific streams onshore over California. The intensity of the 
moisture will ebb and flow through Tuesday.  The moisture will aid in producing rain and higher 
elevation snow along the West Coast from Saturday into Tuesday.  An area of heavy precipitation is 
depicted on the hazards chart, likewise, from Saturday into Tuesday.

On Sunday, moisture from the Western Gulf of Mexico will stream northward over the Plains, 
intersecting a front over the Middle Mississippi Valley and producing an area of heavy rain over 
parts of the Middle Mississippi and Ohio Valleys.

On Monday, a front lingering along the coast will move inland to parts of the Northern 
Intermountain Region into the Great Basin and Central California.  The boundary will aid in 
producing two areas of heavy precipitation, one over parts of the Northern Intermountain Region and 
the second over parts of the Northern Rockies into the Great Basin.

A front extending from the Upper Mississippi Valley roughly southwestward to the Southern Plains 
will intersect moisture over the region by Wednesday. However, at this time, there is uncertainty 
if there will be an area of heavy rain and what the location will be.  WPC will monitor the 
situation to see if it changes over the next few days.

Over Alaska, no hazards are depicted on the hazards chat at this time. Nevertheless, WPC will 
monitor the situation to see if it changes over the next few days.

On Saturday, high winds will be over the Aleutians, but at this time, the wind speed will be less 
than the criteria for high winds. In general troughing will be over the state during this period. 
Although there will be much deeper low pressure over the Gulf of Alaska into the Eastern Pacific, 
the bulk of the weather will be elsewhere, with some snow showers over parts of the state through 
Wednesday.

Ziegenfelder