US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
359 PM EDT Wed Oct 27 2021
 
Valid Saturday October 30 2021 - Wednesday November 03 2021
 
Hazards:
- Heavy rain across portions of the Northeast, Sat-Sun, Oct 30-Oct 31.
- Flooding possible across portions of the Middle Mississippi Valley, the Northeast, and the 
Mid-Atlantic.
- Flooding likely across portions of the Great Lakes, the Middle Mississippi Valley, the 
Mid-Atlantic, the Pacific Northwest, and the Northern Great Basin.
- Much below normal temperatures across portions of the Central Plains, the Great Lakes, the Middle 
Mississippi Valley, and the Southern Plains, Tue-Wed, Nov 2-Nov 3.
- Heavy precipitation across portions of mainland Alaska, Sat-Mon, Oct 30-Nov 1.
- High winds across portions of mainland Alaska and the Aleutians, Sat, Oct 30.
- High winds across portions of mainland Alaska, Sat-Sun, Oct 30-Oct 31.
 
Detailed Summary:

A closed upper-level low will linger over the East this weekend as an anomalously strong low 
pressure system lifts slowly northeastward from the northern Mid-Atlantic to the Northeast. 
Widespread showers and thunderstorms are expected to be ongoing ahead of the occluded frontal 
system as moisture streams in from the Atlantic ahead of and around the northern side of the 
system, with multiple inches of weekend rainfall likley across portions of the Northeast.

Upstream, an amplified Canadian upper trough will dig to the north-central U.S. and Midwest this 
weekend into next week and force a lead cold front down across the central to eastern U.S.. Cooling 
air behind the front may result in below freezing morning lows as far south as from the southern 
High Plains to the Great Lakes by Tuesday and Wednesday. Given the potential for this to be the 
first freeze for some areas with susceptible vegetation, a Much Below Normal Temperatures outlook 
area is shown to highlight this threat.

Additionally, as this cold front moves southward, it may slow as a wave of low pressure moves 
across the Southern Plains. Moisture returning northward from the Gulf with southerly flow ahead of 
the wave of low pressure will lead to increased lift and convergence across the boundary producing 
showers and storms with the potential for local heavy rain. However, given model differences in the 
location of storm coverage and borderline forecast rain amounts, an outlook area will not be 
introduced at this time.

In Alaska, a wet and windy period of weather is expected from the Alaskan Peninsula and Kodiak 
Island through the south-central mainland this weekend into early next week as a strong and slow 
moving low pressure system works into the Gulf of Alaska. Increased moisture feeding inland ahead 
of the system will fuel several days of heavy rain and snow at lower elevations and significant 
mountains snows. This will include the Alaska Range, Chugach Mountains and the Kenai Mountains. 
Several feet of snow is likely, particularly from very heavy accumulations Saturday. Strong 
mountain pass and Chinook winds to the lee are possible.

Schichtel