National Weather Service United States Department of Commerce

Snow Across The North Today, Windy Tonight-Monday

A winter storm will bring snow to northern portions of the region today, with several inches expected. Winds then become strong as the storm system exits east tonight, with northwest gusts exceeding 40 mph at times. There will be impacts to travel, especially where the snow falls. In addition, outdoor holiday decorations will be blown around tonight-Monday if not tightly secured. Read More >

NOAA's CPC Winter 2021-22 Outlook
for the Upper Mississippi River Valley


Released: November 18, 2021

 

Bottom Line for the Local Area...


NOAA's Climate Prediction Center (CPC) forecast for the upcoming winter months of December-February:

  • Temperatures: Warmer than normal is slightly favored across most of the Upper Mississippi River Valley.
     
  • Precipitation: Wetter-than-normal is slightly favored across the Upper Mississippi River Valley.  This does not necessarily imply that this winter will end up being snowier than normal. 

While a moderate La Niña is expected to impact the weather across much of the United States, its impacts in the Upper Mississippi River Valley can be highly variable with both temperatures and precipitation. For more details on why these shifts were made, please see the local winter outlook tab below.

Background...


La Niña is likely to continue through the Northern Hemisphere winter 2021-22 (~90% chance) and into spring 2022 (~50% chance during March-May).  Due to this, the CPC winter temperature and precipitation outlooks are consistent with typical La Niña impacts across much of the United States. In the Upper Mississippi River Valley, these winters can be highly variable with both temperatures and precipitation.

"La Niña strengthened in the last month, with below-average sea surface temperatures (SSTs) evident across most of the equatorial Pacific. The Niño-3.4 index has a 66% chance of reaching a value less than -1.0°C during November 2021 - January 2022, but only a 14% chance of being below -1.5°C. Thus, at its peak, a moderate-strength La Niña is favored" this winter.

The last time that there was a La Niña winter was 2020-21 (also moderate strength). Since 1949-50, 50% (9 out of 18) of La Niña winters have seen a second consecutive time in which the La Niña climate pattern emerged after a transition to ENSO-neutral conditions in the tropical Pacific. These are often referred to as double-dip La Niñas. On two occasions, there have been three consecutive La Niña winters (1973-76 & 1998-2001).  These second La Niña winters are highly variable with their temperatures, precipitation, and snowfall.  In contrast, only five El Niños winters (25%) have been followed by another El Niño winter. For those curious why this occurs, Nat Johnson wrote an article on it for the NOAA Climate Blog on May 27, 2021

Besides La Niña, this winter will also be affected by:

  • Arctic Oscillation (AO) and North Atlantic Oscillation (NAO) - These oscillations can influence the number of Arctic air masses that penetrate into the Southern United States and nor'easters on the East Coast.
  • Eastern Pacific Oscillation (EPO) - This can affect the location of where the cold air masses will be located in the northern United States
  • Madden-Julian Oscillation (MJO) - This can affect both temperatures and precipitation in the weekly time scale.