Matt Makens

We're about a month away from issuing our official winter outlook
[https://www.weather5280.com/tag/winter-outlook] we do each year in early to mid
October. Today we'll take a look at some of the big drivers we are watching for
the next half a year or so, as we begin our shift from the warm (hot) season to
the cool season. 

La Niña will spread its impact across the country for the second year in a row
leaving the West in dire need of water. Ocean conditions point toward continued
drought for the western U.S. as another La Niña event is expected this fall,
winter and spring.

La Niña, and its counterpart El Niño, get a lot of attention this time of the
year, and for a good reason. Both create recognizable weather patterns across
the globe.

The fall through spring 2021-2022 forecast will jog your memory on La Niña years
of the past, most recently last year, which recorded a rapid intensification of
the western and northern U.S. drought as well as sharply cold conditions during
the winter for the central U.S.

Although last year will be looked at, I believe 2013 and 2017 are stronger
candidates as similar years to what we should expect this go-round.

These analogous years show similar ocean and atmosphere conditions, and
therefore are the historical basis for which to build this outlook. In this
case, the combination of the most similar years yielded the following results
for wet (green) and dry (orange) areas from September through May.

Temperatures took on the following combined look of those analogous years with
cooler than average areas in blue and warmer areas in red.

I’m not trying to imply that all La Niña or El Niño years will produce the same
result for your area; however, there are distinct trends that we will look at
now.

Part of the recent trend is to note ocean conditions elsewhere that will, in
this case, work toward reinforcing La Niña’s grip on the West.

Cool water is observed southwest of California and warm water in the northern
Pacific near Alaska, which both lead to reinforcing drier-than-average
conditions across the West. This effectively limits the needed moisture for the
Pacific Northwest to the Desert Southwest.

Some factors will need to be watched closely over the next several months,
mainly that goes to watching when this La Niña fades, and El Niño develops. As
of this writing, that is most likely for later 2022, but an earlier onset would
be an ideal scenario for providing water to the drought-stricken West.

As it stands now, La Niña will control us through early and mid-2022, which is a
lousy situation for water in the West. The first-ever federally declared water
shortage was issued in August for those utilizing the Colorado River, and
recommended conservations/restrictions are certainly prudent considering this
outlook.

Now to the outlook for September 2021 through May 2022:

Northwest: The northeastern parts of the region will fare better for water than
for those elsewhere. That part of the Northern Rocky Mountains may see an uptick
in snowfall in the winter and spring. Wetness here is more frequent than dryness
in similar years. Much of Idaho’s lower country as well as Oregon and Washington
will more frequently end the run drier than average. Fall (September through
November) is more frequently drier than average, as is early to mid-winter. Late
winter through spring will see an increase in moisture. Of the three seasons,
spring has a higher probability of moisture versus fall and winter. In total,
this entire region is 30 percent likely to be wetter-than-average for this
period. There is some model data to indicate that the Pacific Northwest will be
wet throughout the period. That same modeling suggested the same wetness for
last year, which didn’t pan out, and should not be counted on as a reliable data
input at this time. Temperatures are likely to be near to warmer-than-average.

West: These states have a 10 percent probability of ending this period
wetter-than-average. The ocean situation near to and far from this region is too
powerful a drought signal to hope for much moisture. Improvement can come when,
and if, El Niño establishes itself, but that will be well into 2022. Plan on
another bad water year ahead. The best chance to boost snowpack for available
water supply will come during the spring. Temperatures will be
warmer-than-average.

Northern Rockies: Montana and Northwestern Wyoming will likely fare the best in
terms of moisture for this region. Overall, for the period, this region has a 60
percent likelihood of wetter-than-average conditions. The driest areas are
historically eastern South and North Dakotas, which will lead to further drought
conditions here. Although somewhat evenly split between the seasons, the spring
is likely to be the best opportunity for moisture. Model projections are less
optimistic about moisture for this region and keep this area in an equal chance
for above or below average moisture. Temperatures east of the mountains will be
cooler-than-average, with several dangerous cold snaps possible. Although, fall
may be warmer-than-average, with the cooler weather holding until winter and
early spring.

Southwest: The driest of these states will be Utah and Arizona, which have a
historically low likelihood of moisture throughout the period. Northern and
northeastern Colorado has the highest chance for moisture and historically has a
70 percent chance of a wet period. The region in total, however, only stands a
30 percent chance of a wet period. Temperatures for Eastern Colorado will have
the potential to be cooler-than-average, with some dangerous cold periods to
come through for producers. Most of the region, however, will be warmer-than to
near normal.

Upper Midwest: This region in total will end near average in terms of
precipitation. The region's Northern half is likely to be wetter-than-average;
meanwhile, drier-than-average conditions are more typical in this setup for the
southern half, which is much of Iowa. Temperatures will be cooler than average,
with several dangerous cold snaps possible.

South: Kansas, Oklahoma, and western Texas lean drier-than-average in this
setup. These areas have less than a 30 percent likelihood of a wet outlook.
Parts of eastern Texas, Arkansas, Louisiana and Mississippi favor some periods
of wetness and historically have a 70 percent chance for above average moisture
through spring. Computer modeling agrees with the historical assessment.
Temperatures may end up cooler-than-average during the period; look for strong
cold fronts to push south occasionally. Dangerous cold is a possibility as it
was in early 2021.

Ohio Valley: Missouri is likely to be the driest of these states, followed by
Tennessee. Moisture will favor Southern Illinois, Kentucky, Indiana, and Ohio –
the wetter is western Kentucky. West Virginia leans slightly
wetter-than-average, historically. In all, this region will break even; moisture
will favor the eastern areas. Temperatures will be normal to
cooler-than-average.

Northeast: This region will break even in terms of moisture. Historically, and
in forecast modeling, these areas will have hit and miss pockets of moisture.
Nor’easter events will need to be watched for significant moisture in a short
time along the coasts and for parts of inner New England, too. Far northern
areas of this region are most likely to be warmer-than-average.

Southeast: Tropical systems through fall will be the best chance for moisture
here, and that was the primary source of moisture in those most similar years in
the past. Barring tropical activity, this region has a 40 percent chance of a
wetter-than-average period. South Florida is usually the driest of all zones.
Wetness has been more frequent for those in the northern parts of this region.
Temperatures are likely to be near normal.

An early check on the 'winter' outlook for fall 2021 through spring 2022