An atmospheric pattern change during the last week has set up a zone of rapidly changing temperatures, or a baroclinic zone, from the U.S. Southern Plains through the Tennessee River Valley. These zones are typically associated with moderate precipitation and could be heavy if a piece of upper-level energy happens to move along it.
For this week, pieces of energy are weak and more prone across the U.S.-Canada border region. This will produce periods of showers across the south in association with this semi-permanent zone of temperature changes. Rainfall amounts will not be extreme, but on the moderate side and near to above normal for the week. More isolated snow showers can be expected across the northern tier of the country.
Next week, Jan. 25-Jan. 29, introduces some significant changes in terms of the energy being available. The baroclinic zone will drift a little northward but remain in a largely east-west orientation this weekend through next week. But the main change comes with the available energy. A couple of pieces of upper-level energy will dive along and just off the West Coast and then move eastward.
The first in this series of energy impulses starts on Jan. 22. This system will move through the Southwest this weekend with much-needed moderate precipitation, emerging into the Plains late this weekend and early next week, and then heads east along the baroclinic zone. As it does so, it should be able to tap into some moisture from the Gulf of Mexico, giving a risk of moderate to heavy precipitation generally east of the Plains.
At least one more strong piece of upper level energy will follow the same general pattern during mid to late next week. Forecast models indicate this could resemble the prior storm, though tracking this feature more than a week out will likely lead to some changes in the forecast. Still, two significant winter storms are on the horizon for the last third of the month.
With at least some colder Arctic air to tap into, heavy snow would be possible across the north with both of these storm systems as well. Showers are not expected to be overly heavy in the drought areas of the Plains however, and some areas may see rainfall deficits increase. This is more likely to happen in the southwestern Plains around the Texas and Oklahoma Panhandles and adjacent areas of Colorado and Kansas. Winter wheat in these areas is still lacking in soil moisture and the two storms are not expected to have a significant impact in this regard.
We will have to continue to track these features as we progress through the week and weekend as both systems are still over the Pacific Ocean, but the potential is there for the storms to be intense. This pattern is similar to what we would expect from our current La Nina. Equatorial Pacific Ocean sea surface temperatures are running 1.1 degree Celsius (about 2 degrees Fahrenheit) below normal. La Nina is indicated when values are greater than 0.5 degree C (about 1 degree F) below normal.
John Baranick can be reached at firstname.lastname@example.org
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