Regional Seasonal Outlooks

by Tim Ballisty, Meteorologist

Here is what we can expect overall in the month of January 2012. NOAA's Climate Prediction Center (CPC) continues to see weak to moderate La Nina conditions in place, which will continue to impact temperatures and precipitation over much of North America. However, other climate factors can also play a role in overall weather conditions across the United States.

Keep in mind, these outlooks are overall monthly trends. An individual cold front or an upper ridge of high pressure can lead to a brief period of colder or warmer weather respectively. The same front or area of high pressure can bring a brief period of enhanced precipitation or dry spell that may or may not be indicative of the overall monthly trend.


TEMPERATURES


Central and Eastern United States (warmer-than-average)
Western United States (colder-than-average)

December ended up being well above average from the Midwest to the Southeast and Northeast. More of the same is expected throughout January in portions of these regions. La Nina typically favors warmer-than-average conditions from the Mid-Atlantic to the Central Appalachians, Ohio Valley and the south-central states during the winter months. The outlook above shows portions of these same regions are expected to see above-average temperatures during the month of January. In addition, above-average warmth is expected across much of the Midwest including the Northern Plains, where we typically see below-average temperatures in La Nina winters. Any cold outbreaks that do occur in January may be modified by the lack of snow cover.

The North Atlantic Oscillation (NAO) is expected to remain neutral or positive through the first part of the month much like it was in December. This is a big change from last winter when the NAO was negative, leading to plenty of cold and snow in the eastern half of the nation.

Along the West Coast, temperatures are forecast to stay below average throughout much of January. For the Northwest, this is typical of what we would expect in a La Nina winter.

PRECIPITATION

Despite La Nina, several rounds of rain helped the drought situation in Texas during December. Exceptional drought (worst category) fell from 53% to 32%. That said, 84% of the state remains in severe drought so much more improvement is needed.

Drought conditions continue to persist in portions of the Upper Midwest and Southeast.

Due to a lack of frontal systems traversing through the region, conditions are becoming increasingly dry along portions of the West Coast. Snowpack in California's Sierra Nevada was running at just 14% of average as of early January.



Northeast Texas to the mid-Mississippi Valley, Ohio Valley and Great Lakes (wetter-than-average):

Portions of this swath of territory saw above-average precipitation in December and this trend is expected to continue for January. Once again, La Nina's signature shows up in this outlook. La Nina winters typically see above-average precipitation in the mid-Mississippi and Ohio Valleys, just like the January forecast above indicates.

Northwest (wetter-than-average):

La Nina typically brings wetter-than-average conditions to the Pacific Northwest in winter and the forecast for January 2012 reflects this.

Central and Southern California (drier-than-average)

Conditions in portions of California are expected to stay dry in January much like they were in December. As of early January, San Francisco had seen just 35% of its average rainfall so far this season. The forecast for below-average precipitation in portions of the Sierra Nevada is not good news since the snowpack is already running well below average.

Arizona to Texas the Gulf Coast and Florida (drier-than-average)

Much of this swath of territory sees below-average precipitation during La Nina winters and that's what this forecast indicates. We will have to monitor and see if the trend we saw in December of upper-level systems moving across Texas with increased rainfall chances continues or fades away.