NWS UPDATE: 2020-2021 Winter Outlook

From: National Weather Service, Fort Worth
Date: Friday, 30 October 2020 14:32 CDT

Bottom Line

Good afternoon,

NOAA’s official Winter Outlook was released a few weeks ago by the Climate Prediction Center. In late September, we sent an email discussing the La Niña Advisory that had been issued and what that could mean for North and Central Texas this coming winter. The official Winter Outlook continues to support La Niña conditions for our area which favors above normal temperatures and below normal precipitation this winter.

The official press release can be found here: www.noaa.gov/media-release/us-winter-outlook-cooler-north-warmer-south-with-ongoing-la-nina. "NOAA's seasonal outlooks provide the likelihood that temperatures and total precipitation amounts will be above-, near- or below-average, and how drought conditions are favored to change. The outlook does not project seasonal snowfall accumulations..." as snow forecasts are generally not predictable more than a week in advance. Even during a warmer-than-average winter, periods of cold temperatures and snow/sleet/ice can be expected.

Winter 2020 - U.S. Temperature Outlook

Winter 2020 - U.S. Precipitation Outlook

There are many factors other than ENSO [El Niño/La Niña] that can affect our weather during the winter, but these features can’t be predicted very well beyond a couple of weeks. Since these pattern changes happen on short time scales, they can result in abrupt changes to our weather during the winter that can’t be projected on seasonal time scales. Our 7-day forecasts may focus on such anomalies as they become apparent. One significant example is the Arctic Oscillation (AO), a sudden shift of which can increase the likelihood of arctic intrusions and may enhance the potential for wintry precipitation. We want to highlight that there has never been a winter season (Dec- Feb) in our coverage area without winter precipitation since our records.

La Niña winter conditions can oftentimes result in an increased fire weather threat. The wet spring and fall we had helped with extensive vegetative growth that loads fuel for wildfires. With dry and warm conditions expected through the winter and into the spring months, we anticipate the redevelopment of drought conditions is likely.

Winter 2020 - U.S. Drought Outlook

Here are some climate statistics from DFW Airport and Waco Airport for the past 20 years:

Winter 2000-2020 Comparisons (Averages): DFW

Winter 2000-2020 Comparisons (Averages): Waco

What We Are Certain Of:

  • La Niña conditions.
  • Warmer than normal temperatures are more likely than below normal temperatures.
  • Rainfall amounts are more likely to be below normal.
  • Drought is expected to redevelop this winter.
  • There is an enhanced threat of wildfires this winter.
  • There is a reduced risk of heavy rain and flooding events.
  • There is a reduced risk of winter weather events.

What We Are Less Certain Of:

  • How far above normal temperatures will be.
  • How far below normal monthly/seasonal precipitation totals will be.
  • The frequency and severity of arctic outbreaks this winter.
  • The number and intensity of winter weather events.
  • Sub-seasonal anomalies may reduce or reverse the warm/dry trend this winter.

Please let us know if you have any questions.

Jennifer

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Jennifer Dunn
Warning Coordination Meteorologist
National Weather Service Fort Worth, TX
weather.gov/fortworth
Facebook: NWSDallasFortWorth
Twitter: @NWSFortWorth

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