Seasonal Updates

Chris Coleman, ERCOT Senior Meteorologist

Winter 2019-2020 Weather Outlook, published November 7, 2019

2019 has been a mostly above normal year for temperatures in Texas. The January through September period was the 16th warmest of 125 years of weather history. September was the warmest ever on record for the state. October started out as a carryover of September – before colder extremes began to impact ERCOT the second-half of the month.

Extended, seasonal periods of below normal cold has become uncommon. Of the 39 seasons this decade, only three have ranked in the coldest third.

Hotter than normal summers most times are followed by (non-cold) mild winters. Of the 10 hottest summers within the past 30 years, eight were followed by a normal or above normal winter (only two were followed by a colder-than-normal winter).

Even before building the forecast for this winter, there’s strong statistical evidence going against forecasting a strongly cold winter.

While a truly cold winter has also been proven to be uncommon in recent years – we did have one earlier this decade. The winter of 2013-14 became known as the polar vortex winter. We saw an extended period of frequent strong cold fronts, resulting in most days being colder than normal and very limited periods of above normal temperatures. As cold as that was, it was "only" the 30th coldest (or 95th warmest) winter of the past 124 winters.

Also for reference, Last winter (2018-19) was the 31st warmest on record for Texas. And the recent winter of 2016-17 was the #1 warmest on record.

I would expect this winter to be ranked within the 84 warmest since 1895. Okay, that’s not narrowing it down much – but it is excluding the coming winter from being as cold as 2013-14 (polar vortex winter) and falling anywhere within the coldest third of winters on record. There’s a better chance than not this coming winter will be colder than last winter – but not necessarily by a lot. Minimum temperatures (overnight/morning lows) have a good chance to be warmer than normal. Afternoon highs will likely fall somewhere near normal (not extreme in either direction). Thus, the winter mean temperature outlook will fall close to normal.

Winter 2019-20 Temperature Map

Regardless of the fact that late-October into November has shown a much colder pattern, that doesn’t necessarily foretell the winter temperature pattern. There is no direct correlation between November temperatures and winter temperatures. There are indications December will turn warmer, resulting in an above normal temperature month. But cold opportunities may increase mid-to-late-winter. February 2020 has the greatest potential for below normal temperatures this winter.

Recent years that have similarities to current weather patterns include 2015, 2014, and 2007. 2003 and 2004 are a couple others that are being applied.

That being said – the most important takeaway from any winter forecast is the fact that even very mild (warm) winters can have periods of extreme cold. The two coldest days this decade (and two highest load peaks) came in winters that otherwise weren’t cold. February 2, 2011 was the coldest day this decade for the ERCOT system. That winter was the 67th coldest on record. The second coldest day this decade fell on January 17, 2018. That winter was the 75th coldest on record. A very strong cold front can arrive in a winter that otherwise is limited in fronts. It can go from 85 degrees to 15 degrees in less than 24 hours at an ERCOT location in the winter. You won’t see those 50, 60, to 70 degree temperature swings in a short period in the summer. You can in the winter. A peak can come quickly and strongly. So, the mindset given any long-range winter forecast should be that a new peak record could occur. Even in a mild winter. My forecast suggests this winter won’t have a high frequency of strong cold fronts – but it doesn’t exclude the potential for one or two strong fronts.

One factor to keep an eye on that could lead to adjustments to this forecast: the sun is quiet. The current sunspot phase is at its minimum -- and one of the quietest periods in many decades (very few sunspots). The is some loose correlation between solar activity and weather patterns. At this point, I don't see enough evidence for it to overtake other factors, but if there's signs of this winter trending colder, the sun may be to blame (and the forecast may need adjusting).

Precipitation Outlook: 

2019 was off to a very wet start, which continued through June. The 12-month period from July 2018 through June 2019 was the second-wettest in Texas history. This past June was the wettest since 2007. Then July hit, and it stopped raining. The July through September period was the 17th driest, dating back to 1895. October brought some improvements – but not widespread. It appears the winter will also offer some opportunities for beneficial precipitation – but not necessarily widespread. North Texas and especially the Panhandle will offer the best chance for above normal precipitation. Unfortunately, some of the regions of the state most in need of rainfall may see the fewest opportunities this winter, especially West Central Texas, including much of the Edwards Plateau.

Winter 2019-20 Precipitation Map

This coming winter is forecast to be not as wet as last winter. There may be some lingering drought concerns heading into the spring season – though not likely widespread. North Texas is the least likely part of the state to see significant deteriorating drought conditions. Laredo, Del Rio, and San Angelo all face the potential for drought conditions to worsen. Austin and San Antonio are on the fringe, and may not experience significant improvements to the drought this winter.

Fall 2019 Weather Outlook, published September 10, 2019

This summer started very mild and wet for the ERCOT region. This resulted in the coolest June through July period for the state since 2007. However, a significant change in the weather was beginning to build during the month of July, as a much drier pattern set it place. Even with a very dry July, temperatures remained mild due to the high level of soil moisture and green vegetation. That soil and plant life slowly dried in July and by August minor drought concerns began to increase. And it continue to not rain in Texas. Once August hit, the ground had a month to dry significantly and this assisted in turning the temperatures hotter. Texas went from the coolest June through July since 2007 to the hottest August since 2011 – and second hottest August on record. This hot pattern has continued into September, and it’s very likely an above normal temperature pattern will persist on most days until there’s a significant, widespread rainfall or two.

Fall 2019 Temperature Outlook (Oct-Nov):

The above normal, hot period that started in August and has continued into September is also likely to extend into October. This is likely to be a very warm start to the autumn season in Texas. November is showing signs of turning milder and wetter. Mixed signals if it turns much cooler and wetter – or more of a moderately cooler change. Current forecast lean is with the less cooler change, which would result in the season as a whole being a bit warmer than normal.

Spring 2019 Temperature Map

The fall of 2019 is very likely to be warmer than the fall of 2018. It’s likely to start out quite warm in the month of October. The weather pattern should break down some in November, with more frequent, stronger cold fronts and rain opportunities.

Fall 2019 Precipitation Outlook (Oct-Nov):

Drought conditions have deteriorated during the late-summer period. This trend is likely to continue for a large portion of the state into October. Fortunately, the majority of reservoir levels are still relatively high for the time of year (based on historical norms). However, the soil is very dry over most of the state, and lawns, gardens, and some crops or other vegetation have taken a toll with the lack of rainfall since early-summer.

Spring 2019 Temperature Map

At some point, this fall will likely see a return to a noticeably wetter weather pattern. It may happen during the second half of October – or it may hold off until November. But I do not expect the very dry pattern that increased during the summer season to continue toward the end of 2019. It’s likely to change to a rainier pattern during the fall season. There may be some wintry precipitation potential in West Texas in November – but the bigger story will likely be some significant relief coming from the growing drought concerns.