Winter 2015-16 featured anomalous warmth across a vast expanse of the nation, with the strongest departures from normal focused along the northern tier. As a result of persistently mild conditions, energy demand was notably bearish, with significant reductions in year-over-year peak demand observed in nearly all major U.S. power markets. According to NOAA, gas-weighted heating degree days (GWHDDs) totaled a mere 2,288, 15 percent weaker than an average winter season.
Overview
The warm influences associated with El Niño left an indisputable mark on North American weather patterns through the winter season. In terms of average temperature, December 2015 registered as the warmest on record in over 120 years with an incredible temperature departure of over +6°F. In portions of the Midwest and East, anomalies approached 12-15°F above normal! Progressing into January, the jet stream amplified, offering increased variability to the pattern. The highlight of January was a powerful blizzard, which unleashed record-breaking snows upon the Mid-Atlantic region. During February, an impressive cold snap impacted New England. On Valentine’s Day, Boston saw a low of -9°F accompanied by wind chills near -30°F. During the last week of February a severe weather outbreak ravaged portions of the Southeast and Mid-Atlantic.
East Coast
December 2015 exceeded forecast expectations, verifying as the warmest on record for the all of the states along the East Coast, including the entirety of NYISO, NEISO, and PJM. Temperature anomalies ranging from 10-15°F above average led to weak heating load and an extremely bearish demand month overall. This record shattering warmth eased for January and was even replaced by some cool anomalies in the Southeast as an active weather pattern helped suppress temperatures. Despite cool weather in the Southeast, and occasional colder than average episodes, temperatures elsewhere along the East Coast remained near to above normal for January and February, warmer than forecast and bearish for demand.
Midwest and Lower Mississippi Valley
Little in the way of sustained cold developed for the MISO footprint during winter, helping drive much weaker demand compared to the previous two winters. A forecast signal for strong warmth across the Upper Midwest verified well, helping keep heating load in check during the winter season. December was particularly warmer than average, with several MISO states setting new records for warmth during the month. Peak demand came in mid-January at over eight percent weaker levels compared to the prior winter. February was generally warmer than average as well, offering little in the way of a late winter surge in heating load. MISO South did not see the forecasted cooler than average temperatures materialize, however the overall impact on demand was minor.
Plains
Winter got off to a bearish start across the region thanks to temperatures that were consistently mild through December, with most of the region verifying 4-8°F above normal. Volatility began to emerge in January, with ERCOT and SPP reaching their peak winter load during the month, although at much weaker levels compared to the prior winter. Both power markets saw year-over-year peak load declines of over 10 percent. Warm anomalies returned in full strength for the month of February, driving exceptionally weak energy demand. Temperatures averaged 3-6°F above normal across much of the region, with localized warm anomalies exceeding 10°F in the Dakotas. The winter temperature forecast verified well for the Plains, while Texas was warmer than anticipated.
West
The typical El Niño signal failed to materialize for the West Coast in December, with strong precipitation anomalies across the Pacific Northwest and weak anomalies in NorCal, while the Southwest remained mostly dry. The signature intensification of the subtropical jet stream began in January, with valley rains and mountain snows offering promising drought relief for California, while the Pacific Northwest and Interior West remained mostly seasonal. February began with a similar trend, but strong warm anomalies accompanied a significantly dry period to close out the winter, resulting in substantial snow melt across the west. Nonetheless, this winter brought significant year over year improvements in snowpack, drought, and hydropower conditions for California and much of the greater west.
Weather can have a large impact on power demand and generation, especially with the seasonal extremes seen across the U.S. in the summer and winter months. Being able to anticipate weather patterns for the season ahead can help market participants make more informed trading or business decisions. Click here to download Genscape's full Winter 2015-2016 Weather Outlook now.
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