WSI: Cool Weather Will Still Be Confined to Parts of Northern US During Late Spring and Early Summer

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La Nina Impacts Linger as Summer Approaches

WSI US Outlook April-June 2011

The big wild card as we head towards summer is the NAO and whether the recent multi-year stretch of an ‘activated’ North Atlantic pattern will continue.

WSI (Weather Services International) expects the upcoming period (April-June) to average cooler than normal across the northwestern and north-central US, with above-normal temperatures expected across most of the southern and eastern US. The WSI seasonal outlooks reference a standard 30-year normal (1971-2000).

“As we head into spring, the La Nina event is still the primary driver of the northern hemispheric pattern, even though the magnitude of the event is diminishing. The active North Atlantic pattern, as manifested by extreme negative values of the North Atlantic Oscillation (NAO) earlier this winter, has subsided during the last few weeks, allowing for the tropical Pacific signal to dominate. Other than subseasonal variability from the Madden-Julian Oscillation, we expect the general La Nina pattern to continue well into spring,” said WSI Chief Meteorologist Dr. Todd Crawford.

“In general, this means colder-than-normal temperatures across Canada and the northern US, with above-normal temperatures across much of the southern and eastern US. The big wild card as we head towards summer is the NAO and whether the recent multi-year stretch of an ‘activated’ North Atlantic pattern will continue. If it does, a summer similar to 2008 is a likely outcome, with cool central US temperatures surrounded by warm temperatures in much of the southern and eastern US. If the recent stretch of quiet North Atlantic conditions persists into summer, a much warmer summer in the northern US is likely, with below-normal temperatures across the Southeast. We have another month to figure these things out before our first official look at summer is issued on April 26.”

In April, WSI predicts regional temperature anomalies as follows:
Northeast* – Warmer than normal
Southeast*– Warmer than normal
N Central*     – Colder than normal
S Central*     – Warmer than normal
Northwest*    – Colder than normal
Southwest*– Colder than normal

Chris Kostas, Senior Power and Gas Analyst at ESAI, said, “Despite record natural-gas production levels through December (the latest available figures from the EIA) and record inventories to begin the heating season, gas inventories will likely begin the injection season in April around 1,600 Bcf (about one percent above average). Weather-related demand in April typically has minimal effect on gas demand, but the warmer-than-normal temperatures in the Mid-Atlantic region and Northeast will help to minimize any lingering heating demand in the Consuming East. PJM is expecting an above-normal nuclear maintenance season, however, and this should increase demand for natural gas as gas-fired generators are called upon to replace the missing baseload generation. Implied market heat rates in PJM may be firmer than normal despite the lower-than-normal weather-related demand. Cooler-than-normal temperatures in MISO and the West in April should only have a marginal effect on aggregate U.S. heating demand, but should combine with the slightly increased nuclear maintenance season in the East to provide slightly above-normal gas demand for the month.”

In May, WSI sees the monthly breakdown as:
Northeast     – Cooler than normal
Southeast     – Cooler than normal, except Florida
N Central     – Cooler than normal
S Central     – Warmer than normal
Northwest     – Warmer than normal
Southwest – Warmer than normal

Kostas added, “Cooler-than-normal temperatures in the Northeast, Mid-Atlantic, and Great Lakes regions in May should provide for soft electrical demand as the summer approaches. While power prices are likely to be soft on the diminished electrical demand in these regions, heat rates could be normal or even above normal in PJM due to soft gas prices and narrow dark spreads as gas-fired generation pressures less efficient coal generators off the margin as they try to return from maintenance. Some less efficient (i.e. smaller) coal-fired generators in the region could delay their return by a week as they wait for electrical loads to pick up. Slightly warmer-than-normal temperatures in the ERCOT and South will increase power prices and heat rates in that region in response to the slightly above-normal cooling demand. An above-normal hydro season in the Northwest and California should provide enough generation to offset the increased cooling demand in the West in general, and in California specifically.”

In June, WSI forecasts:
Northeast     – Warmer than normal
Southeast     – Warmer than normal
N Central     – Cooler than normal
S Central     – Warmer than normal
Northwest     – Cooler than normal
Southwest – Warmer than normal

“The much warmer-than-normal temperatures that are expected in June in the Northeast and Mid-Atlantic region should provide upside pressure on power prices and implied market heat rates in New York, New England, and Eastern PJM. The cooler-than-normal temperatures in Western PJM, however, will likely keep prices there subdued and could provide for added west-to-east price separation between Northern Illinois and PJM Western Hub. Above-normal cooling demand in Texas (and the South in general) should provide power price and heat rate support in ERCOT to begin the summer. Softer-than-normal power prices and heat rates may be expected in California in June, however, due to the combination of below-normal cooling demand and above-normal hydro generation.” Kostas noted.

WSI, which provides customized weather information to energy traders, will issue its next seasonal outlook on April 26, including the first official summer forecast.

*To view the map defining WSI’s US regions, click here.

About WSI
WSI (Weather Services International) is the world's leading provider of weather-driven business solutions for professionals in the energy, aviation, and media markets, and multiple federal and state government agencies. WSI is a member of The Weather Channel Companies and is headquartered in Andover, Massachusetts with offices in Birmingham, England. The Weather Channel Companies are owned by a consortium made up of NBC Universal and the private equity firms The Blackstone Group and Bain Capital. More information about WSI can be found at

About ESAI
Since its inception in 1984, Energy Security Analysis Inc. (ESAI) has been dedicated to monitoring, analyzing, and synthesizing information about world-wide energy markets. Tapping the talents of its senior-level staff, ESAI provides clients with unparalleled insight into where the markets have been and where they are headed. ESAI provides ongoing systematic analysis of energy prices in the oil, natural gas, and energy markets. For more information on ESAI services, see

Linda Maynard    
(978) 983-6715    
Tommy Sutro
Energy Security Analysis, Inc.
(781) 245-2036

Editorial Contact:
Barbara Rudolph    
Rudolph Communications, LLC
(781) 229-1811

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