VAWS: Expansion of Climate Prediction Center Products

Wednesday, January 17, 2018 at 11:00 AM AKST
Rick Thoman, NWS & Wanqui Wang and Mike Halpert, CPC

Over the past few years, the Climate Prediction Center has begun issuing an expanded array of products to meet stakeholder needs, including seasonal sea ice forecasts and week 3-4 outlooks of temperature and precipitation. Interest in forecasts of Arctic Sea Ice have grown over the past few years, as earlier melting and later freeze ups has resulted in increased interest from energy and transportation concerns, while important decisions in sectors ranging from food security and public health, to emergency management and national security rely on forecast information at timescales out to weeks 3 and 4. To support this interest, CPC began issuing experimental seasonal sea ice forecasts for the Arctic region in March 2015 and experimental week 3-4 temperature and precipitation outlooks in September 2015 (the week 3-4 temperature outlook became operational in May 2017).

Seasonal forecasts of Arctic sea ice were initialized from the 8th-12th of each month from March to October 2015, except for April 2015 as well as in 2016 and 2017, with plans to continue in 2-18. Initial conditions for these outlooks were from the University of Washington Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) for sea ice thickness, and from the National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis (CFSR) for other fields. The forecast model used for the predictions (CFSv2p) is an offline experimental version of the Climate Forecast System, which is the same as the NCEP Climate Forecast System version 2 (CFSv2), except for two modifications, which have enabled these experimental forecasts to be more skillful than outlooks produced by the CFSv2.

The week 3-4 temperature and precipitation product features two category outlooks (above- or below-average) for 2-week mean temperature or 2-week total accumulated precipitation along with a text prognostic map discussion explaining the rationale behind the outlook. The product is released once per week on Friday at 3 PM. This experimental product seeks to close the gap in the NWS seamless suite of outlooks between CPC’s Week-2 and 1-month outlook periods. The science behind these outlooks will be presented along with some preliminary verification and future plans for the products.

Forecasts for conditions one to two weeks in the future occupy that vague middle ground between weather and climate, but many users in Alaska need actionable forecast information at this time scale. Predictability of specific weather events is difficult at best, but more often overall patterns can be anticipated. This presentation will provide an overview of the rapidly developing toolkit to provide state of the art information in this critical but difficult realm.


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