Autumn conditions persisted throughout October as temperatures remained warm and rains intensified. These conditions resulted from the Pineapple Express, a jet stream pattern characterized by strong and persistent flow of atmospheric moisture from as far south as Hawaii. This formed when a persistent ridge of high pressure over the Pacific Northwest diverted the jet stream forcing warm, tropical air north, causing above average temperatures and heavy precipitation in southcentral Alaska and dry, sunny conditions in the Pacific Northwest. Results of this phenomenon led many communities in southcentral Alaska to set new monthly average record high temperatures including Anchorage, Homer and King Salmon. Although temperatures were well above normal for Seward, the average monthly temperature fell short of the record by 0.8 degrees F. However, Seward did set a few new daily records. On October 28th a new daily record high temperature was set at 53 degrees F, beating the 1957 record by 4 degrees F. On October 27th the record high maximum temperature was tied with 50 degrees F. On October 15, 16 and 17th, new record highs for daily minimum temperatures were set at the Seward airport, i.e., the lowest daily temperature (typically recorded during nighttime) was the highest ever recorded for that day. Daily maximum highs stayed within the 40s and 50s (degree F) with a maximum daily high of 58 degrees F recorded on October 4th. Below-freezing temperatures were recorded at the Seward airport on one day, dropping to 30 degrees F on October 24th.
Also of note were the precipitation totals for the month which equaled nearly twice the monthly average at the Seward airport. Due to warm temperatures, this precipitation fell as rain at lower elevations and, at times, at higher elevations, too. End-of-month snowpack was up to a few inches in the mountains and the snowline remained above treeline.
As recorded at the Seward airport, total precipitation for the month was 18.63 inches (199% of normal), 9.28 inches above the 30-year average (1981-2010) for the month. The monthly average temperature for October was 43.6 degrees F; 4 degrees F above the 30-year average.
Also of note:
- The National Weather Service Climate Prediction Center’s three month weather outlook (November-December-January) favors normal temperatures and normal precipitation for the Kenai Fjords area.
- Most of mainland Alaska experienced the warmest mid-October on record, making it feel like September in October.
- The Autumn 2013 Alaska Climate Dispatch is available to download. Check it out to learn more about Summer 2013’s statewide warm temperatures and the status of the 2013 Arctic sea ice.
- To be consistent with NOAA’s use of 30-year periods for the official “climate normals,” the National Snow and Ice Data Center switched its baseline period for sea ice analyses from 1979-2000 to 1981-2010.
- New research published in Geophysical Research Letters looks at the contribution of the Pacific Decadal Oscillation to global mean sea level trends.
- Check out NASA’s latest visualizations of 21st century temperature and precipitation changes, based on the latest finds by the International Panel on Climate Change.
- A new technical report from the 2013 National Climate Assessment summarizes climate change impacts on U.S. oceans and marine resources.
- NOAA climate services portal serves as a single point-of-entry for NOAA’s extensive climate information, data, products, services, and the climate science magazine ClimateWatch.