Is This the New Normal?
Alaska and California seem to be stuck in a pattern since last May. A high pressure aloft over the eastern Pacific has brought abnormally warm weather to Alaska since May and dry weather to California since January. It is hard to make a case that this persistent ridge will remain in place indefinitely but, should it persist through this winter, it will have a significant impact on the California water supply. The 500 mb pressure anomaly for the period of January 1-October 26 over North America. This stubborn pattern has resulted in the driest such period in California records.
NCEP/NCAR reanalysis.Warm October in Alaska
After a frigid April and first half of May much of Alaska (especially the interior) has seen much above normal temperatures. This past summer was one of the warmest such on record for Fairbanks which saw a record 36 days reach 80°F or above. The warmth has continued through October with a monthly average temperature of 36.5°F, its 3rd warmest October on record (the record being 38.3°F in 1923) and 11.9°F above normal. On October 28th the temperature hit 51°F, a new daily record and some +31°F above average. Northway reached 49°F besting its previous daily record high of 37°F (set in 1952) by 12°F. Even more remarkable was the 62°F temperature measured that day at Delta Junction (90 miles southeast of Fairbanks) which smashed its previous daily record by 15°F and was the latest in the season for a 60°F+ temperature by 12 days! In fact, this would have been a record (tied) if it had occurred a month earlier on September 28th instead of October 28th.Maximum Daily temperature records for Delta Junction, Alaska. Note how anomalous the 62°F reading on October 28th was.
Strong winds gusting to 63 mph helped bring back to life a wildfire that has burning in the area since last May. The 67,500-acre ‘Mississippi Fire’ is now the latest in season active fire that the Alaskan Fire Service has had to deal with in their records for an interior Alaskan location. It rained in Fairbanks this past week instead of snowed and Rick Thoman of NWS-Fairbanks had this to say about the lack of snowfall in Fairbanks this month, “Only eight-tenths of an inch of snow has fallen at the airport so far this winter, all of which has long since melted. There have only been two years (1938 and 1969) when the permanent snowpack — defined as one inch of snow on the ground — was established later than this time of year in Fairbanks. The average date for the establishment of the permanent snowpack is Oct. 18. Even in 1938, there was a trace of snow on the ground for Halloween. This year, the ground may be completely bare.”Climate data for Fairbanks this October. The temperature has averaged 11.9°F above normal and all but two days have averaged above normal temperatures.
NWS-Fairbanks.The 500 mb pressure anomaly for October 8-27 over Alaska.
Meanwhile, California has closed out the month with little additional precipitation (except for San Diego which picked up .44” of rain on Sunday) and none forecast for at least another week. The blocking high-pressure system over the eastern Pacific has stubbornly remained in place over the eastern Pacific for virtually the entire year (as illustrated in the map at beginning of blog). A summary of the California situation was posted in my blog last week.
Here are the final precipitation totals for January 1-October 31 at select California locations:KUDOS:
Stu Ostro at TWC for bringing much of this to my attention.
Christopher C. Burt