Climatology 101: The El Niño Winter that wasn’t

Since 1950, there have been 7 recorded strong El Niño events. This year’s version was the first to fail at delivering Tucson above average rainfall.

Between December 1st and February 29th, TIA recorded 2.18″ rainfall. As I mentioned last Thursday during our 6 PM newscast, this is well below our Winter average and the average during a strong El Niño. Blame a persistent ridge of high pressure during the month of February for derailing our anticipated wet Winter.

That February ridge supplied plenty of warmth. Tucson recorded its 2nd earliest 90° day & 6 days with record highs tied or broken.

Below is the complete climate report for February and Winter, compiled by the gurus at NWS Tucson.

February 2016 was a remarkable month with the much cooler than normal start to the month, then the unprecedented period of much above normal high temperatures during the last three weeks of the month..
A fast moving cold front brought strong gusty winds, valley rain and mountain snow to the area on the 1st. Wind speeds began to increase on January 31st and continued into the morning hours of the 1st. Peak wind speeds across the metro area on the 1st were in the 40 to 50 mph with localized spots up to 55 mph. Power outages occurred across the metro area as the strong winds knocked out two substations. Up to 50,000 people were without power for a period of time. Since the storm system was moving rather quickly valley rain amounts were mostly less than two-tenths of an inch. Mt. Lemmon recorded around 5″ of new snow with this storm. Much colder temperatures moved in behind this system with low temperatures in the 20s on the 3rd and the 4th. Little did anyone know that this would be the last winter storm to impact the area for winter 2015-2016.
Unseasonably strong high pressure aloft over the western United States for much of the remainder of the month was the main driver in bringing an unprecedented period of very warm high temperatures. Six record high temperatures were set during the month which included the second earliest first 90° high temperature of the calendar year. The 90° on the 17th ranks as the 5th warmest February high on record. The following is a list of some of the temperature records that were set or tied in February 2016..
Average monthly high temperature:
  • 78.0°: (old record 75.6° in 1954)
Six daily record highs were set or tied:
  • 81° on the 8th (tied, previously occurring in 1930, 1963, 2000 & 2006)
  • 85° on the 11th (old record 84° set in 1951)
  • 87° on the 12th (old record 86° set in 1988)
  • 87° on the 16th (old record 85° set in 1994 & 2014)
  • 90° on the 17th (old record 86° set in 2014)
  • 82° on the 21st (tied, previously occurring in 1999)
Interesting to note that in the previous 23 El Niño events since 1950, there were a combined total of only 7 high temperaturerecords set or tied in February. Click the image on the right for larger view. February record temperatures in El Nino events
One record high minimum temperature was set:
  • 58° on the 19th (old record 55° set in 1980)
Consecutive day temperature records that were set:
  • Consecutive days with highs 77° or warmer – 15 (old record 9 in 1898)
  • Consecutive days with highs 78° or warmer – 14 (old record 8 in 1904 & 1995)
  • Consecutive days with highs 79° or warmer – 14 (old record 7 in 1989 & 1995)
  • Consecutive days with highs 80° or warmer – 14 (old record 7 in 1989 & 1995)
  • Consecutive days with highs 81° or warmer – 14 (old record 7 in 1989)
Consecutive day temperature record that were tied:
  • Consecutive days with highs of 82° or warmer – 7, tied with 1989
Monthly records that were set:
  • Number of days with highs 78° or warmer – 19 (old record 15 in 2014)
  • Number of days with highs 79° or warmer – 19 (old record 11 in 1954)
  • Number of days with highs 80° or warmer – 19 (old record 9 in 1954, 1957 & 2014)
  • Number of days with highs 81° or warmer – 19 (old record 8 in 2014)
  • Number of days with highs 82° or warmer – 17 (old record 7 in 1989 & 2014)
  • Number of days with highs 83° or warmer – 15 (old record 6 in 2009 & 2014)
  • Number of days with highs 84° or warmer – 12 (old record 5 in 1986 & 2014)
  • Number of days with highs 85° or warmer – 7 (old record 5 in 1986)
  • Number of days with highs 86° or warmer – 6 (old record 4 in 1986)
Monthly records that were tied:
  • Number of days with highs 87° or warmer – 4, tied with 1986
  • Number of days with highs 90° or warmer – 1, tied with 1904, 1921, 1957 & 2014)
Temperature extremes for the month ranged from a high of 90° on the 17th to a low of 28° on the 3rd. Seven temperature records (six highs & one high minimum) were set or tied during February. The six record highs were the most in a month since August 2011 (6) and the most in February since 1916 (7).
One of the most remarkable aspects of the extended period of above normal high temperatures was the stretch of highs that were 10° or warmer than normal. The 14 consecutive days of double digit above normal high temperatures is the third most in a row, behind 17 days in March 1972 and 15 days in March 2007, dating back to the early 1970s. The chart, below left, shows this rather nicely.
Hard to believe that with all of the temperature records that were set in February 2016 it didn’t end up being ranked as the warmest on record. But thanks to the first week of the month being the 25th coldest on record, February 2016 goes into the record books as the 2nd warmest on record with an average monthly temperature of 61.1° (tied with 1957). Remarkable yet is that 2016 is 1° cooler than last February which is the warmest on record. The report for last February can be found here. The average monthly high temperature of 78° easily ecliped the old monthly record of 75.6° set in 1954. Tucson now has experienced three of the top four warmest Februarys on record over the past three years.
February 2016 daily high temperature departure from normal February 2016 daily low temperature departure from normal
The images above show daily departure from the 1981-2010 normals. Below normal is blue and above normal is red. The columns colored in burgundy are daily records that were set or tied.
Click on images above for larger view
Hopes were high that February would have a good chance of above normal precipitation thanks to the strong El Niño conditions in the equatorial Pacific. The official CPC forecast for February indicated enhanced probabilities for above normal precipitation but, as mentioned above, only one weather system brought valley rain and mountain snow to the area. Rainfall amounts across the metro area for the month, using several sources like rainlog.org, the Pima County Regional Flood Control District gages and CoCoRaHS, were mostly below 0.25″. The International airport, which is the official recording location for Tucson, recorded 0.18″. This ranks as the 26th driest February on record.
February 2016 stats
Month
Normal
Departure
Average high temperature
78.0°
68.5°
+ 9.5°
Average low temperature
44.2°
42.2°
+ 2.0°
Average temperature
61.1°
55.3°
+ 5.8°
Precipitation
0.18″
0.86″
– 0.68″
2015-16 Water Year rainfall (Oct-Feb)
4.59″
4.19″
+ 0.40″
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