Arizona Climate Summary February 2018 Summary of conditions for January 2018

Arizona Climate Summary February 2018 Summary of conditions for January 2018 January 2018 Temperature and Precipitation Summary January 1 st 19 th : The new year began with a ridge of high pressure over the southwestern U.S. continuing the clear, warm dry conditions we had during late December. Temperatures in the warmer parts of the state were in the upper 70s and lower 80s while the colder locations saw highs in the upper 40s and lower 50s. The high pressure remained in place through the 4 th when a low pressure system began moving down the California coast. The low pressure system reached northern Arizona by the 7 th, dropping light rain at the north and south rims of the Grand Canyon, Canyon de Chelly, Petrified Forest, Springerville, Window Rock, Valle, St. Johns, and Page on the 7 th. The highest amount was 0.10 at the North Rim. This weak system was followed by another stronger low pressure system that crossed Arizona between the 9th and the 12 th. This system had both rain and the first snow of the season. Snowfall on the 10 th totaled 4.7 at Flagstaff Airport, 7.0 at Bellemont, 5.0 at Williams, and 0.2 at the north rim of the Grand Canyon. The storm reached all parts of the state, dropping temperatures to near normal values. During the 4 days, precipitation (liquid water) totals included 1.19 at Flagstaff, 0.24 at Kingman, 0.50 at Grand Canyon Airport, 0.23 at Page, 0.48 at Deer Valley, 0.21 at Sky Harbor, 0.63 at Prescott, 0.13 at Safford, 0.31 at St. Johns, 0.35 at Scottsdale, 0.13 at Sonora Desert Museum, 0.25 at Window Rock, 0.01 at Winslow, 0.17 at Yuma, 0.40 at Alpine, 1.00 at Castle Hot Springs, 0.75 at Carefree, 0.03 at Coronado NM, 0.20 at Cottonwood, 0.30 at East Mesa, 0.65 at Eloy, 0.39 at Apache Junction, 0.42 at Payson, 0.39 at Phantom Ranch, 0.45 at Pinnacle Peak, 0.65 at Seligman, and 0.85 at Show Low. By the 13 th a strong high pressure ridge had returned to the western U.S. and remained in place for a week, forcing some storm systems to the north across the Pacific northwest, Idaho, Montana and Wyoming. January 20 th 31 st : For Arizona, the ridge finally broke down on the 20 th as another cold low pressure system moved down the California coast. For the southwest deserts and warmest parts of the state, temperatures dropped from the mid to upper 70s down into the 60s and upper 50s. In the coldest parts of the state, nighttime temperatures dropped to single digits and negative values. Snow fell across the high elevations of northern and central Arizona from the 20 th through the 22 nd. Snow totals included 9.8 at Flagstaff, 2.1 at Bellemont, 2.5 at Show Low, 2.9 at Payson, 1.5 at Seligman and 3.5 at Williams. Light to moderate rainfall was reported across the entire state with 0.01 at Kingman, 0.03 at Deer Valley, 0.01 at Safford, 0.01 at Scottsdale, 0.02 at Tucson, 0.02 at Winslow, 0.50 at Bisbee, 0.12 at Carefree, 0.02 at East Mesa, 0.12 at Apache Junction, 0.22 at Picacho Peak, 0.18 at Petrified Forest, 0.27 at Show Low, 0.27 at Seligman, and 0.07 at Alpine. This was the last storm of the month for Arizona. By the 24 th, the high pressure ridge had returned and by the 27 th temperatures had risen back into the 80s for the southwest deserts and the 50s and low 60s in the colder locations. The weak La Niña circulation has been quite effective in keeping the southern and central states warm and dry so far this winter. No significant changes are expected for the next few weeks. The warm dry conditions have led to a worsening of drought conditions across California, Arizona, New Mexico, Colorado, Texas, and Oklahoma. In This Issue: Overview of January, graphs of the January daily maximum and minimum temperatures, precipitation, mean daily dew points for Flagstaff, Phoenix, and Tucson; January climate statistics, maps of mean monthly maximum and minimum temperatures, precipitation, dew points, wind speeds for January; short-term drought maps for the beginning and end of January 2018; Long-term Drought Map; and graphs of the mean January temperature and precipitation for the period of record for Tucson, Phoenix, and Flagstaff, graphs of the cumulative precipitation for the calendar year for Flagstaff, Phoenix, and Tucson. Climate calendars for Flagstaff, Phoenix, Tucson, Prescott, Winslow and Yuma, including daily and monthly normals and extremes, for each month of the year, are not yet updated through 2017. See p.22 of this report for calendar abbreviations. Data are preliminary and are from the National Weather Service Forecast Offices in Flagstaff, Phoenix and Tucson. Dr. Nancy J. Selover, State Climatologist http://azclimate.asu.edu 480-965-0580 Edited by Nancy J. Selover 2018 Arizona State Climate Office 1

**Note: The discrepancy between the Statewide Temperature and Precipitation values for Phoenix, Flagstaff and Tucson and the daily values in their graphs are due to the reporting times. Statewide Temperature and Precipitation values are taken at 5pm, while official daily records at the airports are taken from Midnight to Midnight. January 2018 Daily Temperature, Precipitation, & Dew Point for Flagstaff, Phoenix, and Tucson 2

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FLAGSTAFF CLIMATE STATISTICS January 2018 This January was tied for 6 th warmest with 1900 and had no significant ranking for precipitation. Avg Max Temp(F) 49.6 Normal 42.5 Avg Min Temp(F) 19.3 Normal 17.3 Avg Mean Temp(F) 34.4 Normal 29.9 Departure from Normal (F) +4.5 Highest Monthly Avg Temp (F) 37.1 in 2003 Lowest Monthly Avg Temp (F) 12.7 in 1937 Highest Temp this month (F): 63 on 31 st Lowest Temp this month (F): -2 on 22 nd Record High (F): 66 on 1/30/1971 Record Low (F): -30 on 1/22/1937 Temperature or precipitation records this month: 31 st HiMax 63 tied, first set in 1971 Flagstaff Number of Days of: Minimum Temp 25 o F or higher 4 Minimum Temp 10 o F or lower 5 Maximum Temp 60 o F or higher 9 Maximum Temp 50 o F or lower 15 Heating Degree Days 940 Normal 1088 Cooling Degree Days 0 Normal 0 Degree base 65 o F Total January Precipitation 1.71 Normal January Precipitation 2.05 Departure from normal -0.34 Greatest 24-Hr Precipitation 1.05 on 9 th Total Precipitation Year-to-Date 1.71 Departure from Normal -0.34 Total January Snowfall 11.3 Normal 23.2 Record January Snowfall 104.8 in 1949 Number of Days: Clear 25 Partly Cloudy 5 Cloudy 1 Greatest January Precipitation 9.55 in 1993 Least January Precipitation: 0.00 in 1972 Average Wind Speed Highest Peak Gust 5.9 mph 50 mph from 210 o on 9 th PHOENIX CLIMATE STATISTICS January 2018 This January was the warmest on record and the 15 th driest. Avg Max Temp(F) 73.9 Normal 67.2 Avg Min Temp(F) 48.5 Normal 45.6 Avg Mean Temp (F) 61.2 Normal 56.4 Departure from Normal (F) +4.8 Highest Monthly Avg Temp (F) 61.2 in 2018 Lowest Monthly Avg Temp (F) 46.7 in 1964 Highest Temp this month (F) Lowest Temp this month (F): Record High (F): 88 on 1/19/1971 Record Low (F): 16 on 1/17/1913 83 on 25 th 40 on 22 nd and 23 rd 4 Temperature or precipitation records this month: 4 th HiMin 56 set, previous record 54 in 1981 29 th HiMax 83 tied, first set in 1935 30 th HiMax 82 tied, first set in 1935 Phoenix Number of Days of: Minimum Temp 45 o F or lower 6 Minimum Temp 55 o F or higher 2 Maximum Temp 65 o F or lower 5 Maximum Temp 80 o F or higher 5 Heating Degree Days 120 Normal 269 Cooling Degree Days 12 Normal 2 Degree base 65 o F Total January Precipitation 0.21 Normal January Precipitation 0.91 Departure from normal -0.70

Greatest 24-Hr Precipitation 0.16 on 9 th Total Precipitation Year-to-Date 0.21 Departure from Normal -0.70 Greatest January Precipitation 5.22 in 1993 Least January Precipitation 0.00 in 1914, 2006 and 9 other years Number of Days: Clear 8 Partly Cloudy 23 Cloudy 0 Average Wind Speed 5.2 mph Highest Peak Gust 39 mph from 270 o on 20 th TUCSON CLIMATE STATISTICS January 2018 This January was the warmest on record and had no significant ranking for precipitation. Avg Max Temp(F) 73.6 Normal 65.5 Avg Min Temp(F) 44.6 Normal 39.8 Avg Mean Temp(F) 59.1 Normal 52.6 Departure from Normal (F) +6.5 Highest Monthly Avg Temp (F) 59.1 in 2018 Lowest Monthly Avg Temp (F) 41.2 in 1937 Highest Temp this month (F): Lowest Temp this month (F): Record High (F): 88 on 1/04/1927 Record Low (F): 6 on 1/07/1913 82 on 30 th 30 on 22 nd and 23 rd Temperature or precipitation records this month: 13 th HiMax 78 tied, first set in 2006 7 th HiMin 52 tied, first set in 2003 9 th HiMin 58 set, previous record 55 in 1957 30 th HiMax 82 tied, first set in 1987 Tucson Number of Days of: Minimum Temp 40 o F or lower 6 Minimum Temp 50 o F or higher 6 Maximum Temp 70 o F or lower 8 Maximum Temp 80 o F or higher 4 Heating Degree Days 180 Normal 383 Cooling Degree Days 0 Normal 0 Degree base 65 o F Total January Precipitation 0.02 Normal January Precipitation 0.94 Departure from normal -0.92 Greatest 24-Hr Precipitation 0.02 on the 20 th Total Precipitation Year-to-Date 0.02 Departure from Normal -0.92 Greatest January Precipitation 4.81 in 1993 Least January Precipitation 0.00 in 1972, 1926, 1924, and 9 other years. Number of Days: Clear Partly Cloudy Cloudy Average Wind Speed Highest Peak Gust M M M 7.5 mph 42 mph from 130 o on 29 th Data are from the National Weather Service and the National Climatic Data Center and are preliminary. 5

Wind Speeds for January: Day Phoenix Flagstaff Tucson (mph) Avg Max Avg Max Avg Max 1 3.4 13 2.9 18 6.7 19 2 4.5 13 7.1 29 5 14 3 5.2 23 3.2 14 13.1 35 4 3.5 19 4.1 20 4.8 22 5 4.2 12 4.4 20 5 18 6 4.4 12 8.9 27 7 19 7 3.3 14 5.7 25 3.4 13 8 3.7 13 3.5 26 5.8 21 9 11.7 39 12.3 50 9.3 29 10 5.8 18 9.8 29 7.7 36 11 2.4 14 3.5 20 3.6 14 12 3.4 14 4.9 22 5.8 18 13 4.9 20 4.4 17 8.8 31 14 4.2 22 4.7 19 5.3 17 15 3.1 11 2.6 18 6.9 19 16 5.4 15 2.3 15 13.3 34 17 7.3 24 4.2 22 12.8 37 18 3.7 14 1.6 15 8.8 25 19 4.9 15 6.3 25 7.6 20 20 9.9 39 12.1 34 6.8 35 21 7.2 26 7 28 6.9 22 22 4.7 17 3.2 19 5.7 15 23 4 19 7.1 26 5.2 15 24 8 19 2.3 16 11.3 33 25 6.3 19 14.8 49 7.7 23 26 3.3 17 6.9 27 5.5 19 27 3.5 17 3.6 17 6.7 18 28 6.5 24 14.6 37 5.6 20 29 9.8 27 6.2 24 13.4 42 30 4.3 20 2.3 16 9.8 36 31 4.6 14 5.2 22 6.2 19 Dew Points for January: Daily Average Dew Point ( o F): Day Phx Tuc Flg 1 22 21 3 2 20 16 1 3 21 24 4 4 28 25 16 5 31 28 18 6 34 31 26 7 34 33 22 8 38 37 25 9 46 42 29 10 48 40 27 11 45 36 22 12 39 30 21 13 35 25 21 14 33 21 19 15 33 24 22 16 27 21 19 17 28 20 18 18 29 20 17 19 32 26 23 20 27 22 14 21 26 22 7 22 18 13 6 23 14 5 5 24 15 9 9 25 21 12 11 26 19 13 3 27 16 10 4 28 18 8 13 29 19 13 14 30 20 11 14 31 23 15 14 6

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January 2018 The minimum temperatures ranged from -13 o F at Fort Valley to 51 o F at Yuma. The lowest maximum temperature of 50 o F was recorded at Bright Angel Ranger Station and the highest was 86 o F at Yuma. The highest rainfall total was 2.53 at Munds Park, south of Flagstaff. The lowest average dew point was 13 o F at Ryan Field and Winslow and the highest was 35 o F at Yuma, Parker and Paloma. The highest peak wind gust was 35 mph at Roll and Mohave. Average wind speeds ranged from 2 mph in Payson and the Phoenix area to 14 mph at Laughlin-Bullhead City Airport. 8

T January 2018 The highest average minimum temperature was 60 o F at Yuma, and the lowest average minimum temperature was 11 o F at Sunrise Mountain. The highest average maximum temperature was 79 o F at Organ Pipe Cactus National Monument and the lowest average maximum temperature was 41 o F at Snowslide Canyon. 9

Short term drought maps for January 2 nd on left and January 30 th on right. The warm, dry fall led to increased drought across the state, with all areas of the state in Moderate Drought (D1) or worse. The continued dry conditions in January caused Severe Drought (D2) to expand from eastern Arizona into central and southern Arizona, and Extreme Drought (D3) was introduced in east central and southern Arizona. 10

Long-term drought map for January for Arizona shows hydrologic drought, and is based on both precipitation and evaporation using the Standardized Precipitation Index (SPI) and Standardized Precipitation Evaporative Index (SPEI) over the past 24-, 36-, and 48-months. 11

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January January minimum temperatures in eastern Arizona were generally within 2 o F of average while the western 2/3 of the state was 2 to 6 o F warmer than average. Daytime temperatures were 4 to 10 o F warmer than average across the state. Most of the state received less than 70% of normal January precipitation while southern Arizona and central Navajo County received less than 25% of average. 13

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Calendar Year 2018 January minimum temperatures in eastern Arizona were generally within 2 o F of average while the western 2/3 of the state was 2 to 6 o F warmer than average. Daytime temperatures were 4 to 10 o F warmer than average across the state. Most of the state received less than 70% of normal January precipitation while southern Arizona and central Navajo County received less than 25% of average. 15

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s aham, Cochise, La Paz, OPima and 2018 Water Year Water Year 2018 minimum temperatures were 0 to 6 o F warmer than normal across most of the state. La Paz County appears to have been much warmer than normal, but the bullseye may be due to bad data or a station move. Areas of Navajo, Apache and Cochise counties were slightly cooler than normal. Daytime temperatures were 4 to 10 o F warmer than normal across the state. The entire state received less than 50% of normal precipitation since October 1st. 17

January Mean Temperature Graphs Flagstaff, Phoenix, and Tucson 1895-2018: 18

January Mean Precipitation Graphs Flagstaff, Phoenix, and Tucson 1895-2018 19

2018 Cumulative Precipitation Graphs Flagstaff, Phoenix and Tucson: Flagstaff is 0.34 below normal, Tucson is 0.92 below normal, and Phoenix is 0.70 below normal. 20

The downloadable normals and extremes calendars use the following abbreviations: NORM = 30 year (1971-2000) average value (degrees Fahrenheit (F)) OBS = The temperature observation for that day this year AVG = Average daily temperature HI MAX = Highest maximum temperature for that day (F) LO MAX = Lowest maximum temperature for that day (F) LO MIN = Lowest minimum temperature for that day (F) HI MIN = Highest minimum temperature for that day (F) Mx PCP = Maximum precipitation for that day (inches) Mx SNO = Maximum snowfall for that day (inches) 21