Issued: March 22, 2005

Disclaimer - This packet contains official and March Climate Summary non-official forecasts, as well as other information. While we make every effort to verify this informa- Hydrological Drought – Hydrological drought continued to ease in the Southwest. tion, please understand that we do not warrant the accuracy of any of these materials. The user assumes the entire risk related to the use of this data. • Most of southwestern Arizona and southern New Mexico are now consid- CLIMAS disclaims any and all warranties, whether ered free of drought impacts. expressed or implied, including (without limita- tion) any implied warranties of merchantability or fitness for a particular purpose. In no event will • Arizona statewide reservoir storage is above average, while New Mexico CLIMAS or the University of Arizona be liable to you or to any third party for any direct, indirect, statewide average storage is just over half of its average capacity. incidental, consequential, special or exemplary damages or lost profit resulting from any use or Precipitation – Wetter-than-average conditions continue in much of the South- misuse of this data. west. Snowpack remains above average in many regional river basins despite slight decreases in some areas. In this issue:

Temperature – Water year temperatures are above average. The past 30 days have 1 March 2005 Climate Summary generally been warmer than average. 2 Feature: Will the Drought Continue?

Climate Forecasts – The long-lead temperature forecasts call for increased chances Recent Conditions of warmer-than-average conditions in Arizona and far western New Mexico 5 Temperature through September. Increased chances of above-average precipitation are predicted 6 Precipitation through June in New Mexico and western Arizona. 7 U.S. Drought Monitor 8 New Mexico Drought Status 9 El Niño – Models predict that the current weak El Niño will persist through mid to Arizona Reservoir Levels 10 New Mexico Reservoir Levels late summer before neutral conditions began to dominate the tropical Pacific Ocean. 11 Southwest Snowpack

The Bottom Line – Continued improvement is expected in drought conditions Forecasts through June in the Southwest. 12 Temperature Outlook 13 Precipitation Outlook The climate products in this packet are available on the web: 14 Seasonal Drought Outlook http://www.ispe.arizona.edu/climas/forecasts/swoutlook.html 15 Streamflow Forecast 16 Wildland Fire Outlook 17 El Niño Status and Forecast Early forecasts for this year’s crop of wildflowers looked good with some reports that it could be one Forecast Verification 18 of the best seasons on record (Tucson Citizen, Febru- Temperature Verification 19 Precipitation Verification ary 15). So far, dazzling displays of flowers colored the lowland desert of areas such as Death Valley, The Southwest Climate Outlook is jointly pub- California, the Pinacate Natural Reserve in Sonora, lished each month by the Climate Assessment Mexico, and the Kofa National Wildlife Refuge in for the Southwest project and the University of Arizona. Invasive grasses may be winning out over Arizona Cooperative Extension. annual flowers in some spots, but peak blooms Mike Crimmins, Extension Specialist could continue through late April in other areas. Gregg Garfin, CLIMAS Program Manager Wildflower lovers can check for updates at: Shoshana Mayden, Editor http://www.desertusa.com/wildflo/wildupdates.html Kristen Nelson, Assistant Editor Rick Brandt, Graduate Research Assistant http://www.desertmuseum.org/programs/flw_blooming.html Melanie Lenart, Research Associate In early March, fields of golden poppies were in bloom along Highway 86 near Kitt Peak. Photo by Shoshana Mayden. 2 | Feature Article Will the drought continue? Rains bring relief to Southwest, but experts caution the wet spell may be short-lived

BY MELANIE LENART Short-term surplus The boon of precipitation is greening A series of fortunate events has pulled the Southwest and bringing forth a drought-busting precipitation into the colorful cast of wildflowers. Waterways Southwest since about fall. Still, clima- are also responding to the bounty, with tologists warned this doesn’t mean the many reservoirs filling surprisingly region has moved out of the danger fast from streams sometimes bursting zone for long-term drought. at their banks. Floods included a late December overflow of Oak Creek in Tropical rainfall, short-term pressure Sedona, Arizona. to believe that the groundwater has been systems that favored the Southwest, and short-changed over the past 48 months. El Niño conditions conspired to make “It’s really wet out there, that’s for We can’t say that the drought is gone.” the six-month September through Feb- sure,” agreed Tom Pagano, water sup- ruary period the second wettest in Ari- ply forecaster at the National Water Unfortunately, it seems unlikely that zona and third-wettest in New Mexico and Climate Center in Oregon. As of many of the conditions that led to the in the 111-year instrumental record, as mid-March, all three main reservoirs in recent stellar improvement will re-align indicated by a National Climatic Data Phoenix were rebounding dramatically next year. Center (NCDC) online comparison. from years of overdrafts. A spell of relief Meanwhile, New Mexico set a record “The Verde system, for all intents and The improvement arguably began high for November through February purposes, is completely full right now. when a tropical storm—the remnants precipitation, while the same period was Lake Pleasant on the Agua Fria is 99 of Hurricane Javier—drizzled days of the third wettest for Arizona, NCDC percent full. And the Salt system has rain on the Southwest as it cut a north- records show (Figure 1). gone where the Salt has never gone be- easterly diagonal across Arizona. Most fore,” Pagano said, alluding to a recent of the Southwest received at least some The September through February period expansion that allows the Salt system to moisture during the storm’s three-day was also record-breaking when consid- trap more water than it could previously. sojourn that started September 19, with ering the Four Corner states together, a regional high of 5.2 inches of precipi- NCDC reports show. This bodes well Even the San Carlos Reservoir in Gila tation falling on Promontory, Arizona. for spring snowmelt into rivers that sup- County is nearly half full, after hovering ply residents and farmers in the South- at about 4 percent capacity for much of The drizzle served as a gentle way to west, including the Colorado River. the past year. soak parched soils without pummeling them into an erosive state. But rainfall “We’re definitely in recovery mode. We “We’ve been in disbelief,” Pagano said. events linked to hurricanes only affect had to kick over that first domino,” said But he and others cautioned against Arizona every 4.5 years on average, ac- Mark Svoboda, a climatologist with the hailing the end of the drought. “It cording to calculations by Erik Pytlak of National Drought Mitigation Center. sounds really paradoxical, but I think a the National Weather Service’s Tucson “Mother Nature has a way of giving lot of people are concerned that this is office. things back a lot quicker than she takes really just a blip in a long-term drought it away.” situation.” On the heels of the tropical storm came a series of frontal events. Since about A really wet October saturated west- “Yes, we see the drought improving,” October, the Southwest has been re- ern soils roughly everywhere south agreed Charlie Liles, the meteorolo- ceiving a good share of the storms that of Oregon, Idaho, and Wyoming, gist in charge of the National Weather normally would keep clouds over the Svoboda said. With soils sated, addi- Service’s Albuquerque office. “The sur- Pacific Northwest, especially Oregon tional moisture could flow into streams face looks great because of the recent wet and Washington. and reservoirs. weather and the snowpack. But I have continued on page 3

Southwest Climate Outlook, March 2005 3 | Feature Article

7 continued New Mexico Drought, 6 “It’s going to look like an El Niño year El Niño impacts in the 5 when you look at the overall pattern of Southwest tend to center 4 dryness in the Northwest and wetness around winter precipita- 3 2 in the Southwest,” Svoboda said. “But tion. 1 looks can be deceiving.” Precipitation (inches) Precipitation 0 The long and short of it

In fact, the “smoking gun” from late Regardless of which 1896 1902 1908 1914 1920 1926 1932 1938 1944 1950 1956 1962 1968 1974 1980 1986 1992 1998 2004 14 December through January can be way the winds blow, Arizona traced to short-term atmospheric pres- the drought that estab- 12 sure systems, mainly a Madden Julian lished over more than a 10 Oscillation (MJO), said Ed O’Lenic, decade won’t disappear 8 chief of the operations branch for overnight. Nor will its 6 NOAA’s Climate Prediction Center. impacts. 4

Precipitation (inches) Precipitation 2 “The MJO lives and dies on the time “It takes a while to dig 0 scale of about a month. And an El Niño yourself into a hole. And lasts a year or more. They are two very it takes a while to get 1896 1902 1908 1914 1920 1926 1932 1938 1944 1950 1956 1962 1968 1974 1980 1986 1992 1998 2004 different kinds of things,” O’Lenic yourself out of it,” as Year (November-February) explained. “Both of them can have im- Pagano put it. At the Figure 1. Precipitation from November 2004 through February pacts on the weather where we live.” moment, Arizona’s Lake 2005 was the highest on record for New Mexico (top figure) and Powell is still “bottom- the third-wettest on record for Arizona (bottom figure) com- The MJO is a relatively new discovery, ing out,” filled to only pared to previous November-February periods. The data also seem to show a visual increase in variability, or extreme events, and references to it are easier to find on about 35 percent of since about the mid-1970s. Source: Western Regional Climate the internet than in climatology text- capacity with roughly Center. books. “Pineapple express” events that one year’s supply stored. carry moisture over from Hawaii often Pagano anticipated that are succumbing to MJO pressure. it, too, still would be half empty by the Liles and others worry that reservoirs end of July. Or half full—this would be and aquifers could falter for decades, if This particular Madden-Julian Oscilla- a gain of about 4 million acre-feet after long-term ocean patterns are aligning tion dissipated by the end of January. distributing its portion of the Lower to maintain a multidecadal western MJO activity tends to be stronger dur- Basin’s annual share of the Colorado drought. While the MJO might affect ing neutral or weak El Niño years, as River flow. Still it could take decades to regional climate for a month and El a Climate Prediction Center website fill entirely. Niño fluctuations might hold sway for a reports. The ongoing El Niño is consid- year or so, other patterns appear to keep ered weak. Liles used a budget analogy to make a the Southwest in overall drought mode similar point, noting New Mexico had for decades despite these short-term Still, it apparently had enough punch a 25-inch precipitation deficit accrued swings. to make February the wettest for New over five years when the current water Mexico and the second-wettest for Ari- year began on October 1. The state has In particular, the Pacific Decadal Oscil- zona in the instrumental record, accord- garnered about 5 inches of precipitation lation (PDO) and the Atlantic Multi- ing to the NCDC online comparison. toward that negative balance. decadal Oscillation (AMO) are suspect- ed of having holding patterns that can “The February rains appear to have been “Now we’re trying to put some money last some 20 years or so based on obser- related to kind of a late bloom of El back in the bank, but the account’s vations in the instrumental record and Niño,” O’Lenic said. “We pretty much pretty low,” he added. For instance, inferences in the longer-term record re- waited all winter for this to happen.” Elephant Butte Reservoir had dropped constructed from natural archives such to only 9 percent of its average storage as tree rings. These oscillations appear And now the bad news. The El Niño by the end of last summer. Now it’s ap- to be associated with western drought. bloom may already be fading. Forecasts proaching 30 percent of average, but it’s predict a 65 percent chance of neutral a long way from its 2 million acre-feet Julio Betancourt of the U.S. Geological conditions pervailing over El Niño for capacity. Groundwater, too, continues Survey in Tucson is among the research- the March to May period. At any rate, to be “short-changed,” he noted. continued on page 4

Southwest Climate Outlook, March 2005 4 | Feature Article

Drought, continued 10.0 Wet Spell ers arguing that these decades-long fluc- the U.S. Southwest as x tuations contributed to the southwestern well as the rest of the drought that spanned from about the world. Although it re- 1940s through the 1970s (Figure 2). mains unclear exactly how 5.0 Betancourt indicated he fears drought the warming will affect could continue to haunt the Southwest southwestern hydro- for decades to come. logic regimes, consensus is 0.0 emerging on several fronts. drolgic Drought Inde “I haven’t seen any evidence indicating Climbing temperatures that what we’ve seen lately will persist,” will certainly increase lmer Hy -5.0

he said of the recent wet spell. evaporation rates and will Pa likely continue to shorten Dry Spell Liles agreed, noting that an El Niño- winters, resulting in an 1900 1920 1940 1960 1980 2000 inspired wet period spanning about earlier seasonal snowmelt. Year 1956 through early 1958 helped allevi- Figure 2. The Palmer Hydrological Drought Index above ate the drought impacts, but didn’t re- Warmer temperatures indicates that drought is a common occurrence in the South- ally end the drought. may also yield more west, which for this analysis includes the Four Corner states of extreme precipitation Arizona, New Mexico, Utah, and Colorado. Hydrologic drought “People thought drought was over. Look- events, such as droughts tends to be more entrenched than other types of droughts, as ing back, you could see that drought ac- and floods. Interestingly, it takes reservoirs and aquifers longer to rebound. Source: National Climatic Data Center. tually lasted until about the 1980s,” Li- the instrumental records les said (see Figure 2). “I think that Julio for November-February precipitation and I are pretty similar on our concerns in Arizona and New Mexico (Figure 1) Beyond global warming and the other that we were headed into a long-term seem to show an increase in extreme short and long-term influences on cli- drought. I think right now it’s going to events—i.e., greater variability around mate, extreme precipitation events are take a couple of years to really know.” the norm—since about the mid-1970s. part and parcel of life in the semi-arid This is a moment in time that many cli- desert. Another wild card matologists identify as launching a criti- There’s an even longer term potential cal jump in global temperatures. If drought is seen as including any year influence on modern drought regimes when precipitation falls below 75 per- in the Southwest: global warming. The Since then, temperatures have contin- cent of the average, the Southwest is in input of additional greenhouse gases ued an upward trend in the Southwest. drought about 43 percent of the time, into the atmosphere is expected to yield Some of the concern over water supplies as New Mexico State University Profes- a temperature increase on the scale of stems from these rising temperatures. sor Jerry Holechek and colleagues note about 1 degree Fahrenheit per decade For instance, warm temperatures dur- in their 1998 textbook “Range Man- in the Southwest through this century ing March of last year—which soared agement.” By comparison, the Pacific and beyond, as last month’s Southwest to record highs for Arizona and placed Northwest is in drought only 13 percent Climate Outlook article explained. second for New Mexico in the instru- of the time, given this approach. mental record—consumed much of the That warming trend appears to have existing southwestern snowpack without So odds are that relatively wet periods started in earnest in the mid-1970s, in leaving moisture behind. like the current one won’t last long in the Southwest. Resources on the Web • To compare moisture status for different states using the NCDC online tool, visit: http:// “You’re still living in the desert. Average lwf.ncdc.noaa.gov/oa/climate/research/prelim/drought/state-reg-moisture-status.html annual precipitation is a foot a year,” • To compare moisture status for different time frames using the Western Regional Pagano reminded, referring to Tucson. Climate Center online tool: http://www.wrcc.dri.edu/cgi-bin/divplot1_form.pl?0204 “That hasn’t changed.” • For more details on the Madden-Julian Oscillation: http://www.cpc.ncep.noaa.gov/products/intraseasonal/intraseasonal_faq.html Melanie Lenart is a postdoctoral re- • For more on how the PDO influences Southwest climate, see: search associate with the Climate As- http://www.ispe.arizona.edu/climas/learn/pdo/index.html sessment for the Southwest (CLIMAS). http://www.srh.noaa.gov/abq/research/feature.htm

Southwest Climate Outlook, March 2005 5 | Recent Conditions

(through 3/16/05) Figure 1a. Water year '04–'05 (through March 15, 2005) Temperature departure from average temperature. Sources: Western Regional Climate Center, High Plains Regional Climate Center 5 Water year departures are mostly above average across the 4 Southwest (Figure 1a). The warmest anomalies (3–4 degrees 3 2 Fahrenheit) are in northeastern Arizona and north-central 1 New Mexico. Average temperatures since October 1, 2004 0 have ranged from the lower to mid 30’s in north-central New °F -1 Mexico to the mid-60’s in southwestern Arizona (Figure 1b). -2 From mid-February to mid-March average temperatures were generally warmer than average (Figures 1c–d). North-central -3 Arizona had the highest positive temperature departures (4–6 degrees F). Figure 1b. Water year '04–'05 (through March 15, 2005) average temperature. According to the National Climatic Data Center and the Albuquerque National Weather Service (NWS), the 2004– 65 2005 winter has been the 8th warmest since records have 60 been kept (Santa Fe New Mexican, March 9). In Tucson, Ari- 55 zona, February average temperatures were nearly 1 degree F 50 above average, and the winter has been the 13th warmest on 45 °F record through the end of February (Tucson NWS). A recent 40 study reports that winters have been warmer over the past 50 35 years, resulting in less mountain snowpack in the West (Santa 30 Fe New Mexican, February 21). According to the research, 25 the decreasing snowpack is consistent with global warming, and the trend may persist if temperatures continue to warm. Figure 1c. Previous 30 days (February 15–March 16, 2005) departure from average temperature (interpolated). 10 8 Notes: 6 The water year begins on October 1 and ends on September 30 of the 4 following year. Water year is more commonly used in association with 2 precipitation; water year temperature can be used to measure the tem- 0 °F peratures associated with the hydrological activity during the water year. -2 Average refers to the arithmetic mean of annual data from 1971–2000. -4 Departure from average temperature is calculated by subtracting current -6 data from the average. The result can be positive or negative. -8 -10 The continuous color maps (Figures 1a, 1b, 1c) are derived by taking measurements at individual meteorological stations and mathemati- Figure 1d. Previous 30 days (February 15–March 16, 2005) cally interpolating (estimating) values between known data points. The dots in Figure 1d show data values for individual stations. Interpolation departure from average temperature (data collection locations only). procedures can cause aberrant values in data-sparse regions. 10 Figures 1c and 1d are experimental products from the High Plains 8 Regional Climate Center. 6 4 2 0 °F On the Web: -2 For these and other temperature maps, visit: -4 http://www.wrcc.dri.edu/recent_climate.html and http://www.hprcc.unl.edu/products/current.html -6 -8 For information on temperature and precipitation trends, visit: -10 http://www.cpc.ncep.noaa.gov/trndtext.htm

Southwest Climate Outlook, March 2005 6 | Recent Conditions

(through 3/16/05) Figure 2a. Water year '04–'05 through March 16, 2005 percent Precipitation of average precipitation (interpolated). Source: High Plains Regional Climate Center 300 200 Precipitation has been much above average for nearly the 150 entire Southwest since October 1, 2004 (Figures 2a–b). Por- 130 tions of western Arizona and southeastern New Mexico are 110 in excess of 300 percent of average for the water year. Only 100 % small portions of southeastern Arizona and north-central 90 New Mexico have deficits during the period. Precipitation 70 from February 15–March 16 was near to above average for 50 most of the region (Figures 2c–d). The same areas that have 25 experienced drier-than-average conditions for the water year 5 also had below-average precipitation over the past 30 days. Figure 2b. Water year '04–'05 through March 16, 2005 percent of average precipitation (data collection locations only). The anomalously high precipitation amounts have been a boon to regional reservoirs. For example, the capacity of 300 Roosevelt Reservoir near Phoenix increased from 31 percent 200 in late December to 87 percent in mid-March (East Valley 150 Tribune, March 16). The Tucson National Weather Service 130 reports that February was the 23rd wettest on record, and 110 % this winter season is the first with above-average rainfall 100 since 1997–1998. According to the National Climatic Data 90 Center, New Mexico statewide average precipitation is the 70 highest since records began in 1896 (Santa Fe New Mexican, 50 March 9). 25 5 Figure 2c. Previous 30 days (February 15–March 16, 2005) percent of average precipitation (interpolated). 800 Notes: 400 The water year begins on October 1 and ends on September 30 of the 200 following year. As of October 1, 2004 we are in the 2005 water year. The 150 water year is a more hydrologically sound measure of climate and hydro- 125 logical activity than is the standard calendar year. 100 % 75 Average refers to the arithmetic mean of annual data from 1971–2000. Percent of average precipitation is calculated by taking the ratio of cur- 50 rent to average precipitation and multiplying by 100. 25 5 The continuous color maps (Figures 2a, 2c) are derived by taking mea- 2 surements at individual meteorological stations and mathematically interpolating (estimating) values between known data points. Figure 2d. Previous 30 days (February 15–March 16, 2005) Interpolation procedures can cause aberrant values in data-sparse percent of average precipitation (data collection locations regions. only). 800 The dots in Figures 2b and 2d show data values for individual meteoro- 400 logical stations. 200 150 125 On the Web: 100 % For these and other precipitation maps, visit: 75 http://www.hprcc.unl.edu/products/current.html 50 For National Climatic Data Center monthly precipitation and 25 drought reports for Arizona, New Mexico, and the Southwest 5 region, visit: http://lwf.ncdc.noaa.gov/oa/climate/research/2003/ 2 perspectives.html#monthly

Southwest Climate Outlook, March 2005 7 | Recent Conditions

U.S. Drought Monitor tions have deteriorated enough in Washington that Gov- (released 3/17/05) ernor Christine Gregoire has declared a statewide drought emergency (U.S. Water News, March 2005