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Monthly Archive

Southwest Climate Outlook - El Niño Tracker - January 2020

Friday, January 31, 2020

Warm waters continue to linger in the equatorial Pacific (Figs. 1-2), and while sea surface temperatures (SSTs) are expected to fall back within the range of ENSO-neutral, some forecasters made note of these warm conditions as something to keep an eye on in 2020.

Forecast Roundup: On Jan 7, the Australian Bureau of Meteorology noted “the tropical ocean…remains warmer than average” but that ENSO indicators remained consistent with neutral conditions. On Jan 9, the NOAA Climate Prediction Center (CPC) issued their ENSO diagnostic discussion with an inactive alert status and called for a 60-percent chance of ENSO-neutral through spring and a 50-percent chance of ENSO-neutral lasting through summer.  They stated “the oceanic and atmospheric system was consistent with ENSO-neutral, though recent observations reflected a trend toward warmer conditions that will be monitored.” On Jan 9, the International Research Institute (IRI) issued an ENSO Quick Look noting that despite recent above normal SSTs that were likely to last for another month or so, they would not last long enough to meet the criteria for an El Niño event. They maintained a 60-percent chance of neutral conditions through spring (Fig. 3). On Jan 10, the Japanese Meteorological Agency (JMA) maintained their call for a 60-percent chance of ENSO-neutral conditions to continue until spring 2020. The Jan 2020 North American Multi-Model Ensemble (NMME) shows positive SST anomalies into January, but is predicted to return and remain within the range of ENSO-neutral in February (Fig. 4).

Summary: Recent positive SST anomalies in the equatorial Pacific have been attributed to seasonal variability and not the return of El Niño. This appears to still be the case, with forecast consensus on ENSO-neutral conditions lasting into mid-2020. Most recent forecast discussions emphasized that these positive SST anomalies were large enough, but would not last long enough to meet the El Niño criteria, not to mention a lack of atmospheric coupling that is characteristic of El Niño events. A few agencies made note of warm oceanic conditions lasting longer than expected, but so far, all still see ENSO-neutral as the most likely outcome. In the Southwest, ENSO-neutral winters have produced some of the wettest and driest winters (and everything in between). We continue to monitor sub-seasonal and short term forecasts for insight into upcoming events. Given recent and long-term drought conditions in the Southwest, and regardless of ENSO status, a sustained run of regular precipitation events spread out over the cool season would be most welcome.


Online Resources

  • Figure 1 - Australian Bureau of Meteorology - bom.gov.au/climate/enso
  • Figure 2 - NOAA - Climate Prediction Center - cpc.ncep.noaa.gov
  • Figure 3 - International Research Institute for Climate and Society - iri.columbia.edu
  • Figure 4 - NOAA - Climate Prediction Center - cpc.ncep.noaa.gov

Southwest Climate Outlook January 2020 - Climate Summary

Friday, January 31, 2020

Monthly Precipitation and Temperature: December precipitation was average to above average in most of Arizona, while New Mexico ranged from below average to above average (Fig. 1a). December temperatures were average to above average in Arizona and above average to much above average in New Mexico (Fig. 1b). Daily average temperature anomalies for Dec 1 – Jan 15 (Fig. 2) highlight the fluctuations at select stations around the region. Positive anomalies reflect above average daily temperatures, while negative anomalies reflect below average daily temperatures. The histograms show the frequency of the anomalies for each location.

 

 

Seasonal Precipitation: Three month precipitation rankings for Oct-Nov-Dec were above normal or much above normal for most of Arizona and New Mexico, with the notable exception of the Four Corners region (Fig. 3), which continues to miss out on recovery from both short and long term drought conditions.

 

Annual Precipitation and Temperature: Total precipitation for 2019 in Arizona ranged from below average to much above average, while New Mexico ranged from below average to above average (Fig. 4a). Mean temperatures in 2019 were average to above average in Arizona and average to much above average in New Mexico (Fig. 4b).

 

Snowpack & Water Supply: As of Jan 13, snow water equivalent (SWE) was mostly above median in Arizona, New Mexico, and southern Utah and Colorado (Fig 5, see detailed SWE map). Many of the reservoirs in the region are at or above the values recorded at this time last year, but most are below their long-term average (see Arizona and New Mexico reservoir storage).

 

Drought: The Jan. 6 U.S. Drought Monitor (USDM) has scaled back the intensity and extent of some drought characterizations in the Southwest, but the Four Corners region remains consistently in the center of regional drought designations (Fig. 6). A large pocket of “Moderate Drought” (D1) and “Severe Drought” (D2) is centered on the Four Corners region, reflecting acute and accumulated precipitation deficits.

 

ENSO Tracker: Oceanic and atmospheric conditions are generally consistent with an ENSO-neutral outlook for 2020 (see ENSO-tracker for details).

Precipitation Forecast: The three-month outlook for February through April calls for increased chances of below-normal precipitation in California and in small pockets along the U.S.-Mexico borderlands, with equal chances of above or below normal precipitation across much of the rest of the Southwest. Notably, the upper Colorado River Basin is forecast for increased chances of above normal precipitation (Fig. 7, top). Temperature Forecast: The three-month temperature outlook calls for increased chances of above-normal temperatures across Texas, New Mexico, and most of Arizona, along with much of north central Mexico (Fig. 7, bottom).

 

Online Resources

  • Figures 1, 4 - National Centers for Environmental Information - ncei.noaa.gov
  • Figure 2 - Climate Assessment for the Southwest - climas.arizona.edu
  • Figure 3 - West Wide Drought Tracker - wrcc.dri.edu/wwdt
  • Figure 5 - Natural Resources Conservation Service - nrcs.usda.gov
  • Figure 6 - U.S. Drought Monitor - droughtmonitor.unl.edu
  • Figure 7 - International Research Institute for Climate and Society - iri.columbia.edu