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Monthly Archive | CLIMAS

Monthly Archive

Southwest Climate Outlook June 2019 - Climate Summary

Thursday, June 27, 2019

May Precipitation and Temperature: May precipitation was mostly above average to record wettest in Arizona, and New Mexico ranged from below average to much above average but most of the state was average or above-average (Fig. 1a). May temperatures were below average or much below average across most of the Southwest (Fig. 1b).

Seasonal Precipitation and Temperature: Spring precipitation (Mar-Apr-May) was average to above average across most of Arizona and New Mexico (Fig 2a). Temperatures for the same period were mostly average in Arizona and mostly average to above average in New Mexico (Fig. 2b).

 

Drought: Water year precipitation highlights the wet conditions since Oct. 1, which have led to above normal (top 33%) for a vast majority of the Southwest, along with much above normal (top 10%) and smaller pockets of record wettest in Utah, Nevada, and Colorado (Fig. 3). The Jun. 11 U.S. Drought Monitor (USDM) continues to show improvements in regional drought conditions in the Southwest with Arizona nearly clear of drought designations, and the intensity of drought characterizations in the four corners region and northern New Mexico further reduced compared to last month (Fig. 4).

 

 

Snowpack & Water Supply: Late season snowpack and snow water equivalent (SWE) measurements are all but absent in Arizona and New Mexico this time of year, while upper elevation areas in Utah and Colorado that feed into reservoirs are mostly over 200-percent of average (Fig. 5; see Snow Water Equivalent recap along with Arizona and New Mexico Reservoirs).

 

Wildfire, Health, and Safety: May weather conditions (including wetter than average precipitation, mild temperatures, and elevated relative humidity), helped tamp down fire risk in May and into June. Wildfire outlooks for July identify above normal fire risk in lower elevation regions (Fig. 6), linked to widespread fine fuel growth driven by above-average precipitation across the cool season.

 

El Niño Tracker: Atmospheric and oceanic conditions remain in line with a weak El Niño, and most forecasts call for this event to last at least through summer, and possibly longer (see El Niño tracker for more details).

Precipitation and Temperature Forecast: The three-month outlook for July through September calls for increased chances of below-normal precipitation in eastern Arizona, western New Mexico, and the four corners region, with equal chances of above- or below-normal precipitation in much of the rest of Arizona, New Mexico, west Texas, and northern Mexico (Fig. 7, top). The three-month outlook calls for increased chances of above-normal temperatures in Arizona, and parts of northern New Mexico and northern Mexico (Fig. 7, bottom).

 


Online Resources

  • Figures 1-2 - National Centers for Environmental Information - ncei.noaa.gov
  • Figure 3, 5 - Western Regional Climate Center - wrcc.dri.edu
  • Figure 4 - U.S. Drought Monitor - droughtmonitor.unl.edu
  • Figure 6 - National Interagency Fire Center - droughtmonitor.unl.edu
  • Figure 7 - International Research Institute for Climate and Society - iri.columbia.edu

Southwest Climate Outlook - El Niño Tracker - June 2019

Thursday, June 27, 2019

Forecast Roundup: Seasonal outlooks are based on the persistence of sea surface temperature (SST) anomalies consistent with a weak El Niño event (Figs. 1-2), along with the presence of other atmospheric and oceanic indicators (convective anomalies, sub-surface temperatures). On June 10, the Japanese Meteorological Agency (JMA) noted persistent SST anomalies along with atmospheric and sub-surface indicators of El Niño, and called for a 70-percent chance of these conditions continuing into summer, and a 60-percent chance to last into fall. On June 11, the Australian Bureau of Meteorology maintained their ENSO Outlook at watch status, calling for a 50-percent chance of an El Niño event in 2019. On June 13, the NOAA Climate Prediction Center (CPC) maintained their El Niño advisory based on the SST anomalies, along with convective anomalies and sub-surface temperatures. Their outlook dipped to a 66-percent chance of El Niño lasting through summer, and 50- to 55-percent of lasting through fall. On June 19, the International Research Institute (IRI) issued an ENSO Quick Look (Fig. 3), highlighting above-average SSTs and warm subsurface waters, and “some” atmospheric indicators consistent with El Niño. The North American Multi-Model Ensemble (NMME) points toward a weak El Niño lasting into fall 2019 (Fig. 4), with considerable spread based on uncertainty.

 

Summary: El Niño conditions are within the range of a weak event. Based on current models and forecasts, the likely trajectory is for these conditions to persist through summer, with increasing uncertainty and model spread heading into fall and winter. As reported last month, there are two associations of note. The first is enhanced northern pacific tropical storm activity, which could see tropical storms increase our warm season precipitation totals in direct ways (i.e. storms that push into the region) or that provide additional moisture and instability that enhances monsoon activity. This is more commonly seen during the latter half of the monsoon into Fall, and unlike last year with TS Bud, there has not been early season tropical storm activity that pushed moisture into the Southwest. The second association is tenuous given small sample sizes, but El Niño conditions over summer have been linked to a delayed onset of monsoon activity. This linkage appears to be influencing some seasonal forecasts and has been picked up in the media, but the science and our understanding of this link is still evolving. Big picture? El Niño sends mixed signals for seasonal outlooks and will keep us guessing regarding the timing and intensity of tropical storm activity and monsoon precipitation – in other words, a typical summer in the Southwest.


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