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Monthly Precipitation and Temperature: October precipitation in Arizona ranged from below average to record driest, while most of New Mexico was average to above average (Fig. 1a). October temperatures were mostly average to below average in Arizona and New Mexico (Fig. 1b). The daily average temperature anomalies for Oct 1 – Nov 19 (Fig. 2) highlight the fluctuations at select stations around the region including a number of cold spells. (Read More).

Monthly Precipitation and Temperature: September precipitation in Arizona ranged from much below average in the north, to much above average in the south, while most of New Mexico was average to below average (Fig. 1a). September temperatures were mostly average to much above average in Arizona and mostly much above average to record warmest in New Mexico (Fig. 1b). The daily average temperature anomalies for Sept 1 – Oct 15 (Fig. 2) highlight the fluctuations at select stations around the region. (Read More).

Forecast Roundup: Despite warmer waters in the equatorial Pacific, seasonal outlooks and forecasts based on sea surface temperature (SST) anomalies (Figs. 1-2) and other oceanic and atmospheric indicators, all point to ENSO-neutral conditions lasting through 2019 and into 2020. On Oct 10, the Japanese Meteorological Agency (JMA) highlighted lingering warmer-than-normal SSTs in the western equatorial Pacific, and maintained their call for a 60-percent chance of ENSO-neutral conditions to continue until winter 2019-2020. On Oct 10, the NOAA Climate Prediction Center (CPC) issued their ENSO diagnostic discussion with an inactive alert status, and focused on neutral conditions across the oceans and atmosphere. They called for an 85-percent chance of ENSO-neutral conditions persisting through fall 2019, and a 55- to 60-percent chance of ENSO-neutral through spring 2020. On Oct 10, the International Research Institute (IRI) issued an ENSO Quick Look (Fig. 3), emphasizing neutral conditions in oceanic and atmospheric indicators. Their models see ENSO-neutral as the most likely outcome, but remain at “slightly higher chances for El Niño than La Niña”. On Oct 15, the Australian Bureau of Meteorology maintained their ENSO Outlook at ‘inactive’ with most oceanic and atmospheric conditions in the range of neutral. The Oct 2019 North American Multi-Model Ensemble (NMME) saw a turn back towards positive SST anomalies, but is forecast to remain within the range of ENSO-neutral through 2019 (Fig. 4). (Read More)

Single weather stations around the region are useful for comparing long term averages to the current year. Figure 1 summarizes monthly precipitation, and shows 2019 lagged behind 2018 and long term averages in most months at most locations. Plots of daily precipitation for stations around the region (Fig. 2) illustrate the slow start and lower than average totals across the region. This monsoon was notable in how much it deviated from the past few years, where many locations in the Southwest saw a run of above normal monsoon precipitation. This made 2019 particularly disappointing. A look at the long term averages demonstrates that 2019 is consistent with some of the drier monsoons on record, even while specific station locations were at or near record driest. (Read More)

Forecast Roundup: Seasonal outlooks and forecasts based on sea surface temperature (SST) anomalies (Figs. 1-2) and other oceanic and atmospheric indicators all point towards ENSO-neutral conditions lasting through 2019 and into 2020. On Sep 10, the Japanese Meteorological Agency (JMA) highlighted dissipating warmer-than-normal SSTs and maintained their call for a 60-percent chance of ENSO-neutral conditions to continue until winter 2019-2020. On Sep 12, the NOAA Climate Prediction Center (CPC) issued their ENSO diagnostic discussion, which focused on neutral conditions across the oceans and atmosphere. They called for a 75-percent chance of ENSO-neutral conditions persisting through fall 2019. On Sep 12, the International Research Institute (IRI) issued an ENSO Quick Look (Fig. 3), emphasizing neutral conditions in both oceanic and atmospheric ENSO indicators. Their models see ENSO-neutral as the most likely outcome, but with “slightly higher chances for El Niño than La Niña”. On Sep 17, the Australian Bureau of Meteorology maintained their ENSO Outlook at ‘inactive’ with most oceanic and atmospheric conditions in the range of neutral. The North American Multi-Model Ensemble (NMME) is within the range of ENSO-neutral and is forecast to remain neutral through 2019, with more variability and uncertainty into 2020 (Fig. 4). (Read More)

Monthly Precipitation and Temperature: August precipitation was much below average in most of Arizona, while most of New Mexico ranged from above average to much below average, and both states saw small pockets of record driest conditions (Fig. 1a). August temperatures were much above average to record warmest in Arizona and New Mexico (Fig. 1b). The daily average temperature anomalies for Aug 1 – Sep 17 highlight the fluctuations at select stations around the region (Fig. 2) (Read More).

Single weather stations are an imperfect measure of monsoon spatial variability, but they do provide an opportunity to track long term averages compared to the current year. Figure 1 compares 2019 precipitation to date with 2018 and climatology. This reveals 2019 is lagging behind average in terms of precipitation and is also a significant departure from 2018’s widespread activity that continued into September. Daily average and dewpoint temperatures, along with daily and cumulative precipitation illustrate that while increased dewpoint temperatures do not guarantee monsoon precipitation, it is rare to see monsoon precipitation in the absence of these elevated dewpoint temperatures (Fig. 2). (Read More)

Forecast Roundup: Seasonal outlooks and forecasts based on sea surface temperature (SST) anomalies (Figs. 1-2) and other oceanic and atmospheric indicators have all identified the end of this El Niño event. On Aug 6, the Australian Bureau of Meteorology maintained their ENSO Outlook at ‘inactive’, stating that “all climate models indicate the tropical Pacific is likely to remain ENSO-neutral for the rest of 2019”. On Aug 8, the NOAA Climate Prediction Center (CPC) issued their final El Niño advisory, which reflects the end of oceanic and atmospheric conditions indicative of El Niño. They called for a 50-55% chance of ENSO-neutral conditions persisting through winter 2019-2020. On Aug 8, the International Research Institute (IRI) issued an ENSO Quick Look (Fig. 3), confirming the end of El Niño as SSTs returned to normal in July. Their models see ENSO-neutral as the most likely outcome, but with “higher chances for El Niño than La Niña”. On Aug 9, the Japanese Meteorological Agency (JMA) highlighted a return to normal SSTs and other atmospheric indicators and maintained their call for a 60-percent chance of ENSO-neutral conditions to continue until winter 2019. The North American Multi-Model Ensemble (NMME) is within the range of ENSO-neutral and is forecast to remain there through 2019 and into 2020 (Fig. 4). (Read More)

Monthly Precipitation and Temperature: July precipitation was mostly below average to much below average in Arizona, while New Mexico ranged from above average to much below average (Fig. 1a). July temperatures were mostly above average to much above average in Arizona and New Mexico, with a small pocket of record warmest in southwestern New Mexico (Fig. 1b). The daily average temperature anomalies for Jul 1 – Aug 15 (Fig. 2) highlight the fluctuations at select stations around the region. (Read More)

Given the spatial variability of the monsoon, single weather stations are an imperfect measure, but they do provide an opportunity to track long term averages compared to the current year. Figure 1 compares 2019 precipitation to date with 2018 and climatology. This reveals 2019 is lagging behind average in terms of precipitation and is also a significant departure from 2018’s widespread activity by mid-August. Dewpoint temperatures and daily precipitation for the same five stations (Fig. 2) illustrate that while increased dewpoint temperatures do not guarantee monsoon precipitation, it is rare to see monsoon precipitation in the absence of these elevated dewpoint temperatures. Regional monsoon precipitation totals (Fig. 3) demonstrate variable precipitation in the Southwest, with much of the region lagging behind average accumulated precipitation through mid-July (Fig. 4). Percent of days with rain highlight areas with more regular rainfall events (Fig. 5). Mid-August is the approximate monsoon midpoint*, so there is time for below average areas to catch up, since a relatively late start does not necessarily mean decreased activity over the entire monsoon. (Read More)