Category

After a relatively late start, La Niña has ramped up over the past 30 days in terms of observed conditions and projected intensity, with sea-surface temperatures (SSTs) demonstrating a more consistent La Niña pattern (Figs. 1-2). Current forecasts and outlooks suggest a weak-to-moderate La Niña event lasting through the winter. (read more)

Oceanic and atmospheric indicators remain within the range of neutral (Figs. 1-2). Seasonal outlooks and forecasts generally agree that ENSO-neutral conditions are the most likely outcome through winter 2017-2018. read more

Oceanic and atmospheric indicators of the El Niño-Southern Oscillation (ENSO) are still within the range of neutral (Figs. 1-2), although sea-surface temperatures more consistently hint at borderline El Niño conditions compared to atmospheric indicators. Outlooks and forecasts generally agree that ENSO-neutral conditions will persist through the summer and is the most likely scenario for the rest of 2017. A lingering possibility remains of an El Nino event developing later this fall, but forecasts since last month have shifted further from that likelihood. (read more)

The Sawmill fire (Fig. 1) started, reportedly by recreational shooting, on April 23, 2017 in a grass- and shrub-covered area of low-elevation Arizona state lands approximately 40 miles south of Tucson. The fire spread quickly due to dry and windy conditions that day: the temperature reached 98 degrees, relative humidity ranged between 4 and 18 percent, and sustained winds reached 20 mph with gusts up to 30 mph. High winds, high temperatures, and low relative humidity continued through much of the following week, driving rapid growth of the fire (Fig. 2). (read more)

Similar to last month, oceanic and atmospheric indicators of the El Niño-Southern Oscillation (ENSO) are in the range of neutral (Figs. 1-2), and these conditions are forecast to last through the spring and summer. Most forecasts and outlooks indicate that El Niño conditions could return in mid-to-late 2017, but these assessments come with the annual caveat of increased uncertainty associated with the “spring predictability barrier”, during which time the specifics regarding the possibility, timing, and intensity of an El Niño event are elusive. At any rate, the models and forecasts indicate a near-zero probability of La Niña in 2017, leaving forecasters to decide between the probability of neutral or El Niño conditions in later 2017. (read more)

The Southwest saw the first strong burst of widespread monsoon activity near the end of June.  Most of the first half of July was characterized by a distinct break in monsoon activity, as atmospheric circulation patterns and lack of available moisture limited opportunities for widespread storms to develop, especially at lower elevations.  As July progressed, there were increasingly favorable conditions for storms to develop and spread, culminating in an extended period of widespread activity during late July and early August. Tropical Storm Javier helped jumpstart activity in mid-August, just as the previously mentioned extended run was winding down, and provided a brief extension to storm activity via a surge of moisture from the Gulf of California. The remainder of the monsoon window will be a waiting game to see if favorable moisture and atmospheric circulation patterns develop, as well as the potential influence of eastern Pacific tropical storm activity that could supplement storm activity and provide additional moisture to fuel storm activity. (read more)

The southwestern monsoon officially starts June 15 and ends September 30 – the dates the National Weather Service began using in 2008 to identify the window of typical activity for the region. The historical start date of monsoon activity (increased dew point, onset of precipitation events) varies across the region and is reflected in a generally westward migration over the season (Fig. 1). The monsoon ridge also shifts throughout the season, and the location of this ridge helps determine where storms and precipitation events will occur. (read more)

El Niño Recap & La Niña Outlook

This El Niño event was one of the strongest ever recorded (Fig. 5), and if past performance was any indication of what was expected for the Southwest, the region should have seen above-average precipitation over much of the cool season (winter and spring). The Southwest generally saw lower-than-expected precipitation totals that were much closer to average, or even below average in some cases.  There are several reasons why this event did not meet expectations. (read more)

El Niño conditions continued for a 12th straight month, but we have passed the peak intensity of one of the strongest El Niño events on record. This does not mean that El Niño is over, though. Despite the recent warm and dry conditions in the Southwest, we are likely to see more weather events associated with El Niño conditions through spring 2016. (read more)

El Niño conditions continued for an 11th straight month, putting us squarely in the middle of a strong El Niño event that will be among one of the strongest events on record. Forecasts focused on the persistence of sea surface temperature (SST) anomalies (Figs. 1–2) and weakened trade winds, enhanced convective activity in the central and eastern Pacific, and El Niño-related ocean-atmosphere coupling. Models continue to forecast a strong El Niño event that will last through spring 2016, but we are starting to see signs of decline in the overall strength of the event. (read more)

The 2015 eastern Pacific tropical storm season was one of the most active seasons on record, with 18 named storms and 13 hurricanes, nine of which reached “major” hurricane status (category 3 or greater). We also saw the strongest hurricane on record, Patricia, in the eastern Pacific in late October, and the latest-forming major hurricane on record, Sandra, in late November (see NOAA’s National Hurricane Center for more details). This meets or exceeds the high end of the NOAA-Climate Prediction Center (CPC) seasonal forecast (from May 27), which predicted 15 to 22 named storms, seven to 12 hurricanes, and five to eight major hurricanes. The eastern Pacific hurricane forecast was tied to the ongoing El Niño forecast discussion, as conditions linked to El Niño (e.g., decreased wind shear in the tropical Pacific) also favored increased hurricane frequency and intensity in the Pacific region. (read more)

Originally published as part of the Nov 2015 CLIMAS Southwest Climate Outlook

El Niño conditions continued for a ninth straight month, and models continue to forecast a strong El Niño event that likely will last through spring 2016 and remain strong through the early part of the year. Forecasts focused on the persistence of sea-surface temperature (SST) anomalies (Figs.1–2) and weakened trade winds, enhanced convective activity in the central and eastern Pacific, and El Niño-related ocean-atmosphere coupling. (read more)

Image Source - Australian Bureau of Meteorology

Originally published in the Oct 2015 CLIMAS Southwest Climate Outlook

We spent the better part of 2014 (and the first part of 2015) waiting in anticipation for an El Niño event that was initially forecast to be one of the stronger events on record. By early 2015, the event in question had not yet materialized, and some questioned whether El Niño would ever arrive. Eventually it did, and has been going strong for months, with most forecasts indicating that it will remain a strong event through the winter. (read more)

Image Source - Australian Bureau of Meteorology

The monsoon started strong in late June and early July. This early start centered on Arizona, which recorded its second wettest June on record (Fig. 1a), with a return to relatively normal rainfall totals in July. New Mexico saw an increase in precipitation, recording its 10th wettest July on record (Fig. 1b). Rainfall in August and September was mostly below average, which is characteristic of the North American monsoon’s sporadic and spatially limited precipitation events. (read more)

Originally published in the August 2015 CLIMAS Southwest Climate Outlook

El Niño conditions continued for a sixth straight month and forecasts and the most recent outlooks offer a consistent cluster of forecasts calling for a clear El Niño signal similar to past strong events, lasting into early 2016. Forecasts focused on the persistence of sea-surface temperature (SST) anomalies (Figs.1–2) and on weakened trade winds, ongoing convective activity in the central and eastern Pacific, and El Niño-related ocean-atmosphere coupling. (read more)

Image Source - Australian Bureau of Meteorology

El Niño conditions continue for a fifth straight month, and at this point, forecasters are relatively bullish that we are witnessing the development of a moderate-to-strong event that could rival 1997 in absolute magnitude later this year. The most recent outlooks from various sources offer a consistent cluster of forecasts calling for a clear El Niño signal that is maintained or even strengthens well into early 2016. Forecasts focused on the persistence of sea-surface temperature (SST) anomalies (Figs.1 - 2) along with weakening trade winds, ongoing convective activity in the central and eastern Pacific, and El Niño-related ocean-atmosphere coupling. (read more)

Image Source - Australian Bureau of Meteorology

Originally Published in the June 2015 CLIMAS SW Climate Outlook (SWCO)

El Niño conditions continued for a fourth straight month with no signs of weakening or disorganizing. Forecasts focused on the persistence of sea-surface temperature (SST) anomalies (Figs.1 - 2) along with weakening trade winds, ongoing convective activity, and El Niño-related ocean-atmosphere coupling. Despite the high degree of uncertainty associated with forecasting El Niño this time of year (the so-called spring predictability barrier), the most recent outlooks from various sources offer a consistent cluster of forecasts calling for a clear El Niño signal that is maintained or even strengthening. (read more)

Image Source - Australian Bureau of Meteorology

The Colorado River Delta hadn’t seen regularly flowing water in 50 years.  But one year ago the U.S. and Mexico came together to work on a project to move water down the empty riverbed.

On March 23, 2014 these countries released more than 100,000 acre-feet of water into the delta below the Morelos Dam.  This area is along the Colorado River on the U.S.-Mexico border. 

On May 15, 2014, the river finally met the sea. (read more)

A version of this post was also published in the April 2015 Southwest Climate Outlook

Flowers are blooming and trees have sprouted green leaves, signs that spring is in full swing across the Southwest and that, despite a verdant desert, wildfire season is upon us. The outlook for this wildfire season forecasts near-average wildfire activity for much of Arizona and New Mexico.

From the very beginning, Chris Guiterman just wanted an opportunity to expand his collaboration with the Navajo Forestry Department, and to demonstrate what he could do to help them. 

Guiterman is a 2014 recipient of the Climate Assessment for the Southwest (CLIMAS) Climate & Society Graduate Fellows Program. He is currently a PhD student at the University of Arizona, School of Natural Resources and the Environment, working in the Laboratory of Tree-Ring Research.

He used the CLIMAS fellowship to jumpstart a project that he had been struggling to fund.

Tribal nations across the Southwest are increasingly at risk of climate change impacts on the landscape, and because many of these nations rely on the ecosystem services of healthy forests, the risks are intensified. 

“Tasked with managing over 5 million acres of forests and woodlands, the Navajo Forestry Department has identified the need to assess sensitivities of their forests to drought and climate change,” according to the abstract of Guiterman’s research project. Guiterman worked with the NFD foresters to address their needs by quantifying the climatic drivers of forest growth in the Chuska Mountains. (read more)

When Ling-Yee Huang received the Climate Assessment for the Southwest (CLIMAS) Climate & Society Graduate Fellowship a year ago, she proposed to create a climate science curriculum for law schools.  Little did she know, she would actually be teaching her own class on climate science curriculum for lawyers, at the James A. College of Law at The University of Arizona.

Huang is currently a M.S. student in the School of Natural Resources and the Environment (SNRE) at the University of Arizona, as well as a researcher at the Water Resources Research Center (WRRC).  Previously, she earned a J.D. from the University of Florida Levin College of Law and a bachelor’s degree in biology from Rice University.

Before coming to UA, Huang worked as a policy analyst for the Center for Progressive Reform in Washington, D.C.  She provided legal analysis regarding the Clean Water Act and restoration of the Chesapeake Bay, and she developed legal frameworks for climate change adaptation and protecting ecosystem services.

“I have always really liked the idea of combining science and decision making,” said Huang.  “I started grad school having worked in the decision and policy making field for a couple of years and in that experience I felt that there was a real lack of understanding of science.”

Huang said when she learned about the CLIMAS fellowship, she realized it captured her dual interests in both science and policy perfectly. The curriculum and her final project were ideas she had been contemplating for a long time. 

“I found it the perfect fit,” said Huang. (read more)

Originally published in the Feb 2015 CLIMAS Southwest Climate Outlook

A definitive 2014–2015 El Niño forecast remains elusive. Weak El Niño conditions have continued in 2015, but recent backsliding in SST anomalies (Fig. 1), especially in the Niño 1-2 regions (Fig. 2), along with the ongoing lack of coordination between atmospheric and oceanic conditions, give little confidence that the 2014–2015 event will be characterized as anything more than a weak El Niño. (read more)

Image Source - NOAA-National Climatic Data Center

The Climate & Society Graduate Fellows Program supports University of Arizona graduate students whose work connects climate research and decision making. Fellows receive $5,000 and guidance from members of the CLIMAS research team (Climate Assessment for the Southwest) for one year. The program’s main objective is to train a group of students to cross the traditional boundaries of academic research into use-inspired science and applied research. While CLIMAS research generally occurs in the Southwest U.S., the Fellows program allows students to work anywhere in the world. (read more)

From the Dec 18, 2014 - Southwest Climate Outlook - 

We are still waiting for a decisive signal, but conditions indicate we are near, or possibly already into, at least a weak El Niño event. (read more)

The 2014 Pacific hurricane season was the most active season on record since 1992, with 20 named storms (Fig. 1). Fourteen of those storms developed into hurricanes, including eight major hurricanes (category 3 or greater), also breaking a record held since 1992. (read more)

An El Niño Watch, issued by the NOAA Climate Prediction Center (CPC), continues for the seventh consecutive month as signs of an emerging El Niño are just on the horizon, but not quite here yet. Another slug of warm water (also known as a Kelvin wave), has been making its way across the Pacific Ocean from west to east just below the surface and is poised to emerge and help warm sea surface temperatures in the eastern Pacific over the next month or so...(read more)

This post was originally published as part of the October 2014 Southwest Climate Outlook

The song remains the same this month with El Niño not quite here yet, but probably soon. This is now the seventh consecutive month since the NOAA Climate Prediction Center issued an “El Niño Watch” last March. The signs are a bit stronger once again, but it is getting late in the game...(read more)

This post was originally published as part of the September 2014 Southwest Climate Outlook

An “El Niño Watch” continues this month as issued by the NOAA Climate Prediction Center several months ago. The watch is just that: we are waiting and watching for the development of a full-fledged El Niño event that has yet to materialize across the equatorial Pacific Ocean. Several indicators of El Nino-Southern Oscillation (ENSO) status declined, moving back towards ENSO-neutral values over the past month instead of leaning towards an El Niño event as they had been.  These shifts included slight cooling in the eastern Pacific Ocean and near-average wind patterns along the equator. But for those cheering on the development of an El Niño event, not all hope is lost (read more).

This post was originally published as part of the August 2014 Southwest Climate Outlook