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Marzo 2017 Resumen de Clima Regional - CLIMAS SWCO (en Español)

Wednesday, March 22, 2017

Precipitación Y Temperatura: En febrero, Arizona experimentó precipitación media a precipitación por arriba del promedio, mientras Nuevo México experimento precipitación que osciló entre media a por arriba de la media (Fig. 1ª). Temperaturas muy por arriba del promedio se observaron en la mayor parte de la región; el este de Nuevo México experimento las temperaturas mas altas registradas (Fig. 1b).  Las primeras dos semanas de marzo fueron secos para el Suroeste, una inversión de las condiciones mojadas del inicio del invierno (Fig. 2ª). Temperaturas por arriba del promedio se observan en marzo también (Fig. 2b) y incluyen un serie de temperaturas casi record en el mediados de marzo. Para el año pluviométrico, el Suroeste ha experimentado precipitación y temperaturas por encima del promedio (Fig. 3).

La Capa de Nieve Y Suministro de Agua: Después de una serie de tormentas impresionantes en enero y febrero, la actividad de tormentas ha estrechado y las temperaturas siguen aumentando. La capa de nieve y el equivalente de nieve en agua (SWE, por sus siglas en ingles) están generalmente por arriba del promedio para la mayoría de la región Oeste Intermedia (Intermountain West, por su sigla en ingles) (Fig 4). La forma en como las temperaturas altas las dinámicas del almacenamiento de agua en el oeste (nieve contra lluvia, almacenamiento, evaporación, escapada, infiltración) todavía no se ha realizado. Las previsiones de caudal favorecen flujo por encima del promedio. Los gerentes de agua y expertos de sequía siguen observando los cambios potenciales en el tiempo del flujo por su implicaciones para el almacenamiento de agua, ecología, y sequía.

Sequía: Las tormentas este invierno (y desde el inicio del ano pluviométrico) han resultado en la diminución de la designación de condiciones de sequia en la mayor parte del Oeste.  En particular, el estado de California ha visto un retiramiento significativo de las condiciones de sequia. El sur de Arizona (llegando al sur de California) y el nordeste de Nuevo México son los bolsillos restantes que todavía llevan designaciones de sequia- designados como anormalmente secas (D0) o con condiciones de sequia moderada (D1) (Fig.5). Es importante notar que mientras eventos del corto plaza han reducido las designaciones de sequía, el Suroeste ha observado condiciones de sequía para la mayor parte de los últimos 15 año, por lo que queda ver si se mantiene este recuperación y si mejora el almacenamiento de depósitos de agua, condiciones de agricultura y pastizales, el riesgo de incendios forestales, y la sequia ecológica.

Salud Ambiental y La Seguridad: La precipitación de otoño e invierno resultó en una explosión de flores silvestres en el Suroeste, alimentada por una precipitación por encima de la media durante el otoño y el invierno, y aumentado por temperaturas por arriba del promedio recientes. Los niveles de polen también están arriba de la media, y la mayoría de las víctimas de las alergias sentirán los efectos de múltiples fuentes de polen. Algunos eventos graves de polvo ya han resultado en el cierre de carreteras interestatales, y el seguimiento de las condiciones calorosas y secas puede resultar en un aumento de polvo y partículas. El otoño y invierno lluvioso combinado con el calentamiento rápido este primavera también favorece el aumento de la producción de combustibles finos que pueden transportar fuego. Las perspectivas actuales identifican un mayor riesgo de incendio en partes de Nuevo México, pero los gerentes de incendios forestales prestarán mucha atención a las condiciones climáticas estacionales en toda la región para vigilar eventos o condiciones que amplifiquen el riesgo de incendio.

El Niño-Oscilación del Sur (ENOS): Con las condiciones de La Niña ya en el pasado, los pronósticos actuales predicen una potencial de condiciones de El Niño en 2017. La mayoría de los modelos y pronósticos favorecen las condiciones ENSO-neutral hasta por lo menos la primavera 2017 (con una mayor probabilidad de la continuación de condiciones ENSO-neutral hasta verano) aumentando las probabilidades del desarrollo de El Niño hasta otoño 2017 (para mas información, ver el Boletín de ENSO).

Pronostico de Precipitación y Temperatura: El pronostico de el 16 de Marzo de NOAA predice posibilidades iguales de precipitación por debajo, media, o por encima de la media  en abril, y mayor posibilidad de temperaturas por encima de la media en la región. Esas condiciones también se nota en el pronostico estacional de abril a junio, con una probabilidad igual de precipitación por debajo, media, o por encima de la media (Fig 6., arriba) y con una mayor probabilidad de temperaturas por arriba del promedio (Fig. 6, debajo). 

Mar 2017 SWCO - ENSO Tracker

Friday, March 17, 2017

Oceanic and atmospheric indicators of the El Niño-Southern Oscillation (ENSO) are currently neutral (Figs. 1-2), and most forecast agencies predict they will remain so through spring 2017. These agencies also forecast that El Niño conditions could return in mid-to-late 2017, but given the uncertainty of ENSO forecasts associated with the “spring predictability barrier,” we can get only a general sense now of the range of outcomes likely later this year (i.e. La Niña is basically off the table). More detailed information about the timing or intensity of a possible El Niño will start to become available in late spring or early summer.

A closer look at the forecasts and seasonal outlooks provides insight into the range of predictions for the rest of winter and the ENSO signal for the rest of 2017. On March 9, the NOAA Climate Prediction Center (CPC) observed that oceanic and atmospheric conditions were consistent with ENSO-neutral conditions. They forecast a 75-percent chance of ENSO-neutral conditions through spring 2017 (March-May 2017), and a 50- to 55-percent chance of El Niño conditions in the second half of 2017 (July-Dec). On March 10, the Japanese Meteorological Agency (JMA) identified a continuation of ENSO-neutral conditions (last month they determined that observed conditions did not meet the JMA definition for a La Niña event). They forecast a 60-percent probability of ENSO-neutral conditions lasting through summer 2017, and a 40-percent chance of El Niño conditions over summer. On March 14, the Australian Bureau of Meteorology moved their ENSO outlook to El Niño Watch, with a 50-percent chance of an El Niño event. They identified warming oceanic conditions as indicating an increased chance of El Niño conditions in 2017. On March 16, the International Research Institute for Climate and Society (IRI) and CPC forecast a 70-percent chance of El Niño by late summer (Fig. 3), but forcasters also highlighted uncertainty regarding model performance given the spring predictability barrier. The North American Multi-Model Ensemble (NMME) characterizes the current model spread and highlights the variability looking forward through the remainder of 2017. The NMME mean is forecast to remain ENSO-neutral through spring, but reaches the threshold of weak El Niño by early summer (Fig. 4).


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Mar 2017 SWCO - La Niña Recap

Friday, March 17, 2017

This event began in fall 2016, ended in early February 2017, and throughout the period oceanic and atmospheric indicators generally hovered near the boundary between weak La Niña and ENSO-neutral conditions. According to CPC criteria, this was a weak La Niña event (but just barely); other agencies use slightly different criteria (see last month's ENSO tracker for details), highlighting the difficulty in categorizing these borderline events. This weak strength also affects how precipitation and temperature patterns are interpreted. In the Southwest, a La Niña event is more likely than not to bring warmer- and drier-than-average conditions over the cool season, but a weak La Niña event might not even stand out from the normal seasonal variation of typically dry southwestern winters (Fig. 5).

So how did this La Niña event stack up compared to expectations? If last year’s El Niño was an underperformer in terms of producing above-average precipitation, then this year’s La Niña was a welcome deviation from precipitation expectations. Winter (DJF) precipitation was above average to much-above average across most of the West (Fig. 6a)—not the typical pattern associated with La Niña, but perhaps a reminder of just how “borderline” this La Niña event really was. Winter (DJF) temperatures generally matched the expected pattern of warmer than average in a La Niña year (Fig. 6b), although separating out the ENSO influence from general trends and record-warm global temperatures is difficult. The cool season (Oct-May) is not yet over, but the water year temperatures and precipitation values to date (Figs 7-8) generally mirrored the winter (DJF) pattern, save for a pocket of below-average precipitation along the Arizona borderlands region.

Looking to specific weather stations across the region, we see a similar pattern: most of the stations are recording above-average cool-season precipitation totals to date (Figs. 9a-b, 9d), aside from those in southern Arizona (Fig. 9c, 9e). Seasonal totals are not the entire story, and looking at the number of days with rain and dry spells (lower right corner of graphics) is another set of metrics that helps characterize the season. Many of the weather station plots reveal numerous lower-intensity precipitation events and a relatively greater number of days with rain, with correspondingly fewer and shorter dry spells (Figs. 9a-d) while fewer stations saw a smaller number of high-intensity events make up most of their seasonal precipitation total (Fig. 9e). Steady and soaking rains and higher-elevation snowfall are an important part of drought recovery, as more moisture is stored or banked in the system (as snowpack, soil moisture, etc.) and less is lost to runoff and evaporation.

In addition to cumulative seasonal totals and the number of days with rain over the season, precipitation must also be evaluated against the effects of elevated temperatures, which can reduce snowpack and water storage over winter and alter the timing of streamflow during spring and summer. Thus, there were concerns in the run-up to this La Niña event that its typical warmer temperatures and reduced precipitation would exacerbate existing drought conditions. Fortunately, La Niña’s drier tendencies have not come to pass, and current snowpack, streamflow forecasts, and water resource management projections are generally optimistic (Fig. 10), offering hope that this pattern will last through spring and that elevated temperatures do not substantially affect snowpack or the timing of streamflow.

 


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CLIMAS Southwest Climate Outlook - Mar 2017 Climate Summary

Thursday, March 16, 2017

Precipitation & Temperature: February precipitation totals were average to above average in Arizona and ranged from below to above average in New Mexico (Fig. 1a). February temperatures were much-above average across most of region, including record warmest temperatures in eastern New Mexico (Fig. 1b). March precipitation to date has been dry across the Southwest, reversing the wet trends of early winter (Fig. 2a). March temperatures have also been above average across the Southwest (Fig. 2b), including a run of near-record temperatures at the time of this writing. Water-year precipitation and temperature are both above average across much of the Southwest (Fig. 3).

Snowpack & Water Supply: After an impressive run of storms during January and February, activity has tapered and temperatures continue to rise. Snowpack and snow water equivalent (SWE) are both generally well-above average across much of the Intermountain West (Fig. 4). The extent to which persistent above-average temperatures affect water storage dynamics across the West (e.g., rain vs. snow, storage, evaporation, runoff, infiltration, etc.) remains to be seen, although streamflow forecasts remain optimistic for above-average flow. Water managers and drought experts are keeping a close watch on potential changes to streamflow timing given its possible implications for water storage, ecology, and drought. 

Drought: The storms this winter (and since the water year began on Oct. 1) have resulted in a significant scaling back of drought designations across most of the West. California in particular has seen marked improvement. Southern Arizona (extending into Southern California) and northeastern New Mexico have the remaining pockets of drought in the Southwest, designated as either abnormally dry (D0) or in moderate drought (D1) (Fig. 5). It is important to note that while short-term events have scaled back drought designations, the Southwest has been in drought for most of the last 15 years, so it remains to be seen if this recovery holds and brings long-term improvements to reservoir storage, agricultural and range conditions, wildfire risk, and ecological drought.

Environmental Health & Safety: Fall and winter precipitation led to an explosion of wildflowers in the Southwest, fed by above-average precipitation over much of fall and winter, and boosted by recent above-average temperatures. Pollen levels are also up, and most allergy sufferers will feel the effects from a wide range of pollen sources. A few severe dust events have already resulted in interstate closures, and if warm and dry conditions persist, this could lead to increased dust and particulate matter. The wet fall and winter combined with rapid warming this spring also favors increased production of fine fuels that can carry fire. Current outlooks identify increased fire risk for portions of New Mexico, but fire managers will pay close attention to seasonal weather conditions throughout the region to watch for events or conditions that amplify fire risk. 

El Niño Southern Oscillation: With La Niña in the rear-view mirror, forecasts are currently looking towards a possible El Niño event later in 2017. Most forecasts and models call for ENSO-neutral conditions to last through at least spring 2017 (and likely into summer) with a possible return of El Niño conditions in fall 2017 (for more details see ENSO Tracker).

Precipitation & Temperature Forecast: The March 16 NOAA Climate Prediction Center’s outlook for April calls for equal chances of above- or below-average precipitation, and increased chances of above-average temperatures across the region.  Likewise, the three-month outlook for April through June calls for equal chances of above- or below-average precipitation (Fig. 6, top) and increased chances of above-average temperatures (Fig. 6, bottom).


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