Forecast - October | November | December

Temperature

The three-month NOAA temperature outlook (October-December; Figure 5) favors chances of above-average temperatures for all of New Mexico and Texas, through December. The one-month outlook favors chances for above-average temperatures in the western half of New Mexico, and equal chances for below-average, average, or above-average temperatures for all of Texas and eastern New Mexico for October (figure not shown).

Figure 5 (right): NOAA three-month temperature outlook (October-December). Forecast made on September 20, 2018 by CPC.

The SMN outlook for October predicts above-average maximum temperatures in the center of Baja California, Northeast Chihuahua, Northwest and Central Coahuila, and northern Nuevo León and Tamaulipas (Figure 6). Alternatively, below-average maximum temperatures are expected in northern Baja California, a large part of Sonora, and Northwest and southern Chihuahua. For November, above-average maximum temperatures are expected in the central and southern regions of Chihuahua, central and eastern Durango, and northern Zacatecas, while below-average conditions are expected in the Peninsula of Baja California, Sonora, Sinaloa, Coahuila, Nuevo León and Tamaulipas.

Figure 6 (above): Predicted maximum temperature anomalies for northern Mexico in (°C), October (left) and November (right). Forecast made on September 1, 2018 by SMN.

The North American Multi-Model Ensemble (NMME) is an experimental seasonal forecasting system that incorporates forecasts from several different runs of individual models, to create a multi-model ensemble of predictions. This method has been shown to produce better prediction quality, on average, than the ensemble of runs from any single model (CPC). The temperature forecast for October-December favors chances for above-average temperatures for almost all of the Rio Grande-Bravo region (Figure 7).

Figure 7 (above): NMME temperature forecast for October-December. Forecast made by CPC.

Precipitation

The NOAA three-month precipitation outlook (October-December; Figure 8) shows increased chances of above-average precipitation for most of New Mexico and westernmost Texas through December, due to the predicted transition to El Niño during the fall. The forecast calls for equal chances for below-average, average, or above-average precipitation for eastern New Mexico and almost all of Texas through December. The one-month outlook (October; figure not shown) favors chances for above-average precipitation for all of New Mexico and Texas for October.

Figure 8 (right): NOAA three-month precipitation outlook (October-December). Forecast made on September 20, 2018 by CPC.

For October, the SMN precipitation forecast predicts above-average precipitation for the Peninsula of Baja California, Sonora, Southwest Chihuahua, central and western Durango, Central and Northeast Coahuila, much of Nuevo León, and southern Tamaulipas (Figure 9). Below-average conditions are expected for Northwest Baja California, Central Sonora and northern Tamaulipas. For November, above-average conditions are expected in regions of Baja California Sur, central and southern Sonora, Sinaloa, Durango, southern and eastern Chihuahua, Coahuila, Nuevo León, Zacatecas, San Luis Potosí and northern Tamaulipas. Below-average conditions are expected in Baja California, northern Sonora, Northwest Chihuahua, and southern Tamaulipas; the rest of the region is expected to experience precipitation similar to average.

Figure 9 (above): Predicted precipitation anomalies for northern Mexico (in %), October (left) and November (right). Forecast made on September 1, 2018 by SMN.

NMME forecasts increased chances of above-average precipitation for Central and South New Mexico, western and southern Texas, and most of the northern Mexican states, except for southern Tamaulipas, for October-December (Figure 10). The forecast likely reflects the predicted transition to El Niño in the fall.

Figure 10 (above): NMME precipitation forecast for October-December. Forecast made by CPC.

Fire

Monsoon precipitation in the Southwest U.S. and northern Mexico this summer has eliminated prospects for above-average fire potential across the region, according to the U.S. National Significant Wildland Fire Potential Outlook and SMN. Forecasts for October and November indicate average fire potential for all of New Mexico, West Texas, and Mexico, except for the Baja California peninsula where conditions favor increased fire potential (Figure 11). Conditions in the eastern half of Texas favor decreased fire potential.

Figure 11 (above): Fire outlook for October (left) and November (right). Red shading indicates conditions that favor increased fire potential. Green shading indicates conditions that favor decreased fire potential. Forecast from NIFC and SMN.

El Niño-Southern Oscillation (ENSO)

As of mid-September, sea-surface temperatures and atmospheric conditions in the tropical Pacific Ocean continued to indicate ENSO-neutral conditions. Weak El Niño conditions are forecasted to develop by the fall (IRI; NOAA). An El Niño watch is officially in effect. The latest forecasts suggest weak El Niño development by fall (an about 50-55% chance), growing to an ~65-70% chance by winter (Figure 12). If forecasts are correct, chances of a wet winter in the Southwest U.S. and northern Mexico are likely to increase.

Figure12 (above): Probabilistic ENSO Forecast from IRI.

For more ENSO information:
English: http://iri.columbia.edu/our-expertise/climate/enso/enso-essentials/ y http://www.ncdc.noaa.gov/teleconnections/enso/.
Spanish: http://smn.cna.gob.mx/es/climatologia/diagnostico-climatico/enos y http://www.smn.gov.ar/?mod=biblioteca&id=68