The last four weeks are on track for a stronger El Nino to get into place between May and July of 2023. The CPC forecast is on track for this ENSO pattern to come to fruition in the next few months. The sea surface temperature anomalies from 2 to 29 April 2023 image indicate the neutral phase of ENSO is transitioning into a warming phase. How much? Still to be determined, but it is rapidly warming, and a likely strong El-Nino is coming in the summer to fall time. What does that mean for Arizona’s upcoming monsoon season?
The research and past climatological data especially for Tucson, Arizona means an ill-defined relationship or not a strong impact on the summertime weather. However, it has previously indicated that a later monsoon kick-off may be possible. This climatological factor weighed more heavily on the Arizona Weatherman monsoon forecast to delay the initial start of the monsoon especially in southern Arizona to the first week in July. However, after discussing the author’s monsoon forecast with Master General Meteorologist Raiden Storm there were some needed changes and tweaks to the original forecast.
According to Raiden Storm, “The monsoon will more likely kick off in late June and have fewer overall thunderstorms but have more dynamic severe weather associated with the upcoming monsoon.” We were in agreement that while there is not a strong correlation between the El Nino ENSO pattern and the Arizona monsoon, we did see the likelihood of the season being average to below average for rainfall. With fewer thunderstorms to likely occur but will be stronger and have a higher potential for severe weather this summer. So, the main takeaway was an earlier start to the season than the author initially thought by a couple of weeks.
The one wildcard for this monsoon season is still the East Pacific Ocean hurricane season. It may be more active especially from August to October due to the stronger El Nino pattern setting up. Will this cause more hurricanes? It is possible. Will the hurricanes recurve up into Arizona? Possible, but statistically not likely enough to cause a significant overall change in the rainfall amounts for Arizona. Therefore, the Arizona Weatherman is still maintaining the forecast for average to below-average rain amounts, particularly for southern Arizona.