Back in March, when looking for the next great economic scapegoat, we wrote "Goodbye Polar Vortex; Hello Solar Vortex - El Nino Is Coming", because as everyone knows by now, in a centrally-planned world, in which the present always disappoints and the rigged market is driven purely by the overly optimistic future forecasts for five years in a row now (despite the rosy future never, ever materializing in the form of a better than expected present), any deviation from what is "priced to perfection" has to be promptly explained away, usually with such ridiculous gimmicks as the weather, i.e. snow in the winter, hot summers, balmy springs and so on.
Two months later, the Bank of Japan confirmed precisely what we knew would happen when it said it is set to blame El Nino for the upcoming spending collapse (which apparently has nothing to do with the utter failure of Abenomics, or the recession japan Now finds itself in following the sales tax hike earlier this year).
Idiot central-planner and economist "justifications" for always being wrong aside, the reality is that El Nino is on its way even if the slowdown in the economy will be due to every other factor except the weather (start with the Fed) which just so happens is a "recurring" event. So upcoming GDP collapse (that nobody could have foreseen earlier, nobody, certainly not the Fed) notwithstanding, here is what one should really expect as a result of the unique weather formation which whose temperature and precipitation impacts across the United States occur during the cold half of the year, from October through March.
United States El Niño Impacts
By this point, most of you have heard that it looks like El Niño is coming, and maybe you’re wondering why you should care. After all, why should it matter if the tropical Pacific Ocean becomes warmer than average? That’s thousands of miles away from the continental United States. Well, it turns out that El Niño often results in changes in the patterns of precipitation and temperature across many parts of the globe, including North America (Ropelewski and Halpert 1987, Halpert and Ropelewski 1992).
Many folks probably remember the heavy rainfall, flooding, and landslides that occurred in California in 1982/83 and again in 1997/98. As the region suffers through a devastating drought, it could be something of a relief if we knew for certain that El Niño would bring similar soaking rains. But those two events were the 2 strongest El Niños in the past 60 years, and we’ve seen many other El Niño years where California didn’t experience those types of devastating impacts. So assuming El Niño develops, what can we expect across the United States and when can we expect it?
By examining seasonal climate conditions in previous El Niño years, scientists have identified a set of typical impacts associated with the phenomenon (Figure 1). “Associated with” doesn’t mean that all of these impacts happen during every El Niño episode. However, they happen more often during El Niño than you’d expect by chance, and many of them have occurred during many El Niño events.
In general, El Niño-related temperature and precipitation impacts across the United States occur during the cold half of the year (October through March). The most reliable of these signals (the one that has been observed most frequently) is wetter-than-average conditions along the Gulf Coast from Texas to Florida during this 6-month period. This relationship has occurred during more than 80% of the El Niño events in the past 100 years.
In Southern California and U.S. Southwest, strength matters
Over California and the Southwest, the relationship between El Niño and above-average precipitation is weaker, and it depends significantly on the strength of the El Niño. The stronger the episode (i.e., the larger the sea surface temperature departures across the central equatorial Pacific are), the more reliable the signal in this region has been.
For instance, during the two strongest events in the past 60 years (1982/83 and 1997/98), much-above-median rainfall amounts fell across the entire state of California. Median or above-median precipitation was recorded over the entire state during strong episodes in both 1957/58 and 1972/73 (Figure 2). However, strong events in 1991/92 and 2009/10 only provided small surpluses in the southern part of the state, while precipitation during 1965/66 was generally average to below-average across the state.
For weak and moderate strength episodes (Figure 2), the relationship is even weaker, with approximately one-third of the events featuring above-average precipitation, one-third near-average precipitation, and one-third below-average precipitation.
Elsewhere over the United States, El Niño impacts are associated with drier conditions in the Ohio Valley, and there is a less-reliable dry signal in the Pacific Northwest and the northern Rockies. Hawaii also often experiences lower-than-average rainfall totals from the late fall through early spring period.
The climate impacts linked to El Niño help forecasters make skillful seasonal outlooks. While not guaranteed, the changes in temperature and precipitation across the United States are fairly reliable and often provide enough lead time for emergency managers, businesses, government officials, and the public to properly prepare and make smart decisions to save lives and protect livelihoods.
Weak El Niño: Episode when the peak Oceanic Niño Index (ONI) is greater than or equal to 0.5°C and less than or equal to 0.9°C.
Moderate El Niño: Episode when the peak Oceanic Niño Index (ONI) is greater than or equal to 1.0°C and less than or equal to 1.4°C.
Strong El Niño: Episode when the peak Oceanic Niño Index (ONI) is greater than or equal to 1.5°C.
Halpert, M.S. and C.F. Ropelewski, 1992: Surface Temperature Patterns Associated with the Southern Oscillation, J. Clim., 5, 577-593.
Ropelewski, C.F. and M.S. Halpert, 1987: Global and Regional Scale Precipitation Patterns Associated with the El Nino/Southern Oscillation, Mon. Wea. Rev., 115, 1606-1626