Eastern Pacific Surprising Forecasters
Blistering tropical activity so far already surpassing half that of a typical hurricane season
If on August 1st we begin our tropical update in the eastern Pacific, either the Atlantic is in a lull, or the Pacific is unusually interesting. Today it’s a little of both.
As we discussed in yesterday’s newsletter, the Atlantic hasn’t observed a named storms since Tropical Storm Colin weakened over North Carolina on July 3rd, and the gap in storm formation is expected to last through at least this week. The break feels long, but historically it’s not unusual for the Atlantic. Even for the first week of August, we typically only see storm formations on average once every other year in the Atlantic. Some very active years in the Atlantic like 1999 – the 15th most active on record going back 171 years – saw both a big gap in storms early in the season (47 days between Tropical Depression Two on July 3rd and the Depression that became Category 4 Hurricane Bret) and no storm formations for the first half of August. 1999, like 2022, was a La Niña year. The lesson for now is not to read much into the sleepy Atlantic.
On the other hand, the caravan of storms in the eastern Pacific thus far has been a surprise to forecasters. During La Niña years like 2022, waters in the eastern Pacific around the equator are much cooler than average. This – combined with a warm, horseshoe-shaped pattern of waters extending from the northern Pacific into the western and through the southern Pacific – would suggest conditions unfavorable for eastern Pacific tropical activity. These typically reliable predictors led the National Oceanic and Atmospheric Administration (NOAA) – the parent agency of the National Weather Service – to forecast a high chance of a below normal hurricane season across the eastern Pacific in 2022. So far the basin hasn’t received the message.
The eastern Pacific has recorded nearly double the activity it typically observes through July. Six hurricanes and three Category 3 or stronger hurricanes have formed, which doesn’t typically happen until mid-September. While the eastern Pacific is more active sooner than the Atlantic, it usually sees about 30 percent of its total activity through July (for comparison the Atlantic only sees about 8 percent of its total activity through July). So far, the eastern Pacific has observed over half the total activity is averages in an entire year. That’s a truly remarkable start for what’s forecast to be a slow season.
There’s nothing to say the eastern Pacific won’t throttle down later in August, but for at least the next few weeks the parade of storms looks to continue. As for the hurricane season outlooks, NOAA will issue its final update to the 2022 Atlantic hurricane season forecast this Thursday, August 4th. I’ll have more on this later in the week.
If the waters are so cool, why do these Pacific storms keep happening in the COOL regions of La Nina?