Only a few Northeast Pacific hurricanes hold together as tropical cyclones while moving northward along or near the Mexican peninsula of Baja California. Hurricane Kay is on track to enter that select league. The result could be a rare constellation of hurricane-related effects – including rains both helpful and harmful – from far western Mexico all the way into parts of drought-plagued southern California.

A massive slug of moisture aiming inland

As of 2 p.m. EDT Wednesday, Kay was 210 miles southwest of the southern tip of Baja California with top sustained winds of 105 mph, making it a category 2 storm. Kay could intensify a bit more on Wednesday, perhaps even reaching category 3 strength. From Thursday onward, Kay will be moving over cooler waters and interacting with land, so a gradual weakening of the top winds is expected, but Kay will remain a sprawling storm capable of widespread impacts.

Kay’s north-northwest motion is roughly parallel to the peninsula. On this track, Kay is predicted to move over or near the sharp westward jut of mid-Baja on Thursday evening, most likely while still at category 1 strength. This sparsely populated area is home to Mexico’s largest wildlife refuge, the El Vizcaíno Biosphere Reserve. The largest town is Bahía Tortugas (pop. 2,300), which sits on a natural south-facing harbor. Given Kay’s angle of approach and its unusually large wind field, there could be significant storm surge along the coast near and east of Kay’s track. Few hurricanes are known to have struck near Bahía Tortugas; the most recent is Nora (1997).

Kay’s most distinctive feature is its expansive plume of moisture. The hurricane is embedded in an exceptionally moist air mass, with mid-level relative humidity around 80 percent. This moisture will be funneled up the Gulf of California as Kay continues moving north-northwest. Precipitable water values (the amount of water vapor in a vertical column above a given point) are in the 2-to-2.5-inch range over a large area surrounding Kay. Rainfall amounts of 6 to 10 inches are possible throughout Baja California, with localized totals of 15 inches on the peninsula and up to 6 inches on the far west Mexico mainland, bringing the risk of flash floods and mudslides in mountainous areas.

Heavy desert rainfall expected as Kay moves unusually close to SoCal

There’s both high confidence that Kay’s large circulation will move close enough to Southern California for a variety of impacts, and high uncertainty in exactly how things will play out.

The record-smashing heat wave that’s led to unprecedented September heat across the western U.S. – including a number of all-time highs for any month – is one factor in the mix. The heat has been stoked by a record-strong upper-level high across the western U.S., and that high will also help block Kay from moving directly into the southwestern states, a more typical track for recurving Northeast Pacific hurricanes.

Instead, Kay will be forced into a slow leftward bend, arcing away from the coast rather than moving fully inland. This turn is expected to occur on Friday and Saturday somewhere near the northern end of Baja California, perhaps not far from Tijuana and San Diego.  

Figure 1. NHC forecast for Hurricane Kay as of 11 a.m. EDT Wednesday, September 7, 2022. (Image credit: NOAA/NWS/NHC)

There’s no precedent in the satellite era for this specific track, especially for a hurricane as strong and large as Kay, so history is limited as a guide. What we do know is that Kay’s top winds will weaken as it traverses the relatively cool waters just off the coast of northern Baja (SSTs around 23 degrees Celsius or 73 degrees Fahrenheit) while much of the circulation sits over the peninsula. These waters are about 1-2 degrees Celsius (1.8-3.6°F) above average, which will allow Kay to penetrate unusually far north, but Kay will still be a weakening tropical storm as it reaches the northernmost point in its multi-day loop. That point is expected to stay south of San Diego, but it could be close enough to produce gusty offshore winds and exceptionally warm temperatures (especially at night) near the coast. In its 11 a.m. EDT Wednesday wind probability forecast, the National Hurricane Center gave San Diego a 9% chance of experiencing tropical storm-force winds.

Members of the GFS and European model ensembles bring Kay’s center to between 100 and 300 miles from San Diego; the 12Z Wednesday run of the GFS suggests an approach within 100 miles.

The higher-confidence part of the Kay forecast is an infusion of rich moisture into much of California, as moist southerly and southeasterly flow wraps around the northeast side of Kay’s broad circulation. By the weekend, precipitable water values could be at near-record levels for September across much of California east and south of Los Angeles. Clouds and rains will provide welcome relief from recent torrid temperatures, but the downpours could be heavy enough to produce flash flooding, especially along east-facing slopes of coastal mountains from L.A. To San Diego. Some rains may work their way as far north as central California, although the moisture may also enhance the risk of lightning and wildfire starts.

The NWS Weather Prediction Center took the unusual step of issuing a “moderate” risk outlook for excessive rains leading to flash flooding on Friday over parts of the far Southern California desert. The risk could be upgraded to “high,” the center noted, and the flood threat could extend to Los Angeles and parts of the Central Valley by Saturday.

Figure 2. The excessive rainfall outlook issued early Wednesday, September 7, 2022, valid from 8 a.m. EDT Friday to 8 a.m. Saturday. (Image credit: NOAA/NWS/WPC)

“It’s never a good thing to get too much rain all at once, a trait all too common among slow-moving tropical storms,” WPC warned. “Thus, the flash flood potential is summarily also rapidly increasing … This is an area of the world not used to getting widespread multiple inches of rain all in one shot, so despite the ongoing drought, the dry soils can be quite hydrophobic [water-repellent rather than absorbent].”

Figure 3. Infrared satellite image of Hurricane Earl at 1710Z (1:10 p.m. EDT) Wednesday, September 7, 2022. (Image credit: RAMMB/CIRA/CSU)

Earl on course to brush Bermuda; tropical storm warnings in effect         

At 11 a.m. EDT Wednesday, Hurricane Earl was spinning through the Northwest Atlantic about 460 miles south of Bermuda, heading north at 5 mph. Earl’s top sustained winds increased to 85 mph on Wednesday morning, a harbinger of more sustained strengthening just around the corner.

Earl’s gradually recurving path toward the north-northeast will take it just southeast of Bermuda, close enough for a 60% to 80% chance of tropical-storm-force winds and prompting a tropical storm warning for the island. Swells from Earl may extend all the way to parts of the U.S. East Coast, where rip currents will be a hazard into the upcoming weekend.

Satellite imagery on Wednesday showed Earl still fighting the effects of persistent, strong westerly wind shear of 25-30 knots. However, Earl’s shield of showers and thunderstorms (convection) was intensifying on the upshear (west) side on Wednesday, a sign that Earl was organized enough to fend off the shear. Earl’s misaligned upper and lower components have now come more into sync, and the persistent wind shear along Earl’s track is expected to drop to around 10 knots on Thursday.

As Earl travels across unusually warm waters for the Atlantic subtropics, with sea surface temperatures around 29 degrees Celsius (84 degrees Fahrenheit), the relaxing wind shear will provide Earl with a window of opportunity to strengthen noticeably. The DTOPS rapid intensification guidance on Wednesday morning gave Earl a 45% chance of adding at least 25 knots (27.5 mph) to its top sustained wind by Thursday morning.

The NHC forecast at 11 a.m. EDT Wednesday brings Earl up to the threshold of category 4 strength (130 mph sustained winds) by Friday night at the remarkably high latitude of 36.4 degrees north. The only analog for a category 4 storm within 200 miles of Earl’s predicted location on Friday night is Hurricane Sam (2021) – but Sam had reached cat 4 strength well before reaching such a high latitude.

As Earl continues northeast over the weekend, it will interact with a strong midlatitude storm system that should hasten Earl’s transition to post-tropical status in the open Atlantic.

Danielle’s remnants may reach Europe by Monday

The record-warm waters of the mid-latitude North Atlantic that will give Earl a boost have also nurtured Hurricane Danielle, which has maintained hurricane strength at latitudes above 38 degrees for most of the last five days.

Danielle’s days as a hurricane are numbered. Though it remained well organized on Wednesday, with a large, distinct eye, Danielle is now moving over much cooler waters (only about 24 degrees Celsius or 75 degrees Fahrenheit), and the low to moderate wind shear of recent days (around 10 knots on Wednesday) is predicted to increase to around 20 knots by Thursday.

By Friday, Danielle is predicted to become a post-tropical cyclone as it gets swept up within a mid-latitude storm system approaching from the northwest. Danielle is predicted to rotate around the midlatitude low, then move east-southeast with it toward the Iberian peninsula, perhaps bringing squalls and gale-force winds to Spain or Portugal on Monday.

Two more tropical waves to watch

A tropical wave located a few hundred miles west of the Cabo Verde Islands on Wednesday afternoon was headed west to west-northwest at 15-20 mph. This wave, which NHC Wednesday morning designated as Invest 95L, has generally favorable conditions for development through Friday, and is likely to become a tropical depression by then. Satellite images on Wednesday afternoon showed that 95L had a large surface circulation, with a modest number of heavy thunderstorms becoming more organized.

By Saturday, 95L will move into a region with drier air and high wind shear, which should limit further development. Fortunately, the wave is predicted to move into a region of the central Atlantic from which few tropical cyclones ever end up making it to North America. The long-range predictions from the GFS and European model ensembles unanimously show that this wave will recurve to the north by early next week. In its 2 p.m. EDT Wednesday Tropical Weather Outlook, NHC gave the wave 2-day and 5-day odds of development of 70%. The next name on the Atlantic list of storms is Fiona.

A new tropical wave emerging from the coast on Wednesday afternoon is predicted to move west-northwestward on a path similar to that of 95L. While the wave has generally favorable conditions for development, it is too soon to determine if it will end up being a concern for any land areas. In its 2 p.m. EDT Wednesday Tropical Weather Outlook, NHC gave the wave 2-day and 5-day odds of development of 0% and 30%, respectively.

Figure 4. Forecast for Tropical Storm 14W from the 11 a.m. EDT Wednesday, September 7, advisory from the Joint Typhoon Warning Center.

A new typhoon brewing in the western Pacific

A new threat emerged on Wednesday in the western Pacific: Tropical Storm 14W, which threatens to intensify into a typhoon by Thursday as it steams northwestward toward Japan’s Ryukyu Islands. 14W had very favorable conditions for intensification on Wednesday, with sea surface temperatures of 30-31 degrees Celsius (86-88°F), light wind shear of 5-10 knots, and a moist atmosphere. The Joint Typhoon Warning Center (JTWC) 11 a.m. EDT Wednesday advisory called for rapid intensification of 14W into a major typhoon with 140 mph winds by Saturday, followed by slow weakening because of increased wind shear. On Sunday, 14W is expected to turn more to the north-northwest and move through Japan’s Ryukyu Islands, and it could be a threat to China later in the week. The next name on the western Pacific list of storms is Muifa.

Typhoon Hinnamnor blamed for 11 deaths in South Korea

Typhoon Hinnamnor powered ashore on South Korea’s southeastern coast, near Busan (population 3.4 million) at 6 a.m. local time) as a category 2 storm with 105 mph winds. According to JTWC, this was the fourth-strongest landfalling typhoon in the nation. Hinnamnor is being blamed for 11 deaths in South Korea. Seven of the deaths occurred in a flooded underground parking lot at an apartment complex in Pohang as people tried to move their cars while the space was inundated. Damage to South Korea nonetheless appeared to be relatively modest for a typhoon so strong.

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Bob Henson

Bob Henson is a meteorologist and journalist based in Boulder, Colorado. He has written on weather and climate for the National Center for Atmospheric Research, Weather Underground, and many freelance...

Jeff Masters

Jeff Masters, Ph.D., worked as a hurricane scientist with the NOAA Hurricane Hunters from 1986-1990. After a near-fatal flight into category 5 Hurricane Hugo, he left the Hurricane Hunters to pursue a...