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After making a brief landfall on the west coast of Mexico’s Baja California midday Thursday, Hurricane Kay weakened to tropical storm status. However, the large cyclone continued to bring a grab bag of unusual effects to Southern California and far northwest Mexico, including hellacious mountain winds and some welcome rainfall.

Kay made landfall as a minimal category 1 hurricane (sustained winds of 75 mph) at 5 p.m. EDT Thursday, September 9, near Bahia Asunciòn. The storm spent about three hours crossing the sparsely populated Vizcaíno Pensinula, which juts westward from the midpoint of Baja California, then continued moving north-northwest parallel to the main peninsula. Torrential rains and high winds from Kay brought widespread flooding and damage across the sparsely populated mid-peninsula area, including the city of Mulegé on the Gulf of California, where Mexican civil defense activities were based. Three deaths were reported over the weekend in the southwestern state of Guerreo, as Kay began to organize off the coast.

Nuestra #MisiónECO 👷🏽 se encuentra en Vizcaíno, #Mulegé, coordinando con @GobBCS las acciones de preparación ante el posible impacto de #Kay: 🔸Activación de #RefugiosTemporales 🔸Aviso a las comunidades sobre los efectos del #Huracán 🔸Instalación de un puesto de mando pic.twitter.com/cCYfmEUlaU

"Incontables daños, afortunadamente sólo materiales. H. Mulegé y Vizcaíno emergencia por inundaciones. Santa Rosalía fuerte corrida de arroyos y deslaves. #Kay afectando Guerrero Negro, Isla Natividad y Bahía Tortugas. " Vía: Edith Villavicencio. Alcaldesa de #Mulegé pic.twitter.com/A0qd1XCrr7

At 11 a.m. EDT Friday, Kay was centered about 165 miles south of San Diego, California, with top sustained winds down to 50 mph. With much of Kay’s circulation over land and its core moving over progressively cooler water, the storm will continue to weaken. By Saturday afternoon, Kay is predicted to be a tropical depression, moving slowly westward away from the coast.

Even so, Kay’s unusually large circulation will continue to funnel much-appreciated moisture into drought-stricken Southern California.

The easterly flow around Kay – which was notably strong a mile or so above sea level, where frictional effects were not weakening Kay as quickly — led to a bizarre type of downslope wind from San Diego to Los Angeles, where the parched, hot air one would normally get in a Santa Ana wind set-up was replaced by moist yet still-warm gusts.

The outer rainbands associated with TS #Kay have reached #SanDiego this morning in SoCal. I don't think I need to restate how unusual the situation is currently. In terms of "strange obs" the 90F reading at the San Diego airport with *light rain* at *6am* takes the cake. #CAwx pic.twitter.com/QFpFD9FG2W

The overnight low early Friday at Los Angeles International Airport was 80 degrees Fahrenheit (26.7 degrees Celsius). As noted by meteorologist Richard Berler, if this low holds till midnight, it will be the warmest daily minimum in airport history going back to 1944, beating out 78°F from Sept. 27, 1963. At San Diego International Airport, predawn temperatures near 90°F had cooled to low 80s with light rain by late morning.

At Cuyamaca Peak (elevation 6,515 feet), the second-highest point in San Diego County, a gust to 109 mph was reported at 8:27 a.m. PDT. Gusts of 50 to 100 mph may continue into Friday night across mountainous parts of Riverside and San Diego counties.

San Diego could receive 0.5” to 1” of rain through Saturday, with wind gusts as high as 40 mph on Friday afternoon and evening. Light showers may extend to Los Angeles, with up to a half inch of rain possible. Much higher rainfall totals of 1 to 3 inches or more are possible on east-facing slopes of the Laguna, Santa Rosa, and San Jacinto ranges east of the coastal cities.

Even Palm Springs could nab more than an inch of rain on Friday and Saturday—not unprecedented, but a substantial drenching for this desert city. Localized flash floods are a significant concern into the weekend, especially at higher elevations.

After days of struggling to fully organize, Hurricane Earl may fall short of its originally projected peak strength of category 4. At 11 a.m. EDT Friday, Earl remained a category 2 storm, with top sustained winds of 100 mph.

Earl was about 250 miles east-northeast of Bermuda, where the storm’s outer fringes brought showers and wind gusts to 47 mph at Castle Harbor around 4 a.m. local time Friday.

Earl’s strength has waxed and waned over the past day or so. The hurricane has a large shield of strong showers and thunderstorms (convection), with a large, distinct eye, and wind shear has been light since Thursday (less than 10 knots). Moreover, Earl is traveling over sea surface temperatures of around 28-29 degrees C (84-86 degrees Fahrenheit), unusually warm for its latitude. However, the atmosphere has not been exceptionally moist (mid-level relative humidity around 60 percent), and Earl was thwarted for days by a less-than-symmetric structure.

Of the two leading high-resolution intensity models, the HMON continues to be bullish on Earl, bringing it to near category 4 strength briefly, but HWRF does not project any major intensification. As shear will be increasing sharply by Friday night, and SSTs along Earl’s track will cool dramatically on Saturday, the HWRF forecast seems more likely. The National Hurricane Center is predicting Earl will remain a category 2 storm and will become post-tropical on Saturday as it accelerates northeast over the open Atlantic.

Swells and rip currents related to Earl will affect parts of the Atlantic coastlines of the U.S. and Canada into this weekend.

A tropical wave designated as Invest 95L, located about 1,100 miles east of the Leeward Islands on Friday morning, was headed west-northwest at 15 mph. Satellite images showed that this wave had a well-defined surface circulation, but with only a few heavy thunderstorms, and those limited to the system’s northeast side by strong wind shear of 20-30 knots. With only marginally favorable conditions for the next five days, 95L has virtually no model support for development, and the long-range predictions from the GFS and European model ensembles unanimously show the wave recurving to the north by early next week. In its 2 p.m. EDT Friday Tropical Weather Outlook, NHC gave the wave 2-day and 5-day odds of development of only 10%. The next name on the Atlantic list of storms is Fiona.

A tropical wave located a few hundred miles south of the Cabo Verde Islands off the coast of Africa is predicted to move west to west-northwest at 15-20 mph over the next five days. This wave is located along the edge of a large region of dry air, and has little model support for development. In its 8 a.m. EDT Friday Tropical Weather Outlook, NHC gave the wave 2-day and 5-day odds of development of 0% and 10%, respectively.

A tropical wave expected to emerge from the coast of Africa by Monday is predicted to move west to west-northwest at 15-20 mph over the eastern tropical Atlantic early next week. This wave also has little model support for development, and is expected to struggle with dry air, as have so many other systems this hurricane season. In its 8 a.m. EDT Friday Tropical Weather Outlook, NHC gave the wave 2-day and 5-day odds of development of 0% and 20%, respectively.

In the western Pacific, Tropical Storm Muifa developed on Wednesday, well east of the Philippines, and is a threat to develop into a major typhoon that will affect Japan’s Ryukyu Islands this weekend. At 8 a.m. EDT Thursday, the Joint Typhoon Warning Center (JTWC) pegged Muifa’s top winds at 50 mph (1-minute average), moving west at 12 mph. The Japan Meteorological Agency put Muifa’s intensity at 45 mph (10-minute average sustained winds).

Muifa had very favorable conditions for intensification on Thursday, with sea surface temperatures of 30-31 degrees Celsius (86-88°F), light wind shear of 5-10 knots, and a moist atmosphere. JTWC’s 11 a.m. EDT Thursday advisory called for rapid intensification of Muifa into a major typhoon with 115 mph winds by 0Z Saturday, peaking at 125 mph winds by Sunday. Weakening is expected on Sunday as Muifa crosses the cold water plume left behind by category 5 Super Typhoon Hinnamnor, where it will also encounter increased wind shear. Muifa is expected to turn more to the north-northwest and move through Japan’s Ryukyu Islands on Monday, and it could be a threat to China later in the week.

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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... More by Bob Henson

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... More by Jeff Masters