Hurricane Blanca has accomplished the rare feat of reaching Category 4 status on the Saffir-Simpson scale for a second time after weakening to Category 1 level in between. Blanca continued plowing northwestward parallel to the Mexican coastline on Saturday morning after a dramatic burst of intensification overnight pushed its sustained winds to 130 mph, as of the 9:00 am MDT advisory
from the National Hurricane Center. Earlier in the week, Blanca rapidly strengthened from a tropical storm on Tuesday morning to Category 4 strength on Wednesday, then suddenly weakened
to a 110-mph storm in only 12 hours and fell to a Category 1 intensity on Friday afternoon (90 mph) before getting its second wind on Friday night. With peak winds of 140 mph on June 3, Blanca was the fourth strongest Northeast Pacific hurricane for so early in the year. Blanca’s slow forward motion enabled its rapid midweek intensification, as the hurricane parked over a hot spot of deep, warm water, but the slow pace also enabled Blanca to churn up enough cold water to help cause its rapid weakening.Figure 1.
Hurricane Blanca as seen by the MODIS instrument on Saturday afternoon, June 6, 2015. At the time, Blanca was a Category 3 storm with 120 mph winds. Image credit: NASA Worldview.Record-early tropical-storm impacts possible in Baja California
Blanca will continue to benefit from sea-surface temperatures that are more than 2°C above average along its path, with waters at the southern tip of Baja California already close to 26°C. As Blanca proceeds north of that point, its fate will be sealed by increasingly cool sea-surface temperatures. However, the storm could yet make history before running aground on the mountains of Baja California on Monday. The latest track forecast from the National Hurricane Center, issued at 9:00 am MDT Saturday
, brings Blanca onto the west coast of Baja California near Puerto San Carlos as a tropical storm. Because of its nearly parallel track to the coast, Blanca could make landfall considerably north or south of that point. Regardless, Blanca appears likely to bring tropical-storm-force winds to the southernmost part of the peninsula from late Sunday into early Monday. A hurricane watch is in effect from Cabo San Lucas to Santa Fe, with a tropical storm warning from La Paz to Santa Fe, including Cabo San Lucas. Tropical storm watches have been hoisted northward of La Paz to San Evaristo and from Santa Fe to Cabo San Lazaro.
Should Blanca deliver winds of tropical-storm strength to Baja California, it would be the earliest such occurrence since the beginning of modern tropical cyclone records for the Northeast Pacific in 1949. In fact, during that period, only two tropical cyclones have made it within 100 miles of Baja California during the first half of the year (see Figure 2 below). One of these was a tropical depression in 1993 that slid north along the eastern coast of the peninsula, dissipating just east of La Paz. The other was a hurricane that cut just south of the peninsula at minimal Category 1 strength on June 14, 1958. This year looks set to carve many more marks in the history of Northeast Pacific tropical cyclones, given the unusually warm SSTs that prevail as well as the continued strengthening of El Niño, which favors hurricane development in this basin. Figure 2.
Tropical cyclones observed between January and June since modern records began in the Northeast Pacific (1949). Image credit: NOAA Historical Hurricane Tracks
.A splash of rain at a dry time of the year for Arizona
Blanca’s remnants are expected to bring potentially heavy rain to parts of northwest Mexico early next week, with moisture and rains moving into Arizona, Utah, and neighboring states by midweek (see Figure 4 below). However, the active Northeast Pacific is already affecting rainfall over the southwestern United States. Moisture from the remnants of Hurricane Andres has combined with an unseasonably strong upper low over southern California to spark showers and thunderstorms well ahead of the usual monsoon rains of summer. Winds estimated at 60 mph struck
near Gilbert, AZ, on Thursday, and hail up to tennis ball size was reported
in Coconino County, Arizona, on Friday. Phoenix set a daily rainfall record on Friday with 0.16”
, the city’s first measurable rain on that date since records began in 1896. That leaves June 11 as the only calendar date of the year in which Phoenix has never reported measurable rain (although a trace fell on that date in 1991).LinksLive streaming camera
on the very southern tip of Baja California.Another camera is just east of this one
, on the Bay (Bahia) of San Lucas at Sunset Da Monalisa.
Jeff Masters will have an update on Blanca by Monday.
Bob HensonFigure 3.
Category 2 Hurricane Blanca (right) and the remnants of Tropical Storm Andres (left) as seen by the VIIRS instrument on the Suomi spacecraft on June 5, 2015. Image credit: NASA Worldview.Figure 4.
Predicted total precipitation from the 06Z Saturday run of the GFDL model. Areas of 4 - 8" (dark green colors) were forecast along the Baja Peninsula, over Mainland Mexico south of the Arizona border, and in Central Arizona. Image credit: NOAA/GFDL.