Published: June 7,2015
Highlights
- Blanca continues to weaken. As of the 11 p.m. EDT advisory on Sunday, Blanca is a tropical storm packing 65 mph winds
- A Tropical Storm Warning is in effect for Loreto to Punta Abreojos, including Cabo San Lucas. A Tropical Storm Watch is in effect for North of Loreto to Mulege.
- Blanca will continue to track toward Mexico's Baja California peninsula Sunday evening into early Monday.
- The center of circulation will track well west of Los Cabos, however gusty winds to tropical-storm force (39-73 mph) and heavy rainfall are still expected there.
- Moisture from Blanca may push into parts of the U.S. Desert Southwest early this week.
Blanca rapidly morphed into a major hurricane off the Mexican Pacific Coast, reaching Category 4 status on June 3. This made Blanca the earliest-in-season second major hurricane – Category 3 or stronger – of record in the eastern Pacific basin dating to 1971.
(MORE: Hurricane Season Outlook | Hurricane Central | Tropical Update)
Latest Status
Projected Path
Current Tropical Storm Watches and Warnings
Satellite and Current Winds
Blanca then weakened to a Category 1 hurricane late in the week due to the storm's ingesting of dry air to its north, as well as replacing its eyewall - known as an eyewall replacement cycle, which all intense tropical cyclones do - and churning up slightly cooler water while essentially standing still for 3 days.
(INTERACTIVE: Latest Satellite Loop)
Blanca was then able to take advantage of an environment that featured low wind shear and deep, warm waters which fueled the system again on Saturday as it moved to the northwest. As a result, Blanca strengthened to Category 4 status once again.
Late Saturday into early Sunday, Blanca began its final weakening phase as it encountered cooler water temperatures and unfavorable winds aloft along its path, and the cyclone eventually weakened into a Category 1 hurricane Sunday morning before diminishing to a tropical storm Sunday afternoon. More weakening is expected as the system approaches Mexico's Baja California peninsula Monday.
Strange Early Baja Threat
Less than nine months ago, Category 3 Hurricane Odile plowed into Mexico's southern Baja peninsula, including popular tourist destinations in Los Cabos.Odile was the strongest hurricane strike the region had taken since 1989 and tied the strongest landfall of record, there. Over $1 billion (12 billion pesos) in insured losses was attributed to Odile.
Now, the southern Baja peninsula lies in the forecast path for Blanca, and the storm is forecast to bring rain and wind impacts there Sunday into Monday.
That may sound ominous, however Blanca is forecast to weaken before approaching Baja California because of increasing wind shear, drier, more stable air and a track over cooler ocean water. This weakening may occur quickly.
That said, residents and tourists in the southern Baja peninsula, including Los Cabos, should have finalized preparations for the potential of tropical storm conditions.
Regardless of Blanca's exact path, high surf and swells generated from Blanca – and leftovers from Andres – will affect the Mexican Riviera and west coast of the Baja peninsula. Dangerous rip currents are likely. These swells will likley also reach the beaches of Southern California, as well, this weekend.
Heavy rainfall is also likely with 6 to 10 inches expected over much of Baja California Sur and the southern portion of Baja California, with isolated totals up to 15 inches. The heavy rain may produce life-threatening flash floods and mudslides.
According to NOAA's database, only one other pre-July 1 tropical cyclone tracked within 65 nautical miles of Cabo San Lucas, Mexico, a Jun. 14, 1958 Category 1 hurricane whose center passed just south of Los Cabos.
A Desert Southwest Moisture Surge?
The story does not end in Baja California.A somewhat strange early June pattern may deliver some early-season leftover moisture to parts of the Desert Southwest.
Rainfall Forecast
A closed area of low pressure aloft over Southern California is weakening, but building southwestward.
Together with a dome of high pressure aloft over the Rio Grande Valley of Texas, a pipeline of moisture will be pulled north from the Gulf of California, Baja, and eastern Pacific into parts of the Desert Southwest and Rockies early this week.
Interestingly, before that happens, that California low has also pulled some upper-level moisture from former Andres into the Desert Southwest.
The upshot of all this is an increasing threat of rain and thunderstorms in the Desert Southwest and southern Rockies – parts of California, Nevada, Arizona, New Mexico, Colorado, Utah – along with a more humid air mass than one would normally expect in early June.
(MORE: How Eastern Pacific Hurricanes Can Impact the U.S.)
Given the potential tropical moisture feed, locally heavy rain and flooding of normally dry washes and arroyos are possible.
Where thunderstorms will be most numerous and areas with the highest chance of flash flooding remains uncertain.
(FORECASTS: Phoenix | Tucson | Grand Canyon | Albuquerque)
In most years, the wet phase of the North American monsoon, a much weaker version of the more famous Indian/Asian monsoon, imports increasing moisture into the Desert Southwest and northwest Mexico by mid-July.
As a result, thunderstorms fire up most afternoons and evenings, particularly over the higher terrain of the Desert Southwest.
Prior to that, it is typically extremely hot and dry in June.
June is the driest month, on average, in Phoenix, where a paltry 0.02 inches is typically measured at Sky Harbor Airport. The record daily rainfall during the first 11 days of June is only 0.41 inches, recorded 100 years ago on June 3, 1915.
But thanks to that moisture plume from former Hurricane Andres, Phoenix recorded 0.16 inch of rain Friday – the first time Arizona's capital has ever recorded measurable precipitation on June 5 since records began in 1895.
Average rainfall increases by a factor of 52 in July, their average wettest month (1.05 inches).
No comments:
Post a Comment