Thursday, September 4, 2014

Hurricane Norbert: Hurricane Warning For West Coast of Baja Peninsula; Desert Southwest Flood, Southern California High Surf Threats

September 4,2014


 
As Hurricane Norbert bears down on Baja California, a hurricane warning has been issued for the western coast of the Baja Peninsula. In addition, tropical storm watches have been extended farther north along the peninsula. Hurricane Norbert, the ninth hurricane of a busy eastern Pacific hurricane season, will eventually have some peripheral impacts in parts of the Southwest U.S.
Wind and rain is already beginning to lash the Cabo San Lucas area, at the southern tip of Baja California.
(MORE: Expert Analysis | Hurricane Central)

Baja California Threat

Hurricane Norbert is now experiencing wind shear -- different wind speeds and/or directions at different altitudes -- which is limiting its intensification. Norbert is probably near its peak intensity. After that, however, Norbert is expected to move into cooler water temperatures and more stable air, which should cause some weakening by this weekend.
Norbert's center is unlikely to make landfall, but it is expected to creep very slowly to northwest over the next couple of days, passing close enough to parts of Mexico's Baja Peninsula to produce some high surf, rip currents, gusty winds and locally heavy rain.
For this reason, a hurricane warning is in effect for the southern Baja Peninsula, though it is north of Cabo San Lucas. With that said, Cabo San Lucas is still under a tropical storm warning. Tropical storm watches were extended farther north, but still only include parts of Baja California Sur, the southern of the two Mexican states on the peninsula.
Sustained winds had reached 30 mph at Cabo San Lucas as of 7:40 p.m. MDT Thursday, along with occasional heavy rain. Tropical storm-force winds (39 mph or greater) are possible in the warning area through Friday morning. At this time, the center of Norbert is expected to make its closest pass to the Baja Peninsula overnight through Friday night.
Bands of heavy rain, local flash flooding, high surf and rip currents will also be threats in the southern half of the Baja peninsula.
Given Norbert's small hurricane-force wind field, extending out only to 35 miles as of Thursday evening, and its most likely center forecast track, hurricane-force conditions on the southern Baja peninsula appear unlikely.
Conditions should improve in Cabo San Lucas by the weekend, though some high surf, rip currents, and occasional leftover showers are possible there.

Desert Southwest Flood Threat

Norbert's moisture, in tandem with remnant moisture from ex-Tropical Storm Dolly and the residual moisture already in place will combine to enhance rainfall potential in the Desert Southwest into early next week.
(MORE: Pacific's Historical U.S. Threat)
High pressure aloft over the Southern Plains will provide the steering wheel for this deep tropical moisture intrusion.
This has the potential to evolve into a serious flash flood threat in parts of the Desert Southwest, including parts of Arizona, New Mexico, extreme West Texas, southeast California, southern Nevada and perhaps even southwest Colorado.
(FORECASTS: Phoenix | Albuquerque)
Some of this moisture may also trigger scattered thunderstorms with locally heavy rainfall in parts of the L.A. Basin and San Diego metro area early next week, though that forecast remains rather uncertain at this time.
This threat may persist from Friday through at least Monday, if not Tuesday.
(RECAPS: Mt. Baldy, CA Landslide | N. Phoenix Flood)

Southern California High Surf...Again

Like both Lowell and Marie, Norbert will generate southerly swells that will reach south-facing beaches of Southern California.
(RECAPS: Hurricane Marie's Waves | Karina, Lowell, and Marie Satellite Loop)
The graphic above from the National Weather Service in Oxnard, California, breaks down the overall high surf forecast over the next few days.
(MORE: NWS California high surf alerts)
Norbert will not be nearly as large or intense a circulation as Marie, so forecast surf heights are expected to be roughly half the peak heights seen during Marie.
However, there will still be minor coastal flooding, dangerous rip currents, sneaker waves, and large breaking waves through Monday night.
Swimmers and inexperienced surfers should stay out of the water. Rip currents claim about 100 lives each year in the U.S., on average.

MORE: Hurricanes From Space

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