Major Hurricane Sandra Begins to Weaken, Targets Northern Mexico

By Kristina Pydynowski, Senior Meteorologist

November 26,2015; 11:20PM,EST

 

 

Sandra remains on track to make landfall in northern Mexico on Saturday, but it will be much weaker than its current major hurricane status.
Sandra became the latest major hurricane on record to form in the central/eastern Pacific or Atlantic oceans Wednesday afternoon. The equivalent of hurricanes that develop west of the international date line are called typhoons or cyclones.
An unnamed hurricane from 1934 in the Atlantic previously held the record when it was a major hurricane on Nov. 23 of that year. In the eastern Pacific Basin alone, the last latest major hurricane was Kenneth from Nov. 22, 2011.
There have now been nine major hurricanes in the eastern Pacific this year, a record for the basin.

A landfall in Mexico is expected on Saturday as a storm system located over the western half of the United States pulls Sandra to the north, then northeast later this week. Sandra, however, will not be a repeat of dangerous Hurricane Patricia.
Sandra will be well past its peak intensity as it approaches Mexico. Instead, a weakening trend has begun due to strong wind shear.
Wind shear is the rapid change of direction and speed of air flow at different layers of the atmosphere. When wind shear is strong, these changes are very great and can shred apart tropical systems.
Sandra will be a tropical storm as it makes its closest approach to southern Baja California Sur Friday night before moving into mainland Mexico as a tropical depression on Saturday. Landfall is expected near Culiacan in the state of Sinaloa.
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Mexico Weather Center
Latest Statistics on Sandra
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Despite weakening, Sandra will still threaten parts of northern Mexico with flooding rainfall Friday into Saturday.
Around the point of landfall, Sinaloa faces the greatest risk of widespread flooding. The heaviest rain is expected on Saturday with the highest rain totals set to be recorded in the mountains.
"Rainfall amounts of 75-150 mm (3-6 inches) are possible in these areas with local amounts up to 200 mm (8 inches)," stated AccuWeather Meteorologist Eric Leister. "The biggest concern will be heavy rainfall that can cause flash flooding and mudslides."
Bands of heavy rain will also spread across the southern Baja California Sur, including Cabo San Lucas, Friday into early Saturday. The potential exists for rainfall amounts in upwards of around 75 mm (3 inches), which threatens to cause flash flooding. Winds will occasionally gust to 65-95 km/h (40-60 mph) as Sandra makes its closest approach Friday night.

The threat for flooding will not be confined to places near Sandra's path. The storm pulling Sandra to the north will also draw its moisture and downpours much farther to the north across more of southern Baja California Sur and into Chihuahua later Thursday into Saturday.
"[In these areas,] there will be pockets of 25-50 mm (1-2 inches) with locally 100 mm (4 inches)," continued Leister. "The moisture is getting strung out, so that limits the torrential rain. Instead, there will be a 24-hour period of soaking rain with localized areas getting downpours that result in flooding."
Sandra's moisture will stream far enough to the north in the United States to contribute to an extensive period of ice in the southern High Plains and the risk for flooding elsewhere in the South Central states.
After reaching the Mexico coastline, the weakening tropical cyclone will dissipate over the higher terrain of northern Mexico later in the weekend.