Yet for at least part of Thanksgiving weekend, you may see both on our weather map.
An Ice Event and a Tropical Cyclone
However, you may wonder how these two disparate meteorological phenomena can at least exist at the same time in somewhat close proximity.
The Latest on Sandra
Sandra: Very Late
There have been only three other eastern Pacific storms of record dating to 1949 that formed later in the season than Sandra did on November 24. Sandra is the latest storm in the eastern Pacific since Hurricane Winnie was a December oddball in 1983.El Niño seasons such as the one we're currently in typically feature lower wind shear over the eastern Pacific basin, which otherwise rips developing or active tropical cyclones apart.
Sandra formed in a relatively small window of lower wind shear, and also capitalized on water temperatures from 1 to 1.5 degrees Celsius above average to fuel its convection.
(MORE: Strong El Niño to Peak in Winter | 2015 Likely Globe's Hottest Year on Record)
If you booked a Thanksgiving getaway to Los Cabos or Mazatlan, I bet you didn't consider a tropical storm, as few would in late November.
Sandra will be steered to the north, then northeast toward Mexico, at least brushing Los Cabos, before moving into mainland Mexico this weekend.
(FORECAST: Latest on Sandra)
If it does remain intact as at least a tropical depression at landfall, it would be the latest landfalling eastern Pacific tropical cyclone in Mexico in the six-plus-decade database.
Sandra will become "sheared out" by the jet stream, thankfully, upon its approach to the Baja, so it should be weakening rapidly. However, a decent soaking rain is possible in the southern Baja peninsula and parts of mainland Mexico to the east with Sandra.
Percentage
of observations by month due to freezing rain (black bars), sleet
(hatched bars) and freezing drizzle (bars with horizontal tick marks)
from 1976-1990 in U.S. and Canada. Ice Event a Little Early
Winter Storm Cara, together with a potent plunge of Arctic air, will set the stage for sleet and freezing rain in the Plains, possibly as far south as parts of West Texas and eastern New Mexico.(FORECAST: Winter Storm Cara Snow/Ice)
A 2003 study by Stanley Changnon and Thomas Karl of freezing rain in the Lower 48 States from 1948-2000 found December or January to be the peak months for ice events in the Plains region targeted by Winter Storm Cara.
One year later, a second study lead by John Cortinas of the University of Oklahoma examining the U.S. and Canada together over a 15-year period from 1976-1990 found November only was fifth behind January, December, February and March in the distribution of all observations with freezing rain.
Of course we're less than a week away from December, but this ice event does skew early, climatologically speaking.
Again, it doesn't appear much, if any, of Sandra's remnant moisture will ever make it up to "seed" the ice event, as it were. Most of that moisture gets wrung out over Mexico or gets drawn well to the east-northeast perhaps contributing to heavy rainfall in parts of the southern Plains and Lower Mississippi Valley.
So, a very late tropical cyclone plus an early ice event is leading to this potentially bizarre holiday weekend weather potpourri.
Seeing the potential for Sandra to still be a tropical depression early Saturday as little as 500 miles away from an area of freezing rain is a cool, weather geeky factoid you can share either while trying to keep your relatives awake after Thanksgiving dinner or while standing in a long line on Black Friday.
And, by the way, if you think hurricanes can't feed into winter storms, remember Superstorm Sandy's wintry side just over three years ago?
Jonathan Erdman is a meteorologist at weather.com and has been an incurable weather geek since a tornado narrowly missed his childhood home in Wisconsin at age 7. Follow him on Twitter and Google Plus.
No comments:
Post a Comment