No More El Yawño
February 9, 1998
By Mark Hoover
previous
|
next
I'm sitting in front of a deck of cards, but I'm not the
dealer. I have to play what I'm dealt, and it's been a while
since I've seen a face card. Each day, I wonder if I'll be
eating dinner at home, or three time zones from here. I got
both the jokers in the deck this weekend. Our original
planned flight into the jetstream from Alaska is out, and
now the flight from Portland has been cancelled too, thanks
to the vagaries of El Niño. Researchers are scrambling
their schedules to keep up with the suddenly wild storm
season on the west coast, and redeploying their instruments
and planes on very short notice. (Very few of them seem to
notice how much this inconveniences cyber-correspondents.)
There's a lesson here. In the midlatitudes, the only
predictable aspect of an El Niño winter is that
day-to-day, it can be very unpredictable. The recent "regime
change" of the southern jetstream - its change of location -
is the main reason storms have been punishing California. In
weather systems, states can be persistent, but when they
change, they can change suddenly and dramatically.
Forecasters like to use "persistence" as a tool of
prediction. The idea is that on a gross scale, weather tends
to be the same for long periods. If there's drought today,
there'll probably be more drought tomorrow. But forecasters
drop persistence like a wormy apple when they recognize a
regime change coming on, knowing that a whole new set of
conditions is now likely to establish its own persistence.
Californians joked for two months this winter about "El
Yawño," the threat that never materialized...until last
week. The latest forecast says another bad storm will hit
Wednesday. Nobody's joking now. Suddenly and dramatically,
the jetstream has taken up its new residence, and odds are
that there are more storms in store for the west coast.
South of the equator, you can see the same thing happening
in Peru.
There may be a flip side to all this. The NORPEX researchers
are going to extend the jetstream investigations they've
been conducting, but they're going to concentrate their
resources in Hawaii. We may yet get to take that jetstream
flight, at the end of this month, after we return from the
tropics. But it won't be from Anchorage...it'll be from
Honolulu. As soon as I see the next card, I'll show it to
you. It'll either be Aloha...or ha-ha.
previous dispatch
|
next dispatch
|
table of contents