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Knocked off our Airborne Feet
A Guest Dispatch: February 21, 1998
By NOAA research meteorologist Bradley Smull
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As a kid growing up on the High Plains of western Kansas, a
region once traversed by huge herds of Bison but now visited
principally by armadas of wheat-harvesting machines, I gained
a deep appreciation for the importance of weather early on.
The most carefully tended crop could be laid to waste in just
a matter of minutes by wind-driven hail produced by towering
thunderclouds each spring and summer. Upon visiting that
starkly beautiful part of the world, a friend of mine
remarked, "It's a place where the sky and everything in it are
so large that they virtually envelop you." In fact, I can
think of few better words than "enveloped" to describe the
sense of being aboard a research aircraft as it is thrashed
about the cavernous sky by buoyant updrafts and frontal wind
shears that are at the very heart of a cyclone's power. It is
at once a seductively exciting, yet tremendously humbling
experience.
What drives my work as a research professor and scientist with
NOAA's National Severe Storms Laboratory is a desire to
understand weather in a tangible way—in the same way
that it impacts people worldwide on a daily basis—and
ultimately to reduce its toll on society. One can hardly
imagine a more tangible way to study a storm than to fly into
it, and we have had ample opportunity to do so during the
CALJET project (described in earlier dispatches posted by Mark
Hoover). We expected to have many opportunities thanks partly
to the active storm track carrying a bevy of exceedingly wet,
windy storms that typically intercept the West Coast of North
America at this time of year. But the frequency and intensity
of storms have probably also been aided and abetted by subtle
yet significant changes in the global atmospheric circulation
occurring during this record-setting El Niño winter.
Anyone who has even briefly considered the emotional and
financial upheaval of having one's home besieged by a muddy
debris flow, or tossed into the ocean by the unanticipated
rapid advance of eroding coastal cliffs, can certainly
appreciate the motivation behind our work in CALJET. Less
apparent but equally important are the huge "hidden" costs. A
storm that dumps eight inches of rain on the freeways of the
San Francisco Bay Area during morning rush hour—as
opposed to a few hundred miles north on the mist-shrouded
redwood forests of northern California—creates
unanticipated transportation delays, power outages and ensuing
business/government closings. These are the sorts of common
weather forecast errors that CALJET is aimed at reducing.
The featured
Storm Flight found
elsewhere on this Web site does a fine job of describing the
objectives and chronology of one of our very successful CALJET
missions on February 2. This flight, in which the P-3 carried
us hundreds of miles offshore from central California (where
the storm would ultimately strike), was designed in part as a
"proof of concept" test to evaluate the potential value of
revolutionary new offshore observing systems to guard our
vulnerable West Coast. Possible future observing systems
include offshore moorings to house radars capable of detecting
approaching jet streams and frontal circulations, and perhaps
even un-piloted "drone" aircraft that could stay aloft for
days at a time. The aircraft would drop sondes - miniature
weather stations equipped with radio telemetry—that
would collect special wind, temperature and humidity
observations "targeted" to those regions of approaching storms
thought to be most critical to how the storm will actually
develop.
Just one day after the mission highlighted in
Storm Flight on
February 3, we executed a complementary CALJET flight strategy
focusing on the interaction between yet another storm front
with the coastal terrain near Los Angeles. Not only do we use
the P-3 aircraft to collect information in severe weather
environments over remote regions not routinely sampled by any
observing network, but by experiencing (or should I say
enduring!) certain nuances of the atmosphere's and ultimately
the aircraft's behavior, we are sometimes led toward important
discoveries.
For example, on the morning of February 3 we were tracking
east at an altitude of only 1,500 feet through the Santa
Barbara channel (bounded on the north by the coastline with
its steeply rising Santa Ynez Mountains and to the south by
the Channel Islands). Our attention was focused on a severe
squall line that appeared to identify the front some 30 miles
to the east. At the time I was shocked that, even as we
entered the offshore airspace normally used by
departing/arriving flights into LAX, the skies were open to
virtually anything we wanted to do! In fact, Los Angeles air
traffic controllers, who were generally annoyed at our complex
and ever-changing flight track requests) seemed almost HAPPY
to be talking to us! (The image of the forlorn Maytag
repairman somehow came to mind...)
I was jolted out of these musings as we were virtually knocked
off our airborne feet by a radical shift in wind speed and
direction every bit as profound as the front itself. Yet the
front had almost certainly passed this site an hour or more
before! We don't know yet what caused this surprising event,
but I can say with confidence that a small flock of scientists
will soon be poring over the data for clues! We later found
out that the arrival of the severe frontal squall
line—the sort that occasionally produces tornadoes over
Los Angeles and other parts of southern California—had
utterly closed down this huge international airport, yet
another example of the importance of accurate forecasts of
storms in this region.
For over an hour we worked to document the strength and extent
of the exceedingly moist southerly low-level winds hitting the
Santa Ynez Mountains. At peak speeds of around 75 mph several
thousand feet above the surface, these winds represented a
veritable firehose pointed at coastal California. Later, as we
did a reciprocal track around Point Conception and northward
to Monterey, the awesome impact of this storm was apparent in
numerous ways. The streets of Santa Barbara were a parking
lot, inundated by runoff from heavy rains falling on already
saturated soils. North of Point Conception, the lush hillsides
were alive with narrow torrents and waterfalls where none
should be, and the strip of sea immediately adjacent to the
coast had turned an eerie yellow; soil that had once
constituted those hillsides flowed into the ocean. We were
seeing direct results of the powerful "low-level jet(stream)"
that is CALJET's namesake.
Though CALJET flight operations are continuing through the end
of February, and winter storms enhanced by El Nino are
expected to impact the West Coast well into spring, I have
returned to the relatively peaceful confines of my office at
the University of Washington. Nonetheless, from time to time
my thoughts drift back to the challenges of my last few days
in Monterey, which were punctuated by flooded streets, roads
closed by mudslides, and widespread power failures that
impacted our efforts to plan future flights even as they
inconvenienced the broader population. It is perhaps worth
noting that, as an increasingly technological society and one
whose population is ever more concentrated along our coasts,
we are all more and more vulnerable to such disruptions.
Even MY long-scheduled escape from California was stymied, as
my return flight out of Monterey bound for Seattle was delayed
for hour after hour by pounding rains. As I sat in an airline
terminal strangely devoid of airliners, pondering what I might
share in this dispatch, an ironic fact struck me: I may be
privileged to share a few of my experiences from studying the
"business end" of El Niño during CALJET, but ultimately
it is El Niño that will get in the last word!
Bradley Smull is a research meteorologist with the
NOAA/National Severe Storms Laboratory and Research
Associate Professor in the Department of Atmospheric
Sciences, University of Washington
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Photos: (1) B. Smull; (2) R. Hueftle.
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