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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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