>
> *David Reynolds*
>
> *Advances in Weather Forecasting*
>
>
> For the last ten years, David Reynolds has been in charge of the
> National Weather Service (NWS) forecast office that provides
forecasts,
> watches, and warnings for the greater 11 county San Francisco and
> Monterey Bay Area. The National Weather Service is part of the
National
> Oceanic and Atmospheric Administration, NOAA, within the Dept. of
Commerce.
>
> NOAA is completing its 2020 Strategic Plan, within which are
described
> future technologies and decision support services impacting the
NWS.
> These will be highlighted. In addition, Mr. Reynolds will review
an ongoing
> research program called the Hydrometeorological Testbed (HMT),
which is
> being conducted within the greater Bay Area, and whose goal is to
improve
> forecasting of extreme rainfall events leading to flooding.
Finally, Mr.
> Reynolds will briefly discuss a planned statewide drill called
ArkStorm
> that will test the state’s ability to respond to a catastrophic
flood,
> or what could be called California’s Katrina. This drill is an
outgrowth
> of the research from HMT and is part of the USGS Hazard Mitigation
Program
> and follow-on to the Great Shake-Out conducted in southern
California.
>
Mr. Reynolds
began his talk by explaining that the Monterey Office supplies the
forecasts that are the foundation of many weather reports. Not just the
ones used by broadcast media, but also pinpoint forecasts used by tug
boats, airports, and other special applications. Groups like
firefighters sometimes ask questions like "is it safe enough to drop
flame retardant on this wildfire?", which can be nontrivial to answer.
The NWS
computer system puts all of the current weather information into a grid
inside their computer system. Current weather information includes
measurements from observation posts (airports, volunteers, weather
buoys, etc.), satellite data, and interpolations for data points
between measurements. This is then crunched with weather models to
predict the conditions for the next seven days. People can access these
forecasts in a variety of ways, including over the internet from cell
phones and laptops.
Mr. Reynolds
spent quite a bit of time talking about weather forecasts for San
Francisco Airport (SFO). Because of the fog, we have 97% of our delays
caused by weather. Only Denver has a higher percentage, 98%. A team
including the NWS, San Jose State, NASA and others worked together to
develop a better weather predicting model. They developed one good
enough that they could schedule airplane arrivals for just after the
weather clears. This required as much as five hours or more of accurate
lead time, because they take off from distant cities. Delays cost
airlines at least $74/minute that airplanes stay airborne. Since going
live in 2004 the new system has saved $4.2 million per year.
The NWS has
two interesting special forecasts, space forecasts and tsunami
warnings. Space forecasts are valuable to the national security and
communications industries. Solar flare activity is currently low
compared to most of the previous decade. Sun spots are expected to peak
again in 2014. Tsunami warning systems have gotten more integrated
around the Pacific since that Indonesian one that killed a lot of
people a couple of years ago. NWS is looking to improve their coverage
in the Caribbean.
The NWS
likes to improve data collection by partnering with other institutions.
KPIX (CBS 5) has a weather radar that has significantly improved the
ability of the NWS to predict flooding in the Russian River watershed.
They also partner with individuals, who can maintain weather stations
in their back yards and report the information for inclusion in the
data grid that is used to make forecasts. This can improve the accuracy
of the results.
Another tool
for improving forecasts is NEXRAD Dual Polarization radar, which
produces better quality images. The NWS plans to retrofit this into all
122 of their weather radar stations over the next four years.
The NWS has
a very sophisticated computer system, including "Two redundant IBM
Power6-based systems containing 156 nodes (32 processors per node), 4
GB memory/physical processor and IBM's AIX-based high performance
computing parallel environment including GPFS. Each system is capable
of delivering 73TF as measured by Linpack benchmark code. Each
operational system supports a 320 TB disk storage subsystem providing
sustained performance of not less than 9 GB/sec for write and 10 GB/s
for read." These are primarily used for weather forecasting. Compute
time is scheduled far into the future for things like daily forecasts
and climate model testing.
Looking
forward, the NWS has to deal with changes in the demands of office
holders, new technology, budget constraints, and the marketplace. Their
goal is to continue to provide an accurate and timely forecast so that
increased industry reliance on the forecast can just be cost effective
planning.
During Q&A the following details were added:
It takes the
NWS ten years to adopt a new technology. That's way down from what it
used to take.
The highest
risk of flooding in the USA is in New Orleans. The second highest risk
of flooding is in Sacramento. California's worst recorded floods to
date happened in 1862.
This year we
expect a dryish winter. It's a La Nina which will push the
precipitation to the north of us.
Models don't
predict the behavior of boundary layers very well. Too much turbulence
there.