The Storm Prediction Center exists solely to protect life and property
of the American people through the issuance of timely and accurate
watch and forecast products dealing with tornadoes, wildfires and
other hazardous mesoscale weather phenomena.
A team of world-class Applied Meteorologists, Computer Scientists,
and Administrative Professionals that works to protect the American
people from hazardous weather.
This is accomplished by the use of state of the art science and
technology to issue timely and accurate watch and forecast products
for high-impact mesoscale weather including tornadoes, severe
thunderstorms, wildfires, hazardous winter weather, and excessive rainfall.
The Storm Prediction Center (SPC) is part of the National Weather Service
(NWS) and the National Centers for Environmental Prediction (NCEP).
Our mission is to provide timely and accurate forecasts and watches for
severe thunderstorms and tornadoes over the contiguous United States.
The SPC also monitors heavy rain, heavy snow, and fire weather events
across the U.S. and issues specific products for those hazards. We use
the most advanced technology and scientific methods available to achieve
this goal. If you are interested in the history of the SPC we have a set
of pages that document much of the history of the SPC.
The SPC uses its suite of products to relay
forecasts of organized severe weather as much as three days ahead of
time, and continually refines the forecast up until the event has
concluded. All products issued by the Storm Prediction Center are
available on the World Wide Web. Our products are commonly used by
local National Weather Service offices, emergency managers, TV and radio
meteorologists, private weather forecasting companies, the aviation
industry, storm spotters, agriculture, educational institutions and many
other groups. A detailed description of all of the SPC products is
available here.
Our very specialized mission requires meteorologists with a high level
of expertise in convective storm forecasting, as well as excessive
precipitation, winter weather, and conditions leading to high fire
dangers. The SPC staff also is active
in scientific research into severe and
dangerous weather. All SPC forecasters have at least a Bachelor of
Science degree in atmospheric science, and several have done
graduate-level studies or hold a Master of Science degree. Most of the
forecasters at the center have at least 5 years of specialized
experience, with our more veteran forecasters having over 20 years of
severe storm forecasting wisdom. We have participated in several major
scientific experiments and field programs in recent years, including
the
V.O.R.T.EX.
project. The SPC is located in Norman, Oklahoma, home of
the National Severe Storms Laboratory,
University of Oklahoma School of Meteorology
and other weather centers.
Our co-location with these groups should yield even greater scientific
opportunities in the future. Several SPC meteorologists make severe
storms their hobby as well -- being heavily involved
with
storm spotting and storm chasing on their own time.
The lead forecaster serves as the "team leader," overseeing duties among
other forecasters on shift and making sure each product issued is of the
highest quality possible. This is so important that all products and
bulletins from SPC are proofread by at least two pairs of eyes before
they go out, one of which is usually the lead forecaster. The lead
forecaster's job is very complex. He or she must be intimately familiar
with every aspect of SPC operations, every type of forecast we issue,
and a myriad of computers we use to do the job. The stress level of
this job can be quite high on active severe weather days, with the lead
forecaster having to closely monitor several areas of the country for
impending thunderstorm development. A high level of situational
awareness is required in this position.
The main operational duty of the lead forecaster is to
issue Tornado and Severe
Thunderstorm Watches as necessary. This involves a diligent
national weather watch -- monitoring current and forecast weather all
over the country for conditions that lead to violent thunderstorms.
The lead forecaster must coordinate with numerous local NWS offices in
the threat areas, and ensure that the watch process works smoothly.
SPC watches alert the public, local NWS offices, emergency managers and
storm spotters of the threat of severe thunderstorms and/or tornadoes
during the next several hours, covering parts of one or more states.
Besides alerting the general public to the threat for severe storms,
these watches activate storm spotter networks that protect the public
through their efforts.
The lead forecaster also composes
Public Severe Weather Outlooks
(PWOs) when major severe weather outbreaks threaten, and provides
direct assistance and guidance in the preparation of all other forecasts
at SPC.
Mesoscale forecasters specialize in forecasting dangerous weather on
the "mesoscale," which comprises a time frame of up to 6 hours and an
area typically 1/2 the size of Iowa (approx. 35000 sq. mi.). This
involves extensive knowledge of weather processes that lead to severe
thunderstorms, tornadoes, heavy rain, hazardous winter weather, and fire
weather. This person's primary responsibility is to provide short term
guidance on the formation and evolution of severe thunderstorms,
tornadoes, heavy rain, and winter weather events.
Mesoscale forecasters compose concise short-term guidance messages called
Mesoscale Discussions
(MDs) that address areas of current or expected hazardous weather.
The mesoscale forecaster also writes
Status Reports for every severe weather watch in effect, at the top
of the hour during the watch. Status Reports are guidance products
which indicate where the severe weather threat persists within a given
watch. They also discuss watch expiration and cancellation when needed.
The outlook forecaster prepares forecasts of thunderstorm activity
across the continguous United States -- both severe and non-severe.
The Day-1 Outlooks pertain to
today's threat, while the
Day-2 Outlooks
pertain to tomorrow. This involves very detailed analysis of recent and
current weather data and weather trends, followed by intensive examination
of computer forecast models. Due to the large amount of weather data
available in most cases, and the complexity of severe weather
forecasting, many hours of work often go into the preparation of an outlook.
Day-1 and Day-2 outlooks are very important forecast guidance for
local National Weather Service offices, often assisting in staffing
decisions and storm spotter preparedness activities for the
day (or night). They describe where severe weather is possible, when
it may occur, why, how intense it might be, and depict the risk areas
graphically.
Many SPC forecasters and support staff are heavily involved
in scientific research into severe and
hazardous weather.
This involves conducting applied research and writing technical papers,
developing training materials, giving seminars and other presentations
locally and nationwide, attending scientific conferences, and
participating in weather experiments. For example, SPC forecasters
participated in
the V.O.R.T.EX.
project (1994-95), the largest and most intensive field program ever
undertaken in an effort to understand tornadoes and the conditions that
produce them.
Now that the SPC is in Norman, along with
the National Severe Storms Laboratory,
University of Oklahoma School of Meteorology
and
other members of the Oklahoma Weather Center, many more scientific
opportunities and discoveries await from our interaction and cooperation.
SPC's Science Support Branch maintains an extensive array of computer
hardware and software, develops new software in support of forecast
operations, and keeps the science-forecasting connection strong. Within
Science Support, the Science and Operations Officer (SOO) is in charge
of in-house meteorology training and integrating the latest atmospheric
science discoveries into SPC forecasting. The SOO also oversees all SPC
research projects and scientific publications.
Science Support also includes visiting scientists on occasion, as well
as contract staff who deal with various types of computer programming,
numerical modeling of the atmosphere, and network maintenance.
The Administrative Staff oversees all SPC functions, beginning with the
Director, who reports directly to the head of the
National Centers for Environmental
Prediction, SPC's parent agency.
The Director is active in administrative areas, diversity, EEO, broadcast
and print media relations, NWS outreach both internal and external,
strategic planning, tactical planning, resource management, and severe
reports data base management. The Warning Coordination Meteorologist
serves as the SPC's point of contact for NWS field offices, emergency
managers, private sector meteorologists and broadcast and print media.
The Administrative Officer has a wide variety of managerial
responsibilities, ranging from human resource, diversity, budgeting,
acquisitions, tours, broadcast media scheduling, and International
activities. The Administrative Assistant supports a wide variety of
administrative activities and is the SPC's travel coordinator. The
Operations Branch Chief and Science Support Branch Chief direct daily
supervisory/ management duties of forecasters and support staff,
respectively. A complete listing of current SPC staff is available
here.
SPC forecasters have a huge variety of tools at their disposal.
Foremost is their formal training and experience in severe storms
forecasting, which is unique to SPC. Past and current weather
observations allow them to closely monitor changes in the atmosphere
that lead to severe and hazardous weather. These observations come from
satellite imagery, radars, surface weather stations, weather balloon
soundings, wind profilers, lightning detection network, and information
from local NWS offices. They also use such tools to assess how well the
computer models are doing; then they use this knowledge to judge how
reliable the models are for forecast purposes.
The severe weather forecast process at SPC begins with the
Convective Outlook, which is a forecast of where both severe and
non-severe thunderstorms are expected to occur around the country.
Areas of possible severe thunderstorms are labeled "SLGT" (slight risk),
"MDT" (moderate risk), or "HIGH" (high risk), depending upon the coverage
and intensity of expected severe thunderstorms in a region. Many NWS
offices use the Outlook to make emergency staffing decisions before
severe weather begins.
As time progresses, a severe weather threat often becomes better defined
over an area smaller than the Outlook, both in space and time.
Mesoscale Discussions (MDs) are often needed to describe an
evolving severe weather threat, and also to advise of possible watch
issuance. [MDs are also issued for weather hazards that don't
necessarily involve severe thunderstorms, including excessive rain,
heavy snow and general thunderstorm trends.] Meteorological reasoning
in MDs helps forecasters at local NWS offices to understand causes and
prepare for the types of severe weather expected.
If development of severe thunderstorms is imminent, or likely to occur
in the next several hours, the next step is a Severe Thunderstorm
or Tornado Watch. Such watches alert the public, aviators and
local NWS offices that environmental conditions have become favorable
for the development of severe storms or tornadoes. Local storm spotter
networks activate; and forecasters in the threat area closely monitor
radar imagery and spotter reports to issue the appropriate severe
thunderstorm and tornado warnings.
When severe hail (at least 3/4-inch diameter), damaging winds (at least
50 knots or 58 mph) or a tornado appear imminent, local NWS offices will
issue a Severe Thunderstorm Warning or Tornado Warning
as appropriate. The warning rapidly disseminated over NOAA Weather
radio, commercial radio and TV stations and news wires, so that people
in the warning area can find safe shelter to take cover from the storm.
[We also have a detailed explanation of Outlooks, MCDs, Watches and
all other SPC products, available here.]
See also:
History of the SPC
Description of the SPC products
Top/Forecast Products/Home
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