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You are at NWS Houston/Galveston »
Severe Weather Awareness Week » Severe Weather Forecasting
Southeast Texas Severe Weather Awareness Week
February 22 - 28, 2009 |
SEVERE WEATHER FORECASTING
Forecasters at the National Weather Service use a variety of tools to help in forecasting
of severe weather.
AWIPS and Warngen
AWIPS (Advanced Weather Interactive Processing System) is the name of the new computer
system being utilized by the National Weather Service. It enables the forecaster to put
several layers of information on one screen, allowing for faster and more accurate weather
predictions.
Warngen is a tool on AWIPS that allows the meteorologist to create a warning right from
the radar screen. The meteorologist can box in the area he feels will be affected by the
storm, and a warning is automatically created to cover that set of counties. Warngen allows
for faster and more precise warnings from the National Weather Service.
WSR-88D Doppler Radar
The Houston/Galveston National Weather Service office had one of the first WSR-88D (Doppler)
radar systems deployed in the country. The doppler radar differs from traditional radar in
that the radar can detect not only precipitation intensity but also velocities of specific
particles (dust, insects, birds, raindrops) in the atmosphere. A meteorologist can detect
rotation beginning to develop in the middle part of a thunderstorm, and issue a tornado
warning minutes before the tornado actually touches down. In thunderstorms with damaging
downburst winds, high velocities will often show up on radar before they reach the ground.
The WSR-88D also detects the distribution of water inside the thunderstorm, which can
enhance hail prediction. The WSR-88D also enables cross-sections of individual storm cells
and cell tracking.
Satellite
One of the oldest and most reliable tools in severe weather forecasting is the weather
satellite. Meteorologists can monitor evolution of storm systems as they approach the area,
and compare them to computer model predictions of their strength and movement. When
thunderstorms evolve, meteorologists can watch for areas of cooling or warming cloud tops
on infrared satellite imagery to tell if the thunderstorms are intensifying or weakening.
Visible satellite photos can be used to monitor initiation of convection (developing
cumulonimbus clouds) and areas with the highest cloud tops and strongest storms.
Day-to-Day Operations at the National Weather Service
At least two meteorologists are on duty twenty-four hours a day, seven days a week at the Houston/Galveston
National Weather Service office. One meteorologist serves as the lead, making decisions on the
five-day forecast and writing the forecast discussion, a summary of the meteorologist's
scientific reasoning behind his or her forecast. One meteorologist serves as the aviation and
marine forecaster, and concentrates on those activities. The third meteorologist serves
as a technician, answering phones, gathering climate and weather statistics, and monitoring the
radar and NOAA Weather Radio.
During times of severe weather, additional meteorologists will be on duty to help with the
increased workload. Severe weather duties include radar monitoring, issuing warnings,
statements, and short-term forecasts, fielding phone calls from spotters and law enforcement
officials, compiling reports of severe weather, disseminating warning information via NOAA
Weather Radio, pager, and telephone, and issuing the regular products associated with a shift.
Typically, two or three meteorologists will be assigned solely to radar and warning operations
during severe weather events with other duties distributed around as necessary.
Severe Weather Statistics for Southeast Texas (1992-2008 graphs)
 Total Yearly Severe Weather Events- Weather Related Injuries
- Weather Related Deaths
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weather.gov 
National Weather Service Forecast Office
