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The Houston CWSU Tactical
Decision Aid (TDA) 
From time to time, new tools become available on
the web
that may be of some use to a pilot. In some cases, these
tools
may or may not be specific to aviation. The Houston
Center
Weather Service Unit (CWSU) has released a new tool to their
website called the Tactical Decision Aid (TDA). Click here
or on the image to the right to view the TDA program on the
Houston CWSU website.
The TDA evaluates any of the 625
airports that are
serviced by a NWS Terminal Aerodrome Forecast (TAF). In other
words, it is not meant to be used with military airfields or
international airports - even those airports that may issue a TAF.
After visiting the website, the default airport shown is
George
Bush Intercontinental Airport (KIAH) in Houston, Texas.
Let's say you wanted to see the TDA for Orlando International
Airport (KMCO). Type MCO in place of IAH and click on the Get TDA button.
The TDA combines the latest surface observation
and the most recent TAF. It depicts the latest
observation
(1753Z in the example below) in the left column followed by the TAF on
an hour-by-hour basis through 12 hours in subsequent columns to the
right (18Z, 19Z, 20Z, etc). The display is automatically
refreshed every 5 minutes.
The ceiling, visibility, precipitation
and wind are
categorically color-coded based on default parameters. For
example, a cyan color for prevailing ceiling (CIG) would describe
marginal VFR conditions or a ceiling between 1,000 and 3,000 feet.
A yellow category for visibility describes IFR conditions
with
visibility between 1 and 3 miles. One very slick feature is
that
you can customize these parameters. For example, you can
customize the ceiling and/or visibility category to adapt them to your
own personal minimums. Therefore, you can have the red color show up
when the ceiling and/or visibility drops below your personal minimums.
Unfortunately, at this time you can't save these adaptations
to
apply again later.
The tactical decision aid feature is the
evaluation of the
crosswind component for the airport. The tool evaluates the
crosswind component in knots for each runway for that airport.
In
the example below, 13 knots
Keep
in mind that what you see in this categorical presentation isn't a
complete TAF. For example, present weather such as BLDU
(blowing
dust) or FU (smoke) won't be represented. Also, PROB30 groups
appear to be missing; this may simply be an oversight by the program
developer. CB (cumulonimbus) in the cloud group isn't
depicted
either. Frequently TAFs will only carry CB in the cloud group
and
will not carry a TS or VCTS. This is usually the case when
the
forecaster feels there will be thunderstorms in the region, but doesn't
believe a thunderstorm will roll through the terminal area or in the
terminal area's vicinity.
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