Weather and Tools for
Ballooning
Mark Roberson
FAR Part 91.103
Preflight Action
Each pilot in command shall, before beginning
a flight, become familiar with all available
information concerning that flight. This
information must include—
For civil aircraft other than those specified in
paragraph (b)(1) of this section, other reliable
information appropriate to the aircraft, relating
to aircraft performance under expected values
of airport (field) elevation, aircraft gross weight,
wind and temperature.
Wx Tool Box
Thought process – inverted triangle
Gathering wx data and forecast
information
The internet
Identifying RED FLAGS
Time to fly
The forest for the trees
Words of Wx Wisdom
"Understanding current conditions is the
starting point, and the most critical part, of
any weather forecast."
Wx Triangle
National Weather
National Weather
Regional
Local
Local
Balloon Weather and
the Internet
All forecasts are not created
equally
Internet Weather – A great
resource when used wisely
Easy access, PCs, laptops, cell phones,
etc.
Forecasts, radar, satellite, current
conditions all available with just a few
clicks
Access to new experimental forecast
information
Available almost anywhere you fly
Who makes Internet
weather forecasts?
National Weather Service
Private Weather Services
Universities
Government organizations/research
This is “who” really makes
internet forecasts…..
This is “who” really makes
internet forecasts…..
…..and a Good Computer
Geek
How are Internet Weather
Forecasts Made?
Almost all are automated, NO HUMAN
INTERFACE
Database driven
Updated when computer models are
completed (many different models)
Based on either the NWS database or
proprietary models owned/run by private
weather services
Some “fudging” involved
Recipe for Internet
forecasts
Forecast
Even Weather Maps are
Automated
Computer Models
ETA/NAM
GFS
NOGAPS
Canadian
ECWMF
UKMET
NGM
MM5
…and others..
Internet Forecasts
Different websites may use different
models
Most or all websites will not change to
particular model on a day by day basis
Most websites use a “blend” of the
computer model information
Who uses what
Weather.com (aka, The Weather Channel) – stopped
using NWS forecasts, uses own model
Weather Underground – NWS
Accuweather – own model
Intellicast – owned by weather.com
WSI – owned by weather.com
CNN, FOX, etc. usually contracts with above vendors
National Weather Service – taxpayer provided
database, resources, etc.
Accuracy?
Points to Ponder
Pilots who obtain internet forecasts from
commercial providers should use the
information ONLY as a guide
Many internet forecasts do not contain
other elements such as wind forecasts
Add the human element whenever
possible, either yourself or a weather
briefer
Ask the Briefer
Fronts/troughs within 50 miles of launch
site?
Low pressure centers within 50 miles of
launch site?
Precipitation/virga on radar within 50
miles of launch site?
Info from the Briefer
1,000ft winds, greater than 20 mph?
3,000ft winds, greater than 50 mph?
Precipitation?
Visibility less than 5 miles?
Temperature and Dewpoint difference 5 degrees or
less?
Wind Speed greater than 10 mph?
Wind Direction from an easterly direction?
Large pressure differences?
TAFS
What is an Outflow
Boundary?
Thunderstorms often
push a mass of cold
dense air ahead of
them generated by the
cooling effect of the
rain. These are called
outflows.
When and Where Do
They Occur?
Sometimes in a 360
degree radius
around
thunderstorms
Rain showers
Virga
Development of Outflow
Outflow Diagram
Outflow
Outflow
Cold air begins to descend from the middle
and upper levels of a thunderstorm.
As the colder air strikes the Earth's surface,
it begins to “roll”, much like water as a boat
moves through it. As the colder air “rolls”
out, it is compressed causing winds to
increase dramatically - at times even
stronger than a hurricane!
Virga Can Produce
Outflow
What Do Outflows Look
Like?
Examples:
Examples:
Examples:
Examples:
Examples:
Real Life Examples - Hot
Air Balloons
On June 8, 1997 the Great Plains Balloon Race was
being held just south of Sioux Falls. The evening
balloon flight was expected to be rather tranquil.
Instead, a surprise gust front from two isolated
thunderstorms caused some balloons to land with
speeds approaching 30 mph.
The outflows from these two small storms traveled for
four to five hours merging and intensifying as they
reached Sioux Falls.
The two gust fronts continued to move across South
Dakota and were about half way across the state,
before they finally died out. South Dakota is about 400
miles wide. The front traveled in excess of 350 miles.
Most of the rest of the travel was after sunset.
Saturday, July 15, 1995 at
DEERFIELD, MA
The pilot arrived at a balloon festival at
5:30 am and obtained a weather briefing
from three other pilots and the Balloon
Meister. He determined that thunderstorms
were due in the area at about 10:00 am.
Saturday, July 15, 1995 at
DEERFIELD, MA (Cont.)
He departed with two passengers at 6:20
am. The pilot subsequently encountered a
wind shift and strong gusting winds. He
reported that the balloon throat closed due
to the winds. After that, the balloon began
descending and collided with trees.
Saturday, July 15, 1995 at
DEERFIELD, MA (Cont.)
About 25 miles south at Westfield, Ma, the
6:45 am wind was from 090 degrees at 5
knots; at 7:45 am, the wind had changed to
360 degrees at 20 knots with gusts to 40
knots.
Saturday, July 15, 1995 at
DEERFIELD, MA (Cont.)
About 50 miles northwest of the departure
point at Albany, severe thunderstorms with
heavy rain and wind squalls were reported
at 6:50 am. The peak wind at Albany was
reported to be from 310 degrees at 67 knots
at 6:41am.
Forecasting Outflow
Boundaries
Know if thunderstorms are possible in a 360
degree radius from launch site
Are thunderstorms going to occur overnight
or during the morning?
Watch the sky - Is there virga, dissipating
thunderstorms or showers in the area?
Remember….in a 360 degree radius
Check radar and satellite images
Ask briefer if outflow boundaries are present
or HAVE been detected overnight/within 3 to
6 hours of launch
Tools to Detect Outflow
NEXRAD Radar
Surface Observations
Your Eyes
Your Crew
NEXRAD Radar Coverage
NEXRAD Radar Examples
NEXRAD Radar –
Examples- 360 degrees
NEXRAD Radar –
Examples
Surface Observations
Are there any locations reporting current
thunderstorm activity or recent activity?
Are there any reporting stations in a 360
degree radius reporting strong winds
gusts or erratic winds?
Are you in an area with complex
topography which may intensify outflow
speeds?
Your Eyes
Scan the horizon- do you see areas of
dust on the horizon
Do you see low clouds with ragged
edges?
Do you see virga?
Do you see towering Cumulus or CB’s
in the distance (in a 360 degree radius)
Your Crew
Rapid increase in surface wind
Dust on the horizon
Other balloons in the air showing a
rapid increase in air speed
Wx websites
http://www.wunderground.com/cgibin/findweather/hdfForecast?query=orl&se
archType=WEATHER
http:www.usairnet.com/cgibin/launch/code.cgi?Submit=Go&sta=KGI
F&model=avn&state=FL
http://www.weather.com/outlook/travel/busi
nesstraveler/local/USFL0372?from=recent
search
Wx websites continued
http://www.blastvalve.com/weather/weat
her.pl?st=fl&icao1=KMCO&icao2=KGIF
&icao3=KMCO&fb1=KMLB&fb2=KPIE&
fb3=KJAX&When=TM&Submit=Get+Bal
loonCast
http://www.windmapper.com/?Loc=FL
www.pilotmycast.com
Questions?