BUFKIT for BUFKIT for BalloonistsBalloonists

Jay Trobec, Ph.D.KELOLAND TVSioux Falls, SD

jaytrobec.com

Questions we will answerQuestions we will answer

How do I install the free software on my computer?

What is a computer model?What does BUFKIT tell us about…

– Winds aloft?– Temperatures?– Inversions?– Fog/Precipitation forecasting?

How do I install it on my How do I install it on my computer?computer?

Computer modelsComputer models

Give us an approximation of the expected state of the atmosphere

They do not “forecast” the weather – interpretation is required

Three models are beneficial to balloonists, and can be displayed with BUFKIT software– NAM (North American Mesoscale)– GFS3 (Global Forecast System)– RUC (Rapid Update Cycle)

BUFKIT dataBUFKIT data

BUFKIT visual displayBUFKIT visual display

NAM (also called the WRF) NAM (also called the WRF) ModelModel

Created at 0z (6 pm CST), 6z (midnight CST), 12z (6 am CST), and 18z (noon CST)

12 km resolution

1 hr increments

84 hrs

GFS ModelGFS Model

Created at 0z (6 pm CST), 6z (midnight CST), 12z (6 am CST), and 18z (noon CST)

0.5 deg lat/lon3 hr increments180 hrs

RUC (also called RAP or HRRR) RUC (also called RAP or HRRR) ModelModel

Created every hour 13 km resolution 18 hrs

BUFKIT Temperature/Wind DisplayBUFKIT Temperature/Wind Display

BUFKIT Overview Wind DisplayBUFKIT Overview Wind Display

Overview Clouds DisplayOverview Clouds Display

Sky Box Plotted Implied

.00 - .09 none Clear

.10 - .24 Single Cross Hatched Few

.25 - .49 Double Cross Hatched Scattered

.50 - .74 Gray Broken

.75 - 1.00 White Overcast

Environmental Lapse Rate (ELR)Environmental Lapse Rate (ELR)

Decrease of temperature with altitude in a stationary atmosphere

0.5°C/100 meters3.5°F /1000 feet

1500 ft: 54.8°1500 ft: 54.8°

1000 ft: 56.51000 ft: 56.5°

500 ft: 58.3500 ft: 58.3°

Ground: 60°Ground: 60°

Subsidence,

sinking air

under High

pressure

Temperature InversionTemperature Inversion

Thin layer in the atmosphere in which air temperature increases with height

Caused by:

Warm Fronts

or

Cold Fronts

Subsidence InversionSubsidence Inversion

Radiational InversionRadiational Inversion

Effects of InversionEffects of Inversion

Speed of ascent slows when rising through subsidence layer

Effects of InversionEffects of Inversion

Speed of descent slows when descending through layer

Effects of InversionEffects of Inversion

Winds often have different directions/speeds above and below an inversion

Inversion display on BUFKITInversion display on BUFKIT

Fog forecastingFog forecasting

BUFKIT utilizes “crossover temperature” technique developed by UPS

Also assesses change in humidity with height, and atmospheric stability

Technique is designed for radiational fog, not advection or other types of fog