User Manual
MSO Weather Station
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MSO Weather Station™
User Manual
Version 1.00
Serial Number: ___________________
Date Purchased: __________________
All specifications subject to change without notice.
Printed in U. S. A.
Columbia Weather Systems, Inc.
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© Copyright 2011 Columbia Weather Systems, Inc. All Rights Reserved.
Proprietary Notice: Orion, Orion LX, Capricorn 2000, Capricorn 2000MP and Capricorn 2000EX are
trademarks of Columbia Weather Systems, Inc. The information and drawings contained herein are the
sole property of Columbia Weather Systems, Inc. Use of this publication is reserved exclusively for
customers of Columbia Weather Systems, Inc. and their personnel. Reproduction of this material is
forbidden without the express written consent of Columbia Weather Systems, Inc.
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Welcome!
Congratulations on your purchase of an MSO Weather Station.
Please read this manual completely prior to installation.
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Important Notice: Shipping Damage
BEFORE YOU READ ANY FURTHER, please inspect all system components for obvious shipping
damage. The MSO is a high precision instrument and can be damaged by rough handling. Your unit was
packaged to minimize the possibility of damage in transit. Please save the shipping container for any
future shipment of your weather station.
In the event your order arrives in damaged condition, it is important that the following steps be taken
immediately. The title transfers automatically to you, the customer, once the material is entrusted to the
transport company.
NOTE: DO NOT RETURN THE INSTRUMENT TO COLUMBIA WEATHER SYSTEMS until the following
steps are completed. Failure to follow this request will jeopardize your claim.
1. Open the container and inspect the contents. Do not throw away the container or any damaged
parts. Try to keep items in the same condition as originally received.
2. Notify the transport company immediately.
3. Request the transport company’s representative inspect the shipment personally.
4. After inspection, request a Return Materials Authorization (RMA) from Columbia Weather
Systems by calling (503) 629-0887.
5. Return approved items to us at the following address:
Columbia Weather Systems, Inc.
2240 NE Griffin Oaks Street, Suite 100
Hillsboro, OR 97124
6. After a repair evaluation, an estimate of the cost of repair will be sent to you.
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ESD Protection
Electrostatic Discharge (ESD) can cause immediate or latent damage to electronic circuits. The Weather
Station is adequately protected against ESD for its intended use. However, it is possible to damage the
product by delivering electrostatic discharges when touching, removing, or inserting any objects inside the
equipment housing.
To avoid delivering high static voltages yourself:
1. Handle ESD sensitive components on a properly grounded and protected ESD workbench. When
this is not possible, ground yourself with a wrist strap and a resistive connection cord to the
equipment chassis before touching the boards. When neither of the above is possible, at least
touch a conductive part of the equipment chassis with your other hand before touching the
boards.
2. Always hold the boards by the edges and avoid touching the component contacts.
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Table of Contents
WELCOME! ..................................................................................................................................3
IMPORTANT NOTICE: SHIPPING DAMAGE .......................................................................5
ESD PROTECTION ......................................................................................................................................................6
SECTION 1: INTRODUCTION ..................................................................................................9
THE MSO WEATHER STATION ...................................................................................................................................9
SPECIFICATIONS .........................................................................................................................................................9
Operating Conditions ............................................................................................................................................9
Wind Speed ............................................................................................................................................................9
Wind Direction ......................................................................................................................................................9
Relative Humidity ..................................................................................................................................................9
Temperature.........................................................................................................................................................10
Barometric Pressure............................................................................................................................................10
Precipitation (optional) .......................................................................................................................................10
Input Voltage .......................................................................................................................................................10
SECTION 2: PHYSICAL DESCRIPTION...............................................................................11
MSO SENSOR TRANSMITTER ...................................................................................................................................11
Sensor Transmitter Components..........................................................................................................................11
Wind Speed and Wind Direction..........................................................................................................................11
Temperature and Humidity..................................................................................................................................11
Barometric Pressure............................................................................................................................................11
INTERFACE MODULE ................................................................................................................................................12
SURGE/LIGHTNING PROTECTORS (OPTIONAL)..........................................................................................................13
WEATHERMASTER SOFTWARE (OPTIONAL) .........................................................................................................14
WEATHER DISPLAY CONSOLE (OPTIONAL) ..............................................................................................................15
WEATHER MICROSERVER ........................................................................................................................................16
SECTION 3: INSTALLATION..................................................................................................17
SYSTEM DIAGRAM ...................................................................................................................................................17
UNPACKING THE UNIT ..............................................................................................................................................18
INSTALLING THE 10-FOOT SENSOR MAST ................................................................................................................19
Roof/Ground Mounting........................................................................................................................................19
INSTALLING THE MSO SENSOR TRANSMITTER.........................................................................................................20
Direction alignment.............................................................................................................................................20
INSTALLING THE PANEL TEMPERATURE SENSOR .......................................................................................................21
INSTALLING THE SOLAR RADIATION SENSOR ............................................................................................................21
CONNECTING SENSORS TO THE INTERFACE MODULE AND MICROSERVER ...............................................................22
Connecting the MSO sensor transmitter to Interface Module .............................................................................22
Connecting sensors to the MicroServer...............................................................................................................22
Connecting to MicroServer to RS-485.................................................................................................................23
SECTION 4: USER SUPPORT INFORMATION ...................................................................24
LIMITED WARRANTY ...............................................................................................................................................24
EXCLUSIONS......................................................................................................................................................24
RETURN FOR REPAIR PROCEDURE ............................................................................................................................24
REFERENCE...............................................................................................................................26
GLOSSARY ................................................................................................................................................................26
Aspirating Radiation Shield.................................................................................................................................26
Barometric Pressure............................................................................................................................................26
Celsius Temperature Scale ..................................................................................................................................26
Dew Point ............................................................................................................................................................26
Density Altitude ...................................................................................................................................................26
Fahrenheit Temperature Scale ............................................................................................................................26
Global Radiation .................................................................................................................................................26
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Heat Index ...........................................................................................................................................................26
Pyranometer ........................................................................................................................................................26
Relative Humidity ................................................................................................................................................26
Sea Level Pressure...............................................................................................................................................26
Solar Radiation....................................................................................................................................................27
Wind Chill............................................................................................................................................................27
UNIT CONVERSION ...................................................................................................................................................27
Speed....................................................................................................................................................................27
Temperature.........................................................................................................................................................27
Distance...............................................................................................................................................................27
Pressure...............................................................................................................................................................27
TABLES AND FORMULAS ..........................................................................................................................................28
Wind Chill Chart .................................................................................................................................................28
Wind Chill Equation ............................................................................................................................................28
Heat Index ...........................................................................................................................................................29
Dew Point ............................................................................................................................................................29
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SECTION 1: INTRODUCTION
The MSO Weather Station
The MSO weather station provides wind direction and speed measurements, capacitive relative humidity,
temperature and barometric pressure readings – all in a single sensor module. A separate and optional
tipping bucket rain gauge is available.
High accuracy and fine resolution make this system ideal for precision weather monitoring.
MSO data can be monitored with our proprietary Weather Display Console and WeatherMaster™
Software.
The Weather MicroServer is available for Ethernet connectivity, Modbus/TCP, Modbus RTU and SNMP
interface, Weather Underground and CWOP interface, XML weather data, and FTP.
Specifications
Operating Conditions
Temperature Operation: -40 to +60°C (-40 to +140°F)
Relative humidity: 0 to 100%
Pressure: 14.77 to 32.50 InHg (500 to 1100 hPa)
Wind: 0-112 mph (0 to 50 m/s)
Wind Speed
Range: 0-112 mph (0-50 m/s)
Accuracy: ±2%
Starting Threshold: 1 m/sec
Resolution: 1 mph (1 m/s)
Units Available: knots, mph, km/hr, m/s
Wind Direction
Azimuth: 0-360°
Accuracy: ±5°
Starting Threshold: 1 m/sec
Resolution: 1°
Units Available: ° Azimuth
Relative Humidity
Range: 0 - 100%
Accuracy: ±4%
Resolution: 1%
Units Available: %RH
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Temperature
Range: -60 to 140°F (-40 to +60°C)
Accuracy: ±0.9°F (±0.5°C)
Resolution: 0.1°F
Units Available: °F, °C
Barometric Pressure
Range: 14.77 to 32.50 InHg (500 to 1100 hPa)
Accuracy: ±0.06 InHg (±2 hPa) at 25°C
Resolution: 0.01 InHg (0.1 hPa)
Units Available: Kpa, mbar, InHg
Precipitation (optional)
Range: cumulative
Collection diameter: 6 inches
Accuracy: ±1% at 2 inches/hour or less
Resolution 0.01 in. (0.254mm)
Units Available: mm, inches
Input Voltage
The MSO is supplied with a wall mount switching power supply
Input: 100 - 240 VAC, 50/60 HZ, 0.6A
Output: 12 VDC, 1.25A
The MSO can also be powered directly using a DC voltage source
Input: 9 to 17 VDC (4 mA at 12 VDC).
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SECTION 2: PHYSICAL DESCRIPTION
MSO Sensor Transmitter
The MSO Sensor Transmitter is an all-in-one sensor unit containing wind speed and direction sensor,
temperature sensor, relative humidity sensor, and barometric pressure sensor.
The temperature, and relative humidity sensors are combined in a single module housed in a selfaspirating radiation shield.
Sensor Transmitter Components
Wind Speed and Wind Direction
The MSO sensor transmitter uses a three cup anemometer, for accuracy, sensitivity, and durability. The
cups are connected to a shaft, which turns a sensing element that converts the rotation into a series of
electronic pluses.
A lightweight vane tail provides the motive power for the wind direction portion of the sensor. As the vane
tail moves it turns a shaft on a pair of bearings. That shaft turns a sensing element that converts the
rotation into analog voltage.
Temperature and Humidity
Both Temperature and Humidity are built into the temperature shield at the bottom of the sensor. The
integral shield limits errors due to solar radiation. The RH sensor is a capacitive element enclosed in a
protective membrane.
Barometric Pressure
A solid state pressure sensor built into the sensor electronics provides accurate measurement of
barometric pressure changes over a wide range. Electronic temperature compensation is included for
highest accuracy over the operating temperature of the sensor.
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Interface Module
The Interface Module is used to supply power to the sensor transmitter and to provide two RS-232
communication ports.
The Interface Module has two LED indicators. The green LED is a power indicator and the red LED is a
data indicator. In normal operation, the red LED will flash every second to indicate a data record being
transmitted.
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Surge/Lightning Protectors (Optional)
A nearby lightning strike may induce a high voltage surge which the internal suppressor of your weather
instrument may not be able to withstand, causing significant damage to the weather station. Protect your
weather station investment with the Surge Protector. This compact transient overvoltage suppressor is
designed for weather stations in areas with an elevated risk of lightning strikes such as the top of high
buildings, or installations with cable lengths greater than 100 feet.
•
Superior 3-stage surge protection
•
Tolerates up to 10kA surge currents
•
Both differential and common mode protection on each channel
•
Filtering against HF and RF noise
•
Two power channels and two data channels
•
Environmental protection class IP66
Catalog Number: 8355
Includes adjustable mounting kit
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WeatherMaster
 Software (Optional)
WeatherMaster is professional grade weather monitoring software. This software package is designed for
specialized markets that require robust weather calculations, interoperability with computer models, and
data interfaces to other industrial systems. WeatherMaster utilizes Microsoft Access database for easy
data access and manipulation.
Please refer to the WeatherMaster user manual for installation and operation procedures
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Weather Display Console (Optional)
Displays weather information • Designed to be viewed clearly from a distance • Industrial grade WVGA
touchscreen.
Seven-inch, TFT color LCD panel with 800 x 480 pixel resolution.
Performs computations for wind chill, heat index and other calculated parameters • 200MHz ARM9 CPU
Serial or Ethernet connection: Connects directly to weather station with serial port or connects to a
Weather MicroServer over a network utilizing an existing Ethernet infrastructure -- no extra wiring. The
MicroServer configuration also allows for data from one weather station to be monitored from multiple
display consoles at various locations.
Screens can be factory-customized to meet specialized market and industry requirements.
The Weather Display is also available in a 19” rack-mount chassis and a panel-mount configuration.
Please refer to the Weather Display Console user manual for more information.
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Weather MicroServer
The Weather MicroServer uses a small computer board that runs an embedded Linux operating system.
The MicroServer has 2GB flash memory for data logging and operation.
The MSO transmitter connects to the MicroServer via COM1.
The MicroServer has two RS-232 COM ports and an Ethernet port
The MicroServer offers the following:
•
XML Weather Data
•
FTP weather data in XML or CSV format
•
Modbus/TCP, Modbus RTU (Serial RS-232), and Modbus ASCI interfaces
•
SNMP interface
•
Weather Underground interface
•
CWOP interface
•
Three months of data logging at 1-minute interval
•
Interface to optional visibility and solar radiation sensors
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SECTION 3: Installation
System Diagram
Installation Overview
Unpacking the Unit
Installing the 10-foot mast
Installing the MSO Sensor Transmitter
Installing the panel temperature sensor
Installing the solar radiation sensor
Connecting sensors to the Interface Module and MicroServer
Connecting to MicroServer to RS-485
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Unpacking the Unit
The sensor transmitter comes in a custom shipping container. Be careful when removing the device.
Unpack the MSO weather station and verify that all parts are included.
1. Standard system includes:
MicroServer in weatherproof enclosure
MSO Sensor Transmitter with 50 ft sensor cable
Solar radiation sensor with 50 ft cable
Panel Temperature with 50 ft cable
MSO and MicroServer User Manuals
10-foot steel mast
Roof/Ground hardware kit
Inspect all system components for obvious shipping damage (Refer to “Important Notice: Shipping
Damage” in case of damage).
NOTE: Save the shipping carton and packing material in case the unit needs to be returned to the factory.
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Installing the 10-Foot Sensor Mast
Roof/Ground Mounting
The Roof/Ground Mounting Kit (Cat. No. 88002) is suitable for both roof and ground installation. The
figure and table below illustrates and describes the individual parts.
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Description
Pkg. Ref
Catalog No.
Mast, 10 ft. (two 5-ft sections)
1
1
88005
Universal Mast Mount
1
2
88010
Lag Screw, Roof Mast Mount
4
3
88030
Cable Standoffs, Wood Screw
4
5
88050
Guy Wire Clamps, 1/8"
3
4
88070
Steel Guy Wire, Galvanized
50 ft. 6
88080
Eye Bolt Wood Screws, 1/4" x 3"
4
7
88090
Turnbuckles, 6" open x 4" closed
3
(not shown)
88100
Cable Nail Clips
20
8
88110
Cable Feed Through Bushings
4
10
88140
1/4" x 2 1/4" (for comp. roofs)
Installing the MSO Sensor Transmitter
Use quick mount u-bolts to install on vertical or horizontal mast, pole or pipe.
Tighten nuts, keeping sensor level.
Direction alignment
Install alignment shoulder screw into wind direction vane hub.
Align sensor so wind direction counterweight is to the South, vane tail is to true North.
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Installing the panel temperature sensor
The panel temperature sensor can be attached to the solar panel using a 5-minute epoxy.
Use provided tie wraps to secure the cable to the panel frame.
Installing the solar radiation sensor
The solar radiation sensor can be installed on the mast using the hardware provided to secure to the
solar panel frame.
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Connecting sensors to the Interface Module and MicroServer
Connecting the MSO sensor transmitter to Interface Module
Connecting sensors to the MicroServer
Connect the solar radiation sensor to Channel 1
Connect the panel temperature sensor to Channel 2
Connect the air temperature sensor to Channel 3. This sensor is provided only in systems that do not
include the MSO sensor transmitter. The MSO sensor transmitter includes an air temperature sensor as
part of the module.
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The air temperature sensor is installed in the self-aspirating radiation shield.
Connecting to MicroServer to RS-485
The Modbus RTU is setup to 9600 baud rate, even parity with a Modbus address of 51.
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SECTION 4: USER SUPPORT INFORMATION
This section consists of the following items:
1. One-Year Limited Warranty: Please read this document carefully.
2. Return for Repair Procedure: This procedure is for your convenience in the event you must return
your Weather Station for repair or replacement. Follow the packing instructions carefully to protect
your instrument in transit.
Limited Warranty
Columbia Weather Systems, Inc. (CWS), warrants the MSO Weather Station to be free from defects in
materials and/or workmanship when operated in accordance with the manufacturer’s operating
instructions, for one (1) years from date of purchase, subject to the provisions contained herein. CWS
warranty shall extend to the original purchaser only and shall be limited to factory repair or replacement of
defective parts.
EXCLUSIONS
Certain parts are not manufactured by CWS (i.e., certain purchased options, etc.) and are therefore not
covered by this warranty. These parts may be covered by warranties issued by their respective
manufacturers and although CWS will not warrant these parts, CWS will act as agent for the
administration of any such independent warranties during the term of this warranty. This warranty does
not cover normal maintenance, damage resulting from improper use or repair, or abuse by the operator.
Damage caused by lightning or other electrical discharge is specifically excluded. This warranty extends
only to repair or replacement, and shall in no event extend to consequential damages. In the event of
operator repair or replacement, this warranty shall cover neither the advisability of the repair undertaken,
nor the sufficiency of the repair itself.
THIS DOCUMENT REFLECTS THE ENTIRE AND EXCLUSIVE UNDERSTANDING OF THE PARTIES,
AND EXCEPT AS OTHERWISE PROVIDED HEREIN, ALL OTHER WARRANTIES, EXPRESS OR
IMPLIED, PARTICULARLY THE WARRANTIES OF MERCHANT ABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE ARE EXCLUDED.
This warranty gives you specific legal rights, and you may also have other rights which vary from state to
state.
Return for Repair Procedure
1.
In the event of defects or damage to your unit, first call the Service Department Monday through
Friday, 8:30 am to 4:00 pm PST, (503) 629-0887 to determine the advisability of factory repair.
The Service Department will issue an RMA number (Return Merchandise Authorization) to help
us identify the package when received. Please write that number on the outside of the box.
2.
In the event factory service is required, return your Weather Station as follows:
A.
Packing
Wrap the Sensor Transmitter in a plastic bag first.
Pack in original shipping carton or a sturdy oversized carton.
Use plenty of packing material.
B.
Include:
A brief description of the problem with all known symptoms.
Your telephone number.
Your return street shipping address (UPS will not deliver to a P.O. box).
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Write the RMA number on the outside of the box.
C.
Shipping
Send freight prepaid (UPS recommended).
Insurance is recommended. (The factory can provide the current replacement value of
the item being shipped for insurance purposes.)
D.
Send to:
Columbia Weather Systems, Inc.
2240 NE Griffin Oaks Street, Suite 100
Hillsboro, Oregon 97124
E.
C.O.D. shipments will not be accepted.
3.
If your unit is under warranty, after repair or replacement has been completed, it will be returned
by a carrier and method chosen by Columbia Weather, Inc. to any destination within the
continental U.S.A. If you desire some other specific form of conveyance or if you are located
beyond these borders, then you must bear the additional cost of return shipment.
4.
If your unit is not under warranty, we will call you with an estimate of the charges. If approved,
your repaired unit will be returned after all charges, including parts, labor and return shipping and
handling, have been paid. If not approved, your unit will be returned as is via UPS COD for the
amount of the UPS COD freight charges.
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Reference
Glossary
Aspirating Radiation Shield
A device used to shield a sensor such as a temperature probe from direct and indirect radiation and rain
while providing access for ventilation.
Barometric Pressure
The pressure exerted by the atmosphere as a consequence of gravitational attraction exerted upon the
“column” of air lying directly above the point in question.
Celsius Temperature Scale
A temperature scale with the ice point at 0 degrees and the boiling point of water at 100 degrees.
Dew Point
The temperature to which a given parcel of air must be cooled at constant pressure and constant watervapor content in order for saturation to occur. When this temperature is below 0°C, it is sometimes called
the frost point.
Density Altitude
Density altitude is a meteorological variable that is important to pilots, especially during the summer. The
density altitude is the altitude in a standard atmosphere where the density is the same as the given
atmospheric density. During a hot muggy summer day, a pilot begins take off from an airport with an
elevation of 2500 feet. Because of the warm temperature and the moisture in the air, the airplane has to
work as if it was taking off at an airport at an elevation of 6000 feet resulting in the plane needing more
power and a longer roll down the runway to take off.
Fahrenheit Temperature Scale
A temperature scale with the ice point at 32 degrees and the boiling point of water at 212 degrees.
Global Radiation
The total of direct solar radiation and diffused sky radiation received by a unit horizontal surface. Global
radiation is measured by a pyranometer.
Heat Index
The heat index or apparent temperature is a measure of discomfort due to the combination of heat and
high humidity. It was developed in 1979 and is based on studies of evaporative skin cooling for
combinations of temperature and humidity.
Pyranometer
It measures the combined intensity of incoming direct solar radiation and diffused sky radiation. The
pyranometer consists of a radiation-sensing element, which is mounted so that it views the entire sky.
Relative Humidity
Popularly called humidity. The ratio of the actual vapor pressure of the air to the saturation vapor
pressure.
Sea Level Pressure
The atmospheric pressure at mean sea level, either directly measured or, most commonly, empirically
determined from the observed station pressure.
In regions where the earth’s surface pressure is above sea level, it is standard observational practice to
reduce the observed surface pressure to the value that would exist at a point at sea level directly below.
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Solar Radiation
The total electromagnetic radiation emitted by the sun. 99% of the sun’s energy output falls within the
wavelength interval from 0.15 microns to 4.0 microns, with peak intensity near 0.47 microns. About onehalf of the total energy in the solar beam is contained within the visible spectrum from 0.4 to 0.7 microns,
and most of the other half lies near infrared, a small additional portion lying in the ultraviolet.
Wind Chill
That part of the total cooling of a body caused by air motion.
Unit Conversion
Speed
Kilometers per hour = 1.610 x miles per hour
Knots = 0.869 x miles per hour
Meters per second = 0.448 x miles per hour
Feet per second = 1.467 x miles per hour
Temperature
Temperature in °C = 5/9 (temperature in °F - 32)
Temperature in °F = (1.8 x temperature in °C) + 32
Distance
Millimeters = 25.4 x inches
Pressure
Millibars = 33.86 x inches of mercury
Kilopascals = 3.386 x inches of mercury
Pounds per square inch = 0.49 x inches of mercury
Standard atmospheres = 0.0334 x inches of mercury
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Tables and Formulas
Wind Chill Chart
In 2001, NWS implemented an updated Wind chill Temperature (WCT) index. The change improves upon
the former WCT Index used by the NWS and the Meteorological Services of Canada, which was based
on the 1945 Siple and Passel Index.
In the fall of 2000, the Office of the Federal Coordinator for Meteorological Services and Supporting
Research (OFCM) formed a group consisting of several Federal agencies, MSC, the academic
community (Indiana University-Purdue University in Indianapolis (IUPUI), University of Delaware and
University of Missouri), and the International Society of Biometeorology to evaluate and improve the
windchill formula. The group, chaired by the NWS, is called the Joint Action Group for temperature
Indices (JAG/TI). JAG/TI's goal is to upgrade and standardize the index for temperature extremes
internationally (e.g. Wind chill Index).
The current formula uses advances in science, technology, and computer modeling to provide a more
accurate, understandable, and useful formula for calculating the dangers from winter winds and freezing
temperatures.
Wind Chill Equation
WC = 35.74 + 0.6215 T -35.75(V0.16) + 0.4275 T(V0.16)
Where:
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WC = wind chill temperature in °F
V = wind velocity in mph
T = air temperature in °F
Note: Wind chill Temperature is only defined for temperatures at or below 50 degrees F and wind speeds
above 3 mph.
Heat Index
Temperature in °F
70
75
80
85
90
95
100 105 110 115 120 125 130 135
0
64
66
73
78
83
87
91
95
99
5
64
69
74
79
84
88
93
97
102 107 111 116 122 126
10
65
70
75
80
85
90
95
100 105 111 116 123 131
15
65
71
76
81
86
91
97
102 108 115 123 131
20
66
72
77
82
87
93
99
105 112 120 130 141
25
66
72
77
83
88
94
101 109 117 127 139
30
67
73
78
84
90
96
104 113 123 135 148
35
67
73
79
85
91
98
107 118 130 143
40
68
74
79
86
93
101 110 123 137 151
45
68
74
80
87
95
104 115 129 143
50
69
75
81
88
96
107 120 135 150
55
69
75
81
89
98
110 126 142
60
70
76
82
90
100 114 132 149
65
70
76
83
91
102 119 138
70
70
77
84
93
106 124 144
75
70
77
85
95
109 130 150
80
71
78
86
97
113 136
85
71
78
87
99
117 140
90
71
79
88
102 122 150
95
71
79
89
105 126
100
72
80
90
108 131
RH
103 107 111 117 120
Dew Point
B = (ln (RH/100) + ((17.2694*T) / (238.3+T))) / 17.2694
Dew Point in °C = (238.3 * B) / (1-B)
Where:
RH = Relative Humidity
T = Temperature in °C
Ln = Natural logarithm
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Columbia Weather Systems, Inc.
2240 NE Griffin Oaks Street, Suite 100
Hillsboro, OR 97124-6463
Telephone
(503) 629-0887
Fax
(503) 629-0898
Web Site
http://www.columbiaweather.com
Email
info@columbiaweather.com
Version 1.00
Printed in U.S.A.
Columbia Weather Systems, Inc.
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