Useful Conversions

 
 

 

  

Useful Charts and conversions:

Convert Degrees Minutes Seconds to Decimal Degrees Conversion
Latitude:
Longitude:


The following conversion scripts courtesy of Tim Brice and Todd Hall of the National Weather Service in El Paso, TX;

Wind Speed Conversion
Enter a wind speed:
Answers:
mph                      mph
knots knots
m/s m/s
ft/s ft/s
km/h km/h
 
Relative Humidity to Dewpoint Conversion
Enter temperature, relative humidity, and actual station pressure:
Temperature: wet-bulb unit dewpoint
° F ° C ° Kelvin ° F
RH: ° C
% ° Kelvin
Enter your actual station pressure:  
in HG mm HG
               mb (hPA) 		 
 
Pressure Unit Conversion
Enter an atmospheric pressure:
Answers:
in HG in HG
mm HG mm HG
millibars millibars
hPA hPA
kPA kPA
lbs psi lbs psi
 
Altimeter Setting
Enter the elevation of the station
and choose your units: 		Altimeter Setting in in. of HG:
feet meters in HG
Enter your station pressure
(not the altimeter setting)
and choose your units: 		Altimeter Setting in mm of HG:
in HG mm HG
               millibars (hPA) 		mm HG
 
  Altimeter Setting in mb. (hPa):
  mb (hPA)
 
Temperature Conversion
Enter a temperature:
Answers:
Fahrenheit  ° F
Celsius  ° C
Kelvin  ° K
Rankine  Rankine
 
Heat Index
Enter a temperature:
Enter a temperature that you would
like and choose your units: 		What the temperature feels
like to your body:
Fahrenheit Celsius ° F
Enter your relative humidity:  
% ° C
 
WIND STRENGTH CHART:
Reporting Terms Wind M.P.H Specifications for Use on Land Weather Forecast Terms
Calm   Under 1 Smoke rises vertically  Light
Slight Breeze 4 - 7 Direction of wind shown by smoke drift, but not by wind vanes Light
Gentle Breeze 8 - 12 Leaves & small twigs in constant  motion; light flags extended     Gentle
Moderate Breeze 13 - 18 Raises dust & loose paper; small branches move Moderate
Fresh Breeze 19 - 24 Sm. trees in leaf begin to sway;  crested wavelets on inland water Fresh
Strong Breeze 25 - 31 Large branches in motion; whistling heard in telephone wires  Strong
High Breeze 32 - 38 Whole trees in motion; inconvenience in walking against wind  Strong 
Gale   39 - 46 Breaks twigs off trees; generally impedes progress    Gale
Strong Gale 47 - 54 Slight structural damage occurs Whole Gale
Whole Gale 55 - 63  Seldom experienced inland, tree uprooted; much damage occurs Whole Gale
Storm    64 - 75 Very rarely experienced; accompanied by widespread damage Whole Gale
Hurricane  75+   Hurrican 
FUJITA SCALE FOR TORNADOS:
-------------------------

Scale Number   Wind Speed (mph/[kph])     Damage Type
_____________________________________________________

    F0           40- 73   [ 64-117]       Light

    F1           74-112   [118-180]       Moderate

    F2          113-157   [181-251]       Considerable

    F3          158-206   [252-330]       Severe

    F4          207-260   [331-417]       Devastating

    F5          more than 261+ [418+]       Incredible

HAIL SIZE ESTIMATE COMPARISON CHART:

Pea...................0.25 inches;
Penny.................0.75 inches;
Quarter...............1.00 inches;
Half Dollar...........1.25 inches;
Golfball...............1.75 inches
Tennis ball............2.50 inches
Baseball...............2.75 inches
Grapefruit.............4.00 inches
(Borrowed from the NOAA/NWS publication, ADVANCED SPOTTER'S FIELD GUIDE.)

Saffir-Simpson Scale:
  Maximum Sustained Winds Barometric Pressure Storm Surge Damage
Type KNOTS MPH millibars inches of mercury Feet Meters  
Depression less than 34 less than 39 ------ ------ ------ ------ ------
Tropical Storm 35 - 63 39 - 73 ------ ------ ------ ------ ------
Category 1 64 - 82 74 - 95 greater than 980 greater than 28.94 3 - 5 1.0 - 1.7 minimal
Category 2 83 - 95 96 - 110 979 - 965 28.50 - 28.91 6 - 8 1.8 - 2.6 moderate
Category 3 96 - 113 111 - 130 964 - 945 27.91 - 28.47 9 - 12 2.7 - 3.8 extensive
Category 4 114 - 135 131 - 155 944 - 920 27.17 - 27.88 13 - 18 3.9 - 5.6 extreme
Category 5 136+ 156+ less than 920 less than 27.17 19+ 5.7+ catastrophic

 

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Copyright © 2008 Tim Groman
Last modified: 01/13/08