Here are the steps to analyze the Hodograph.
Step1:
1) Copy paste this link
https://www.tropicaltidbits.com/analysis/models
2) Go to the 'Regions tab' down the map and Select India.
3) Choose your time from the reference
Ex: For example, if the GFS initial time is 00Z (5.30 am IST), select 006Z (11.30 am IST) for forecast after 6 hours the initial Time.
4) Click on the location you want and the graph opens like this.
(I have mentioned Isotherms, Isobars in the graph, make a note of it)
Step2:
In the above graph, you can see the two lines :
1)Redline- Temperature
2)Blue line- Dewpoint Temperature (Temperature+Humidity)
Axis of the Graph:
Vertical-Pressure as a representation of Height.
Horizontal- Temperature.
First, you have to find the following parameters:
1)Lifted Condensation level
2)Level of Free convection
3)Cin (Convective inhibition)
4)CAPE(Convective Available Potential Energy)
5)LI (Lifted index)
-Lifted Condensation Level:
This is the level at which the base of Cloud forms.
1) First, see the dew Point temperature origin point and follow (Sat mix Ratio) line, draw the line and join Temperature (Red line)
2) Secondly, see the temperature origin point and follow Dry adiabats, draw a line upto the previous line and locate the point of intersection.
3)This point is called the Lifted Condensation level. This level is the height at which the base of the cloud forms.
-Level of Free Convection:
1)From the intersection point (Lifted Condensation Level), draw a line following (Wet Bulb line) and mark the intersection point with the Temperature line.
2) That point gives the Level of Free Convection.
3) Till this point from Lifted condensation level, the moisture requires no force but freely moves and reaches this point.
-Convective inhibition:
1)The area between the Temperature line and the Lifted condensation level is called Convective inhibition.
2) It is a destructive Force. Hence it should be as small as possible.
-CAPE(Convective Available Potential Energy)
1)Continue drawing the line from Level of free convection to the point where you meet the temperature line again
2) The area is called CAPE. More the cape, more strong the Thunderstorms will be. Provided, good amounts of Moisture reaches till Level of free convection.
-LI(Lifted Index)
1)This is another parameter, determining the nature of Thunderstorm. Lifted index shows good thunderstorms if it is in Negative values.
2) To plot Lifted index, see the temperature of the line that you have already drawn at 500 mb. Mark the corresponding Isotherm (Constant Temperature).
3) Also mark the next temperature from isotherm at temperature-Red line.
4) Take the difference (More negative-Less Negative)
5)Then you arrive at the Lifted index.
K-Index:
K-index is very useful to tell the intensity of Thunderstorm. To get this one, mark on the isotherms and find the below-given parameters and calculate.
Legend for K-Index:
