HODO

Plots a hodograph of upper-air data.

Format

HODO station time day [keywords]

Parameters

station	4-character station ID, or 5-digit station ID number, e.g., KGRB or 72645
time	observation time (default=0 if current time is between 0 UTC and 11:59 UTC, otherwise default=12)
day	observation date; valid formats include YYYYDDD, YYYY/MM/DD and DD/MON/YYYY where YYYY, DDD, MM and DD are integers and MON is three or more letters, e.g., JAN or JANUARY (default=current)

Keywords

ANAlysis=	text gra		controls display of sounding/parcel analysis values in the text frame and graphics frame; specify YES in text to list all the values in the text frame; specify YES in gra to plot selected values in the graphics frame below the hodograph; specify NO in either or both to suppress the values (default=NO YES)
COLor=	low mid hi lab bg title par graphics color level for each component;specify 0 to omit the component (default=2 3 7 1 8 3 1)
	low	line segments depicting low (surface to 699 mb) winds
	mid	line segments depicting middle (700 mb to 400 mb) winds
	hi	line segments depicting high (399 mb to 1 mb) winds
	lab	wind speed labels, sounding table labels, and wind points
	bg	background grid (wind speed circles)
	title	plot title and sounding/parcel analysis values
	par	sounding/parcel analysis labels
DATaset=	mand sig		source ADDE point dataset names for mandatory- and significant-level data; specify as group/descriptor or alias; you must specify NONE in the sig parameter or SIG=NO keyword to use only mandatory data, i.e., ignore the significant data (mand default=RTPTSRC/UPPERMAND; sig default=RTPTSRC/UPPERSIG if mand =RTPTSRC/UPPERMAND, otherwise sig default=NONE)
DEPth=	depth in mb from the surface to include in the parcel analysis; the range is 0 - 400 where 0 means use only surface data (default=100)
GRA=	graphic frame number to display the hodograph (default=current)
INT=	interval for wind speed circles in the units specified in the UNIT keyword (default=calculated, based on the maximum wind speed)
OUTlonly=	YES	draws a hodograph without any data
	NO	draws a hodograph and plots the upper-air data for the specified station (default)
PRAnge=	min max		mimimum and maximum pressure in mb; all winds in this range are plotted (default=all pressures)
SIG=	YES	include data from the significant-level dataset specified in the DATASET keyword (default)
	NO	do not include data from the significant-level dataset specified in the DATASET keyword; use only its mandatory-level dataset
UNit=	units for wind speed circles; run CU LIST to list the valid units and abbreviations (default=KTS)

Remarks

HODO automatically erases the graphics before plotting the data.

A hodograph is a profile of a wind sounding representing the changing wind shear with height. Wind direction is the azimuth from the origin and wind speed is the radial distance from the origin. Northerly winds are plotted below the origin, and westerly winds are plotted to the right of the origin. The curve, or hodogram, between any two plotted points gives the wind shear between the two levels.

The table to the left of the wind speed circles lists pressure, height, wind speed and wind direction. The table includes all mandatory levels, plus significant wind and pressure levels whose pressure difference (from the adjacent levels in the table) is at least 30 mb.

Use the ANA keyword to list all available sounding/parcel analysis values in the text frame and plot selected values in the graphics frame below the diagram. To obtain the sounding/parcel analysis values, the reported heights are recomputed for hydrostatic consistency, though the adjustments are generally less than 10 meters. Also, the computed parcel temperature of a 12 UTC sounding is warmed 2 K to account for daytime heating. No adjustment is made to the computed parcel temperature of a 0 UTC sounding.

The following abbreviations are used for the sounding/parcel analysis values below the diagram: KI=K Index, LI=Lifted Index, SwI=Sweat Index, TTI=Total Totals Index, CVT=Convective Temperature in C, FMAX=Forecast Maximum Temperature in C, ThE=Equivalent Potential Temperature in K, EL=Equilibrium Level in mb, MIX=Mixing Ratio in g/kg, PW=Precipitable Water in mm, CAPE=Convective Available Potential Energy in J/kg, and HELI=Helicity in m**2/s**2. See Appendix E, Stability Parameters for definitions of these parameters.

Examples

HODO OUTL=YES

This entry plots a blank hodograph without data from any station.

HODO KOUN 0

This entry plots a hodograph of mandatory- and significant-level data for Norman, Oklahoma at 0 UTC of the current day. The sounding table to the left of the hodograph lists pressure, height, wind speed and wind direction at each level. Note that you can also specify the station using Norman's 5-digit station ID number, 72357.

HODO KEYW 12 PRANGE=400 1000 INT=10 UNIT=MPH ANA=YES

This entry plots a hodograph of mandatory- and significant-level data for Key West, Florida at 12 UTC of the current day. Only winds between 1000 and 400 mb are plotted. Since there are only five wind speed circles and an interval of 10 miles per hour was specified with the INT and UNIT keywords, the circles represent 10, 20, 30, 40 and 50 MPH winds respectively. The ANA=YES keyword outputs all parcel/sounding analysis values in the text frame and selected values below the hodograph in the graphics frame.

HODO KMFR 12 06/JUNE/1998 DATASET=LOCAL/MAND.1017

This entry plots a hodograph of mandatory-level data for Medford, Oregon at 12 UTC on 6 June 1998. The data is obtained from the file in position 1017 of the dataset LOCAL/MAND.

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