SFCPLOT

Plots surface hourly data from ISFC-schema point files.

Formats

SFCPLOT param map time day [keywords]
SFCPLOT par1-par2 map time1-time2 day1-day2 [keywords]

Parameters

param	parameter to plot; valid parameters are those defined in the SFCPLOT.CORE, SFCPLOT.SITE and SFCPLOT.USER files; see the Remarks for more information and a list of the parameters in SFCPLOT.CORE (default=PLOT)
par1-par2	parameter difference to plot, e.g., T-TD for dewpoint depression; see the Remarks
map	map for the plot; see the MAP command for a list of valid predefined maps, for example, FL, MID, USA, WORL (default=do not draw a map; use the navigation of the frame specified with NAV keyword)
time	observation time; see the Remarks (default=current or most recent reporting hour)
time1-time2	time difference to plot, e.g., 12-6 to subtract 6 UTC data from 12 UTC data; see the Remarks
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, for example, JAN or JANUARY (default=current)
day1-day2	day difference to plot, e.g., 2000110-2000109 to subtract day 2000109 data from day 2000110 data; see the Remarks

Keywords

CHIlltype=	CURRENT	compute the wind chill values for the CHILL option using the formula implemented by the National Weather Service in November 2001 (default)
	OLD	compute the wind chill values using the pre-2001 formula
COLor=	graphics color level (default=3); specify as a single number, e.g., COLOR=5, or in format color[min-maxBinc] to assign multiple colors for the parameter, based on its values; e.g., COLOR=2[30-59B10] plots values 30-39 in level 2, values 40-49 in level 3, values 50-59 in level 4, values less than 30 in level 1, and values greater than 59 in level 5
DATaset=	ADDE point dataset name and position; specify as group/descriptor.position or alias.position where position is a positive integer (absolute position), 0 or a negative integer (relative position), or ALL (default=RTPTSRC/SFCHOURLY.ALL)
DEClut=	YES	declutter the plot, meaning do not plot overlapping values (default)
	NO	do not declutter the plot
GRA=	graphic frame number for the display (default=current)
LSIze=	height of the plot characters, in pixels (default=8)
NAV=	num	frame to use for navigation
	C	use the current frame's navigation (default)
	you cannot use the NAV keyword if you specify a map with the map parameter
PTYpe=	ALT	plot altimeter setting for pressure values if the PLOT option is specified, or use altimeter setting when computing station pressure for use in the equations that generate the plotted values if the PSTN, MIX, THA or THAE option is specified (default); see the Remarks
	PMSL	plot sea-level pressure for pressure values if the PLOT option is specified, or use sea-level pressure when computing station pressure for use in the equations that generate the plotted values if the PSTN, MIX, THA or THAE option is specified
UNIt=	units for the specified parameter; see the Remarks for defaults; run the CU LIST command to list the valid units and abbreviations for the parameters that can be changed

Remarks

SFCPLOT builds and runs a PTDISP command to display surface hourly data from ISFC-schema point files. SFCPLOT accepts all the keywords in the PTDISP command except LAT, LON, MAP, PRO, SLAT, SLON and PARAM because they may conflict with SFCPLOT's parameters or keywords. You can use the PTDISP SELECT keyword to limit the plot to a specified list or range of values, but you cannot specify a different parameter, time, day or unit than those defined by the SFCPLOT parameters or keywords.

The table below lists the parameter name, default units and a description of each parameter defined in the SFCPLOT.CORE file. Default units enclosed in parenthesis cannot be changed. The .CORE file is supplied with McIDAS-X and should not be modified. The .USER file overrides the .SITE file, which overrides the .CORE file. This order of precedence allows you or your site to change existing parameters and/or add new parameters in your .USER or .SITE file. To create a .USER or .SITE file, copy the .CORE file from ~mcidas/data to your $HOME/mcidas/data directory (or another MCPATH directory), rename it, then edit the existing predefined parameters and/or add new ones.

param	Default Units	Description
ID	(text)	three- or four-character ICAO station ID
OBS	(dots)	observation locations
ELEV	FT	station elevation
OBTIME	(HMS)	actual time of observation
PLOT	A	station plot of the T, ALTIM or PMSL (set with the PTYPE keyword), ID, TD and WX1 parameters in clockwise order from top left of plot, and cloud coverage symbol at the center with wind barb extending from it; units are A, for American, or M, for metric
WX1	(text)	weather type (first four characters)
WX2	(text)	weather type (next four characters)
WX	(text)	weather type (combined WX1, WX2)
WXS	(symbols)	weather type (combined WX1, WX2)
WXC	(symbols)	WMO codes for present weather (combined WXC1, WXC2, WXC3, WXC4)
T	F	temperature
CHILL	(F)	wind chill index
HEAT	(F)	heat index
TD	F	dew point temperature
MIX	(G/KG)	mixing ratio
RH	(%)	relative humidity
THA	(K)	potential temperature
THAE	(K)	equivalent potential temperature
DIR	(degrees)	wind direction
SPD	KTS	wind speed
GUS	KTS	wind gusts
WIND	(deg) KTS	two-digit wind direction and two- or three-digit speed, in the form DDSSS
WINDB	(barb)	wind barb (DIR and SPD); flag=25 mps (~50 kts), long barb=5 mps (~10 kts), short barb=2.5 mps (~5 kts)
WINDV	(vector)	wind vector (DIR and SPD)
ALTIM	MB	altimeter setting
PMSL	MB	sea-level pressure
PSTN	(MB)	station pressure
VIS	MI	visibility
PCP	IN	three- or six-hour precipitation total; three-hour total reported only at 3, 9, 15, 21 UTC; six-hour total reported only at 0, 6, 12, 18 UTC; see the Remarks
PCP3	IN	three-hour PCP total; reported only at 3, 9, 15, 21 UTC; see the Remarks
PCP6	IN	six-hour PCP total; reported only at 0, 6, 12, 18 UTC; see the Remarks
PCP24	IN	24-hour precipitation total; reported at 12 UTC; see the Remarks
SNO	IN	snow depth; reported only at 0, 6, 12, 18 UTC; see the Remarks
CAC	(code)	ceiling cloud amount; 0=clear, 5=few, 1=scattered, 2=broken, 3=overcast
CA1	(code)	first non-ceiling cloud amount; 0=clear, 5=few, 1=scattered, 2=broken, 3=overcast
CA2	(code)	second non-ceiling cloud amount; 0=clear, 5=few, 1=scattered, 2=broken, 3=overcast
SKY	(code)	sky cloud amount (combined CAC, CA1, CA2)
CZC	FT	height of cloud ceiling
CZ1	FT	height of first non-ceiling cloud layer
CZ2	FT	height of second non-ceiling cloud layer

The time default is the current hour for all parameters except PCP, PCP3, PCP6, PCP24 and SNO. Because PCP and SNO are not reported every hour in METAR reports, the default for these parameters is the most recent hour storing the data. PCP is reported every three hours starting at 0 UTC. PCP3 represents the three-hour totals in PCP; it is reported at 3, 9, 15, and 21 UTC. PCP6 represents the six-hour totals in PCP; it is reported at 0, 6, 12, and 18 UTC. PCP24 represents the 24-hour precipitation totals and is reported at 12 UTC only. SNO is reported every six hours at 0, 6, 12, and 18 UTC.

This means, for example, that the time default for PCP is 0 if the current time is between 0:00 and 2:59 UTC; the time default for PCP3 is 3 if the current time is between 3:00 and 8:59 UTC; the time default for SNO and PCP6 is 6 if the current time is between 6:00 and 11:59 UTC. The time default for PCP24 is 12 UTC today if the current time is between 12:00 and 23:59 UTC, and is 12 UTC yesterday if the current time is between 0:00 and 11:59 UTC.

If you specify both a time difference (time1-time2) and a day difference (day1-day2), SFCPLOT plots the values equal to the parameter at time1,day1 minus the parameter at time2,day2. If you specify a parameter difference (par1-par2) with a time difference and day difference, SFCPLOT plots the values equal to the parameter difference at time1,day1 minus the parameter difference at time2,day2. For example,
SFCPLOT T-TD MID 0-12 2000123-2000122 plots the values equal to the dewpoint depression at 0UTC, day 2000123 minus the dewpoint depression at 12UTC, day 2000122.

Parameters with their default units enclosed in parenthesis in the table above (e.g., ID, CHILL and THA) cannot be used with the differencing options (par1-par2, time1-time2 and day1-day2).

In the PTYPE keyword, specify either PMSL or SLP for sea-level pressure, and ALT, ALTM or ALTIM for altimeter setting. The default is ALT for the PLOT option and the calculated options that contain station pressure in their equations (PSTN, MIX, THA and THAE). Altimeter setting is the default in the calculated options because it's correct to use it (rather than sea-level pressure) when computing station pressure for use in the equations.

The cloud coverage symbols displayed with the PLOT option depict the maximum cloud amount (CLR, FEW, SCT, BKN or OVC) reported in the ISFC-schema MD files cloud coverage keys (CIGC, CC1 and CC2). The symbols and sky coverage in oktas for each amount (sources: NOAA-1 | NOAA-2 | Texas A&M) are shown below.

Examples

SFCPLOT

This entry plots station model data for the current day and time using the navigation of the current frame.

SFCPLOT T MID DECLUT=NO

This entry plots temperature over a map of the Midwest for the current day and time. The data is not decluttered, so all data is plotted and some values may overlap.

SFCPLOT PCP6 UNIT=MM

This entry plots the most recent six-hour precipitation totals in millimeters using the navigation of the current frame. For example, if the current time is 17 UTC, the 12 UTC data is plotted since six-hour precipitation totals are reported only at 0, 6, 12 and 18 UTC.

SFCPLOT WINDB USA 22 COLOR=7 LSIZE=12 SELECT='SPD[KTS] 25 200' DECLUT=NO TITLE='22 UTC winds of at least 25 knots' 7 420 150

This entry plots wind barbs for all 22 UTC wind speeds of 25 knots or greater over the United States. The barbs are drawn in graphics color level 7 with a plot size of 12 pixels. The default title below the plot is replaced with the text 22 UTC winds of at least 25 knots near the center of the frame in graphics color level 7. SELECT and TITLE are PTDISP keywords.

SFCPLOT SNO NA 12 17/JAN/1996 DATASET=CLIMATE/1996 DECLUT=NO

This entry plots all snow depth reports over a map of North America at 12 UTC on 17 January 1996 using the data in the dataset CLIMATE/1996. The data is not decluttered, so all data is plotted and some values may overlap.

SFCPLOT T OK 18 2000130-2000129

This entry plots the 24-hour temperature change in degrees Celsius from 18 UTC, day 2000129 to 18 UTC, day 2000130 over a map of Oklahoma.

SFCPLOT MIX FL

This entry plots mixing ratio over a map of Florida for the current day and time. It uses the default for the PTYPE keyword, meaning that altimeter setting is used when computing station pressure for use in the mixing ratio calculation.

SFCPLOT PSTN CO 12 PTYPE=PMSL

This entry plots station pressure over a map of Colorado at 12 UTC of the current day. Mean sea-level pressure is used instead of altimeter setting when calculating the station pressure values. This may yield some error in the values, with higher station elevations usually having larger errors.

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