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<p class=MsoNormal>THU 10MAY07: 0940PDT<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Hi<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I was wondering if anyone has done Heat Index (HI) plotting
in GRADS? I have the correct HI formula, but I get erroneous output since GRADS
is calculating the HI at every point for every temp. However, HI should only be
calculated for temps > 80F (26C). So, what happens is, GRADS calculates the
HI for values < 80F (< 26C) when these points should NOT have HI values
and the plot is a mess – showing both valid and non-valid HI values. I am
pretty adept using GRADS, however, I’ve been working on this for days and
can’t seem to figure out how to get GRADS to ignore values below the HI
threshold. Has anyone come across this problem before? I am using GFS data.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Many thanks!<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Below is a typical GRADS script for producing HI. <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Regards</span><span
style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'> <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Kevin
M Levey, MSc (University of Cape Town)</span><span style='font-size:12.0pt;
font-family:"Times New Roman","serif"'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Director
of Meteorological Operations</span><span style='font-size:12.0pt;font-family:
"Times New Roman","serif"'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>CustomWeather,
Inc</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>San
Francisco, CA, USA</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'> <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><a
href="http://www.1stweather.com"><span style='font-size:10.0pt;font-family:
"Verdana","sans-serif";color:blue'>http://www.1stweather.com</span></a><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'><a
href="http://www.myforecast.com"><span style='color:blue'>http://www.myforecast.com</span></a></span><span
style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><a
href="http://www.customweather.com"><span style='font-size:10.0pt;font-family:
"Verdana","sans-serif";color:blue'>http://www.customweather.com</span></a></span><o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<div style='mso-element:para-border-div;border:none;border-bottom:dotted windowtext 3.0pt;
padding:0in 0in 1.0pt 0in'>
<p class=MsoNormal style='border:none;padding:0in'><o:p> </o:p></p>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>*002hr 0 DAY 1<o:p></o:p></p>
<p class=MsoNormal>'set mpdset hires'<o:p></o:p></p>
<p class=MsoNormal>'set mpt * off'<o:p></o:p></p>
<p class=MsoNormal>'set mpt 0 1 1 6'<o:p></o:p></p>
<p class=MsoNormal>'set mpt 1 1 1 1'<o:p></o:p></p>
<p class=MsoNormal>'set display color white'<o:p></o:p></p>
<p class=MsoNormal>'clear'<o:p></o:p></p>
<p class=MsoNormal>'open /prod/custom/intModel/GFS/temp/gfs_001.ctl'<o:p></o:p></p>
<p class=MsoNormal>'set xsize 800 600'<o:p></o:p></p>
<p class=MsoNormal>'set lat -36 -16'<o:p></o:p></p>
<p class=MsoNormal>'set lon 10 36'<o:p></o:p></p>
<p class=MsoNormal>'set map auto 1 1 6'<o:p></o:p></p>
<p class=MsoNormal>'set lev 1000'<o:p></o:p></p>
<p class=MsoNormal>'define temp = TMP2M - 273.16' <o:p></o:p></p>
<p class=MsoNormal>'define tempF = (temp *1.8) +32'<o:p></o:p></p>
<p class=MsoNormal>'define v = VGRDprs*3.6'<o:p></o:p></p>
<p class=MsoNormal>'define u = UGRDprs*3.6'<o:p></o:p></p>
<p class=MsoNormal>'define windkmh = mag(u,v)'<o:p></o:p></p>
<p class=MsoNormal>'define rh = RH2M'<o:p></o:p></p>
<p class=MsoNormal>'define HI = ((-42.379 + (2.04901523*tempF) +
(10.14333127*rh) - (0.22475541*tempF*rh) - (0.00683783*pow(tempF,2)) -
(0.05481717*pow(rh,2)) + (0.00122874*pow(tempF,2)*rh) +
(0.00085282*tempF*pow(rh,2)) - (0.00000199*pow(tempF,2)*pow(rh,2)))-32)*5/9'<o:p></o:p></p>
<p class=MsoNormal>*draw heat index map<o:p></o:p></p>
<p class=MsoNormal>'run /prod/custom/intModel/GFS/scripts/rgbset_HI1.gs'<o:p></o:p></p>
<p class=MsoNormal>'set gxout shaded'<o:p></o:p></p>
<p class=MsoNormal>'set cint 2.5'<o:p></o:p></p>
<p class=MsoNormal>'set cmin 40'<o:p></o:p></p>
<p class=MsoNormal>'set csmooth on'<o:p></o:p></p>
<p class=MsoNormal>'set grads off'<o:p></o:p></p>
<p class=MsoNormal>'d HI'<o:p></o:p></p>
<p class=MsoNormal>'set ccolor 0'<o:p></o:p></p>
<p class=MsoNormal>'set gxout contour'<o:p></o:p></p>
<p class=MsoNormal>'set cint 2.5'<o:p></o:p></p>
<p class=MsoNormal>'set cmin 30'<o:p></o:p></p>
<p class=MsoNormal>'set csmooth on'<o:p></o:p></p>
<p class=MsoNormal>'d HI'<o:p></o:p></p>
<p class=MsoNormal>'run /prod/custom/intModel/GFS/scripts/SA_cities.gs'<o:p></o:p></p>
<p class=MsoNormal>'run /prod/custom/intModel/GFS/scripts/cbarn'<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>'draw title HEAT INDEX (C)\INIT: 12UTC 13MAR07 VALID:
02H00 TUE 13 MAR 2007'<o:p></o:p></p>
<p class=MsoNormal>'printim /prod/custom/intModel/GFS/temp/GFS_HEAT_INDEX_PLOT1.png
png x800 y600'<o:p></o:p></p>
<p class=MsoNormal>'reinit'<o:p></o:p></p>
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