National Weather Service Data

tmpsfc (surface air temperature, K)
tmp2m (air temperature at 2m, K)

rh2m (relative humidity at 2m, %)

rerddap::info('ncep_global')

<ERDDAP info> ncep_global
 Base URL: https://upwell.pfeg.noaa.gov/erddap/
 Dimensions (range):
     time: (2011-05-06T12:00:00Z, 2020-07-08T12:00:00Z)
     latitude: (-90.0, 90.0)
     longitude: (0.0, 359.5)
 Variables:
     dlwrfsfc:
         Units: W m-2
     dswrfsfc:
         Units: W m-2
     pratesfc:
         Units: kg m-2 s-1
     prmslmsl:
         Units: Pa
     rh2m:
         Units: %
     tmp2m:
         Units: K
     tmpsfc:
         Units: K
     ugrd10m:
         Units: m s-1
     vgrd10m:
         Units: m s-1

On Jul 6, 2020, at 5:47 PM, Philip <herd_dog at cox.net> wrote:

Thanks for getting back to me.  It is good to know that I am on the right 
track.

I understand now that the output byte location of the data in the grib2 
file not the actual data which in this case would be the 2 am forecast six 
hours into the future.  Can you advise me which of the examples in Dr. 
Bowman's rNOMADS documentation will get me the tem[perature and relative 
humidity data?

Philip.

-----Original Message----- From: Roy Mendelssohn - NOAA Federal
Sent: Monday, July 6, 2020 10:43 AM
To: Philip
Cc: stephen sefick ; r-help
Subject: Re: [R] National Weather Service Data

Hi Philip:

Results look correct to me.  This might help you:

https://www.cpc.ncep.noaa.gov/products/wesley/wgrib2/default_inv.html

-Roy

On Jul 6, 2020, at 9:29 AM, Philip <herd_dog at cox.net> wrote:

I am trying to access National Weather Service forecasting data through 
the rNOMADS package.  I?m not sure if the Weather Service software ? 
grib2 ? loaded correctly.  Second, some of the examples in the rNOMADS 
documentation seem to run correctly but I?m not sure what the output 
means.  Any anvise would be greatly appreciated.

1 - I tried to load the wgrib2 software from instructions in the 
following website:

https://bovineaerospace.wordpress.com/2015/04/26/how-to-install-rnomads-with-grib-file-support-on-windows/

2 ? the instructions say that if it loaded correctly I should get a 
laundry list similar to what is below from the command: 

 >system(?wgrib2?).

The list I get looks different.  Below is the first 20 or so entries. 
How can I check to see if the wgrib2 loaded correctly?

wgrib2 v0.1.9.9 9/2013 Wesley Ebisuzaki, Reinoud Bokhorst, Jaakko 
Hyv??tti, Dusan Jovic, Kristian Nilssen, Karl Pfeiffer, Pablo Romero, 
Manfred Schwarb, Arlindo da Silva, Niklas Sondell, Sergey Varlamov
-0xSec           inv  X      Hex dump of section X (0..8)
-MM              inv         reference time MM
-N_ens           inv         number of ensemble members
-RT              inv         type of reference Time
-S               inv         simple inventory with minutes and seconds 
(subject to change)
-Sec0            inv         contents of section0
-Sec3            inv         contents of section 3 (Grid Definition 
Section)
-Sec4            inv         Sec 4 values (Product definition section)
-Sec5            inv         Sec 5 values (Data representation section)
-Sec6            inv         show bit-map section
-Sec_len         inv         length of various grib sections
-T               inv         reference time YYYYMMDDHHMMSS
-V               inv         diagnostic output
-VT              inv         verf time = reference_time + forecast_time 
(YYYYMMDDHHMMSS)
-YY              inv         reference time YYYY

3 ? As I said, some of the documentation examples work and for some I get 
error messages.  Below is an example of one that seemed to work but I don?t 
understand the output.

#GribInfo - page 20
urlsOut <- CrawlModels(abbrev="gfs_0p50",depth=2)
ModelParameters <- ParseModelPage(urlsOut[2])#[1] is most recent model
MyPred <- ModelParameters$pred[grep("06$",ModelParameters$pred)]
 Levels <- c("2_m_above_ground","800_mb")
 Variables <- c("TMP","RH")
 GribInfo <- GribGrab(urlsOut[2],MyPred,Levels,Variables)
GribInv <- GribInfo(GribInfo[[1]]$file.name,"grib2")

The command GribInv$inventory returns:

$inventory
[1] "1:0:d=2020070606:TMP:800 mb:6 hour fcst:" 
"2:148450:d=2020070606:RH:800 mb:6 hour fcst:"
[3] "3:414132:d=2020070606:TMP:2 m above ground:6 hour fcst:" 
"4:571266:d=2020070606:RH:2 m above ground:6 hour fcst:"

This is supposed to be temperature and relative humidity 2 meters above 
the ground and at 800 milibars for 2020 ? July 6 ? at ZULU time 0600. 
But I have no idea what the numbers 414132 ? second line ? mean.

Any advise would be greatly appreciated.

Philip Heinrich

From: stephen sefick
Sent: Thursday, July 2, 2020 3:20 PM
To: Philip
Cc: r-help
Subject: Re: [R] National Weather Service Data

I am unfamiliar with Rnomads. Could you provide a minimal reproducable 
example? You are more likely to receive help this way.


On Thu, Jul 2, 2020, 18:06 Philip <herd_dog at cox.net> wrote:

Is anyone out there familiar with rNOMADS?  It is a package to get into 
National Weather Service forecasting data with R?

I'm not sure the Weather Service software named wgrib2 loaded correctly 
because some of the stuff won't run and I can't make much sense out of 
some of the output.

Thanks.
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Government or NOAA."
**********************
Roy Mendelssohn
Supervisory Operations Research Analyst
NOAA/NMFS
Environmental Research Division
Southwest Fisheries Science Center
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Phone: (831)-420-3666
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e-mail: Roy.Mendelssohn at noaa.gov www: https://www.pfeg.noaa.gov/

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Jr.