Observed vs. NAM and Parallel Forecast PBL Soundings

This site contains a two-week archive of animations comparing forecast soundings from the operational NAM and the real-time parallel runs with observed soundings.   Skew-T plots go up to 600 mb, focusing on the PBL at 3-h resolution, and are available from sites over CONUS and the Caribbean out to 48h.   The companion page comparing full tropospheric profiles every 12h out to 84h is available here.

For cycles starting from 2008080112 and later, each plot compares the following:

  • Observed soundings with winds are plotted in thick, bold black lines and are labeled "Obs" at the bottom of the plots.

  • Parallel NAMY soundings are plotted with winds in red.   The NAMY is run with partial cycling and changes to cloud radiation and the LSM during winter.

  • Parallel NAMEXP soundings are plotted with winds in blue.   The NAMEXP is the same as the NAMY, but with the new, modified shallow convection.

  • Parallel NAMX soundings are plotted with no winds in green.   The NAMX is run with partial cycling.

    • *** Compare the blue versus red profiles to evaluate the impact of the new shallow convection ***

    *** Compare the red versus green profiles to evaluate the impact of the cloud radiation change and the winter LSM change ***

    Values of CAPV (CAPE computed using virtual temperature), CINV (CIN computing using virtual temperature), and LCLP are displayed at the top for the observed sounding (1st row), the parallel NAMY (original shallow convection, 2nd row), and the NAMEXP (new shallow convection, 3rd row).   Along the right side of the plot are shown the observed winds (left, black), forecast winds from the NAMY parallel (middle, red), and the NAMEXP parallel (right, blue).   At the top of the page, the feature (blue links) is used to display different forecast hours every 3 h out to 48 h.

    For cycles starting from 2008080100 and earlier, each plot compares the following:

  • Observed soundings with winds are plotted in thick, bold black lines and are labeled "Obs" at the bottom of the plots.

  • Parallel NAMX soundings are plotted with winds in red.   The NAMX is run with partial cycling with the original shallow convection.

  • Parallel NAMY soundings are plotted with winds in green.   The NAMY is run with partial cycling with the new, modified shallow convection.

  • Operational NAM soundings are plotted with no winds in blue.

    • *** Compare the green versus red profiles to evaluate the impact of the new shallow convection, both with the new partial cycling ***

    *** Compare the red versus blue profiles to evaluate the impact of partial cycling, both with the original shallow convection ***

    Values of CAPV (CAPE computed using virtual temperature), CINV (CIN computing using virtual temperature), and LCLP are displayed at the top for the observed sounding (1st row), the parallel NAMX (original shallow convection, 2nd row), and the NAMY (new shallow convection, 3rd row).   Along the right side of the plot are shown the observed winds (left, black), forecast winds from the NAMX parallel (middle, red), and the NAMY parallel (right, green).   At the top of the page, the feature (blue links) is used to display different forecast hours every 3 h out to 48 h.

    Links to NAM parallel runs matched with rawinsonde observations for the past 2 weeks

    20080825 20080824 20080823 20080822 20080821 20080820 20080819
    12z 12z 12z 12z 12z 12z 12z
    00z 00z 00z 00z 00z 00z 00z
    20080818 20080817 20080816 20080815 20080814 20080813 20080812
    12z 12z 12z 12z 12z 12z 12z
    00z 00z 00z 00z 00z 00z 00z

    Disclaimer: This web page is not "operational" and therefore not subject to 24-h monitoring by NCEP's Central Operations staff.   These products are experimental and are intended for internal use at EMC.

    For more information contact:

  • Brad Ferrier on the contents of this page,

  • Geoff DiMego, Head of the Mesoscale Modeling Branch

    • (Page last updated on 16 July 2008)