NCC, GOES-16 and the Pacific Northwest

Another round of storms are headed for the Pacific Northwest, bringing high winds and precipitation. Updates on the storms can be seen via the following link.

An observer on the ground can see the current storm via satellite, utilizing polar-orbiting data. A data product that comes from the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument on-board the Suomi-National Polar-orbiting Partnership (Suomi-NPP) satellite is the Near-Constant Contrast (NCC). The NCC is a derived product of the Day/Night Band (DNB) sensor which utilizes a sun/moon reflectance model to illuminate atmospheric features, sense emitted lights and assists with cloud monitoring during the nighttime. Figure 1 below shows the NCC image in AWIPS-II displaying the synoptic-scale storm over the western part of the United States at 0935Z, 7 April 2017. In this case, the NCC can show the location of the storm, recognize clouds and snow via reflected moonlight, sense the emitted city lights and highlight the gas flares in western North Dakota. In the top-right hand corner of Figure 1, the moon percent visibility and moon elevation angle are provided where a positive moon elevation angle implies that the moon is above the horizon, which in turn, provides crisp, distinct satellite imagery.

                                                             Figure 1

Picture1

Although the NCC does express limitations, with one of them in that users can only receive two satellite images per day (one during the day, one during the nighttime), users can use NCC in complement to the new GOES-16 data that just arrived within the past month in tracking storms. In Animation 1 below, utilizing the same domain in AWIPS-II, GOES-16 visible imagery (0.64um) was loaded and users can see the most-recent updates of the evolution of the storm, as it moves northward throughout the state of Washington. GOES-16 data ranges from 13-19Z, 7 April 2017.

                                                             Animation 1

animation

Disclaimer: The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing.  Users bear all responsibility for inspecting the data prior to use and for the manner in which the data are utilized.

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Lake-effect showers off Salt Lake and Seasonal Lakes

The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing.  Users bear all responsibility for inspecting the data prior to use and for the manner in which the data are utilized.

By Darren Van Cleave (NWS Salt Lake City)

On the morning of April 4, lake-effect showers existed off Salt Lake of Utah, as seen in the GOES-16 0.64 micron “Red” visible band:

lakeEffectRedVis

 

This temporal resolution (every 5 minutes) essentially offered information at the same rate as radar scans on the band’s development and movement. The spatial resolution also reveals interesting convective details.

For a comparison with current GOES 15 imagery, there are up to 4 visible images available (depending on system legacy):

new_goes_vis_loop

 

This comparison illustrates how valuable the temporal resolution can be, regardless of GOES-16 becoming GOES-East or GOES-West.

For overnight feature identification, we can also compare improvements between current GOES-IR:

goes15_IR

and the GOES-16 IR band:

goes16_IR

Several seasonal “lakes” in western Utah have standing water currently (including the relatively rate Sevier “Lake”), this can be easily seen in the 0.86 micron “Veggie” band on GOES-16 since this band offers significant contrast between water and land surfaces as water surfaces are quite dark:

seasonalLakesVeggie

 

compare this to the 0.64 micron “Red” visible band:

seasonalLakesRedVis

the same features are more difficult to discern.

This illustrates that the water/land differences of the 0.86 micron “Veggie” band are useful beyond just coastal regions.  As shown here, it even has utility in the Great Basin.

Posted in Convection, GOES R, Lake Effects | Leave a comment

23 March 2017 Convection and Dust in Texas / New Mexico

The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing.  Users bear all responsibility for inspecting the data prior to use and for the manner in which the data are utilized.

On the afternoon of 23 March 2017, an upper level trough in the western US moving eastward was responsible for a strong lee cyclogenesis event.  The mesoscale sector for GOES-16 observed convection along the dryline with blowing dust on either side of it:

http://rammb.cira.colostate.edu/templates/loop_directory.asp?data_folder=training/visit/loops/23mar17/vis_meso&loop_speed_ms=80

The dust is lighter in color.  To the east of the dryline, it’s oriented in boundary layer rolls oriented NNW-SSE while west of the dryline where the boundary layer is much deeper in a hot / dry air mass, the dust is much more widespread.  What additional details can you see in the convection that you normally would not see with GOES-13/15?

In a GOES-16 4 panel loop showing all 3 water vapor bands in addition to the RGB Air Mass Product:

http://rammb.cira.colostate.edu/templates/loop_directory.asp?data_folder=training/visit/loops/23mar17/wv_amrgb&loop_speed_ms=80

What additional features do you see?  Do you see the blowing dust in any of the water vapor bands?  Why would the dust be observed in these band(s)?  Hint, see the weighting function profile for the 3 GOES-16 water vapor bands, based on the sounding from Amarillo, TX at 0000 UTC 24 March:

ama_wf

 

Remember that the weighting function profile is valid for clear skies only

Posted in Convection, Dust, GOES R, Severe Weather | Comments Off

24 March 2017 fog / low stratus in the West

The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing.  Users bear all responsibility for inspecting the data prior to use and for the manner in which the data are utilized.

On the morning of 24 March 2017, there were some interesting fog / low stratus events in the West.  In northeast Montana, we can see fog surging up the Milk River Valley in the GOES-16 visible imagery:

http://rammb.cira.colostate.edu/templates/loop_directory.asp?data_folder=training/visit/loops/24mar17/MT&loop_speed_ms=80

Saturated soil (due to snowmelt runoff flooding) from the Big Muddy Creek contributed to the fog event:

Meanwhile, at the same time in Arizona we see fog / low stratus sloshing back and forth (most likely in a canyon or valley) south of Sedona:

http://rammb.cira.colostate.edu/templates/loop_directory.asp?data_folder=training/visit/loops/24mar17/AZ&loop_speed_ms=80

 

Posted in Ceilings, Fog, GOES R, Orographic Effects, Visibility | Comments Off