RAMMB: GOES-R Proving Ground Blog

Upon inspection of the synthetic infrared (10.35 micron) imagery from the NSSL WRF-ARW model: http://rammb.cira.colostate.edu/templates/loop_directory.asp?data_folder=training/visit/loops/13oct11_syn_ir your attention may be drawn to the region of southwest Colorado since we see a region of cold brightness temperatures  that does not move and persists for the duration of the loop (1600-0000 UTC).  Could these be low clouds / fog? Let’s look at the GOES visible imagery for 1630 UTC: Skies are clear across southwest Colorado, so we are not looking at low clouds / fog.  However, note that there is snow cover over the mountains. What we’re looking at in the synthetic imagery…

Let’s analyze the following loop of the synthetic fog product, generated from the 4-km NSSL WRF-ARW model: http://rammb.cira.colostate.edu/templates/loop_directory.asp?data_folder=training/visit/loops/10oct11_syn_fog/ In this color table, grey into light blue represents increasing confidence in liquid water clouds.  Our example from the 0000 UTC 10 October 2011 NSSL WRF-ARW model run shows a large area of liquid water clouds (most likely stratus) across Texas extending northward through the central US.  The darker shades of grey and black correspond to ice clouds (most likely cirrus) forecast by the model. The region of blue in Arizona and Utah extending southward into northwest Mexico that does not move…

Synthetic satellite imagery can be useful in forecasting temperature.  This example from September 20-21, 2011 demonstrates the utility of synthetic imagery from the 4-km NSSL WRF-ARW model in forecasting the overnight low temperature. Focusing on southeast Wyoming, examine the synthetic infrared imagery from late afternoon (2000 UTC) through the late night hours (0800 UTC): http://rammb.cira.colostate.edu/templates/loop_directory.asp?data_folder=training/visit/loops/20sept11_syn&image_width=800&image_height=600 Early in the loop, there is afternoon convective clouds in southeast Wyoming, which diminishes by 0300 UTC.  However, notice the region of clouds (indicated by the colder brightness temperatures) developing across southeast Wyoming in the 0300-0800 UTC time range.  If the forecast is correct, the…

A new synthetic difference product is now being produced from the NSSL WRF-ARW output: the fog product, or 10.35 – 3.9 μm.  In order to generate synthetic 3.9 μm imagery in a timely manner, it’s necessary to assume that it’s always night because the solar reflected calculations are too expensive.  This allows the traditional fog product to be displayed for all forecast hours of the WRF.  In the example above, the color scheme for the synthetic fog product (left) is designed such that grey into light blue represents increasing confidence in liquid water clouds.  Note the forecast stratus clouds in the…

Synthetic imagery from the 4-km NSSL-WRF ARW model is produced at CIRA and is available in real-time here: https://ramsdis.cira.colostate.edu/ramsdis/ The following loop shows Hurricane Irene at the time it was east of Florida: https://ramsdis.cira.colostate.edu/loop?data_folder=dev/lindsey/loops/nssl_wrf_g13_irene&image_width=1024&image_height=384 The right side shows the synthetic infrared imagery from the 0000 UTC 25 August model run, and the corresponding GOES infrared imagery is on the left.  Keep in mind some of the known biases with the model such as brightness temperatures typically warmer than GOES, and anvil cirrus from convection that is typically underdone.  Synthetic imagery can be compared with GOES imagery to look for forecast…

For this blog entry, we’ll consider applications of the NSSL 4-km WRF-ARW model synthetic imagery towards a severe weather event that occurred on June 22, 2010.  The synthetic imagery is one of the GOES-R proving ground real-time products.   Synthetic imagery is model output that is displayed as though it is satellite imagery.  Analyzing synthetic imagery has an advantage over model output fields in that the feature of interest appears similar to the way it would appear in satellite imagery.   The primary motivation for looking at synthetic imagery is that you can see many processes in an integrated way compared…

On the morning of 19 Jan. 2011, a nice example of using the simulated WRF imagery to forecast low clouds presented itself.  The image on the right is the 17-hour forecast from the 00Z WRF run, and low clouds are evident in the Arkansas River Valley in southeast Colorado, as denoted with the arrow.  The left image is the corresponding GOES-13 IR image at 17 UTC, showing that these clouds were indeed observed.  A forecaster might then look at the forecast images over the next several hours to see whether the model dissipates the clouds.