VIIRS DNB Reflectance & NT Microphysics RGBs Assist Low Cloud Forecast

Numerous showers and thunderstorms over eastern NM on Wednesday, July 31, 2013 left behind significant atmosphere moisture and wet soils over the region.  A low cloud deck that was expected to develop over eastern as indicated by several guidance members did not pan out.  The day shift aviation forecaster anticipated broken low cloud development at the Las Vegas (KLVS) TAF site around 10Z Thursday, August 1, 2013.  The following shift continued to mention the MVFR low cloud ceilings on the 06Z TAF cycle.  The 850-700mb layer humidity from the 08Z RUC13 model still indicated low cloud development over much of eastern NM (Figure 1).  A VIIRS satellite pass at 0816Z across this region indicated low cloud development was not occurring around Las Vegas.  The hybrid 11-3.9micron imagery at this time showed a mixed area of low and mid level cloud cover as indicated by the blue and yellow pixels over northeastern NM and southeastern CO (Figure 2).  The Colorado Springs, CO observation supports the low cloud deck at 2,200′ where a widespread area of yellow is observed.  The VIIRS Reflectance RGB imagery (Figure 3) indicates cloud cover over this area but does not offer much information about its thickness or height on first inspection.  There are a few interesting features in this image including lightning flashes over eastern NM and city lights around Colorado Springs.  The low cloud cover in this area must then be very thin.  The NT Microphysics shows the most significant amount of detail in this area.  The low clouds clearly stand out from the mid level cloud deck over the entire region.  Given the lack of low cloud development based on satellite imagery and observations, the KLVS TAF was amended to remove the mention of a broken MVFR cloud deck prior to the issuance of the 12Z TAF cycle.

08Z 08/01/2013 RUC13 850-700mb Layer Humidity for Eastern NM.

Figure 1. 08Z 08/01/2013 RUC13 850-700mb Layer Humidity for Eastern NM.

0816Z 08/01/2013 Hybrid 11-3.9micron.

Figure 2. 0816Z 08/01/2013 Hybrid 11-3.9micron.

0816Z 08/01/2013 VIIRS DNB Reflectance RGB.

Figure 3. 0816Z 08/01/2013 VIIRS DNB Reflectance RGB.

0816Z 08/01/2013 VIIRS NT Microphysics.

Figure 4. 0816Z 08/01/2013 VIIRS NT Microphysics.

One thought on “VIIRS DNB Reflectance & NT Microphysics RGBs Assist Low Cloud Forecast

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s