Night Microphysics RGB changes as convection develops over the Texas panhandle
The mp4 animation above (produced using CSPP Geosphere‘s latest beta version) shows strong convection over Oklahoma and the eastern Texas panhandle, with lower clouds (in a bluish hue) over the northwestern Texas panhandle. With time, the Night Microphysics RGB acquires a reddish hue (as cloud tops cool), and then convection develops. A nowcaster can use changes in the colors of this RGB to anticipate initiation. (A similar recent example is shown here).
The AWIPS imagery from 0701 UTC below shows the RGB with Level 2 Products: Cloud Top Phase — showing liquid water clouds over Texas where the RGB suggests low clouds, and Cloud Top Temperature — where values of 7-8oC are common. The default color table Cloud Top Temperature has been changed. Recall also that the Level 2 Cloud Top Temperature product is not produced for the CONUS sector, so Full-Disk values are shown. Surface winds suggest low-level convergence: winds are northeasterly over the NW Texas panhandle, and southeasterly to easterly over the southern portions of the Texas panhandle. GOES-16 Cloud Top Heights (not shown) show cloud heights around 12000 feet over the NW Texas panhandle.
Fifty minutes later, at 0751, the band of low clouds over the northeastern Texas panhandle has reddened somewhat (click here for a toggle between 0701 and 0751). Cloud top temperatures in that cloud band have dropped to between 1o and 4oC, and cloud top heights have increased to 14000 feet. Cloud-top phase is still liquid however (except over northern New Mexico, as might be inferred by the yellower tinge to those low clouds in the RGB). There is also a red tint to the RGB just north of the obvious east-west band of clouds near the Hereford TX airport (where the temperature and dewpoint are 65 and 60, respectively, and no wind is reported). Convective initiation is likely occurring in these regions.
From 0801 to 0816 UTC, shown below, supercooled clouds are noted, as the Night Microphysics RGB continues to redden. By 0816 UTC, mixed phase clouds are noted in the line developing near Hereford. Cloud-top heights increase from 15000 to 21000 feet between 0811 and 0816 UTC.
By 0826 UTC, Cloud Tops are shown to include ice over the line developing over the east-central part of the Texas panhandle.
A rocking animation of the 4-panels above, from 0801 to 0901 (and back) is here. If convection is expected overnight, and low clouds are present, use the Night Time Microphysics RGB to monitor when convection might initiate. Color changes in the low clouds give important information.
