Why 1-Minute data matters: Tracking Cloud Layers in a Winter Storm

February 5th, 2016 |
GOES-14 Visible (0.63 µm) images, 1-minute time-step [click to play rocking animated gif]

GOES-14 Visible (0.63 µm) images, 1-minute time-step [click to play rocking animated gif]

There are two animations a the top of this blog post, one with a 1-minute timestep, above, and one with a 15-minute timestep, below. The strong winter storm that hit Colorado on Monday 1 February (Blog Post) was accompanied by multiple cloud layers and snow during the day on Monday was not steady. Was it related to the holes that are present in the clouds? How easy is it to track the different clouds to predict the arrival, overhead, of a gap in the high clouds? Especially for the low clouds in eastern Colorado in this example, cloud hole tracking can be done with more confidence with 1-minute imagery. Decision Support related to short time-scale variability in snow accumulations can be done with more confidence with the 1-minute imagery.

GOES-14 Visible (0.63 µm) images, 15-minute time-step [click to play rocking animated gif]

GOES-14 Visible (0.63 µm) images, 15-minute time-step [click to play rocking animated gif]


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On 7 February 2016, GOES-14 in SRSO-R monitored the development of a very strong storm over the Atlantic Ocean (blog post) east of the United States. Consider the animations below, starting with the standard GOES-East time steps (nominally every 15 minutes with some gaps). If you are monitoring the storm development, or the motion of the individual convective clouds, the 15-minute temporal gaps are insufficient for confident detection of cloud motions. When, for example, does the surface circulation first appear? Do the cloud towers that appear in the 15-minute animation persist over the course of 15 minutes, or do they decay and reappear? In the succeeding animations below, at 5- and 1-minute intervals, increasing amounts of detail are present because the better temporal resolution is convincingly following features. Additionally, the precise timing of events is better captured.

GOES-14 Visible (0.63 µm) images, 15-minute time-step [click to play animated gif]

GOES-14 Visible (0.63 µm) images, 15-minute time-step [click to play animated gif]

GOES-14 Visible (0.63 µm) images, 15-minute time-step [click to play animated gif]

GOES-14 Visible (0.63 µm) images, 5-minute time-step [click to play animated gif]

GOES-14 Visible (0.63 µm) images, 15-minute time-step [click to play animated gif]

GOES-14 Visible (0.63 µm) images, 1-minute time-step [click to play animated gif]

The differences between 1-, 5- and 15-minute time steps are visualized in the rocking animation below. The right-most panel has a 15-minute timestep always, the middle panel starts with a 15-minute time step before switching to 5-minute, and the left-most panel shows 15-minute, 5-minute and 1-minute time steps. Note how the convective towers appear and disappear on timescales that make resolution in the 5-minute time step difficult and in the 15-minute timestep impossible. The region below is excised from the animations above, and is over the ocean south of the developing low pressure system.

GOES-14 Visible (0.63 µm) images, 15-minute time-step (right panel), 15-minute then 5-minute time step (middle panel) and 15-minute, then 5-minute, then 1-minute time step (left panel) [click to play animated gif]

GOES-14 Visible (0.63 µm) images, 15-minute time-step (right panel), 15-minute then 5-minute time step (middle panel) and 15-minute, then 5-minute, then 1-minute time step (left panel) [click to play animated gif]

GOES-14 SRSO-R: heavy snow in the Upper Midwest, severe thunderstorms in the Deep South

February 2nd, 2016 |

GOES-14 Visible (0.63 µm) images [click to play MP4 animation]

GOES-14 Visible (0.63 µm) images [click to play MP4 animation]

A strong occluded mid-latitude cyclone moved from the central Plains northeastward across the Upper Midwest on 02 February 2016 (surface analyses). This storm produced a variety of precipitation, most notably heavy snow — exceeding 12 inches at some locations in Nebraska, Iowa, Minnesota, Wisconsin, and the Upper Peninsula of Michigan (map) — and blizzard conditions. One-minute interval Super Rapid Scan (SRSO-R) GOES-14 Visible (0.63 µm) images (above; also available as a large 151-Mbyte animated GIF) showed the cloud-top shadows and textured appearance that is indicative of embedded convection — in fact, many sites in Iowa and southern Wisconsin reported thundersnow which produced snowfall rates of 1-2 inches per hour.

Farther to the south, as moisture from the Gulf of Mexico was drawn northward (GOES-14 sounder Total Precipitable Water derived product images) in advance of the eastward-moving cold frontal boundary (surface analyses) associated with the aforementioned Upper Midwest storm, areas of strong to severe thunderstorms developed across the Mississippi River and Tennessee River Valley regions during the afternoon and evening hours. GOES-14 Infrared Window (10.7 µm) images (below; also available as a large 208-Mbyte animated GIF) showed the cold cloud-top IR brightness temperatures (orange to red color enhancement) exhibited by the widespread convective activity.

GOES-14 Infrared Window (10.7 µm) images [click to play MP4 animation]

GOES-14 Infrared Window (10.7 µm) images [click to play MP4 animation]

GOES-14 Visible (0.63 µm) images [click to play MP4 animation]

GOES-14 Visible (0.63 µm) images [click to play MP4 animation]

Taking a closer look at the severe thunderstorms which produced multiple tornadoes from eastern Mississippi  into far western Alabama (SPC storm reports), GOES-14 Visible (0.63 µm) images (above; also available as a large 66-Mbyte animated GIF) revealed numerous overshooting tops; the counties where tornadoes were reported are indicated by their dashed red outlines. Another visible image animation from RAMMB/CIRA is available here. NWS storm damage surveys (Jackson MS | Birmingham AL) found EF-1 to EF-2 damage in both Mississippi and Alabama.

The corresponding GOES-14 Infrared Window (10.7 µm) images (below; also available as a large 37-Mbyte animated GIF) indicated that the coldest cloud-top IR brightness temperatures were in the -50º to -60º range (darker orange to red color enhancement), which was at or above the tropopause level according the Jackson MS and Birmingham AL rawinsonde data.

GOES-14 Infrared Window (10.7 µm) images [click to play MP4 animation]

GOES-14 Infrared Window (10.7 µm) images [click to play MP4 animation]

GOES-14 SRSO-R: Return flow of Gulf of Mexico moisture in eastern Texas; blowing dust and a wildfire in western Texas

February 1st, 2016 |

GOES-14 Visible (0.63 µm) images, with surface observations [click to play MP4 animation]

GOES-14 Visible (0.63 µm) images, with surface observations [click to play MP4 animation]

Day 1 of the 01-25 February 2016 test period of GOES-14 Super Rapid Scan Operations for GOES-R (SRSO-R) revealed some interesting features across the state of Texas. During the morning hours, the northward “return flow” of moisture from the Gulf of Mexico could be seen in the form of widespread fog and low stratus across the eastern part of the state on 1-minute interval GOES-14 Visible (0.63 µm) images (above; also available as a large 83 Mbyte animated GIF). Surface reports showed that dew point temperatures were as high as the 60s F along and just inland of the coast. GOES-13 derived products such as the MVFR Probability, LIFR Probability, and Low Cloud Thickness (FLS product training) showed the northward motion of the fog and low stratus during the preceding overnight hours.

During the afternoon hours, GOES-14 Visible (0.63 µm) images (below; also available as a large 91 Mbyte animated GIF) revealed the hazy signature of areas of blowing dust across southwest Texas, both ahead of and also in the wake of a cold frontal passage (surface analyses). Much of the blowing dust ahead of the cold front originated from dry lake beds in northern Mexico, which was then transported northeastward across Texas by strong southwesterly winds (an enhanced visible MP4 animation which shows the blowing dust better is available here). Blowing dust along and behind the cold front restricted the surface visibility to 1.0 miles at Big Spring (KBPG) and 2.5 miles at Midland (KMAF). Also note that early in the animation — beginning at 1800 UTC — there were small convective bands moving northeastward over the El Paso area, which produced light to moderate accumulating snow that reduced surface visibility to 1.0 miles at El Paso and Biggs Army Air Field (KBIF), and 2.0 miles at Ciudad Juarez, Mexico (MMCS).

GOES-14 Visible (0.63 µm) images, with surface reports [click to play MP4 animation]

GOES-14 Visible (0.63 µm) images, with surface reports [click to play MP4 animation]

GOES-14 Shortwave Infrared (3.9 µm) images (below; also available as a large 52 Mbyte animated GIF) showed the “hot spot” signature (darker black to red pixels) associated with a large grass fire which developed in the Big Bend National Park area, beginning around 2300 UTC. The hot spot was seen to diminish not long after the arrival of cooler air (lighter shades of gray) behind the cold front. Surface air temperatures were quite warm in Texas ahead of the cold front, with daytime highs of 91º F at Del Rio (KDRT)  and 95º F — the highest temperature recorded for the day in the lower 48 states — farther to the southeast at Cotulla.

GOES-14 Shortwave Infrared (3.9 µm) images [click to play MP4 animation]

GOES-14 Shortwave Infrared (3.9 µm) images [click to play MP4 animation]

GOES-14 Water Vapor (6.5 µm) images (below; also available as a large 57 Mbyte animated GIF) showed a broad ascending belt of moisture curving cyclonically over central and eastern Colorado, where moderate snow and significant accumulations were occurring at a number of locations.

GOES-14 Water Vapor (6.5 µm) images, with surface weather symbols [click to play MP4 animation]

GOES-14 Water Vapor (6.5 µm) images, with surface weather symbols [click to play MP4 animation]

A blog post discussing this ascending belt of moisture in more detail can be found here; a YouTube animation of GOES-14 Infrared Window (10.7 µm) images is available here.

===== 02 February Update =====

GOES-14 Shortwave Infrared (3.9 µm) images [click to play MP4 animation]

GOES-14 Shortwave Infrared (3.9 µm) images [click to play MP4 animation]

During the subsequent overnight  hours, an undular bore developed along and just ahead of the advancing cold front, as seen in GOES-14 Shortwave Infrared (3.9 µm) images (below; also available as a large 107 Mbyte animated GIF). A detailed view of the undular bore was also captured at 0859 UTC (3:59 AM local time) on Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (below).

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]