Hail Storm in Daytona Beach

March 6th, 2021 |

GOES-16 Convection RGB over Florida, 1431 – 1701 UTC on 6 March 2021 (Click to animate)

Accumulating hail fell in Daytona Beach FL (Link) on 6 March 2021 in association with a front over the Florida peninsula.  Preliminary storm reports from SPC (link) show reports of 1″ to 1.75″ hail. (The region was under a general thunderstorm outlook from SPC: link). The animation above shows the Convection RGB from 1431 through 1701 UTC on 6 March, bracketing the hail event over Daytona Beach near 1600 UTC. A strong white/yellow signal develops in a cell over Volusia County (Dayton Beach is within Volusia County) around 1545 UTC. This is the cell that deposits the hail.

NOAA/CIMSS ProbSevere display, 1535 UTC on 6 March 2021 (click to enlarge)

ProbHail values for this event (from this website) were small, at less than 10%. The value of ProbSevere here could be in identifying the cell responsible for the Hail, and showing values for the radar object that exceed others nearby; that is, providing guidance as to which radar cell to interrogate most often. The image above shows ProbSevere at 1535, just before a Severe Thunderstorm Warning was issued. The image below shows ProbSevere at 1600 UTC, just after the Special Marine Warning was issued (and while the Severe Thunderstorm warning was still in effect).

NOAA/CIMSS ProbSevere readout, 1600 UTC on 6 March 2021 (click to enlarge)

The time series plot for the radar object that produced the hail is shown below. Note that ProbHail (and lightning) increased (marginally) before the hail events (reported between 1535 and 1615 UTC) before collapsing.

ProbSevere values associated with Storm Object 84638, which object produced hail over Daytona Beach, 1500-1800 UTC on 6 March 2021 (click to enlarge)

There are several features in the visible imagery, below, that might be affecting the thunderstorm producing the hail. An east-west boundary is moving down the Atlantic coastline, passing through Daytona Beach around 1551 UTC. A very strong reflective signal becomes apparent after 1541 UTC as well (link): the convective cell has penetrated through the cirrus shield in the region.

GOES-16 Band 2 Visible (0.64 µm) imagery, 1431 – 1701 UTC on 6 March 2021 (click to animate)

This was a challenging forecast in a marginal environment.

Blowing dust in Texas

March 5th, 2021 |

GOES-16 Dust RGB and Split Cloud Top Phase (11.2-8.4 µm) images [click to play animation | MP4]

GOES-16 Dust RGB and Split Cloud Top Phase (11.2-8.4 µm) images [click to play animation | MP4]

GOES-16 (GOES-East) Dust RGB and Split Cloud Top Phase (11.2-8.4 µm) images (above) showed signatures of blowing dust — brighter shades of magenta/pink on the Dust RGB and darker shades of blue on the Split Cloud Top Phase images — moving southward across southwestern Texas on 05 March 2021. Winds were not particularly strong on this day (with peak gusts only in the 30-40 knot range), so the dust signatures were not as vivid as was seen in similar recent events such as 15 Jan 2021 and 30 Jan 2021. The blowing dust did restrict surface visibility to 2.5 miles at Midland, Texas (KMAF).

GOES-16 True Color RGB images created using Geo2Grid (below) did not reveal a distinct blowing dust signature until later in the day, when a more favorable forward scattering geometry helped to highlight the feature.

GOES-16 True Color RGB images [click to play animation | MP4]

GOES-16 True Color RGB images [click to play animation | MP4]

Consolidation of ice within Green Bay

March 4th, 2021 |

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the wind-driven consolidation of ice within Green Bay during the 03 March – 04 March 2021 period. Northerly winds in the wake of a cold frontal passage on 03 March led to the fracturing of land-fast ice in the far northern portion of Green Bay — this ice then began drifting south-southwestward.

By sunrise on 04 March, GOES-16 Visible images indicated that the fractured ice had continued to drift farther southward overnight, eventually merging with the land-fast ice that had been covering the southern half of Green Bay; overnight low temperatures in the upper teens to low 20s F likely aided this merger process. Note that some filaments of ice had also migrated through gaps between islands, drifting southward across far western Lake Michigan (just off the coast of Wisconsin).

A toggle between 250-meter resolution Aqua MODIS True Color RGB images (source) on the 2 days is shown below.

Aqua MODIS True Color RGB images [click to enlarge]

Aqua MODIS True Color RGB images [click to enlarge]

As an aside, farther inland the tornado damage path from an EF3 tornado in northeastern Wisconsin was still evident, 13.5 years later (below).

Aqua MODIS True Color RGB images [click to enlarge]

Aqua MODIS True Color RGB images [click to enlarge]

Snow squalls in Montana

February 27th, 2021 |

GOES-16 “Red” Visible (0.64 µm) and Day Cloud Phase Distinction RGB images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) and Day Cloud Phase Distinction RGB images [click to play animation | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Day Cloud Phase Distinction RGB images (above) showed a cluster of convective features propagating south-southeastward over and to the east of Billings, Montana on 27 February 2021. The shades of green in the RGB images indicated that some of these cloud tops were glaciating, suggesting enough vertical development to produce significant precipitation — and the resulting snow squalls could have contributed to a multi-vehicle accident which closed down Interstate 90 (between Billings and the I-90/I-94 junction) shortly after 1900 UTC. A brief accumulation of 1.3 inches was reported just north of Billings around the time of the accident, and the 1900 UTC surface visibility dropped to 3/4 mile at Billings airport (but was likely lower where the more intense snow squalls were occurring farther east).

The corresponding GOES-17 (GOES-West) Visible/RGB animations are available here: GIF | MP4. A toggle between the 1901 UTC Day Cloud Phase Distinction RGB images from GOES-16 and GOES-17 is shown below. The satellite viewing angles are nearly equivalent from both satellites (around 60 degrees) — but the apparent location of the snow squall features is shifted, due to parallax.

1901 UTC Day Cloud Phase Distinction RGB images from GOES-16 and GOES-17 [click to enlarge]

1901 UTC Day Cloud Phase Distinction RGB images from GOES-16 and GOES-17 [click to enlarge]