GOES-15 0.62 µm Visible Imagery at time of Tornado

Tornadoes touched down on Long Island within the confines of New York City on September 8th, 2012. This image shows the terminal radar velocities from Newark associated with the two touch downs. This google map link shows both Canarsie and Breezy Point on a map of eastern Long Island.

The GOES-15 image above, from 1500 UTC, (Here is the same image without a map drawn on it) is for the approximate time of the tornadic touch down in Canarsie — GOES-15 was scanning across Long Island at 1504 UTC. The oblique view allows the satellite to see under the anvil of a glaciated storm over central Long Island, and to view a storm of modest appearances over eastern Long Island that produced the tornado. This tornadic cell is part of a convergence line that stretches southward down the coast of New Jersey. Stretching of local convergence by a strong updraft can cause brief tornadic events.

GOES-13 0.63 µm visible and 10.7 µm IR images (click image to play animation)

GOES-13 (GOES-East) also viewed this cell. Unfortunately, the touch-down occurred when GOES-13 was performing a routinely scheduled full-disk image, so imagery at 1445 UTC and 1515 UTC is available, and at 1545 UTC (housekeeping on GOES-13 is performed for 10 minutes starting at 1534 UTC). The routine schedule for GOES-13 is here. Nevertheless, the animation of the Visible and IR imagery shows the development of the tornadic cell along the convergence line. The 30-minute timestep between images, however, makes computation of convective predictors such as Cloud-top Cooling ineffective. The tornadoes were on the ground in between the 1445 UTC and 1515 UTC GOES-East images. Note that Canarsie is indicated by the red square in the infrared imagery.

GOES-14 0.63 µm visible and 10.7 µm IR images (click image to play animation)

GOES-14 was in SRSOR on September 8th, and its every-minute imagery captured the evolution of the tornadic cell very well. The animation above plays steps more slowly for the times when the tornado is on the ground. The animation reinforces the notion that the tornadic cell in the visible imagery is prosaic. The 1-minute imagery allows careful scrutiny of the cloud-top temperature as the cells evolve. The loop below, from 1445 UTC to 1509 UTC, spans the time of tornadic activity, and the initial cloud-top cooling and subsequent anvil spreading is readily apparent. This graph shows the coldest IR Brightness temperature over the developing/evolving tornadic cell as a function of time. It’s uncertain from the imagery alone whether the cloud-top cooling is occurring because the top of the cloud is reaching higher into the atmosphere, or because thickening clouds at lower levels are limiting the amount of radiation upwelling through the cloud. There is certainly a cooling trend, however, at the time of the tornadoes.

Magnified GOES-14 10.7µm IR images (click image to play animation)

(Added: Click here for a QuickTime movie of the visible imagery on September 8th from 1415 UTC to 1859 UTC. Click here to see an animated gif loop that compares the temporal coverage of GOES-13 — present GOES — to that of GOES-14 — simulating GOES-R)

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GOES-13 0.63 µm visible channel images

Hurricane Michael became the first Category 3 hurricane of the 2012 Atlantic Basin season on 06 September. GOES-13 0.63 µm visible channel images (above) and GOES-13 10.7 µm IR channel images (below) from the CIMSS Tropical Cyclones site showed that Michael displayed a well-defined eye.

GOES-13 10.7 µm IR channel images

A comparison of 375-meter resolution Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel images (below) offered a more detailed view of the eye structure at 15:42 UTC.

Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel images

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GOES-13 10.7 µm IR images (click image to play animation)

A thunderstorm complex over the northern Gulf of Mexico on the morning of September 5th is being monitored for tropical development. This cluster originated as a mesoscale convective system that emerged from the southern edge of Isaac’s decaying circulation, as shown in the animation above. The animation, starting from Isaac’s landfall over the Mississippi Delta on 29 August, shows a complex developing over northern Alabama on 3 September and dropping southward through that state on 4 September, emerging into the Gulf on 5 September. An analysis of wind shear and Sea Surface Temperatures (taken from the CIMSS Tropical Weather Website) suggests that the system is moving into an environment favorable for strengthening. A loop of 850-mb vorticity also shows the evolution of the system, and the piece of Isaac that breaks off and heads back to the Gulf of Mexico.

Further information on this system is available from the National Hurricane Center.

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Suomi NPP VIIRS 0.7 µm Day/Night Band image + Precipitation reports

An AWIPS image of the Suomi NPP VIIRS 0.7 µm Day/Night Band (above) showed a night-time view of large swaths of wet ground across much of Kansas at 07:58 UTC (2:58 AM local time) on 05 September 2012. Many parts of central Kansas received significant rainfall as thunderstorms moved eastward across the state; five sites reported over 1 inch of precipitation, with as much as 1.90 inches falling near Potwin. In southeastern Kansas, also note the bright southeast-to-northwest oriented “streak” — a signature of lightning illuminating the cloud top as the VIIRS instrument was scanning that area.

Many areas of Kansas had been experiencing extreme to exceptional drought (below). Since the moon was in the Waning Gibbous phase, moonlight from 75% of the disk was able to provide sufficient illumination to reveal the darker rain-soaked ground surfaces, which stood out in contrast to the surrounding dry ground across the state.

Kansas drought monitor

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