Remnant from Isaac emerges into northern Gulf of Mexico

September 5th, 2012 |
GOES-13 10.7 µm IR images (click image to play animation)

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.

Wet ground as seen using the VIIRS Day/Night Band

September 5th, 2012 |
Suomi NPP VIIRS 0.7 µm Day/Night Band image + Precipitation reports

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

Kansas drought monitor