MODIS true color RGB image (viewed using Google Earth)

An interesting pattern of “snow streaks” across parts of Illinois, Indiana, and Kentucky was seen on a MODIS true color Red/Green/Blue (RGB) image from the SSEC MODIS Today site on 03 January 2012 — this pattern was caused by narrow cells of convective snowfall which propagated southeastward across the region on the previous day. The amount of snow on the ground was only a Trace to 1 inch, which allowed the snow streaks to quickly melt during the day.

View only this post Read Less

GOES-12 3.9 µm shortwave IR channel images (click image to play animation)

As a result of prolonged drought and a mid-summer heat wave across southern Chile, a number of wildfires were burning in parts of the region on 01 January – 02 January 2012 (surface analysis). GOES-12 3.9 µm shortwave IR images (above; click image to play animation) showed a number of fire “hot spots” (yellow to red color enhancement) between Concepcion (station identifier SCIE) and Chillan (station identifier SCCH) from the late afternoon on 01 January until the early morning hours on 02 January.

During the subsequent daytime hours, GOES-12 0.63 µm visible channel images (below; click image to play animation) revealed a long hazy smoke plume that was drifting northwestward out over the adjacent Pacific Ocean. As daytime heating increased, cumulus clouds with a few thunderstorms could also be seen developing farther inland over the higher terrain of the Andes Mountains.

GOES-12 0.63 µm visible channel images (click image to play animation)

Rawinsonde data from Santo Domingo (station identifier SCSN) at 12 UTC indicated that southeasterly winds existed near the top of the deep temperature inversion, between 741 hPa (2.6 km) and 700 hPa (3.1 km) — so this is likely the approximate altitude of the smoke plume seen drifting toward the northwest on the GOES-12 visible satellite imagery.

Santo Domingo, Chile rawinsonde data plot

A high-resolution MODIS true color image of the fire smoke plume can be seen on the NASA Earth Observatory site.

View only this post Read Less

EUMETSAT Meteosat-9 High Resolution Visible (HRV) images

EUMETSAT Meteosat-9 High Resolution Visible (HRV) images (above) showed the classic signature of a “warm seclusion“: a nearly cloud free eye-like structure at the center of the circulation. Surface station wind barbs (in knots) are also plotted in cyan on the images.

A similar eye-like appearance was seen on Meteosat-9 water vapor channel images (below) as the mature cyclone moved just north of the British Isles on 28 December 2011.

EUMETSAT Meteosat-9 water vapor channel images

Hurricane force wind gusts were observed at Tiree, Scotland (station identifier EGPU), with a peak gust of 69 knots (79 mph) at 14:20 UTC (below).

Tiree, Scotland (EGPU) surface reports

Surface analyses from the NWS/NCEP Ocean Prediction Center (below) showed the intensification and evolution of the cyclone during the day.

Ocean Prediction Center surface analyses

Warm seclusions are also sometimes observed with intense cyclones along the East Coast of the US, as in this 20 December 2009 case.

View only this post Read Less

MTSAT-1R 10.8 µm IR channel images

MTSAT-1R 10.8 µm IR channel images from the CIMSS Tropical Cyclones site (above) showed Category 1 Tropical Storm Thane (06B) in the Bay of Bengal, moving toward the east coast of India on 28 December 2011.

Contours of 850-200 hPa satellite-derived deep layer wind shear overlaid on MTSAT-1R 6.75 µm water vapor channel images (below) indicated that Thane was in an environment of low wind shear, which favored some intensification prior to making landfall.

MTSAT-1R 6.75 µm water vapor channel images + Deep layer wind shear

It is interesting to note that the MIMIC Total Precipitable Water product (below) showed the northern counterclockwise circulation of Tropical Storm Thane and the southern clockwise circulation of Tropical Storm Four (04S) — each drawing moisture from the Inter-Tropical Convergence Zone (ITCZ).

MIMIC Total Precipitable Water product

===== 30 December Update =====

Tropical Storm 04 S intensified in a similar low wind shear environment, becoming Tropical Cyclone Benilde in the South Indian Ocean. Benilde was forecast to intensify, with wind gusts up to 140 knots. Meteosat-7 visible/shortwave IR images with an overlay of ASCAT scatterometer surface winds (below) showed the structure of Benilde.

Meteosat-7 visble/shortwave IR imagery + ASCAT surface winds

View only this post Read Less