MIMIC Total Precipitable Water product

AWIPS images of the MIMIC Total Precipitable Water (TPW) product (above) revealed the formation of a long “atmospheric river” of moisture over the North Atlantic Ocean during the 17-19 November 2009 period. MIMIC TPW values were as high as 60 mm (darker orange color enhancement) within the moisture plume.

The surface analysis (below) showed that this moist plume was along and ahead of a cold front that was trailing southward from a deepening mid-latitude cyclone. This plume of moisture was contributing to very heavy rainfall and significant flooding over parts of the United Kingdom — Seathwaite reported a 24-hour rainfall amount of 12.36 inches (314 mm), which if confirmed as accurate will set a new record for 24-hour precipitation in the UK (UK Met Office).

MIMIC TPW with surface analysis

A composite of GOES-12 and Meteosat-9 water vapor imagery (below) suggested that this long atmospheric river tapped into a pocket of deep tropical moisture (associated with the remnants of what was formerly Hurricane/Tropical Storm Ida), and was then brought northward within the warm conveyor belt in advance of the deepening cyclone over the North Atlantic Ocean.

GOES-12 and Meteosat-9 water vapor imagery

The Blended Total Precpitable Water – Percent of Normal product (below) indicated that this moist plume was rather anomalous for the season over the North Atlantic region, containing values of TPW that exceeded 200% of normal (yellow color enhancement).

Blended Total Precipitable Water - Percent of Normal

MODIS true color images (30 September, 01 November, 10 November)

A sequence of three MODIS true color images from the SSEC MODIS Today site (above) showed an increasing level of turbidity of the water along the Gulf Coast — the 3 images are from 30 September, 01 November, and 10 November 2009. This increase in turbidity can be directly attributed to the runoff of sediment-rich water due to heavy precipitation across much of the Gulf Coast states from late October into early November, as shown in the 14-day observed precipitation map (below). Special thanks to Steve Davis and Jeff Craven at the National Weather Service forecast office at Milwaukee/Sullivan for creating/capturing these images and bringing this case to our attention!

14-day observed precipitation

AWIPS images of the MODIS Sea Surface Temperature (SST) product (below) showed that the Gulf of Mexico immediately offshore was significantly colder due to this discharge of sediment-rich water from rivers draining from the Gulf Coast states — SST values were in the low to mid 60s F (darker green colors) right along the coast, compared to the mid 70s to near 80º F (darker red colors) farther offshore.

MODIS Sea Surface Temperature product (November 10 - 12)