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). 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 brou