Status:Ongoing analysis Material from: Linus, Fernando
Discussed in the following Daily reports: http://intra.ecmwf.int/daily/d/dreport/2014/04/28/sc/
1. Impact
On the 27 April 7pm local time (00UTC 28 April), tornadoes hit towns north and west of Little Rock, Arkansas killing approx 17 people (http://edition.cnn.com/2014/04/28/us/severe-weather/index.html?hpt=hp_c2).
2. Description of the event
The WV satellite image shows an active cyclone located in Colorado with a cold front attached moving eastwards crossing the SE Texas and Arkansas. A very active region of convection is seen ahead of the cold front where most of the severe weather events have been reported.
Radar animation for the 27 April from www.weatherunderground.com .
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3. Predictability
3.1 Data assimilation
The "rejection charts" (left) highlight a cluster of wind and temp observations with low weight which seems to be related with the strong convective activity in the region. The increment charts at 200 hPa (right) suggest that the observations are trying to "correct" the background even under these conditions.
3.2 HRES
CAPE for 27 April +24h and precipitation for +23h to +24h. Little Rock is marked with an hourglass symbol.The maximum 1-hour precipitation was 20 mm/h.
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