Synoptically evident event
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Overview of 24 May 2011 Case & NSSL Experiments Corey Potvin 1,2 , Thomas Jones 1,2 , Dusty Wheatley 1,2 , Louis J. Wicker 2 1 Cooperative Institute for Mesoscale Meteorological Studies 2 NOAA/OAR National Severe Storms Laboratory
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Overview of 24 May 2011 Case & NSSL Experiments Corey Potvin 1,2 , Thomas Jones 1,2 , Dusty Wheatley 1,2 , Louis J. Wicker 2 1 Cooperative Institute for Mesoscale Meteorological Studies 2 NOAA/OAR National Severe Storms Laboratory. Synoptically evident event. - PowerPoint PPT Presentation
Transcript of Synoptically evident event
Overview of 24 May 2011 Case & NSSL Experiments
Corey Potvin1,2, Thomas Jones1,2, Dusty Wheatley1,2, Louis J. Wicker2
1Cooperative Institute for Mesoscale Meteorological Studies
2NOAA/OAR National Severe Storms Laboratory
Synoptically evident event
• Left exit region of jet max within negatively tilted shortwave trough strong large-scale ascent
• Advancing dryline provided additional lift• Rapid moisture advection from Gulf, aided by southerly flow induced by strong low over OK panhandle
• Extreme instability (ML CAPE 3000-4000 J/kg)• Exceptional vertical wind profiles
Surface 1925 Z
500 hPa 0000 Z
Day 2 06 UTC (from 23 May)
Day 1 13 UTC
18 UTC Norman RAOB
Fig. 3, Fierro et al. (2012)
Chronology
• Dryline initiation ~19 UTC, rapid supercell formation• As low-level jet intensifies, 0-1 km SREH > 300 m2s-2
• Tornadoes develop 2030-2230 UTC and race NE toward OKC metro
• Storms weaken as they approach I-35, possibly due to increasing convective inhibition
1850 Z 1920 Z 1950 Z
2020 Z 2050 Z 2120 Z
Storm evolution – MRMS dBZ 2 km AGL
Tornado Paths
Canton Lake EF-3 (2015-2043)
Lookeba EF-3 (2031-2046) / El-Reno EF-5 (2050-2235)
Chickasha EF-4 (2209-2300)Goldsby EF-4 (2226-2305)
NSSL-WoF nearly suffers a “setback”
11 fatalities, 293 injuries
Adapted from http://www.srh.noaa.gov/oun/?n=events-20110524
Mesoscale DA – GEFS-based NME
• Dusty will give more details• WRFv3.4.1; Δ=15 km; 51 levels; 36 members
• 1-way 3-km nest – used to initialize storm-scale DA
Storm-scale DA• WRF v3.4.1; Δ=3km; 51 levels; Thompson microphysics• DART-EAKF or NSSL-LETKF• 36 members; 5-min cycles starting ~1845 UTC• Vr, dBZ from KTLX, KVNX, KFDR (OPAWS: Δ=6km)
– Objective QC (Chris Karstens web tools)– “no-precip” obs: dBZ < 10 set to 0– 3 m/s & 5 dBZ errors
• Mesonet u, v, T, TD (errors: 1.75 m/s, 1.75 K)• Additive noise (0.5 m/s, 0.5 K) and adaptive inflation• Covariance localization cutoffs: 18 km / 6 km
NSSL Projects
• All use mostly the same settings• Dusty – dBZ-based dw/dt forcing• Corey – Running-In-Place• Thomas – satellite DA
