Case Description: 8 February 2019

Summary

Many convection initiations over and around the AMF1

Description

Multiple convection initiations occur within the immediate region of the AMF1 starting at 17:30 that result in four systems near the AMF1 by 20 UTC that then merge into a single system by 21:30. All mesoscale ensembles capture the phase but dramatically underestimate the magnitude of the upscale growth, potentially due to the coarse resolution used. CAPE values are at the threshold between the top and middle third of their ranges (at 18 UTC MUCAPE=3212; MLCAPE=2375 kg^-1).

Available assets

CSAPR2 (goes down part way through event), GOES rapid scan

Unavailable: CSU C-Band, G-1, RELAMPAGO data

Critical period: 17:30–21:30

30 Beginning of systems initiating along ridgeline
00 Two systems within the domain, which grow in a sheared environment
00 Two more systems initiate between the two systems, close to the AMF1
30 The two inner systems have merged and deepened
30 All of the systems have merged into one and have deepened

Brightness temperature, 2019-02-08 21:15 UTC — Figure 11 GOES-16 band 13 brightness temperature at 2019-02-08 at 21:15 UTC. Four convection initiations are observable by the CSAPR2 that later merge into a single, large system.

Available LES ensemble members

Table 11 Summary of LES cloud behavior for 2019-02-08
Impression	Ensemble Member	Cloud Behavior
Bust	EDA03	CSI Skill less than half of respective meso run. Only develops southern system and no northern or central systems.
Acceptable	EDA03-Morr	CSI Skill is very good and much better than respective meso run. Cell at southern domain edge overdeveloped but very good run until 19:30 UTC when errant cell starts over the AMF1 and the morphology in the northern cell deviates from observed, but not badly.
Bust	EDA08	Convection initiates hours late and weaker when it oes, albeit in about the right places.