Small Scale Post-Frontal Convection During OLYMPEX: A start at the 10 Dec 2015 case Ed Zipser, University of Utah with contributions from Gerald Heymsfield. NASA GSFC, and Simone Tanelli. NASA JPL

Small Scale Post-Frontal Convection During OLYMPEX: A start at the 10 Dec 2015 case Ed Zipser, University of Utah with contributions from Gerald Heymsfield. NASA GSFC, and Simone Tanelli. NASA JPL along with many others, who bear no responsibility, and may or may not agree, with anything I might say here today

Following the example set by Hobbs, Houze, Bosart, others, let’s start by studying this very rich dataset with an open mind, and attention to detail.

X X X X Horizontal scale of convective cores: About 1-2 km

Horizontal scale of ~ 10 m/s updrafts: about 1-2 km

Now we view a well-observed convective cloud system, up the valley, at about 1705 UTC, first from HIWRAP+CRS+ CoSMIR, then from D3R, then from APR-3.

X X

What sounding should we use to initialize a high-resolution WRF model simulation of this kind of post-frontal convection? We have a great sounding set. Several offshore, onshore flow about 20 m/s from DC-8 Several CSU soundings from NPOL Following are one of each, very close to the time of these examples (1720 and 1736 Z on 10 Dec.) They are superficially similar, but are they? Reason for differences?

Another interesting question: Why did NONE of the convective cells sampled by the aircraft between 1600 – 1900 Z on 10 Dec 15 have any lightning, while some convection before and after did have lightning? Partial answer: The literature suggests that if we have 35-40 dBZ echoes in the mixed phase region, say about -5°C (consistent with much work by Rutledge, Petersen, and our group, including Chuntao Liu and Sarah Bang), probability of lightning is very high. SO, why did some clouds on this day meet this criterion, while most did not?

No evidence of 38-40 dBZ (Ku) in mixed phase region 38-40 dBZ (Ku) reaches above -15°C near

SUMMARY – Tentative and Incomplete – There is a lot of work to be done! Good news: Multi-frequency, multi-parameter radars from ground and from aircraft are excellent tools

SUMMARY – Tentative and Incomplete – There is a lot of work to be done! Good news: Multi-frequency, multi-parameter radars from ground and from aircraft are excellent tools More good news: The sounding dataset is excellent – today’s fine scale WRF + advanced microphysics schemes should be useful

SUMMARY – Tentative and Incomplete – There is a lot of work to be done! Good news: Multi-frequency, multi-parameter radars from ground and from aircraft are excellent tools. Passive microwave data are also excellent and should be integrated into these case studies more. More good news: The sounding dataset is excellent – today’s fine scale WRF + advanced microphysics schemes should be useful These convective clouds and small mesoscale systems are not Houze or Zipser squall lines and they probably need to be handled by statistical approaches One regret: There are not nearly enough direct aircraft penetrations of these cloud systems: Need direct vertical velocity and microphysics data

THANK YOU!

Now, Simone will take questions!