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Message: Telecon summary - 6 Jan 98

Posted by Stan Benjamin on 7 Jan 98, 17:57 MT

Summary of RUC2 evaluation teleconference - 6 Jan 98
(for the participants as well as others on the
field test distribution list)

FSL - Tom Schlatter, Stan Benjamin

Storm Prediction Center

Phillip Bothwell, Russ Schneider, Paul Janish

NWS Western Region -

Mary Cairns - RNO

NWS Central Region -

Preston Leftwich - HQ

Karl Jungbluth, Dan Smith - DSM

Paul Wolyn - PUB

NWS Southern Region

Rusty Pfost - JAN

Rich Wynne - AMA

Mike Cammarata - CAE

NWS Eastern Region

Paul Sisson, Will Murray, Chuck McGill - BTV

NCEP - Laurie Morone

NCAR - Peggy Bruehl

Next telecon - 30 Jan 1998 - 10 AM MST.
Field test end - 17 Jan 1998

Stan B. - There are 2 purposes of the field test. One is to get initial responses for preliminary recommendation to make to CAFTI for replacement of RUC1 with RUC2. The other, which is at least as important to the developers, is the co-education between developers and users on RUC2. We know that some of the users will be doing a more prolonged evaluation over the next several months on RUC2, and we developers want to encourage the ongoing discussions. We will learn faster from field people how to make changes in the future if we keep this going. To that end, we will keep the evaluation web site going on an indefinite basis and wish to hear from field users individually and perhaps have group teleconferences periodically on an ongoing basis if there is interest in this.

Agenda items w/ responses

*Receiving output
* Is everybody getting something out there?

Western Region still not distributing grids yet - holiday hold-ups of various sorts (Mary C.)

Central Region - BUFR model soundings not yet on server, but do have other files (Preston L.)

SPC - pulling down model soundings now. 12z and 00z runs are later than others. (Phillip B.)

FSL - Current timeliness of RUC2 is hampered by running on Cray J90 (slower) at current time than on Cray C90 (faster) where it will run by late January. So, things will speed up (esp. at 12z and 00z), current timeliness is not what we'll have in a few weeks. (Stan B.)

Paul Wolyn (PUB) - bandwidth is a problem. Any isentropic field forthcoming?

FSL - No pure isentropic field will be distributed from RUC2, but we thought that AWIPS and other facilities allowed fairly easy isentropic interpolation. (Stan B.). A few other agreed. SPC using GEMPAK for isentropic cross-sections.

Comments on RUC2 output from a meteorological standpoint

JAN (Rusty P.) - using soundings -- they look good. Dates in files are incorrect. [fixed on Wed at 12Z in RUC2]

Paul W. (PUB) - RUC2 superior to RUC1 for cold surges in RUC1, including weekend cold air/fog event which hampered air traffic at Denver over last weekend. 700 mb vertical velocities noisy in RUC2.

Stan B. - We know that vertical velocities in RUC2 are stronger in mountain waves than in Eta or Meso-Eta. John Brown in our group has looked at them extensively, including comparisons with higher-resolution mesoscale models and analytical solutions. Although we have a few questions, We think the RUC2 vertical velocities are reasonable, including the strong mountain wave responses.

Mike C. (CAE) - RUC2 very good for short-range fcsts and useful for cold wedge situations. RUC2 delineated and moved wedge/coastal front N thru SC and then back S very accurately. Low-level winds look better than RUC1. Uses LIs and low-level winds. Too widespread precip over Gulf Stream.

Stan B. (FSL) - Yes, precip areas over warm water are too large. The area coverage is probably much better if you ignore amounts below 0.10 inches. The solution is probably in some improved physics, esp. shallow convection to better handle the marine boundary layer. This will be investigated and tested over the next few months.

Phillip B. (SPC) - Change to precip type on Monday seems to have helped. Ice pellet areas look much better. Good RUC2 fcst for Sat night Jan 3 for thunder snow/ice in NW KS.

Mike C. (CAE) - All NWP models, esp. RUC2, good for 900 mb moisture flux. RUC2 good in pointing out recent area of convection over South Carolina.

Will M. (BTV) - Sfc temp, dewpoint, and winds significantly better with RUC2 than RUC1. Precip type looks better after 4 Jan change. Snow depth field looks goofy [see update on this in web site for7 Jan from Stan B.] Good in recent NE US storm -- RUC2 identified axis of max snowfall.

Paul S. (BTV) - Lots of interesting weather recently near VT. RUC2 good on shallow cold air over St. Lawrence Valley. Precip type good, esp. on local variations near Great Lakes -- rain near lakes but snow a little inland. 24 Dec storm - heavy snow at Worcester - RUC2 fcst was excellent. QPF appears better in RUC2 overall. Negative - slow in overrunning precip, maybe by ~3h, and snow field not correct for them at current time.

Stan B. (FSL) - Slowness on overrunning precip may be result of inaccuracies in cloud fields. RUC2 must build up hydrometeors, due to use of cloud microphysics, before precip can occur. Cloud analysis, which is main focus of RUC2 upgrade later in 1998, should improve this.

Rusty P. (JAN) - RUC2 missed 4" of rain last night in s. MS and near New Orleans, model much too low.

Phillip B. (SPC) - 50 severe reports over TX previous night. RUC2 vertical motion fields showed good continuity with this area of convection.

BUFR soundings - BTV and AMA and others would still like to see them sorted by station and with hourly output. FSL - RUC2 limited at NCEP in post-processing time. Can work toward doing this when we put RUC2 post-processing off C90 onto smaller computer. This will be a few months off.

End of initial phase of field test

Turnoff date for RUC1? (Phillip - SPC). 11 Feb (Stan and Laurie - NCEP). Will mimic 212 grid products currently from RUC1 with RUC2 output for some transition period.

Will current 60km sfc RUC cycle be turned off on 11 Feb (Mary C.)? No, it will not (Laurie M.)

Add description of freezing level diagnostic to web stuff (Will M. - BTV). [This was done on Wednesday - Stan B.] See http://maps.fsl.noaa.gov/vartxt.cgi

End of field test initial phase - 17 January 1998. Participants can mail results in to Tom Schlatter, NOAA/FSL, R/E/FS1, 325 Broadway, Boulder, CO 80303, or email to either Tom or Stan (schlatter@fsl.noaa.gov, benjamin@fsl.noaa.gov).

FSL will compile NWS results. AWC and SPC will write their own summaries.

Next teleconference - Fri 30 Jan 98 - 10 am MST

AWC addition - Wed Jan 8
Tom S., John Brown, and Stan B. talked to Tim Mahony and Don McCann today

Tim. - AWC looking at 5 different variables: RH profiles at 7 locations (INL, MFD, SLC, ALB, TOP, LCH, and CAE), wind shear, icing using neural net (FL000-060), turbulence at FL300-400, CAPE.

CAPE - much better after Tuesday change, was bad in fcsts before that.

RH - mixed results, perhaps slightly better overall for RUC2 compared ot RUC1. RUC2 analyses are definitely better than those from RUC1. Less difference in fcsts.

Turbulence - RUC2 much improved over RUC1

Shear - generally positive results for RUC2

Don M. - looked at RUC2 carefully over last 2 weeks of shifts. Noted case of shear in RUC2 but not in nearby profiler [FSL - could have been from aircraft data but not sure]. Concerned about low static stability in negative potential vorticity regions. [FSL - can get negative PV in RUC2 as well as in atmosphere. Stability can get slightly lower in isentropic part of RUC2 domain since isentropic separation is now 2 K instead of 4 K.] Some very remarkable hits for RUC2.

Thanks again for everyone's help. This was a good exchange, and we at FSL really appreciate both the positive feedback and the criticisms so that we can make improvements. -- Stan

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