# Presentation: 544012

##    A Brief Overview of NCEP SREF:

*Where are we and where are we heading*?
-         Jun Du, Geoff DiMego, Zoltan Toth,
-               Jeff McQueen and Binbin Zhou
_*Acknowledgements*_*: Eric Rogers, Tom Black, Geoff Manikin, Brad Ferrier, Dusan Jovic, Matt Pyle, Hui-Ya Chuang, Henry Juang, Jongil Han, Zavisa Janjic, George Gayno, Kenneth Mitchell, NCO stuff as well as Stephen Lord*
*and Louis Uccellini*

- _[http://www.emc.ncep.noaa.gov/mmb/SREF/SREF.html](http://www.emc.ncep.noaa.gov/mmb/SREF/SREF.html)_
**(NCEP Ensemble User Workshop, Oct. 31 – Nov. 2, 2006**_**)**_

## 1.How to capture uncertainties

-    (ensemble system design)
- 2._ How to convey forecast uncertainty_
-    (ensemble products and data)
- 3. _Downstream applications of the SREF_
-     (driving other prediction systems)
- 4. _Verification_

## (1) To Capture Uncertainty 

_**Atmospheric IC uncertainty*__:_
- (1) **Multi-analysis (GFS and NAM)**
- (2) **Perturbed analysis: bred vector** (current), ET (ongoing/2007), and ET with DA-based rescaling (future, work with Mozheng Wei)
_**Atmospheric LBC uncertainty:*_* *
- (1) **different LBCs for different members simply provided by various NCEP global ensemble members**
- (2) plan to work on how to better couple LBC and IC in future
_**Lower boundary/Earth surface forcing uncertainty*__:_
- (1) Land surface: **currently not perturbed** but soil moisture perturbation design is underway -- first a simple approach (Du, 2007) and then** **might be an ET-like approach** **in near future
- (2) Water/sea surface temperature, flux etc.: (**currently not perturbed**)
_**Upper boundary uncertainty from space????*_

** **

## f00

- f12

- f24

- f36

- Perturb both IC & LBC

-   perturb LBC only               perturb IC only

- Small domain: 500H spread, May 19, 1998, Eta32, 5 members

## 3h-apcp forecast with WRF_ARW model

- _3h-apcp forecast with WRF_ARW model_

- with NAM soil moisture

-   with GFS soil moisture

-     Diff between the two forecasts (“nam” -  “gfs”)

## With nam soil moisture (NMM)

- With gfs soil moisture (NMM)

- T2m diff (namSM – gfsSM, NMM)

- Within WRF_NMM model:
- Impact on T2m is significant!

## different IC (NMM; namSM)

- different models (nmm vs. arw; namSM)

- Diff soil moisture (nam – gfs; NMM)

- T2m -- impact comparison (NMM):
- Soil moisture impact on T2m is bigger
- Than that of IC and of model difference!

***_*Model uncertainty (both dynamics and physics):*_
- (1) multi-model: **Eta, RSM, WRF-NMM, WRF-ARW (current), **plan to replace** **Eta and RSM members with all WRF members in 2008 (_issue: how important will the diversity of model dynamics be?) _*(disadvantage: difficult to maintain; different model has different bias)*
- (2) multi-physics: **GFS, Eta, MM5, BMJ/SAT, KF/DET, SAS/RAS (current)**, diversity in LSM, cloud, PBL, radiation as well as WRF-GFS, WRF-RUC in near future [*disadvantage: don’t produce enough spread in larger scale (Du) and cannot maintain extra spread after a certain time length (according to Peter H.*)]
- (3) stochastic physics: currently an ongoing research on NCEP global ensemble (Dingchen Hou) and could be adopted to SREF once it’s ready. (_issue: can stochastic physics alone perform as well as or exceed what multi-model and multi-physics ensemble can currently provide in a consistent manner?)_

## Slide 10

## Slide 11

##       RSM Error

-       RSM Error

-       Corr. Coeff.

## Accuracy of probabilistic forecast measured by RPSS and Reliability

- Before introducing “physics diversity”                   After introducing “physics diversity”

## Cold season case 1 (09z, March 5, 2004):  spgt charts comparison at 39h fcst

-   Before physics diversity (988mb)

- After physics diversity (988mb)

## PAR SREF                                                    OPS SREF

- Warm season: June and July, 2004

## 41-case averaged outlier rate at all fcst lead time

- SLP

- 500H

- 850T

- 850U

- 250U

- 850RH

- Par: - - - - -
- Opl: --------

## Cold season case 1(09z, March 5, 2004): ens spread comparison at 63h fcst: similar 

- Cold season case 1(09z, March 5, 2004): _ens spread_ comparison at 63h fcst: _similar_

- OPS/SLP

- PAR/12h-apcp

- PAR/SLP

- OPS/12h-apcp

## IC-ensemble                               PHY-ensemble

- Eta_BMJ_ctl                         Eta_BMJ_ctl
- Eta_BMJ_n1                         Eta_KFc_ctl
- Eta_BMJ_p1                         Eta_SAT_ctl
- Eta_BMJ_n2                         Eta_DET_ctl
- Eta_BMJ_p2                         Eta_CON_ctl
- Eta_BMJ_n3                         Eta_Fer_ctl
- Eta_BMJ_p3                         Eta_RAS_ctl

-     _*Sensitivity Experiment on IC vs Physics (Experiment I)*_

## IC-ensemble spread (SLP at 63h)

- _IC-ensemble_ spread (SLP at 63h)

-    _PHY-ensemble_ spread (SLP at 63h)

-  PHY-ensemble mean 63h fcst (SLP)

- More sensitive to IC pert than PHY
- Diversity in general except for the
- Cyclone region where is more convective

## IC-ensemble spread (12h-apcp at 63h)            

- IC-ensemble spread (12h-apcp at 63h)

- PHY-ensemble spread (12h-apcp at 63h)

- PHY-ensemble mean 63h fcst (12h-apcp)

- Similar sensitivity to both IC pert and to
- PHY Diversity for precip in general.
- PHY diversity enhances sensitivity in
- Convective areas.

## IC-ensemble spread (CAPE at 63h)

- PHY-ensemble spread (CAPE at 63h)

- PHY-ensemble mean 63h fcst (CAPE)

- Equally sensitive to IC pert and PHY
- Diversity for CAPE (focusing different
- Sub-regions though)

_**Residual Part (either uncounted or over estimated uncertainties)*_: post processing to calibrate ensemble system to have a reliable probabilistic forecast. **Currently, work is going on only for the 1****st****-moment (statistical decaying average by Cui and dynamical/flow-dependent dual-resolution approach by Du (2007).**
** **
- BMA-type approach is planned to be tested in future for the 2nd- and higher moments (Toth);  Huiling Yuan of GSD (former FSL) is also working on a bias correction method for the SREF.

- Besides dealing with the uncertainties in initial state, external forcing, governing laws and numerical methods as discussed above

##     Post-processing with Hybrid-Ensembling appraoch (Du, 2004): fcst error of 21-mem ens mean

-     Post-processing with Hybrid-Ensembling appraoch (Du, 2004): fcst error of 21-mem ens mean
-     of 500mb H at 3.5 days

- Raw SREF fcst error

-        Hybrid SREF fcst error

## Without extra observation within uncertainty source area:

- Without extra observation within uncertainty source area:

-        With Extra observation within uncertainty source area (_uncertainty reduced_):

- f00

- f00

- F51 – targeted time

- F51 – targeted time

- 21z, May 11, 2005 SREF SLP spread forecast (current cycle)

## Without extra observation within uncertainty source area:

- rms error of SLP by ensemble mean forecast (_error reduced in targeted region_)

- With extra observation within uncertainty source area:

## SREF Configuration

- 21 members (**5 Eta_bmj, 5 Eta_kf, 5 RSM, 3 WRF_nmm, 3 WRF_arw**  about 10 WRF_nmm & 10 WRF_arw in 2008)
**32-45km ** 32km for all members (2007)  20-25km (2009)
- Four cycles per day (**03,09,15,21z**)  00,06,12,18z in future
**3hrly output to 87hr each cycle** (possibly hourly output in future)
- Three output domains: **CONUS, Alaska and Pacific/Hawaii**

## (2) To Convey Uncertainty

## SPC first-ever Day-2 “High Risk” outlook for April 7, 2006’s “over 60 tornadoes” event

- SPC’s Significant Tornado Probability forecast
- Derived from SREF (David Bright)

## Subject: SREF and the sig tornado event last FridayFrom: David Bright David.Bright@noaa.govDate: Mon, 10 Apr 2006 09:44:12 -0500To: Jun Du Jun.Du@noaa.govHi Jun,I wanted to show you the image SREF attached. This is an experimental parameter one of the forecasters is testing and it's definitely not ready for prime time (i.e., I'm not convinced its formulation is entirely defensible at this point, and its false alarm ratio has yet to be determined!).  But, this F039 hour SREF forecast from last Thursday (09 UTC SREF 6 April 2006) shows the primary significant tornado threat centered over nrn AL, nrn MS, and parts of TN (with SREF mean 850 mb height overlaid).The SREF played a large part in the first ever Day 2 "HIGH RISK" outlook ever issued by the SPC (http://www.spc.noaa.gov/products/outlook/archive/2006/day2otlk_20060406_1730.html).  Of course, other deterministic models, climatology, and forecaster experience were involved in the decision process, but the SREF played a key role.  Again, this product only in the evaluation stage, but I thought you'd be interested nonetheless.DavidLouis Uccellini wrote:Joe/Russ: Between this SREF result, the first time Day 2 High Risk and the 1.0 POD for over 60 tornadoes, I think it is time to celebrate in a big way. I recommend that you guys need to put together a one pager and work with Dennis and Carmeyia to highlight this historic accomplishment(s). Louis

## Subject:SREF done good!From:Richard Grumm Richard.Grumm@noaa.govDate:Wed, 25 Jan 2006 10:24:26 -0500To:Jun Du Jun.Du@noaa.govJun,Hello, hope you are doing well. The recent event of 22-23 January was another good example of the SREF doing quite well with PTYPE issues. Humans, like the 2-3 April 2005 event did not heed the guidance.FYIhttp://nws.met.psu.edu/severe/2006/23Jan2006.pdfRich 

##   Ensemble Product type in general:

_*  *__*Ensemble Product type in general:*_
- 1. _single outcome_: mean, median, mode, extremes
- 2._ uncertainty_: spread, *confidence factor*
- 3. _distribution_: probability, spaghetti, meteogram, postage
-                  stamps, *clustering*

## Slide 33

## ■ SREF Aviation product List (Binbin)

|      Variables (14) |        Products |  Levels/Regions | Algorithms |
| --- | --- | --- | --- |
| Icing | Prob  of occurrence | FL240,180,150,120
090,060,030,FL000 | T-RH-Vertical drift |
| Clear air turbulence (CAT) | Prob of occ (LGT,MDT,SVR) | FL420,390,360,330
300,270,240,FL210 | Ellrod 1992 |
| Cloud | Mean/spread
Prob of ovc,sct,bkn,clr  | Ceiling, cloud base | Model-output |
| Visibility | Mean/spread | Surface | Stoelinga 1999 |
| Ceiling | Mean/spread | Ceiling, cloud base | Conditional |
| Flight-Restriction | Prob of LIFR,IFR,MVFR,VFR | Vis and/or Ceiling | Visibility-ceiling |
| Jet-stream | Prob of >60,80,100 kt | 4500, 18000, 34000 ft. | Model-output |
| 10m-wind speed | Mean/spread
Prob of >10,20,30 kt | 10m | Model-output |
| Convective cloud | Mean/spread/directions |  | Grid convective cloud |
| Low level wind shear (LLWS) | Mean/spread
Prob of severe (20 kt/2000 ft) |  | Wind vector difference |
| Tropopause | Mean/spread |  | Model-output |
| Freezing-level | Mean/spread | Sfc, 4000, 8000, 12000, 16000 | Model-output |
| Fog | Prob  of occurrence | Surface | Cloud base/top threshold |
| Mountain obscuration
to be added  | Prob  of occurrence | Mountains | RH ≥ 80%, 90%
Cloud water/ice/snow |

**■** **SREF Aviation product List (Binbin)**

## Transition?

**Currently, all those ensemble products are generated using an ensemble product generator code**
- In future, they** **should be generated using NAWIPS ensemble functionality package

## Field Forecasters like SREF web products

- Date: Mon, 13 Feb 2006 15:40:15 +0000
- From: David Eastlack <David.Eastlack@noaa.gov>
- Subject: SREF web page
- To: Jun.Du@noaa.gov, _[Jeff.Mcqueen@noaa.gov](mailto:Jeff.Mcqueen@noaa.gov)_
-          Greetings, I felt compelled this morning to send a message of appreciation for your outstanding SREF web site! **We peruse the SREF products regularly, and find them a beneficial part of the forecast process.**  Once again,  great work!  I hope that it will be possible, sometime in the near future, **to have products such as these considered operational**.  We do realize though that since this is an experimental page, it is not guaranteed to be always updated. Again, thanks and great work!
-     Dave Eastlack – MET WFO - OAX (Omaha, NE)

## Slide 37

## The problem is that 

- It’s not operational but run at personal account (not reliable)
- Solution is that **it needs to be transferred to NCO** (a user survey strongly supports this)

## Survey announcement (09/08/2006)

- List:
- Since the current SREF web page (http://www.emc.ncep.noaa.gov/mmb/SREF/SREF.html)
- is a developement display tool in nature and not operational, it's not 100% reliable
- to users and not friendly enough. As you may also know that NCO has developed an
- official operational SREF web (http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/)
- but not enough products on it currently. However, the former should be eventually
- replaced by the later for everybody's good.
- There will be an ensemble user workshop at NCEP from Oct. 31 -Nov. 2 this year.
- Zoltan suggested that we gether a list of products which field forecasters use from
- SREF before the workshop. As a first step, you might compare my current personal
- SREF page and the NCEP official page to let us know what products need to be
- transferred to the official page. Surely, you can also request whatever you might
- want to see.
- Although I received emails from forecasters from time to time about the SREF web
- products, I didn't keep a track of it (such as a forecaster from Texas area requested
- the Post Stamp charts, but I couldn't recall his email address). So, please circulate
- this servey to field forecasters where you see proper. Remember that this servey
- should be done before Oct. 27. So, please act as soon as you can.
- Thanks a lot.
- Jun

## Subject: Re: [Fwd: SREF web products servey]From: Jon Zeitler Jon.Zeitler@noaa.govDate: Sun, 10 Sep 2006 11:36:00 -0500To: Peter Manousos <Peter.Manousos@noaa.gov>, Jun.Du@noaa.gov                                                                                             Jun/Pete, FYI, I was the one requesting the postage stamp graphics.                                                                                             Transferring Jun's personal page to the operational versionis exactly what I would like to see (except of courseanything still in development). The postage stamps,ability to select thresholds for the spaghetti charts, andthe probability. Eventually, it would be nice to getthese into AWIPS like the GFSEnsemble data we currentlyreceive. Many thanks,_____________________________________________Jon W. Zeitler   Science and Operations OfficerNational Weather ServiceAustin/San Antonio Weather Forecast Office2090 Airport RoadNew Braunfels TX 78130 USA

## From John.Kwiatkowski@noaa.govJohn,Sally forwarded your email to me since she knows I look at the SREF on a consistent basis.  When I am trying to forecast QPF/probabilities/timingin addition to looking at forcing and RH, I use the QPF probabilitiesprovided by the model and IMHO have found these to work better than MOSwhen strictly looking at QPF POPs and timing for my developing of aforecast. Also, I use the instability and kinematic fields when tryingto forecast whether or not the possibility exists and/or the magnitudeof severe weather in the 12-60 hr period. One improvement I suggest isto have more forcing/upward vertical velocity field products. Thiswould help specifically in terms of cap erosion forecasting andstratiform QPF, but most importantly in the forecasting process ingeneral. Bryan.Smith@noaa.gov                                                                                             

## Subject: Re: [Fwd: SREF web products servey]From: Seth Binau <Seth.Binau@noaa.gov>Date: Mon, 18 Sep 2006 13:22:57 -0500To: Jun Du <Jun.Du@noaa.gov>CC: Dan Baumgardt <Dan.Baumgardt@noaa.gov>                                                                                             Jun,                                                                                             Thanks for the opportunity for the field to provide some input on SREF.  We use SREF heavily in our office, and continue to increase our use as more and more. While I use the NCO SREF page a great deal, I do prefer your page due to the wide array of products not available on NCO's page.                                                                                             If NCO takes this over explicitly...there are some products we would like them to make available as listed below...                                                                                             As far as PROBABILITY...1) 3/6/12/24 hour precipitation and snowfall with the thresholds you have (0.01"...0.10"...0.25"....0.50" etc)2) precipitation type (rain/sleet/frozen/snow/)3) CAPE/CINH                                                                                             As far as Mean & Spread1) MSLP2)  850T3) 500 Hght and Vorts4)  Precipitation (3/6/12/24 hr) (mean)5)  Snowfall (3/6/12/24 hr) (mean)6) Precipitable Water7) Instability                                                                                             As far as SPAGHETTI (all thresholds you have)1)  MSLP2) 850T3)  500 Heights4) Precipitation (3/6/12/24 hr)                                                                                             As far as Individual Members (stamp charts)1) MSLP2)  850T3) 500 Hght and Vorts4)  Precipitation (3/6/12/24 hr)5) Precipitable Water6) CAPE/CINH                                                                                             Thanks for providing such great support to the field!                                                                                             Seth Binau, NWS ARX                                                                                             

## Subject: Re: SREF web products serveyFrom: Dan Baumgardt Dan.Baumgardt@noaa.govDate: Fri, 13 Oct 2006 15:39:47 -0500To: Jun Du Jun.Du@noaa.govJun Du – I STRONGLY agree that your SREF maintained site should migrate to operational!! The data is great that you have and be AT LEAST the starting point for the ops version!                                                                                             We are using these data heavily! October 7 is the last data - oh no!  Thanks!                                                                                             Dan Baumgardt    -    KC9IWMScience and Operations OfficerNational Weather ServiceN2788 County Road FA, La Crosse, WI 54601Phone: (608)784-8275 x766   Fax: (608)784-8238Email: dan.baumgardt@noaa.govhttp://www.crh.noaa.gov/arx                                                                                             

## Subject: Re: [Fwd: SREF web products servey]From: David Zaff David.Zaff@noaa.govDate: Sun, 22 Oct 2006 08:53:17 +0000CC: "jun.du >> Jun Du" <Jun.Du@noaa.gov>                                                                                             Jun,                                                                                             I like the AniS java applet on the official page. It'd be nice if you could add a "framelabel" section with date/time stamps so when one zooms in/out we'll have some clue as to where we are in the forecast.  The probability graphics are a big hit in the BUF office, particularly with precip. Nice job. These and other ensemble charts really opened our eyes to some of the utilities to ensemble forecasting.                                                                                             Dave

## Subject: SREF request followup from 8 Sept 2006From: Walter Drag Walter.Drag@noaa.govDate: Mon, 23 Oct 2006 06:43:53 -0400To: Jun Du Jun.Du@noaa.govCC: David Vallee David.Vallee@noaa.govGood morning Jun,                                                                                             Surveying our Taunton (KBOX) office,  we would like to see some of the following added to the NCO SREF page. Probability of sustained winds greater than 33 knots (marine assistance) every 3 hrs out to 87 hours.                                                                                             Probability of 24 hour snowfall  (0.1,  2, 4, 8, 12, 16 inches).Walter Drag                                                                                             cc: Our KBOX Science and Operations Officer - David Vallee                                                                                             

## Subject: Re: SREF web products serveyFrom: James A Nelson James.A.Nelson@noaa.govDate: Fri, 27 Oct 2006 13:10:45 -0800To: Jun Du Jun.Du@noaa.govJun,In Alaska, we would like to see the same data you have on your web site to be carried to the NCO web site.  There is no SREF data for AK on the NCO Site.  As far as additional probability fields, I would recommend a CAPE value > 200 as well as a wind speed greater than 63 kt. The CAPE value seems to be a good indicator of convection in AR. At least for the Anchorage forecast area. The wind speed greater than 63 kt speaks to the hurricane force wind warnings for our marine areas.Jim (Alaska Region)

## Subject: Re: SREF web products serveyFrom: Jeff Craven Jeffrey.Craven@noaa.govDate: Fri, 27 Oct 2006 16:31:35 -0500 To: Jun Du Jun.Du@noaa.govJun Du...thanks for asking.Probability of exceedance charts are extremely useful.Surface Visibility < 1/2 mile10m Winds (sustained) >15, >20, >25, >34, >50 knots10m Gusts (mean wind in mixed layer >25, >35, >50, >64 knots850 mb Temps <0, <-2, <-5Sfc Temp <32, <28, <24, <0Sfc Temp >90, >100Sfc Td >55, >60, >65, >70, >7512 hour Precip >0.01, >0.10, >0.25, >0.50, >1.00, >2.0024 hour Precip same as aboveCAPE >0, >250, >500, >1000, >2000, >30000-6 km Shear >20 knots, >30 knots, >40 knots, >50 knots0-1 km Shear >15 knots, >20 knots, >25 knots, >30 knotsCombination of CAPE >500, 0-6 shear >40 knots, and Conv Precip >0.01Combination of CAPE>1000, same as aboveCombination of CAPE >2000, same as aboveCombination of CAPE >1000, 0-6 shear >30 knots, and Conv Precip >0.01Combination of CAPE >2000, same as aboveCombination of CAPE >3000, same as aboveCombination of CAPE >1000, 0-6 shear >20 knots, and Conv Precip >0.01Combination of CAPE >2000, same as aboveCombination of CAPE >3000, same as aboveCombination of 2m RH <30%, 10m wind >15 mph, 2m temp >60Probability of Precip TypeSnow, Freezing Rain, Ice Pellets, RainMean and Standard DeviationPrecipitable Water 1000-500 mb RH850 RH, 700 RH, 500 RH, 300 RH12 hour QPF12 hour SnowSurface PMSL850 mb temp850 mb Tdsurface Td (2 m)surface temp (2 m)surface wind (10 m)700 mb temp500 mb temp500 mb Height850 mb wind500 mb wind250 mb windJeff Craven, SOO Sullivan/Milwaukee WI 

## SREF data

- Raw data, 2-year archive at NCEP supercomputer (accessible to NCEP service centers)
- ftp site: mean/spread/prob as well as individual members of selected variables in grib1 format (e.g. Penn State office; to public)
- NOMADS (e.g. Stony Brook etc.; to public)
- NAWIPS 2007 (all WFOs)

##  SREF 

** ****SREF **
_***Grib Mean/Spread Products***_

_***Mean and spread Parameters***__***	***__***	***__***Units***__***	***__***	***__***Level***__***	***__***               ***_***(*= not in Spread files)***
**2m Temperature****	****	****	****	****[K]****	****	****	****Sfc****	****	****	**
**10m U, Vwind****	****	****	****	****	****[m/s]****	****	****	****10 m****	**
**Total precipitation(3,6,12,24hr)****	****[kg/m2]****	****	****Sfc****	****	****	**
**Convective Avail. Pot. Energy ****	****	****[J/kg]****	****	****	**
**Convective inhibition (CIN) ****	****	****[J/kg]****	****	****	****	**
**Storm RElative Helicity (SREH)****	****[m2/s2]****	****	****0-3000 m****	****	**
**Lifted Index****	****	****	****	****	****[K]****	****	****	****0-30 mb abv grnd****	**
**Sea Level Pressure****	****	****	****	****[Pa]****	****	****	****Sfc****	****	**
**Pressure****	****	****	****	****	****	****[Pa]****	****	****	****1000-50 mb (every 50 mb) ?****	****	****	**
***Categorical rain *******	******	******	******	******[y/n]******	******	******	******Sfc******	******	******	***
***Dominant precip type (over 3hr)* ******	******[1-7]******	******	******	******Sfc                                  ***
***12hrly Large scale Snow Fall*******	******	******[kg/m2]******	******	******Sfc******	******	***
***12hrly Snow Depth* ******	******	******	******	******[kg/m2] ******	******	******Sfc***
**12hrly Accumulated Snow Fall****	****	****[kg/m2]****	****	****Sfc****	*****	******	***
***Absolute vorticity*******	******	******	******	******[/s]******	******	******	******1000-50 mb (every 50 mb)?*****	**
**Geopotential height****	****	****	****	****[gpm]****	****	****1000-50 mb (every 50 mb)?****	**** **
**Relative humidity****	****	****	****	****[%]****	****	****	****1000-50 mb (every 50mb)?**
**U, V- wind ****	****	****	****	****	****[m/s]****	****	****	****1000-50 mb (every 50 mb)**
**Temperature****	****	****	****	****	****[K]****	****	****	****1000-50 mb (every 50 mb)?****	**
**Thickness ****	****	****	****	****	****[gpm]****	****	****1000-850, 1000-500, 850-700mb**
**Total preciptable water**

##  SREF 

_***Probabilistic Parameters***__***	***__***	***__***	***__***      Units***__***	***__***	***__***           Threshold____________***_
**Convective Avail. Pot. Energy ****	****	****  [J/kg]****	****      ****≥****  500, 1000, 2000, 3000, 4000****	**
**Convective Inhibition (CIN) ****	****	****	****  [J/kg]****	****      ****≤****  -50, -100, -200, -300, -400****	**
**Storm Relative Helicity (SREH)         [m2/s2]****	****      ****≥****  100, 150, 200, 250, 300**
**Lifted Index****	****	****	****	****	****	****    [K]           ****≤****  0, -2, -4, -6, -8 ****	**
**Precipitation (3, 6, 12, 24 hr)****	****	****       [Inches]****	****       ****≥****  0.1, 0.25,0.5, 1.0, 2.0            12hrly Accumulated Snow Fall****	****       [Inches]****	****       ****≥****  1, 2.5, 5, 10, 20 **
**Prob precip type is rain****	****	****                  [%]**
**Prob precip type is freezing rain            [%]**
**Prob precip type is snow or sleet            [%]**

** ****SREF **
_***probabilistic products***_

## SREF Variables at NAWIPS/2007

- _Means/Spreads_
- Heights at 1000, 850, 700, 500, 250 mb
- U+V at 1000, 850, 700, 500, 250 mb & 10 m
- Temperature 850, 700, 500 mb & 2 m
- Dew Point (RH) 850, 700, 500 mb & 2 m
- QPF at 3, 6, 12 and 24 hour totals
- 12-hr Snowfall
- Sea Level Pressure
- Precipitable Water
- _Probabilistic Fields_
- 3-hr/6-hr QPF				GE .01”, .25”, .50”, 1.0”
- 12-hr/24-hr QPF 			GE 01”, .25”, .50”, 1.0”, 2.0”
- 12-hr Snowfall 				GE 1”, 4”, 8”, 12” (have 2.5, 5, 10, 20”)
- Temperature at 2 m & 850 mb	LE 0oC
- 10 m Wind 				GE 25 kt, 34 kt, 50 kt
- CAPE 					GE 500, 1000, 2000, 3000, 4000
- Lifted Index 				LE 0, -4, -8
- Surface Visibility 			LE 1 mi, 3 mi
- Cloud Ceiling 				LE 500 ft, 1000 ft, 3000 ft
- Probability of precipitation types (have rain, frozen, & freezing)
- 6-hr/12-hr/24-hr QPF Best Category

## Slide 52

## Slide 53

## Slide 54

## Slide 55

## Slide 56

## 3. Downstream Applications of SREF

- DTRA dispersion model (HPAC/SCIPUFF, Jeff McQueen, Patrick Hayes, Steve Hanna and PSU/David Stauffer)
- SREF drives Air Quality Forecast system (research, a student of Prof. Eugenia Kalnay from UMD, Ms. Debra Baker, is working with us now)
- Hydrology in future?

## 4. Verification

**Grid2grid package (against analysis, current)**
**Grid2obs package (fvs, against station obs, current)**
- Unified package in plan (lead by Toth and Geoff.  Yuejian will have a presentation on this from global ensemble/NAEFS side)

## Thank You and Looking forward to work with you in times to come!

**Thank You and Looking forward to work with you in times to come!**