IMPLEMENTATION OF A REAL TIME SHORT RANGE

ENSEMBLE FORECAST (SREF) SYSTEM AT NCEP

Steve Tracton and Jun Du

NCEP/EMC

NCEP

Where the nation’s climate and weather services begin

MOTIVATION

NON REAL-TIME SREF RAN EXPERIMENTALLY FROM APRIL 2000 – APRIL 2001

CASE STUDIES, ANECDOTAL EVIDENCE SUGGESTED SREF POTENTIALLY VALUABLE FOR OPERATIONAL FORECASTING

PQPF

WINTER STORMS

CONVECTIVE OUTLOOKS

STORM TRACKS

AVIATION WEATHER

EXTREME/RARE EVENTS

MOTIVATION (CONT.)

BUT, EXPERIMENTAL SYSTEM

RAN ON DEVELOPMENT SIDE OF IBM – NOT RELIABLY AVAILABLE (DEVELOPER SUPPORT ONLY)

RAN IN DELAYED MODE – NOT SUFFICIENTLY TIMELY FOR THOROUGH FORECASTER EVALUATION (7:30Z FOR 00Z RUNS, 19:30Z FOR 12Z RUNS)

PRODUCTS AVAILABLE ON WEB ONLY – NOT NAWIPS

SYSTEM JUDGED SUFFICIENTLY MATURE FOR REAL TIME TEST AND EVALUATION

NCEP SERVICE CENTERS REQUIRE SREF PRODUCTS RELIABLY, TIMELY AND ON NAWIPS BEFORE FULL IMPLEMENTATION CAN BE ENDORSED

JAN 2000 SNOWSTORM: 12 HR PRECIP FROM 00Z 24JAN VT12Z 25JAN.25:

REAL TIME TEST AND EVALUATION (RTT&E)

RTT&E MODE IS A DESIGNATION THAT INDICATES:

INTERNAL NCEP IMPLEMENTATION

RUN ON THE PRODUCTION IBM WITH NCEP/NCO PRODUCTION STANDARDS AND SUPPORT

STEP ABOVE “PARALLEL” RUNS ON DEVELOPMENT IBM

PRODUCTS NOT (YET) SANCTIONED NOR DISTRIBUTED BY THE NWS OPERATIONAL

IN THIS SENSE, SREF COMPARABLE IN STATUS TO CURRENT RUNS OF THE NESTED 10KM MESO ETA (“THREATS” RUNS)

RUN IN EXISTING WINDOWS OF THE IBM PRODUCTION SUITE AND DOES NOT IMPACT ANY OTHER OPERATIONAL JOBS

SREF SYSTEM

10 MEMBERS (5 ETA, 5 RSM)

48 KM RESOLUTION

FULL ETA DOMAIN

RUN TWICE DAILY; FROM 09Z AND 21Z TO 63 HOURS

PRODUCTS AVAILABLE ABOUT SAME TIME AS NEXT OPERATIONAL 12Z AND 00Z ETA RUNS

“REGIONAL BREEDING” FOR INITIAL CONDITION PERTURBATIONS

LATERAL BOUNDARY CONDITIONS FROM 9 HR OLD GLOBAL ENS

RTT&E PHASE I (JUNE 5, 2001)

SREF OFFICIALLY INTRODUCED INTO NCEP PRODUCTION SUITE

GRIB AND GEMPAK “THINNED” GRIDDED DATA – ONE FILE PER MEMBER – AVAILABLE ON NCODAS FOR SERVICE CENTER ACCESS (FTP* OF GRIB FILES FOR EXTERNAL USERS);

THINNED >> Output at all times at 3-hour intervals, but for selected parameters and levels only (same as global ensemble +) Z: 1000, 850, 700, 500, 250 : U,V: 850, 500, 250 PMSL: T: 2M, 850, 700, Tmax, Tmin RH: 850, 700: ABSV: 500, 250 PRECIP: LI, CAPE, CIN

SAME PRODUCT SET AND ACCESS AS PREVIOUS NON-REAL TIME SYSTEM (EXCEPT OUTPUT AT 3 HOUR INTERVALS)

MOSTLY WEB BASED (http://lnx48.wwb.noaa.gov/SREF/SREF.html)

NCEP SERVICE CENTERS’ CONCENSUS “BASE” SET

ENSEMBLE MEANS, SPREAD, SPAGHETTI CHARTS, PROBABILITES

SELECTED PARAMETERS/LEVELS

RTT&E PHASE II (~ MID AUGUST 2001)

OFFICIAL BASE PRODUCT SET – SAME AS ON WEB -

GENERATED ON IBM

COMPONENT OF SREF PRODUCTION SUITE

PRODUCTS IN GRIB FORMAT WITH APPROPRIATE ENSEMBLE SPECIFIC GRIB EXTENSIONS (FTP ACCESS FOR EXTERNAL USERS*)

* FTP SITE: ftp.ncep.noaa.gov;

LOGIN: anonymous;

PASSWD: your email address;

DIRECTORY: pub/data1/sref/sref.yymmdd).

WHAT FOLLOWS BEGINNING OF REAL TIME T&E?

EDUCATION AND TRAINING IN USE OF SREF AT SERVICE CENTERS;

“MISSIONARY WORK” – ON SITE VISITS (TRAVEL FUND LIMITED)

WEB BASED TUTORIALS/ “VISIT VIEW”

PRODUCT DEVELOPMENT (BEYOND BASE SET)

COMMON TO ALL SERVICE CENTERS (E.G., STD PARAMETER METEOGRAMS): FOLLOW LEAD OF MET OFFICE EXPERIENCE

SERVICE CENTER SPECIFIC (E.G., “SPAGHETTI” HODOGRAPHS) STATISTICAL POST PROCESSING (E.G., CALIBRATE PROBABILITIES, ENSEMBLE MOS)

NCEP SOO’S, IN COLLABORATION WITH EMC, RESPONSIBLE FOR REFINEMENTS TO COMMON PRODUCT SUITE AND DEVELOPMENT AND TESTING OF NEW SPECIALIZED PRODUCTS

ISSUES:

NEED TO DEFINE PROCESS FOR INTRODUCING NEW COMMON PRODUCTS INTO PRODUCTION SUITE

CENTER SPECIFIC PRODUCTS: NEED TO DETERMINE WHETHER TO RUN IN PRODUCTION, ON IBM WITH PRIORITY, OR RUN LOCALLY

WHAT FOLLOWS BEGINNING OF REAL TIME T&E? (CONT)

EVALUATION – SYSTEM PERFORMANCE AND VALUE

OBJECTIVE VERIFICATION (E.G., RMS ERRORS, RANKED PROBABILITY SCORE, TALAGRAND HISTOGRAMS, RELIABILITY DIAGRAMS)

SUBJECTIVE – USER FEEDBACK NCEP SERVICE CENTERS (HPC, SPC, TPC, MPC) FIELD (SELECTED “BETA” SITES)

SYSTEM DEVELOPMENT

PARALLEL TEST SYSTEM ON DEVELOPMENT SIDE OF IBM

PERTURB PHYSICS ?

ADDITIONAL MEMBERS ?

ADDITIONAL MODELS (E.G., RUC) ?

INCREASED RESOLUTION ?

TRANSITION TO WRF (LONGER TERM)

WHAT FOLLOWS BEGINNING OF REAL TIME T&E? (CONT)

SYSTEM DEVELOPMENT

PARALLEL TEST SYSTEM ON DEVELOPMENT SIDE OF IBM PERTURB PHYSICS ?

MORE MEMBERS ?

ADDITIONAL MODELS (E.G., RUC) ?

INCREASED RESOLUTION ?

TRANSITION TO WRF (LONGER TERM)

ISSUES FOLLOWING BEGINNING OF REAL TIME T&E

RESOURCES:

CURRENTLY ONLY ONE FULL TIME PERSON DEDICATED TO SREF (NO BACKUP)

EXPLORING FAA FUNDING, COMET (UMD STUDENT) OTHER ? LIMITED WINDOW AVAILABLE ON PROD SIDE OF IBM

MOTTO: “DO NOT LET WHAT YOU CANNOT DO INTERFERE WITH WHAT YOU CAN DO” SET PRIORITIES W.R.T. ITEMS ON PREVIOUS SLIDE GIVEN AVAILABLE RESOURCES!!!!

OPERATIONAL IMPLEMENTATION: TARGET: MID 2002

(MAY 2001 SYSTEM, PENDING DECISIONS ON ALTERNATIVES)

COUNTDOWN ON “MODEL PRE-IMPLEMNTATION CHECK LIST” FOLLOWED REQUIRE NWSHQ TO PLAN AND EXECUTE BROADER (THAN JUST NCEP) PROGRAM FOR TRAINING, COMMUNICATIONS, PRODUCT DISSEMINATION (AWIPS), ETC.

010519/0000V63 SREFX-CMB 500MB; 5820M

010519/0000V63 SREFX-CMB; SFC LOWS

010519/0000V63 SREFX-CMB; 24HR PQPF OF .25”

010519/0000V63 SREFX-CMB; SHADED, IN AT LEAST 60% OF MEMBES

010519/0000V63 SREFX-CMB; SPGHETTI .25”

010519/0000V63 SREFX-CMB; LIFTED INDEX PROB 0F < -4

010519/0000V63 SREFX-CMB; CAPE > 2000J/KG