North Central River Forecast Center



WSR-88D Z/R Relationship Table

This table shows WSR-88D Z/R relationships for sites used in the North Central River Forecast Center Multisensor Precipitation radar mosaic. A Z/R relationship is an empirical formula used to estimate rainfall rates from reflectivity signal strength. Parameters that can be varied at each radar site are shown in red. Max Precip Rate is an adjustable parameter which limits overestimation from hail contamination, ground clutter, etc. The Bias Correction Factor shows three elements: the duration (in hours) used to calculate the bias, the bias (in red), and the number of non-zero gage/radar pairs used to calculate the bias for that duration.

Most stratiform rain has a reflectivity signal strength of 20-40dBZ with peaks to 45dBZ, but rarely anything higher (that isn't "brightbanding"). For more information, authorization, instructions, and recommendations regarding Z/R relationships, see the Radar Operations Center's page.

Radar SiteRadar IdWFO IdTime Reported (UTC) Z/R FormulaMax Precip
Rate(in/hr)
Z/R TypeBias Correction Factor
Aberdeen, SDABRABR28 Jan 2015 03:00Z=130R24.09Cool Season (East)
Stratiform Z/R
168-hr:0.90 #25
Over-estimation
Bethune 10S, SKXBEWWG28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
720-hr:1.41 #30
Under-estimation
Bismarck, NDBISBIS28 Jan 2015 03:00Z=200R1.67.87Marshall/Palmer
Stratiform Z/R
720-hr:1.36 #22
Under-estimation
Chicago, ILLOTLOT28 Jan 2015 03:00Z=130R23.44Cool Season (East)
Stratiform Z/R
168-hr:1.30 #134
Under-estimation
Des Moines, IADMXDMX28 Jan 2015 03:00Z=130R25.91Cool Season (East)
Stratiform Z/R
168-hr:0.83 #210
Over-estimation
Detroit, MIDTXDTX28 Jan 2015 03:00Z=130R24.53Cool Season (East)
Stratiform Z/R
168-hr:1.51 #37
Under-estimation
Dryden 6NNE, ONXDRWTO28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
720-hr:1.65 #22
Under-estimation
Duluth, MNDLHDLH28 Jan 2015 03:00Z=130R24.09Cool Season (East)
Stratiform Z/R
168-hr:1.36 #11
Under-estimation
Exeter 5NNE, ONWSOWTO28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
720-hr:1.67 #156
Under-estimation
Foxwarren 4NE, MBXFWWWG28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
720-hr:0.98 #50
No Bias
Gaylord/NC Lwr MIAPXAPX28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
720-hr:1.28 #444
Under-estimation
Grand Rapids, MIGRRGRR28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.17 #38
Under-estimation
Green Bay, WIGRBGRB28 Jan 2015 03:00Z=130R24.09Cool Season (East)
Stratiform Z/R
168-hr:1.07 #29
Under-estimation
Indianapolis, ININDIND28 Jan 2015 03:00Z=200R1.62.95Marshall/Palmer
Stratiform Z/R
168-hr:1.16 #39
Under-estimation
La Crosse, WIARXARX28 Jan 2015 03:00Z=130R23.00Cool Season (East)
Stratiform Z/R
168-hr:1.39 #26
Under-estimation
Lasseteer Lake, ONXNIWTO28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
720-hr:1.66 #33
Under-estimation
Lincoln/Ctl IllinoisILXILX28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.22 #145
Under-estimation
Marquette, MIMQTMQT28 Jan 2015 03:00Z=130R24.09Cool Season (East)
Stratiform Z/R
720-hr:1.34 #181
Under-estimation
Mayville/Grand ForksMVXFGF28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
720-hr:1.10 #61
Under-estimation
Milwaukee, WIMKXMKX28 Jan 2015 03:00Z=130R23.94Cool Season (East)
Stratiform Z/R
168-hr:1.41 #44
Under-estimation
Minneapolis, MNMPXMPX28 Jan 2015 03:00Z=130R23.25Cool Season (East)
Stratiform Z/R
168-hr:0.96 #18
No Bias
Minot AFB, NDMBXBIS28 Jan 2015 03:00Z=200R1.67.87Marshall/Palmer
Stratiform Z/R
168-hr:1.33 #10
Under-estimation
Montreal River, ONWGJWTO28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
720-hr:1.67 #97
Under-estimation
North Webster/Nrn INIWXIWX28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.44 #41
Under-estimation
Omaha/Valley, NEOAXOAX28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.28 #15
Under-estimation
Owensville, INVWXPAH28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.64 #146
Under-estimation
Paducah, KYPAHPAH28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:0.78 #207
Over-estimation
Pleasant Hill, MOEAXEAX28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.30 #27
Under-estimation
Quad Cities, IA/ILDVNDVN28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.30 #147
Under-estimation
Sioux Falls, SDFSDFSD28 Jan 2015 03:00Z=130R24.09Cool Season (East)
Stratiform Z/R
168-hr:0.88 #27
Over-estimation
Springfield, MOSGFSGF28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.42 #20
Under-estimation
St. Louis, MOLSXLSX28 Jan 2015 03:00Z=200R1.66.00Marshall/Palmer
Stratiform Z/R
168-hr:1.32 #234
Under-estimation
Woodlands 6SW, MBXWLWWG28 Jan 2015 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
720-hr:1.30 #30
Under-estimation


Generated by get_ZR script Wed 01/28/2015 03:35 UTC