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, SDABRABR25 Oct 2014 23:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:0.99 #80
No Bias
Bethune 10S, SKXBEWWG25 Oct 2014 23:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.15 #17
Under-estimation
Bismarck, NDBISBIS24 Oct 2014 18:00Z=200R1.67.87Marshall/Palmer
Stratiform Z/R
168-hr:0.98 #19
No Bias
Chicago, ILLOTLOT25 Oct 2014 23:00Z=200R1.63.44Marshall/Palmer
Stratiform Z/R
168-hr:1.29 #321
Under-estimation
Des Moines, IADMXDMX25 Oct 2014 23:00Z=200R1.65.91Marshall/Palmer
Stratiform Z/R
168-hr:1.06 #875
Under-estimation
Detroit, MIDTXDTX25 Oct 2014 23:00Z=300R1.44.53Summer Deep Convection Z/R168-hr:1.92 #169
Under-estimation
Dryden 6NNE, ONXDRWTO25 Oct 2014 23:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.35 #29
Under-estimation
Duluth, MNDLHDLH25 Oct 2014 23:00Z=130R24.09Cool Season (East)
Stratiform Z/R
168-hr:0.92 #240
Over-estimation
Exeter 5NNE, ONWSOWTO25 Oct 2014 23:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.37 #62
Under-estimation
Foxwarren 4NE, MBXFWWWG25 Oct 2014 23:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.02 #19
No Bias
Gaylord/NC Lwr MIAPXAPX25 Oct 2014 23:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:1.62 #231
Under-estimation
Grand Rapids, MIGRRGRR25 Oct 2014 23:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:1.46 #315
Under-estimation
Green Bay, WIGRBGRB25 Oct 2014 23:00Z=130R24.09Cool Season (East)
Stratiform Z/R
168-hr:1.64 #384
Under-estimation
Indianapolis, ININDIND25 Oct 2014 23:00Z=200R1.63.94Marshall/Palmer
Stratiform Z/R
168-hr:1.35 #89
Under-estimation
La Crosse, WIARXARX25 Oct 2014 23:00Z=200R1.63.00Marshall/Palmer
Stratiform Z/R
168-hr:1.31 #656
Under-estimation
Lasseteer Lake, ONXNIWTO25 Oct 2014 23:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.59 #50
Under-estimation
Lincoln/Ctl IllinoisILXILX25 Oct 2014 23:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.35 #355
Under-estimation
Marquette, MIMQTMQT25 Oct 2014 23:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.46 #211
Under-estimation
Mayville/Grand ForksMVXFGF25 Oct 2014 23:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.02 #85
No Bias
Milwaukee, WIMKXMKX25 Oct 2014 23:00Z=200R1.63.94Marshall/Palmer
Stratiform Z/R
168-hr:1.36 #448
Under-estimation
Minneapolis, MNMPXMPX25 Oct 2014 23:00Z=200R1.63.25Marshall/Palmer
Stratiform Z/R
168-hr:1.07 #389
Under-estimation
Minot AFB, NDMBXBIS25 Oct 2014 23:00Z=200R1.67.87Marshall/Palmer
Stratiform Z/R
168-hr:0.92 #23
Over-estimation
Montreal River, ONWGJWTO25 Oct 2014 23:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.81 #141
Under-estimation
North Webster/Nrn INIWXIWX25 Oct 2014 23:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.75 #236
Under-estimation
Omaha/Valley, NEOAXOAX25 Oct 2014 23:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.14 #310
Under-estimation
Owensville, INVWXPAH25 Oct 2014 23:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:1.07 #142
Under-estimation
Paducah, KYPAHPAH25 Oct 2014 23:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:0.94 #181
Over-estimation
Pleasant Hill, MOEAXEAX25 Oct 2014 23:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.01 #240
No Bias
Quad Cities, IA/ILDVNDVN25 Oct 2014 23:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.62 #600
Under-estimation
Sioux Falls, SDFSDFSD25 Oct 2014 23:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:1.38 #158
Under-estimation
Springfield, MOSGFSGF25 Oct 2014 23:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:1.07 #156
Under-estimation
St. Louis, MOLSXLSX25 Oct 2014 23:00Z=200R1.66.00Marshall/Palmer
Stratiform Z/R
168-hr:1.17 #407
Under-estimation
Woodlands 6SW, MBXWLWWG25 Oct 2014 23:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.24 #35
Under-estimation


Generated by get_ZR script Sat 10/25/2014 23:35 UTC