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, SDABRABR22 Dec 2014 11:00Z=130R24.09Cool Season (East)
Stratiform Z/R
168-hr:1.81 #19
Under-estimation
Bethune 10S, SKXBEWWG22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
720-hr:1.51 #56
Under-estimation
Bismarck, NDBISBIS22 Dec 2014 11:00Z=200R1.67.87Marshall/Palmer
Stratiform Z/R
720-hr:1.19 #31
Under-estimation
Chicago, ILLOTLOT22 Dec 2014 11:00Z=130R23.44Cool Season (East)
Stratiform Z/R
168-hr:1.15 #181
Under-estimation
Des Moines, IADMXDMX22 Dec 2014 11:00Z=130R25.91Cool Season (East)
Stratiform Z/R
168-hr:1.08 #344
Under-estimation
Detroit, MIDTXDTX22 Dec 2014 11:00Z=130R24.53Cool Season (East)
Stratiform Z/R
168-hr:1.15 #111
Under-estimation
Dryden 6NNE, ONXDRWTO22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
720-hr:1.56 #57
Under-estimation
Duluth, MNDLHDLH22 Dec 2014 11:00Z=130R24.09Cool Season (East)
Stratiform Z/R
2-hr:0.66 #11
Over-estimation
Exeter 5NNE, ONWSOWTO22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:0.99 #37
No Bias
Foxwarren 4NE, MBXFWWWG22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
720-hr:0.91 #112
Over-estimation
Gaylord/NC Lwr MIAPXAPX22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:0.99 #98
No Bias
Grand Rapids, MIGRRGRR22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.18 #145
Under-estimation
Green Bay, WIGRBGRB22 Dec 2014 11:00Z=130R24.09Cool Season (East)
Stratiform Z/R
168-hr:0.96 #133
No Bias
Indianapolis, ININDIND22 Dec 2014 11:00Z=200R1.62.95Marshall/Palmer
Stratiform Z/R
168-hr:1.19 #63
Under-estimation
La Crosse, WIARXARX22 Dec 2014 11:00Z=130R23.00Cool Season (East)
Stratiform Z/R
5-hr:1.14 #12
Under-estimation
Lasseteer Lake, ONXNIWTO22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
720-hr:1.64 #95
Under-estimation
Lincoln/Ctl IllinoisILXILX22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.49 #236
Under-estimation
Marquette, MIMQTMQT22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.23 #64
Under-estimation
Mayville/Grand ForksMVXFGF22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
720-hr:1.09 #129
Under-estimation
Milwaukee, WIMKXMKX22 Dec 2014 11:00Z=130R23.94Cool Season (East)
Stratiform Z/R
168-hr:1.27 #137
Under-estimation
Minneapolis, MNMPXMPX22 Dec 2014 11:00Z=200R1.63.25Marshall/Palmer
Stratiform Z/R
5-hr:0.92 #15
Over-estimation
Minot AFB, NDMBXBIS22 Dec 2014 11:00Z=200R1.67.87Marshall/Palmer
Stratiform Z/R
720-hr:1.16 #75
Under-estimation
Montreal River, ONWGJWTO22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.51 #46
Under-estimation
North Webster/Nrn INIWXIWX22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.23 #134
Under-estimation
Omaha/Valley, NEOAXOAX22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
1-hr:1.03 #10
No Bias
Owensville, INVWXPAH22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.09 #159
Under-estimation
Paducah, KYPAHPAH22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:0.91 #214
Over-estimation
Pleasant Hill, MOEAXEAX22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.03 #134
No Bias
Quad Cities, IA/ILDVNDVN22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.26 #237
Under-estimation
Sioux Falls, SDFSDFSD22 Dec 2014 11:00Z=130R24.09Cool Season (East)
Stratiform Z/R
1-hr:1.01 #18
No Bias
Springfield, MOSGFSGF22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.48 #114
Under-estimation
St. Louis, MOLSXLSX22 Dec 2014 11:00Z=200R1.66.00Marshall/Palmer
Stratiform Z/R
168-hr:1.13 #366
Under-estimation
Woodlands 6SW, MBXWLWWG22 Dec 2014 11:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
720-hr:1.23 #74
Under-estimation


Generated by get_ZR script Mon 12/22/2014 11:35 UTC