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, SDABRABR29 Aug 2014 03:00Z=300R1.44.09Summer Deep Convection Z/R3-hr:2.10 #14
Under-estimation
Bethune 10S, SKXBEWWG29 Aug 2014 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:2.34 #277
Under-estimation
Bismarck, NDBISBIS29 Aug 2014 03:00Z=300R1.47.87Summer Deep Convection Z/R168-hr:1.30 #100
Under-estimation
Chicago, ILLOTLOT29 Aug 2014 03:00Z=300R1.43.44Summer Deep Convection Z/R0-hr:1.07 #11
Under-estimation
Des Moines, IADMXDMX29 Aug 2014 03:00Z=300R1.45.91Summer Deep Convection Z/R1-hr:1.12 #10
Under-estimation
Detroit, MIDTXDTX29 Aug 2014 03:00Z=300R1.44.53Summer Deep Convection Z/R168-hr:1.23 #201
Under-estimation
Dryden 6NNE, ONXDRWTO28 Aug 2014 05:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.17 #54
Under-estimation
Duluth, MNDLHDLH29 Aug 2014 03:00Z=300R1.44.09Summer Deep Convection Z/R10-hr:0.52 #11
Over-estimation
Exeter 5NNE, ONWSOWTO29 Aug 2014 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.24 #54
Under-estimation
Foxwarren 4NE, MBXFWWWG29 Aug 2014 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.21 #528
Under-estimation
Gaylord/NC Lwr MIAPXAPX29 Aug 2014 03:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:0.97 #189
No Bias
Grand Rapids, MIGRRGRR29 Aug 2014 03:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:0.71 #450
Over-estimation
Green Bay, WIGRBGRB29 Aug 2014 03:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:0.93 #379
Over-estimation
Indianapolis, ININDIND29 Aug 2014 03:00Z=200R1.64.92Marshall/Palmer
Stratiform Z/R
168-hr:0.74 #242
Over-estimation
La Crosse, WIARXARX29 Aug 2014 03:00Z=300R1.43.00Summer Deep Convection Z/R0-hr:3.22 #16
Under-estimation
Lasseteer Lake, ONXNIWTO29 Aug 2014 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.97 #55
Under-estimation
Lincoln/Ctl IllinoisILXILX29 Aug 2014 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
0-hr:0.64 #11
Over-estimation
Marquette, MIMQTMQT29 Aug 2014 03:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:1.15 #137
Under-estimation
Mayville/Grand ForksMVXFGF29 Aug 2014 03:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:1.05 #312
No Bias
Milwaukee, WIMKXMKX29 Aug 2014 03:00Z=300R1.43.94Summer Deep Convection Z/R0-hr:0.47 #11
Over-estimation
Minneapolis, MNMPXMPX29 Aug 2014 03:00Z=300R1.43.25Summer Deep Convection Z/R1-hr:5.05 #25
Under-estimation
Minot AFB, NDMBXBIS29 Aug 2014 03:00Z=300R1.47.87Summer Deep Convection Z/R168-hr:1.37 #271
Under-estimation
Montreal River, ONWGJWTO29 Aug 2014 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.15 #68
Under-estimation
North Webster/Nrn INIWXIWX29 Aug 2014 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
1-hr:0.60 #11
Over-estimation
Omaha/Valley, NEOAXOAX29 Aug 2014 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
2-hr:0.84 #11
Over-estimation
Owensville, INVWXPAH29 Aug 2014 03:00Z=300R1.44.09Summer Deep Convection Z/R2-hr:0.60 #11
Over-estimation
Paducah, KYPAHPAH29 Aug 2014 03:00Z=300R1.44.09Summer Deep Convection Z/R3-hr:0.69 #15
Over-estimation
Pleasant Hill, MOEAXEAX29 Aug 2014 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
10-hr:0.81 #18
Over-estimation
Quad Cities, IA/ILDVNDVN29 Aug 2014 03:00Z=300R1.44.09Summer Deep Convection Z/R0-hr:0.74 #12
Over-estimation
Sioux Falls, SDFSDFSD29 Aug 2014 03:00Z=300R1.44.09Summer Deep Convection Z/R3-hr:1.70 #12
Under-estimation
Springfield, MOSGFSGF29 Aug 2014 03:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:0.77 #67
Over-estimation
St. Louis, MOLSXLSX29 Aug 2014 03:00Z=300R1.44.09Summer Deep Convection Z/R2-hr:0.80 #22
Over-estimation
Woodlands 6SW, MBXWLWWG29 Aug 2014 03:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.37 #272
Under-estimation


Generated by get_ZR script Fri 08/29/2014 03:35 UTC