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, SDABRABR19 Apr 2014 20:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:1.22 #28
Under-estimation
Bethune 10S, SKXBEWWG19 Apr 2014 20:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
10-hr:1.53 #11
Under-estimation
Bismarck, NDBISBIS19 Apr 2014 20:00Z=130R27.87Cool Season (East)
Stratiform Z/R
720-hr:1.79 #36
Under-estimation
Chicago, ILLOTLOT19 Apr 2014 20:00Z=200R1.63.44Marshall/Palmer
Stratiform Z/R
168-hr:1.18 #491
Under-estimation
Des Moines, IADMXDMX19 Apr 2014 20:00Z=300R1.45.91Summer Deep Convection Z/R168-hr:0.82 #1059
Over-estimation
Detroit, MIDTXDTX19 Apr 2014 20:00Z=300R1.44.53Summer Deep Convection Z/R168-hr:1.40 #315
Under-estimation
Dryden 6NNE, ONXDRWTO19 Apr 2014 20:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:2.08 #24
Under-estimation
Duluth, MNDLHDLH19 Apr 2014 20:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
3-hr:0.76 #15
Over-estimation
Exeter 5NNE, ONWSOWTO19 Apr 2014 20:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:2.38 #75
Under-estimation
Foxwarren 4NE, MBXFWWWG19 Apr 2014 20:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
5-hr:1.01 #16
No Bias
Gaylord/NC Lwr MIAPXAPX19 Apr 2014 20:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.08 #389
Under-estimation
Grand Rapids, MIGRRGRR19 Apr 2014 20:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.07 #530
Under-estimation
Green Bay, WIGRBGRB19 Apr 2014 20:00Z=130R24.09Cool Season (East)
Stratiform Z/R
168-hr:1.34 #481
Under-estimation
Indianapolis, ININDIND19 Apr 2014 20:00Z=200R1.63.94Marshall/Palmer
Stratiform Z/R
168-hr:1.25 #137
Under-estimation
La Crosse, WIARXARX19 Apr 2014 20:00Z=200R1.63.00Marshall/Palmer
Stratiform Z/R
168-hr:1.07 #952
Under-estimation
Lasseteer Lake, ONXNIWTO19 Apr 2014 20:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.67 #12
Under-estimation
Lincoln/Ctl IllinoisILXILX19 Apr 2014 20:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.18 #607
Under-estimation
Marquette, MIMQTMQT19 Apr 2014 20:00Z=130R24.09Cool Season (East)
Stratiform Z/R
168-hr:2.01 #141
Under-estimation
Mayville/Grand ForksMVXFGF19 Apr 2014 20:00Z=200R1.64.92Marshall/Palmer
Stratiform Z/R
10-hr:1.44 #11
Under-estimation
Milwaukee, WIMKXMKX19 Apr 2014 20:00Z=200R1.63.94Marshall/Palmer
Stratiform Z/R
168-hr:1.08 #678
Under-estimation
Minneapolis, MNMPXMPX19 Apr 2014 20:00Z=200R1.63.25Marshall/Palmer
Stratiform Z/R
168-hr:0.99 #579
No Bias
Minot AFB, NDMBXBIS19 Apr 2014 20:00Z=130R27.87Cool Season (East)
Stratiform Z/R
10-hr:1.31 #17
Under-estimation
Montreal River, ONWGJWTO19 Apr 2014 20:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.98 #51
Under-estimation
North Webster/Nrn INIWXIWX19 Apr 2014 20:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.26 #387
Under-estimation
Omaha/Valley, NEOAXOAX19 Apr 2014 20:00Z=130R24.09Cool Season (East)
Stratiform Z/R
168-hr:1.26 #312
Under-estimation
Owensville, INVWXPAH19 Apr 2014 20:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:0.97 #288
No Bias
Paducah, KYPAHPAH19 Apr 2014 20:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.06 #346
Under-estimation
Pleasant Hill, MOEAXEAX19 Apr 2014 20:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:0.77 #231
Over-estimation
Quad Cities, IA/ILDVNDVN19 Apr 2014 20:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:0.97 #928
No Bias
Sioux Falls, SDFSDFSD19 Apr 2014 20:00Z=130R24.09Cool Season (East)
Stratiform Z/R
168-hr:1.18 #188
Under-estimation
Springfield, MOSGFSGF19 Apr 2014 20:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:1.06 #165
Under-estimation
St. Louis, MOLSXLSX19 Apr 2014 20:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:1.00 #651
No Bias
Woodlands 6SW, MBXWLWWG19 Apr 2014 20:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
5-hr:1.26 #17
Under-estimation


Generated by get_ZR script Sat 04/19/2014 20:35 UTC