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, SDABRABR21 Sep 2014 09:00Z=300R1.44.09Summer Deep Convection Z/R10-hr:1.08 #10
Under-estimation
Bethune 10S, SKXBEWWG21 Sep 2014 09:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.53 #79
Under-estimation
Bismarck, NDBISBIS21 Sep 2014 09:00Z=300R1.47.87Summer Deep Convection Z/R168-hr:1.02 #24
No Bias
Chicago, ILLOTLOT21 Sep 2014 09:00Z=300R1.43.44Summer Deep Convection Z/R2-hr:0.94 #24
Over-estimation
Des Moines, IADMXDMX21 Sep 2014 09:00Z=200R1.65.91Marshall/Palmer
Stratiform Z/R
5-hr:1.04 #11
No Bias
Detroit, MIDTXDTX21 Sep 2014 09:00Z=300R1.44.53Summer Deep Convection Z/R0-hr:1.68 #22
Under-estimation
Dryden 6NNE, ONXDRWTO21 Sep 2014 09:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
10-hr:1.64 #21
Under-estimation
Duluth, MNDLHDLH21 Sep 2014 09:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
1-hr:1.14 #17
Under-estimation
Exeter 5NNE, ONWSOWTO21 Sep 2014 09:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
2-hr:1.87 #11
Under-estimation
Foxwarren 4NE, MBXFWWWG21 Sep 2014 09:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
10-hr:0.81 #15
Over-estimation
Gaylord/NC Lwr MIAPXAPX21 Sep 2014 09:00Z=300R1.44.09Summer Deep Convection Z/R0-hr:0.94 #26
Over-estimation
Grand Rapids, MIGRRGRR21 Sep 2014 09:00Z=300R1.44.09Summer Deep Convection Z/R0-hr:1.04 #33
No Bias
Green Bay, WIGRBGRB21 Sep 2014 09:00Z=300R1.44.09Summer Deep Convection Z/R0-hr:3.04 #19
Under-estimation
Indianapolis, ININDIND21 Sep 2014 09:00Z=200R1.64.92Marshall/Palmer
Stratiform Z/R
2-hr:1.20 #10
Under-estimation
La Crosse, WIARXARX21 Sep 2014 09:00Z=300R1.43.00Summer Deep Convection Z/R3-hr:1.13 #18
Under-estimation
Lasseteer Lake, ONXNIWTO21 Sep 2014 09:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
10-hr:1.74 #12
Under-estimation
Lincoln/Ctl IllinoisILXILX21 Sep 2014 09:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
2-hr:1.55 #14
Under-estimation
Marquette, MIMQTMQT21 Sep 2014 09:00Z=300R1.44.09Summer Deep Convection Z/R1-hr:1.83 #15
Under-estimation
Mayville/Grand ForksMVXFGF21 Sep 2014 09:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
5-hr:1.61 #11
Under-estimation
Milwaukee, WIMKXMKX21 Sep 2014 09:00Z=300R1.43.94Summer Deep Convection Z/R2-hr:1.07 #22
Under-estimation
Minneapolis, MNMPXMPX21 Sep 2014 09:00Z=300R1.43.25Summer Deep Convection Z/R5-hr:1.15 #27
Under-estimation
Minot AFB, NDMBXBIS21 Sep 2014 09:00Z=300R1.47.87Summer Deep Convection Z/R168-hr:1.30 #99
Under-estimation
Montreal River, ONWGJWTO21 Sep 2014 09:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.50 #121
Under-estimation
North Webster/Nrn INIWXIWX21 Sep 2014 09:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
1-hr:1.46 #24
Under-estimation
Omaha/Valley, NEOAXOAX21 Sep 2014 09:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
10-hr:0.62 #15
Over-estimation
Owensville, INVWXPAH21 Sep 2014 09:00Z=300R1.44.09Summer Deep Convection Z/R5-hr:0.96 #11
No Bias
Paducah, KYPAHPAH21 Sep 2014 09:00Z=300R1.44.09Summer Deep Convection Z/R5-hr:1.05 #10
No Bias
Pleasant Hill, MOEAXEAX21 Sep 2014 09:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
168-hr:1.03 #228
No Bias
Quad Cities, IA/ILDVNDVN21 Sep 2014 09:00Z=300R1.44.09Summer Deep Convection Z/R3-hr:0.96 #17
No Bias
Sioux Falls, SDFSDFSD21 Sep 2014 09:00Z=300R1.44.09Summer Deep Convection Z/R10-hr:0.88 #14
Over-estimation
Springfield, MOSGFSGF21 Sep 2014 09:00Z=300R1.44.09Summer Deep Convection Z/R168-hr:1.05 #202
No Bias
St. Louis, MOLSXLSX21 Sep 2014 09:00Z=300R1.46.00Summer Deep Convection Z/R2-hr:0.95 #12
No Bias
Woodlands 6SW, MBXWLWWG21 Sep 2014 09:00Z=200R1.64.09Marshall/Palmer
Stratiform Z/R
10-hr:1.59 #25
Under-estimation


Generated by get_ZR script Sun 09/21/2014 09:35 UTC