National Weather Service United States Department of Commerce

Zone Changes

Effective Tuesday, September 6th, 2022, four county public forecast zones for the National Weather Service Northern Indiana office (IWX) will be reconfigured into different zones. Please read the overview sections below for details or if you prefer, jump to the images or table below. 

Overview (public zones)

The National Weather Service Northern Indiana office (IWX) will add 4 new county segments within our land area for the County Warning Area (CWA).

Complete Service Change notification is available online. 

In Michigan

  • Berrien county will be split into northern Berrien and southern Berrien along 42.0° N. 

In Indiana

  • La Porte county will be split into northern La Porte and southern La Porte along US Highway 6
  • St. Joseph county will be split into western St. Joseph and eastern St. Joseph just west of South Bend along 86.358 W
  • Kosciusko county will be split into northern Kosciusko and southern Kosciusko along US Highway 30. 

Zone Changes

original public zone map (February 2022)
Figure 1: Current Zone Alignment 

reconfigured public zones (September 2022)
Figure 2: New zone alignment changes. 

Justification
Climatologically, several counties across northern Indiana and southwest Michigan are affected by lake effect snow events, depending on prevailing wind direction off lake Michigan.  This climatology of lake effect snows provides unique boundaries that can assist in dividing the county into additional zones that will more accurately represent forecast weather and expected hazards.

Table 1: WFO IWX Affected Public Weather Forecast Zones

Current Zone Name / Current UGZ (Z) New Public Zone Name / New UGZ (Z)
Berrien (MIZ077) Northern Berrien (MIZ177)
Southern Berrien (MIZ277)
La Porte (INZ003) Northern La Porte (INZ103)
Southern La Porte (INZ203)
St. Joseph (INZ004) Eastern St. Joseph (INZ104)
Western St. Joseph (INZ204)
Kosciusko (INZ016) Northern Kosciusko (INZ116)
Southern Kosciusko (INZ216)

 

Table 2: WFO IWX Products Affected by These Changes

Product Name WMO Header AWIPS ID

Special Weather Statement

WWUS83 KIWX SPSIWX

Zone Forecast Product

FPUS53 KIWX ZFPIWX

Hazardous Weather Outlook

FLUS43 KIWX HWOIWX

Non-Precipitation Watch/Warning/Advisory

WWUS73 KIWX NPWIWX

Winter Weather Watch/Warning/Advisory

WWUS43 KIWX WSWIWX

Area Forecast Matrices

FOUS53 KIWX AFMIWX

Point Forecast Matrices

FOUS53 KIWX PFMIWX

Fire Weather Message

FNUS53 KIWX FWFIWX

Fire Weather Watch/Red Flag Warning

WWUS83 KIWX RFWIWX

Flood Watch/Warning/Advisory

WGUS63 KIWX FFAIWX

Hydrologic Outlook

FGUS73 KIWX ESFIWX

Hydrologic Statement

FGUS83 KIWX RVSIWX

Hydrologic Summary

SRUS43 KIWX RVAIWX

Daily River and Lake Summary

FGUS53 KIWX RVDIWX

Public Information Statement

NOUS43 KIWX PNSIWX

Area Forecast Discussion

FXUS63 KIWX AFDIWX

Air Quality Alert

AEUS73 KIWX AQAIWX

Surf Zone Forecast

FZUS53 KIWX SRFIWX

Coastal Hazard Message

WHUS43 KIWX CFWIWX


If you are affected by these changes, take the appropriate action so your system(s) recognize the new zone (Z) Universal Geographic Codes (UGC) and the new zone alignments. 

Shape Files

Updated public and fire zone map shapefiles are available for download

at: https://www.weather.gov/gis/PublicZones

The proposed changes to the IWX zone boundaries have been closely coordinated with local partners and customers to be ready for implementation on September 6th, 2022.

If you have any questions concerning this change, please contact:

Michael Lewis
Warning Coordination Meteorologist

National Weather Service Northern Indiana
7506 E 850 N
Syracuse, IN 46567
574-834-1104

Kimberly McMahon
Public Weather Services Program Leader
NOAA National Weather Service
Forecast Services Division/Analyze, Forecast, and Support Office
Silver Spring, MD  200910
301-337-1844