National Weather Service United States Department of Commerce

Hawaii and Guam Concerns; Record Warmth Spreads Eastward; Heavy Snow for Sierra-Nevada; Severe Weather for the Plains

A very active spring pattern with tropical concerns across the Pacific. Heavy rainfall will continue to impact Hawaii this weekend. Meanwhile we continue to monitor a developing typhoon that may affect Guam into early next week. For the Lower 48, heavy snow for mountains of California this weekend, increase threat for severe thunderstorms next week for the Plains and record warmth spreads east. Read More >

Grand Rapids, MI

Weather Forecast Office

GRR Winter Weather Forecasts

Weather.gov > Grand Rapids, MI > GRR Winter Weather Forecasts

72 Hour Snow Amount Potential
Experimental -
Expected 72 Hour Snowfall - Official NWS Forecast
 

What's this? 		High End 72 Hour Amount
1 in 10 Chance (10%) of Higher Snowfall

What's this?
Low End 72 Hour Amount
9 in 10 Chance (90%) of Higher Snowfall

What's this?

Low End Amount – 9 in 10 Chance (90%) of Higher Snowfall over 72 hours

 

This map depicts a reasonable lower-end snowfall amount for the time period shown on the graphic, based on many computer model simulations of possible snowfall totals. This lower amount is an unlikely scenario with a 9 in 10, or 90% chance that more snow will fall, and only a 1 in 10, or 10% chance that less snow will fall. This number can help serve as a lower-end scenario for planning purposes.

"Point Map" is Expected Snowfall - 72hr Official NWS Forecast

 

The "Point" map is the official 72 hour NWS snowfall forecast in inches during the time period shown on the graphic. This snowfall amount is determined by NWS forecasters to be the most likely outcome based on evaluation of data from computer models, satellite, radar, and other observations.

"Range Map" is Experimental Probabilistic Snowfall Range Amounts over 72 hours

The "Range" map is the 25th percentile (lower number) to 75th percentile (higher number) of possible snowfall amounts based on the Weather Prediction Center (WPC) Super Ensemble output during the time period of the graphic. The official NWS snowfall forecast influences this range of values either up or down depending upon how closely they match.

High End Amount – Only a 1 in 10 Chance (10%) of Higher Snowfall over 72 hours

 

This map depicts a reasonable upper-end snowfall amount for the time period shown on the graphic, based on many computer model simulations of possible snowfall totals. This higher amount is an unlikely scenario, with only a 1 in 10, or 10% chance that more snow will fall, and a 9 in 10, or 90% chance that less snow will fall. This number can help serve as an upper-end scenario for planning purposes.
 
The purpose of these experimental probabilistic snowfall products is to provide customers and partners a range of snowfall possibilities, in complement to existing NWS deterministic snowfall graphics, to better communicate forecast uncertainties during winter weather events. For more information visit this project's Product/Service Description Document, and please provide us your feedback here.
Percent Chance That 72 Hour Snow Amounts in Will Be Greater Than...
Experimental -
What's this?

Percent Chance That 72 Hour Snow Amounts Will Be Greater Than

 

This series of maps shows the probability (that is, the likelihood) that snowfall will equal or exceed specific amounts during the time period shown on the graphic. These forecasts are based on many computer model simulations of possible snowfall totals.
Hover over thumbnails below to view larger image.
>=0.1"
>=1"
>=2"
>=4"
>=6"
>=8"
>=12"
>=18"

72 Hour Snowfall Totals by Location
Experimental -
What's this?

Snowfall Totals by Location

 

These tables show the snowfall forecast for individual locations, and provide the same information as the graphics on this web page, just shown in a different way. All of these values are valid for the same time period as depicted on the graphics.

 

Location Low-End
Amount		 Expected
Amount		 High-End
Amount		 Chance of Seeing More Than
 
Snow Amount Potential
Experimental -
Expected 72 Hour Snowfall - Official NWS Forecast
 

What's this? 		High End 72 Hour Amount
1 in 10 Chance (10%) of Higher Snowfall

What's this?
Low End 72 Hour Amount
9 in 10 Chance (90%) of Higher Snowfall

What's this?

Low End 72 Hour Amount – 9 in 10 Chance (90%) of Higher Snowfall

 

This map depicts a reasonable lower-end snowfall amount for the time period shown on the graphic, based on many computer model simulations of possible snowfall totals. This lower amount is an unlikely scenario with a 9 in 10, or 90% chance that more snow will fall, and only a 1 in 10, or 10% chance that less snow will fall. This number can help serve as a lower-end scenario for planning purposes.

"Point Map" is Expected Snowfall - 72hr Official NWS Forecast

 

The "Point" map is the official 72 hour NWS snowfall forecast in inches during the time period shown on the graphic. This snowfall amount is determined by NWS forecasters to be the most likely outcome based on evaluation of data from computer models, satellite, radar, and other observations.

"Range Map" is Experimental Probabilistic Snowfall Range Amounts over 72 hours

The "Range" map is the 25th percentile (lower number) to 75th percentile (higher number) of possible snowfall amounts based on the Weather Prediction Center (WPC) Super Ensemble output during the time period of the graphic. The official NWS snowfall forecast influences this range of values either up or down depending upon how closely they match.

High End 72 HourAmount – Only a 1 in 10 Chance (10%) of Higher Snowfall

 

This map depicts a reasonable upper-end snowfall amount for the time period shown on the graphic, based on many computer model simulations of possible snowfall totals. This higher amount is an unlikely scenario, with only a 1 in 10, or 10% chance that more snow will fall, and a 9 in 10, or 90% chance that less snow will fall. This number can help serve as an upper-end scenario for planning purposes.
 
The purpose of these experimental probabilistic snowfall products is to provide customers and partners a range of snowfall possibilities, in complement to existing NWS deterministic snowfall graphics, to better communicate forecast uncertainties during winter weather events. For more information visit this project's Product/Service Description Document, and please provide us your feedback here.
Percent Chance That 72 Hour Snow Amounts Will Be Greater Than...
Experimental -
What's this?

Percent Chance That 72 Hour Snow Amounts Will Be Greater Than

 

This series of maps shows the probability (that is, the likelihood) that snowfall will equal or exceed specific amounts during the time period shown on the graphic. These forecasts are based on many computer model simulations of possible snowfall totals.
Hover over thumbnails below to view larger image.
>=0.1"
>=1"
>=2"
>=4"
>=6"
>=8"
>=12"
>=18"
72 Hour Ice Accumulation Potential
Experimental -
Expected 72 Hour Ice Accumulation - Official NWS Forecast
 

What's this?
 

This is the elevated flat surface ice accumulation. It is not radial/line ice. Radial/line ice is typically 39% of the elevated flat surface ice. For more information on this, see this module.

 High End 72 Hour Amount
1 in 10 Chance (10%) of Higher Ice Accumulation

What's this?
Low End 72 Hour Amount
9 in 10 Chance (90%) of Higher Ice Accumulation

What's this?

Low End 72 Hour Amount – 9 in 10 Chance (90%) of Higher Ice Accumulation

 

This map depicts a reasonable lower-end ice accumulation amount for the time period shown on the graphic, based on many computer model simulations of possible ice accumulation totals. This lower amount is an unlikely scenario with a 9 in 10, or 90% chance that more snow will fall, and only a 1 in 10, or 10% chance that less snow will fall. This number can help serve as a lower-end scenario for planning purposes.

"Point Map" is Expected 72 Hour Ice Accumulation - Official NWS Forecast

 

The "Point" map is the official NWS ice accumulation forecast in inches during the time period shown on the graphic. This ice accumulation amount is determined by NWS forecasters to be the most likely outcome based on evaluation of data from computer models, satellite, radar, and other observations.

"Range Map" is Experimental Probabilistic Ice Accumulation Range Amounts over 72 hours

 

The "Range" map is the 25th percentile (lower number) to 75th percentile (higher number) of possible ice accumulation amounts based on the Weather Prediction Center (WPC) Super Ensemble output during the time period of the graphic. The official NWS ice accumulation forecast influences this range of values either up or down depending upon how closely they match.

High End 72 Hour Amount – Only a 1 in 10 Chance (10%) of Higher Ice Accumulation

 

This map depicts a reasonable upper-end ice accumulation amount for the time period shown on the graphic, based on many computer model simulations of possible ice accumulation totals. This higher amount is an unlikely scenario, with only a 1 in 10, or 10% chance that more snow will fall, and a 9 in 10, or 90% chance that less snow will fall. This number can help serve as an upper-end scenario for planning purposes.
 
The purpose of these experimental probabilistic ice accumulation products is to provide customers and partners a range of ice accumulation possibilities, in complement to existing NWS deterministic ice accumulation graphics, to better communicate forecast uncertainties during winter weather events. For more information visit this project's Product/Service Description Document, and please provide us your feedback here.
Percent Chance That 72 Hour Ice Accumulation Will Be Greater Than...
Experimental -
What's this?

Percent Chance That 72 Hour Ice Accumulation Will Be Greater Than

 

This series of maps shows the probability (that is, the likelihood) that ice accumulation will equal or exceed specific amounts during the time period shown on the graphic. These forecasts are based on many computer model simulations of possible snowfall totals.
Hover over thumbnails below to view larger image.
>=0.01"
>=0.1"
>=0.25"
>=0.5"
>=0.75"
>=1"
>=1.25"
>=1.5"
72 Hour Ice Accumulation by Location
Experimental -
What's this?

72 Hour Ice Accumulation Totals by Location

 

These tables show the ice accumulation forecast for individual locations, and provide the same information as the graphics on this web page, just shown in a different way. All of these values are valid for the same time period as depicted on the graphics.

 

Location Low-End
Amount		 Expected
Amount		 High-End
Amount		 Chance of Seeing More Than
 
72 Hour Ice Accumulation Potential
Experimental -
Expected 72 Hour Ice Accumulation - Official NWS Forecast
 

What's this?
 

This is the elevated flat surface ice accumulation. It is not radial/line ice. Radial/line ice is typically 39% of the elevated flat surface ice. For more information on this, see this module.

 High End 72 Hour Amount
1 in 10 Chance (10%) of Higher Ice Accumulation

What's this?
Low End 72 Hour Amount
9 in 10 Chance (90%) of Higher Ice Accumulation

What's this?

Low End 72 Hour Amount – 9 in 10 Chance (90%) of Higher Ice Accumulation

 

This map depicts a reasonable lower-end ice accumulation amount for the time period shown on the graphic, based on many computer model simulations of possible ice accumulation totals. This lower amount is an unlikely scenario with a 9 in 10, or 90% chance that more snow will fall, and only a 1 in 10, or 10% chance that less snow will fall. This number can help serve as a lower-end scenario for planning purposes.

"Point Map" is Expected 72 Hour Ice Accumulation - Official NWS Forecast

 

The "Point" map is the official NWS ice accumulation forecast in inches during the time period shown on the graphic. This ice accumulation amount is determined by NWS forecasters to be the most likely outcome based on evaluation of data from computer models, satellite, radar, and other observations.

"Range Map" is Experimental Probabilistic Ice Accumulation Range Amounts over 72 hours

 

The "Range" map is the 25th percentile (lower number) to 75th percentile (higher number) of possible ice accumulation amounts based on the Weather Prediction Center (WPC) Super Ensemble output during the time period of the graphic. The official NWS ice accumulation forecast influences this range of values either up or down depending upon how closely they match.

High End 72 Hour Amount – Only a 1 in 10 Chance (10%) of Higher Ice Accumulation

 

This map depicts a reasonable upper-end ice accumulation amount for the time period shown on the graphic, based on many computer model simulations of possible ice accumulation totals. This higher amount is an unlikely scenario, with only a 1 in 10, or 10% chance that more snow will fall, and a 9 in 10, or 90% chance that less snow will fall. This number can help serve as an upper-end scenario for planning purposes.
 
The purpose of these experimental probabilistic ice accumulation products is to provide customers and partners a range of ice accumulation possibilities, in complement to existing NWS deterministic ice accumulation graphics, to better communicate forecast uncertainties during winter weather events. For more information visit this project's Product/Service Description Document, and please provide us your feedback here.
Percent Chance That 72 Hour Ice Accumulations Will Be Greater Than...
Experimental -
What's this?

Percent Chance That 72 Hour Ice Accumulations Will Be Greater Than

 

This series of maps shows the probability (that is, the likelihood) that ice accumulation will equal or exceed specific amounts during the time period shown on the graphic. These forecasts are based on many computer model simulations of possible ice accumulation totals.
Hover over thumbnails below to view larger image.
>=0.01"
>=0.1"
>=0.25"
>=0.5"
>=0.75"
>=1"
>=1.25"
>=1.5"
Winter Storm Severity Index (WSSI) Winter Storm Outlook (WSO)
Winter Storm Severity Index
Winter Storm Outlook
Local Snow Reports National Snowfall Analysis
National Snow Reports
National Snowfall Analysis
Days 4-7 Winter Weather Outlook
 
Day 4 Winter Weather Outlook Day 5 Winter Weather Outlook
Day 4 Winter Weather Outlook Day 5 Winter Weather Outlook
 
Day 6 Winter Weather Outlook Day 7 Winter Weather Outlook
Day 6 Winter Weather Outlook Day 7 Winter Weather Outlook


Click here for an interactive map

 
CPC Week-2 Experimental Heavy Snow Risk
 
CPC Week-2 Experimental Heavy Snow Risk
 
CPC Temperature & Precipitation Maps
 

Days 6-10
Temperature  Precipitation
6-10 day temperature 6-10 day precipitation
 
 

Days 8-14
TEMPERATURE  PRECIPITATION
8-14 day temperature 8-14 day precipitation
 
 

Week 3-4

TEMPERATURE

PRECIPITATION
Week 3-4 Temperature Week 3-4 precipitation

Selected City Charts
Expected Snowfall - Box and Whisker Plot
box and whisker 		Expected Snowfall - Exceedance Bar Plot
exceedance bar
 
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