Snow and Ice Forecasts & Services

Atmospheric River in the Pacific Northwest and Northern Rockies this Weekend

A Pacific storm and atmospheric river will impact the Pacific Northwest states and northern Rockies this weekend, bringing locally heavy low elevations rain and heavy high elevation snow in the mountains. By Sunday over the Interior Northwest, rain combined with snowmelt will increase the risk of flood hazards. Flood Watches are in effect. Read More >

Quick Page Navigation

Jump to:

Snow Amount Potential Graphics
Snow Amount Exceedance Graphics
Snowfall Totals by Location

Switch Office

Snow Amount Potential Experimental - Leave feedback Click here for more information on these products Click here for the NWS Probabilistic Precipitation Portal
Expected Snowfall - Official NWS Forecast What's this?	High End Amount 1 in 10 Chance (10%) of Higher Snowfall What's this?
	Low End Amount 9 in 10 Chance (90%) of Higher Snowfall What's this?
Low End 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. Expected Snowfall - Official NWS Forecast This map is the official 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. High End Amount – 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 Snow Amounts Will Be Greater Than...

Experimental - Leave feedback

Click here for more information on these products

What's this?

Hover over thumbnails below to view larger image.

>=0.1"	>=1"	>=2"	>=4"	>=6"	>=8"	>=12"	>=18"

Snowfall Totals by Location

Experimental - Leave feedback

Click here for more information on these products

What's this?

Location	Low-End Amount	Expected Amount	High-End Amount	Chance of Seeing More Than
Location	Low-End Amount	Expected Amount	High-End Amount

Ice Accumulation Potential
Expected Ice Accumulation - Official NWS Forecast
What's this?
Most Likely Ice Accumulation Represents our official ice forecast in inches within the next one to three days. The ice accumulation amounts are provided in ranges.

Ice Accumulation Potential

Expected Ice Accumulation - Official NWS Forecast

What's this?

>=0.1"

>=1"

>=2"

>=4"

>=6"

>=8"

>=12"

>=18"

Other Snow/Ice Information
Observed Snow/Ice Amounts	Winter Storm Severity Index

What's this?	What's this?
Reported Snow and Ice As snow and/or ice reports come into the NWS we consolidate and post them here. You can email reports to lwx-report@noaa.gov or X to @NWS_BaltWash. With the map linked here, and the supporting reports listed below it, you can keep tabs on how much has fallen. Note you can toggle between mapping snow and ice reports using the drop down menu just above the map. Winter Storm Severity Index The purpose of the Winter Storm Severity Index (WSSI) is to provide NWS partners and the general public with an indication of the level of winter precipitation (snow and ice) severity and its potential related societal impacts.

Other Snow/Ice Information

Observed Snow/Ice Amounts

Winter Storm Severity Index

What's this?

Onset/End of Wintry Precipitation
Onset of Wintry Precipitation (For areas under Warning or Advisory)	End of Wintry Precipitation (For areas under Warning or Advisory)

What's this?	What's this?
Precipitation Onset Most likely time of winter precipitation onset (snow, sleet, freezing rain). Rain is not included here. This information is provided when we issue a Warning or Advisory for expected snow or ice accumulation; typically six to 24 hours in advance. Times are only given for places that are under a Warning or Advisory. They will be blank in areas outside Warnings or Advisories. Precipitation End Time Most likely time that the accumulating winter precipitation ends (snow, sleet, freezing rain). Rain is not included here. This information is provided when we issue a Warning or Advisory for expected snow or ice accumulation; typically six to 24 hours in advance of the onset. Times are only given for places that are under a Warning or Advisory. They will be blank in areas outside Warnings or Advisories.

Onset/End of Wintry Precipitation

Onset of Wintry Precipitation
(For areas under Warning or Advisory)

End of Wintry Precipitation
(For areas under Warning or Advisory)

What's this?

Precipitation Onset

Most likely time of winter precipitation onset (snow, sleet, freezing rain). Rain is not included here. This information is provided when we issue a Warning or Advisory for expected snow or ice accumulation; typically six to 24 hours in advance. Times are only given for places that are under a Warning or Advisory. They will be blank in areas outside Warnings or Advisories.

Precipitation End Time

Most likely time that the accumulating winter precipitation ends (snow, sleet, freezing rain). Rain is not included here. This information is provided when we issue a Warning or Advisory for expected snow or ice accumulation; typically six to 24 hours in advance of the onset. Times are only given for places that are under a Warning or Advisory. They will be blank in areas outside Warnings or Advisories.

Winter Storm Severity Index (WSSI)

Winter Storm Outlook (WSO)

Useful Winter Weather Information
Historic Mid-Atlantic Winter Storms	Winter/Snowfall Statistics	El Niño and DC/Baltimore Winters
Watches, Warnings, & Advisories	How to Measure Snow	La Niña and DC/Baltimore Winters
BE PREPARED!
At Home	On the Road	Outside in the Cold

Long-Range Forecast

Days 4-7
Day 4 Winter Weather Outlook	Day 5 Winter Weather Outlook


Day 6 Winter Weather Outlook	Day 7 Winter Weather Outlook


Days 4-5 Forecast Precipitation	Days 6-7 Forecast Precipitation



Days 6-10
Temperature	Precipitation



Days 8-14
TEMPERATURE	PRECIPITATION



Week 3-4
TEMPERATURE	PRECIPITATION

Atmospheric River in the Pacific Northwest and Northern Rockies this Weekend

Snow and Ice Forecasts & Services

Quick Page Navigation

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

Expected Snowfall - Official NWS Forecast

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

Percent Chance That Snow Amounts Will Be Greater Than

Snowfall Totals by Location

Most Likely Ice Accumulation

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

Expected Snowfall - Official NWS Forecast

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

Percent Chance That Snow Amounts Will Be Greater Than

Reported Snow and Ice

Winter Storm Severity Index

Precipitation Onset

Precipitation End Time