Snow and Ice Forecasts & Services

Snow Impacts in the Sierra Nevada and Great Lakes

Heavy snow over parts of the Sierra Nevada Mountains and Upper Great Lakes will cause slick roads into Monday morning. Travel could be very difficult to impossible in the Sierra Nevada. Read More >

>=0.1"

>=1"

>=2"

>=4"

>=6"

>=8"

>=12"

>=18"

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"

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

What's this?	What's this?	What's this?
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?
Low Tracks Graphic The graphic depicts the forecast location of significant surface lows impacting the 48 contiguous United States in 12 hour increments out to 72 hours into the future. The low position and track forecast by NCEP WPC meteorologist is in white. Each low position is accompanied by a lead time (Eastern Time). The circles around each low represents a 75% probability the observed low will be located with the circle. Note: The probability is derived using previous season's verification data. For reference, existing surface lows are depicted with a red marker without yellow circles. 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. Reported As snow and/or ice reports come into the NWS (you can email reports to lwx.webmaster@noaa.gov or Tweet to @NWS_BaltWash), we will pass them on here. With the map linked here, and the supporting reports below it, you can keep tabs on how much has fallen. 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.

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

Winter Storm Severity Index (WSSI)

Winter Storm Outlook (WSO)

Snow Amount Potential Experimental - Leave feedback
Expected Snowfall - Official NWS Forecast (for time range indicated) Point Range 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. In an ongoing winter event, it might not represent the complete storm total snowfall (refer to the Event Total map on the red-colored tab). 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.

Snow Amount Potential Experimental - Leave feedback
Expected Snowfall - Official NWS Forecast Point Range 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.

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

Snow Impacts in the Sierra Nevada and Great Lakes

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

Low Tracks Graphic

Precipitation Onset

Precipitation End Time

Reported

Winter Storm Severity Index