Snow and Ice Forecasts & Services

High-Impact and Far-Reaching Winter Storm Continues; Cold Expands and Persists

A major winter storm will shift its impacts into the Northeast U.S. with heavy snow through tonight while over the Mid-Atlantic, sleet and freezing rain will diminish. Extremely cold air behind the storm will prolong dangerous travel and infrastructure impacts. Sub-zero low temperatures are expected nearly every morning from the Northern Plains through the Ohio Valley and into the Northeast. Read More >

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Ice Accumulation Potential Experimental - Leave feedback Click here for more information on these products Click here for the NWS Probabilistic Precipitation Portal
Expected 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. 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 Amount 1 in 10 Chance (10%) of Higher Ice Accumulation What's this?
	Low End Amount 9 in 10 Chance (90%) of Higher Ice Accumulation What's this?
Low End 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. High End 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.

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.

Percent Chance That Ice Accumulation Will Be Greater Than...

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>=0.01"	>=0.1"	>=0.25"	>=0.5"	>=0.75"	>=1"	>=1.25"	>=1.5"

Ice Accumulation by Location

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

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Precipitation Onset/End Timing
Onset of Wintry Precipitation	End Timing of Wintry Precipitation

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 of winter precipitation ending (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 Onset/End Timing

Onset of Wintry Precipitation

End Timing of Wintry Precipitation

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Winter Storm Severity Index (WSSI)

Winter Storm Outlook (WSO)

Observed Snow/Ice Amounts

National Snowfall Analysis

Snow and Sleet Amount Potential Experimental - Leave feedback Click here for more information on these products Click here for the NWS Probabilistic Precipitation Portal
Expected Snowfall and Sleet - Official NWS Forecast The "Point" 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. 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 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. 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 and Sleet 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 The "Point" 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. 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 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. 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.

Days 4-7 Winter Weather Outlook

Day 4 Winter Weather Outlook	Day 5 Winter Weather Outlook


Day 6 Winter Weather Outlook	Day 7 Winter Weather Outlook

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CPC Week-2 Experimental Heavy Snow Risk



CPC Temperature & Precipitation Maps

Days 6-10
Temperature	Precipitation



Days 8-14
TEMPERATURE	PRECIPITATION



Week 3-4
TEMPERATURE	PRECIPITATION

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

High-Impact and Far-Reaching Winter Storm Continues; Cold Expands and Persists

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

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

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

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

Percent Chance That Snow Amounts Will Be Greater Than

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

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

Percent Chance That Ice Accumulation Will Be Greater Than

Ice Accumulation Totals by Location

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

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

Percent Chance That Ice Accumulations Will Be Greater Than

Precipitation Onset

Precipitation End Time