Experimental Probabilistic Snowfall Products

Probabilistic Snowfall Forecasts
Ice Accumulation Forecasts
Other Snow/Ice Information
Long-Range Forecast

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

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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.

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.

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Percent Chance That Snow Amounts Will Be Greater Than...

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Snowfall Totals by Location

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Expected Ice Accumulation - Official NWS Forecast
Ice Accumulation Potential
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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.

Winter Storm Severity Index * Experimental *	NDFD Graphic Forecast Displays
Other Snow/Ice Information

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Storm Track	Reported Snow/Ice Totals

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. Winter Storm Severity 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. The WSSI does not depict official warnings, and should always be used in context with official NWS forecasts and warnings. Because this is a prototype, it may not update in a timely fashion. Always check the creation and valid times. NDFD Graphic Forecast Displays The NWS’s NDFD graphic products are derived from a prescribed set of data contained within the NDFD. These graphics are representations of the official NWS digital forecast. The graphics are created on national and regional scales and will follow a standardized format prescribed by the NWS to best meet the needs of its users 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. Reported As snow and/or ice reports come into the NWS (you can email reports to %webmaster% or Tweet to %twitterHandle%), 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.

NWS Greenville-Spartanburg Products
HAZARDOUS WEATHER OUTLOOK	FORECAST DISCUSSION	SPECIAL WEATHER STATEMENT	PUBLIC INFORMATION STATEMENT

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