Climate Prediction Center Heavy Snow Map: How to Read NOAA's Week 2 Hazards Outlook

The “Climate Prediction Center heavy snow map” is NOAA’s U.S. Week-2 Hazards Outlook: a human-drawn map of where heavy snow is a risk 8 to 14 days out, shaded slight (more than a 20% chance), moderate (more than 40%) or high (more than 60%). It shows risk, not snow totals, and CPC redraws it every afternoon. The issuance we read, made Nov. 6, 2026 and valid Nov. 14-20, puts a moderate risk of high elevation heavy snow over the Klamath and Sierra Nevada Mountains on Nov. 14-15.

This page explains how to read the map, what the colors and words mean, and which other NOAA maps to use for the days before and after CPC’s window. One section describes the current map, and it is pinned to the issuance we read, last re-checked at 13:00 UTC (8 a.m. EST) on Saturday, Nov. 7, 2026. Nothing here is our own forecast.

What is the Climate Prediction Center heavy snow map?

It is the heavy snow layer of the Climate Prediction Center’s U.S. Week-2 Hazards Outlook, which covers Days 8 to 14 from the day it is issued. The Climate Prediction Center (CPC) is part of the National Weather Service. Its hazards outlook flags several kinds of hazards for the second week ahead: heavy precipitation, heavy snow, high winds, much above or below normal temperatures, flooding and rapid onset drought.

The product comes in two forms:

• The composite map. One map with every hazard on it. CPC’s product description calls this the operational map.
• The probabilistic maps. A separate map for each hazard type (temperature, precipitation, wind and snow), each shaded in slight, moderate and high risk bands. These layers were introduced as experimental in 2025, and CPC opened a public comment period on them that ran through June 30, 2025.

When a news story shows a “heavy snow map” from CPC, it is usually the snow layer of one of these two maps.

What do slight, moderate and high risk mean?

Each level is a chance of exceeding CPC’s heavy snow threshold in the shaded area, not a forecast that a snowstorm will happen. In the table below, the first column is the label on the map and the second is the chance CPC attaches to it, worded as in Part 2 of its Product Description Document.

Three points help when reading it:

• The composite map shows the moderate-risk area. CPC says the area covered by a moderate risk is what goes on the operational composite map. A slight risk shows up only on the probabilistic map and in the text.
• Above 40% is CPC’s general bar for drawing a hazard. The product description says that, in general, probabilities above 40% warrant a hazard depiction.
• The areas are drawn by forecasters. CPC describes the outlines as human-drawn, built from model guidance and calibrated tools, with forecasters judging whether a given event would actually threaten life or property.

A slight risk still means CPC sees roughly a one-in-five chance or better. It is a signal to keep watching, not a reason to change plans.

How does CPC define heavy snow?

CPC defines heavy snow by precipitation, not by inches of snowfall: a 3-day accumulated total above the 85th climatological percentile, more than 0.5 inch of liquid equivalent, and temperatures near values favorable for snow. That is the nominal threshold in Table 1 of the Product Description Document.

What that means in practice:

• The bar is local. “Above the 85th percentile” compares a place with its own climate, so the same amount can be unusual in one place and routine in another.
• Liquid equivalent is melted snow. Half an inch of liquid can become very different snow depths depending on how wet or dry the snow is, which is why this page does not translate it into inches of snow.
• CPC also uses an experimental tool that gives objective probabilities of snow water equivalent.
• The definitions are flexible. Because earlier conditions shape impacts, CPC says its hazard definitions are “only guidelines”.

Watch for the words “high elevation” in the text. When CPC writes “high elevation heavy snow”, the risk is in the mountains. It is not a forecast of snow in valleys or cities.

When is a new map issued?

CPC issues the Week-2 Hazards Outlook every day, typically about 3 p.m. Eastern Time, and each new map replaces the one before it. CPC’s archive holds hazards texts stamped 3 p.m. on weekends, including Saturday, Oct. 24, Saturday, Oct. 31 and Sunday, Nov. 1, 2026.

CPC’s own 2025 product description says the outlook is released Monday through Friday by 4 p.m. ET. The weekend issuances in the archive show it has been going out seven days a week this fall.

Because the window always starts eight days ahead, it slides forward one day with each issuance. A map issued Nov. 6 covers Nov. 14-20; a map issued Nov. 7 covers Nov. 15-21. A risk dated for the first day of one map can fall outside the next map entirely. That day then comes within range of the Weather Prediction Center’s Day 3-7 map instead.

There can be a gap, though. WPC’s Day 3-7 map is made on weekdays only, so a day that leaves CPC’s window over a weekend may not appear on WPC’s map until Monday’s issuance. This weekend, Nov. 14 drops out of CPC’s window with the Saturday map, while WPC’s posted map ends Nov. 13; WPC’s next map, due Monday, Nov. 9, covers Nov. 12-16.

What does the current CPC heavy snow map show?

The issuance we read shows a moderate risk of high elevation heavy snow over the Klamath and Sierra Nevada Mountains on Nov. 14-15, with slight risks reaching the Cascades and parts of the Rockies through Nov. 17. That map is “Made November 06, 2026”, issued 3 p.m. EST (20:00 UTC) on Friday, Nov. 6, valid Saturday, Nov. 14 to Friday, Nov. 20, with forecaster Thomas Collow. It was still the current map when we last checked at 13:00 UTC (8 a.m. EST) on Saturday, Nov. 7. A new map was due about 3 p.m. EST that afternoon, valid Nov. 15-21, so check CPC’s page for the latest.

CPC’s heavy snow hazards in that issuance, in its own words:

• Moderate risk of high elevation heavy snow across the Klamath and the Sierra Nevada Mountains, Sat-Sun, Nov. 14-15. This is the area on the composite map.
• Slight risk of high elevation heavy snow across the Cascades, Klamath and Sierra Nevada Mountains, Sat-Tue, Nov. 14-17.
• Slight risk of heavy high elevation snow for parts of the Northern Intermountain, Great Basin, and Central and Northern Rockies, Sat-Tue, Nov. 14-17.

The same West Coast system drives other hazards on the map. CPC lists a moderate risk of heavy precipitation for parts of southwest Oregon and northern and central California, and a moderate risk of high winds along the coasts of Washington, Oregon and much of California, both Nov. 14-15. A slight risk of heavy precipitation reaches into the Southwest, Great Basin and Southern Rockies through Nov. 17. CPC flags flooding concerns there over ground that is already saturated.

How it changed from the day before:

• The Nov. 5 issuance had the Klamath and Sierra moderate snow risk on Nov. 13-15. That day CPC called it “more marginal”, citing lower chances for large 3-day snow amounts and high snow levels.
• In its Nov. 6 discussion, CPC describes removing the moderate snow risk from the Cascades, consistent with lower probabilities (20-30 percent) in its extremes tools, although the Nov. 5 hazards list itself named only the Klamath and Sierra Nevada for that risk. CPC adds that many of those areas had less than 50 percent of normal precipitation over the past 30 days.

Elsewhere, CPC posted no hazards for Alaska. It noted possible heavier rain across the Southern Plains, Mississippi Valley and Gulf Coast late in the period, but drew no hazard there because of recent swings in the model guidance.

Headlines such as “3 states”, “winter storm map” or “next week” are not CPC’s wording. CPC names mountain ranges and regions, not a count of states, and its window is Days 8-14, which in this issuance means Nov. 14-20.

How is CPC’s map different from WPC’s Day 3-7 Hazards Outlook?

WPC’s Day 3-7 Hazards Outlook covers the nearer part of the coming week, while CPC’s map starts at Day 8. CPC’s page itself points readers to the Weather Prediction Center (WPC) for 3-7 day hazards. WPC took that product over from CPC in early 2019; CPC still issues the 8-14 day chart.

Key differences:

• Schedule. WPC issues its Day 3-7 graphic once a day, by 3:30 p.m. EST, Monday through Friday only. WPC warns that its weekend page may be out of date.
• Heavy snow test. WPC uses a 40% probability of moderate snow-related impacts on its experimental Probabilistic Winter Storm Severity Index, rather than CPC’s precipitation-percentile threshold.

The WPC map on the page over this weekend was created Friday, Nov. 6 and is valid Nov. 9-13. It has no heavy snow hazard. It shows heavy precipitation in western Washington and heavy rain along the coast from northern California through Oregon into southwest Washington on Nov. 13, heavy rain and high winds in the Alaska Panhandle early in the week, and frost or freeze around the Tennessee and Ohio Valleys on Nov. 9. WPC’s next Day 3-7 map is due Monday, Nov. 9.

Where do I find snow probabilities for the next three days?

For Days 1 to 3, use WPC’s Winter Weather Desk, which maps the chance of reaching set snowfall amounts in each 24-hour period. WPC routinely issues these products from Sept. 15 to May 15 for the Lower 48. The graphics come out twice daily, at 0900 and 2100 UTC (4 a.m. and 4 p.m. EST).

• Final snow maps show the probability of at least 4, 8 and 12 inches of snow and sleet; preliminary maps run from 1 to 18 inches.
• Freezing rain has its own map, with a final threshold of 0.25 inch.
• A written discussion goes with each set and names the areas WPC is watching.

WPC’s discussion issued 1:48 a.m. EST Saturday, Nov. 7, valid to 7 a.m. EST Nov. 10, covered only the Washington Cascades, around Washington Pass and State Route 20, with minor impacts expected. It put the chance of significant ice anywhere in the Lower 48 below 10 percent. That discussion is replaced twice a day.

What does WPC’s Day 4-7 winter outlook add?

It gives the chance of significant snow and sleet, more than 0.25 inch of liquid equivalent in a 24-hour period, for Days 4 to 7, in between the Winter Weather Desk’s Day 1-3 maps and CPC’s Week 2 map. Each panel covers one 24-hour period. WPC’s medium-range forecasters build it from WPC’s own precipitation forecast and ensemble guidance, and update it twice daily.

Like CPC’s threshold, it is measured in liquid equivalent rather than snow depth, and it does not cover freezing rain.

Do CPC’s 6-10 and 8-14 day outlooks show snow?

No: CPC’s 6-10 and 8-14 day outlooks show only the probabilities of above-, near- or below-normal temperature and precipitation. They are a different product from the Week-2 Hazards Outlook, even though the 8-14 day outlook covers the same days.

A wet 8-14 day outlook in a cold mountain range can line up with a heavy snow risk on the hazards map. But the outlook itself never says whether the precipitation will fall as rain or snow. The versions issued 3 p.m. EST Nov. 6 favored wetter than normal conditions along much of the West Coast and warmer than normal temperatures over most of the Lower 48. CPC rated its confidence 4 out of 5 for the 6-10 day period and 3 out of 5 for the 8-14 day period.

For the season-long picture, see our 2026-27 U.S. winter forecast explainer and our look at what El Niño means for snow this winter .

Does a heavy snow risk mean a winter storm warning?

No: CPC’s map is an outlook, and warnings, watches and advisories come only from local National Weather Service forecast offices. When a storm gets close, the office for your area decides whether to issue a Winter Storm Watch, a Winter Storm Warning or a Winter Weather Advisory.

At 13:00 UTC (8 a.m. EST) on Saturday, Nov. 7, the National Weather Service alerts feed showed no active Winter Storm Warnings, Winter Storm Watches, Winter Weather Advisories or Blizzard Warnings anywhere in the country. That changes quickly, so check your local office or weather.gov for the current status.

How should I read the map, step by step?

Start with the issuance date, then the color, then the text, and switch to shorter-range maps as the days get closer.

1. Check the “Made” date and valid dates at the top of CPC’s page. A screenshot in a news story may be a day or more old.
2. Find the hazard dates. Each risk carries its own days, often only the first two or three of the week.
3. Read the risk level as a chance. Slight is above 20%, moderate above 40%, high above 60%.
4. Read the hazard wording. “High elevation” points to the mountains, not towns at lower altitude.
5. Read the discussion under the map for CPC’s reasoning and for what changed since yesterday.
6. Move to WPC’s Day 3-7 and Day 4-7 products as the dates come inside a week, then the Winter Weather Desk’s Day 1-3 maps.
7. Act on local NWS watches and warnings, not on a Week 2 risk area.

Sources

• NOAA Climate Prediction Center: U.S. Hazards Outlook (Days 8-14)
• CPC: Hazards Outlook text, Nov. 6, 2026
• CPC: Hazards Outlook text, Nov. 5, 2026
• CPC: Hazards Outlook text, Oct. 31, 2026
• CPC: Hazards Outlook text, Nov. 1, 2026
• CPC: Product Description Document, 8- to 14-day Hazards Outlook (Feb. 4, 2025)
• CPC: Probabilistic heavy snow layer (KML)
• CPC: Composite heavy snow layer (KML)
• CPC: 6-10 and 8-14 day outlook discussion
• NOAA Weather Prediction Center: Day 3-7 U.S. Hazards Outlook
• WPC: About the Day 3-7 Hazards Outlook
• WPC: Day 3-7 precipitation hazards layer (KML)
• WPC: Winter Weather Desk forecasts
• WPC: About WPC products
• WPC: Probabilistic Heavy Snow and Icing Discussion
• WPC: Day 4-7 Winter Weather Outlook
• National Weather Service: Active alerts API