National Weather Service United States Department of Commerce

Flooding Threats in the West and the Southeast

The active monsoon season will continue the rest of the week for portions of the Southwest into the Great Basin and Rockies. A stalling front and Gulf moisture will produce slow-moving storms capable of producing heavy rain and flash flooding along the Gulf Coast. Localized areas of critical fire weather conditions are possible in the Pacific Northwest into the Northern Plains Thursday. Read More >

State College, PA

Weather Forecast Office

Winter Weather Experimental Probabilistic Snow and Ice

Weather.gov > State College, PA > Winter Weather Experimental Probabilistic Snow and Ice

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

Expected Snowfall - Official NWS Forecast
What's this?		 High End Amount
1 in 10 Chance (10%)
of Higher Snowfall
Maximum Potential Snow Accumulation
What's this?
Low End Amount
9 in 10 Chance (90%)
of Higher Snowfall
Minimum Potential Snow Accumulation
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 -
 
What's this?

Percent Chance That Snow Amounts Will Be Greater Than

 

This series of maps shows the probability (that is, the likelihood) that snowfall will equal or exceed specific amounts during the time period shown on the graphic. These forecasts are based on many computer model simulations of possible snowfall totals.
Hover over thumbnails below to view larger image.
>=0.1"
>=0.1"		 >=1"
>=1"		 >=2"
>=2"		 >=4"
>=4"		 >=6"
>=6"		 >=8"
>=8"		 >=12"
>=12"		 >=18"
>=18"

Snowfall Totals by Location
Experimental -
 
What's this?

Snowfall Totals by Location

 

These tables show the snowfall forecast for individual locations, and provide the same information as the graphics on this web page, just shown in a different way. All of these values are valid for the same time period as depicted on the graphics.
County:
 
Snow Amount Potential
Experimental -
 
Expected Snowfall - Official NWS Forecast
Point Range

Expected Snowfall - Official NWS Forecast
What's this?		 High End Amount
1 in 10 Chance (10%)
of Higher Snowfall
Maximum Potential Snow Accumulation
What's this?
Low End Amount
9 in 10 Chance (90%)
of Higher Snowfall
Minimum Potential Snow Accumulation
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 -
 
What's this?

Percent Chance That Snow Amounts Will Be Greater Than

 

This series of maps shows the probability (that is, the likelihood) that snowfall will equal or exceed specific amounts during the time period shown on the graphic. These forecasts are based on many computer model simulations of possible snowfall totals.
Hover over thumbnails below to view larger image.
>=0.1"
>=0.1"		 >=1"
>=1"		 >=2"
>=2"		 >=4"
>=4"		 >=6"
>=6"		 >=8"
>=8"		 >=12"
>=12"		 >=18"
>=18"
Ice Accumulation Potential
 

Expected Ice Accumulation - Official NWS Forecast
Most Likely Ice Accumulation

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.
Other Snow/Ice Information

 
Onset of Wintry Precipitation
 
End Timing of Wintry Precipitation		  
Winter Storm Severity Index (WSSI)
Winter Precipitation Onset
Winter Precipitation End Time
Winter Storm Severity Index
    What's this?
 
NDFD Graphic Forecast Displays		 72-hr Winter Storm Impacts - WSSI
(Winter Storm Severity Index)
NDFD Graphical Forecast Viewer
Winter Storm Severity Index
What's this? What's this?
 
72-hr Snowfall - Central PA		  
72-hr Snowfall - Pennsylvania		 72-hr Snowfall - WSSI
(Winter Storm Severity Index)
72-hr Snowfall - Central PA
72-hr Snowfall - Pennsylvania
Winter Storm Severity Index - Snowfall
    What's this?

 
72-hr Ice Accumulation - Central PA
 
72-hr Ice Accumulation - Pennsylvania
72-hr Ice Accumulation - WSSI
(Winter Storm Severity Index)
72-hr Snowfall - Central PA
72-hr Snowfall - Pennsylvania
Winter Storm Severity Index- Ice Accumulation
    What's this?

Storm Track
Snow/Ice Analysis
Historical Snowfall Info
Storm Total Ice Graphic
Snow analysis
Snow analysis
What's this? What's this? What's this?

Reported Snow/Ice Totals
Text Reported Snow/Ice Totals
REPORT SNOW/ICE TO US
Latest snow and ice reports
Text Snow/Rain Reports
Text Snow/Rain Reports
What's this? What's this? What's this?
From the Middle Atlantic River Forecast Center

24-hr Observed Snowfall
Observed Snow Depth
Modeled Snow Water Equivalent
MARFC Snow Fall Map
MARFC Snow Depth Map
MARFC Snow Water Equivalent Map

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.

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 ctp.webmaster@noaa.gov or Tweet to @NWSStateCollege), 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.

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.

 

 

State College 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 4 Winter Weather Outlook Day 5 Winter Weather Outlook
 
Day 6 Winter Weather Outlook Day 7 Winter Weather Outlook
Day 6 Winter Weather Outlook Day 7 Winter Weather Outlook
 
Days 4-5 Forecast Precipitation Days 6-7 Forecast Precipitation
Days 4-5 Precip Days 6-7 Precip
 
 

Days 6-10
Temperature  Precipitation
6-10 day temperature 6-10 day precipitation
 
 

Days 8-14
TEMPERATURE  PRECIPITATION
8-14 day temperature 8-14 day precipitation
 
 

Week 3-4

TEMPERATURE

PRECIPITATION
Week 3-4 Temperature Week 3-4 precipitation

 

Daily Snowfall Reports
REPORT SNOW/ICE TO US
Text Snow/Rain Reports
What's this?

Reported Snow/Ice Totals
Text Reported Snow/Ice Totals
Snow/Ice Analysis
Latest snow and ice reports
Text Snow/Rain Reports
Snow analysis
What's this? What's this? What's this?

Historical Snowfall Info
Snow analysis
What's this?
From the Middle Atlantic River Forecast Center

24-hr Observed Snowfall
Observed Snow Depth
Modeled Snow Water Equivalent
MARFC Snow Fall Map
MARFC Snow Depth Map
MARFC Snow Water Equivalent Map
Winter Storm Threat: 3-7 Days From Now
Experimental - Leave feedback

 

Hover over (or click) Days 3-7 thumbnails to see full-size maps showing daily Confidence vs. Potential Impact matrices.

 
Day 3 Day 4 Day 5 Day 6 Day 7
Day 3 Winter Storm Threat Day 4 Winter Storm Threat Day 5 Winter Storm Threat Day 6 Winter Storm Threat Day 7 Winter Storm Threat
Winter Storm Threat

 

High High threat of high impact winter storm. Potential impacts include significant travel delays, closures, and threats to life and property.  Plan ahead to minimize impact on you and your family.
Moderate Moderate winter storm threat. Potential impacts include significant travel delays and closures. Plan ahead to minimize impact on you and your family.
Enhanced Enhanced winter storm threat. Primary threat is disruption to travel.
Slight Slight winter storm threat. If threat materializes, may cause travel disruptions.
None No significant winter storm threat is currently expected. However, light wintry precipitation may still be possible.

** EXPERIMENTAL ** EXPERIMENTAL ** EXPERIMENTAL **

Day 4-7 Winter Weather Outlook

(Winter Liquid Equivalent Exceedance Graphics)
 
Day 4 Day 5 Day 6 Day 7
Day 4 Winter Storm Threat Day 5 Winter Storm Threat Day 6 Winter Storm Threat Day 7 Winter Storm Threat
Winter Storm Threat

 

These images are created using WPC Probability of Exceeding 0.25"
Liquid Equivalent of Snow/Sleet. (Freezing Rain is not included)

** EXPERIMENTAL ** EXPERIMENTAL ** EXPERIMENTAL **
High High Threat for a Plowable Snow. Potential impacts include travel delays and closures. Plan ahead to minimize impact on you and your family.
Medium Moderate Threat for a Plowable Snow. Primary threat is disruption to travel.
Low Slight Threat for a Plowable Snow. If threat materializes, may cause travel disruptions.
None No significant winter storm threat is currently expected. However, light wintry precipitation may still be possible.
Weather Type and Coverage Forecast
 
**Prototype Under Development**
**Not to be relied on for operational decision making**
 
 

 


 
 

Detailed information on the Precipitation Type Graphic can be located here.

 

 

Follow us on Twitter  Follow us on Twitter
Follow us on Facebook  Follow us on Facebook
CTP RSS Feed  CTP RSS Feed

NWS State College

PAST WEATHER
Additional Links