Atmospheric River Forecast Products

This page contains graphics designed to forecast the presence and strength of Atmospheric Rivers using data from the NCEP Global Forecast System (GFS), North American Mesoscale Forecast System (NAM), and Global Ensemble Forecast System (GEFS) models. The GEFS products are produced by Dr. Jason Cordeira at Plymouth State University as a cooperative effort with CW3E.

NCEP Global Forecast System (GFS) and North American Mesoscale Forecast System (NAM)

Integrated Water Vapor (IWV) Click on an image to see forecasts out to 180 hours from the GFS and NAM

North Pacific (GFS only)
Northeast Pacific
U.S. West Coast
North America
North Atlantic (GFS only)
North Pacific GFS IWV Northeast Pacific GFS IWV U.S. West Coast GFS IWV North America GFS IWV North Atlantic GFS IWV

Integrated Water Vapor Transport (IVT) Click on an image to see forecasts out to 180 hours from the GFS and NAM

North Pacific (GFS only)
Northeast Pacific
U.S. West Coast
North America
North Atlantic (GFS only)
North Pacific GFS IVT Northeast Pacific GFS IVT U.S. West Coast GFS IVT North America GFS IVT North Atlantic GFS IVT

Time-Integrated IVT Click on an image to see 24-, 48-, and 72-h time-integrated forecasts out to 180 hours from the GFS

North Pacific
Northeast Pacific
U.S. West Coast
North Pacific GFS TIVT
Northeast Pacific GFS TIVT
U.S. West Coast GFS TIVT

Water Vapor Flux and Relative Humidity GFS Meteograms

These meteograms illustrate the forecasted conditions over a given locations for the 3 or 7-day forecast period from the GFS. The top panel includes water vapor flux (g/kg*m/s) or relative humidity (%) shaded with the 0°C isotherm and wind barbs(m/s), gray shading indicates location elevation. The middle plot illustrates the 3-hour precipitation represented by the bars, total 72-hour precipitation, height of the 0oC isotherm, and location elevation. When the freezing level is below the location elevation, line and bars are blue representing the likelihood of snow and when the freezing level is above the location elevation line and bars are green representing the likelihood of rain. The bottom plot illustrates the IWV and IVT, as well as the presence of AR conditions shaded in gray. The red dot on the map indicates the location of the current plot.

Select Type of Meteogram, Latitude and Longitude to generate plot. Click image to open in new tab.

Type

Latitude

Longitude



Water Vapor Flux GFS Cross Sections

These cross sections illustrate the forecasted conditions along a longitudinal line from 25-52°N for the given forecast time from the 0.25° GFS model. The top panel shows water vapor flux (g/kg*m/s) and wind barbs (m/s) and the bottom panel illustrates the IWV and IVT. The dashed lines on the bottom panel illustrate thresholds for AR conditions. The map on the left shows the location of the cross section as well as the IVT (kg/m/s) at the forecast time from the GFS. Gray shading indicates the rpesence of AR conditions (IVT >250kg m-1s-1 and IWV >20 mm).Place your mouse over a forecast hour for a given longitude to see the cross section or click to open in a new window.

Select Longitude and Forecast Hour to generate plot

Longitude:  

Forecast Hour:  



West Weather Research and Forecasting (West-WRF) Model

Integrated Water Vapor (IWV) Click on an image to see forecasts out to 180 hours from the GFS and NAM

Northeast Pacific (9 km)
California (3 km)
Northeast Pacific WWRF IWV
California WWRF IWV

Integrated Water Vapor Transport (IVT) Click on an image to see forecasts out to 180 hours from the GFS and NAM

Northeast Pacific (9 km)
California (3 km)
Northeast Pacific WWRF IVT
California WWRF IVT

NCEP Global Ensemble Forecast System (GEFS)

U.S. West Coast AR Landfall Tool Courtesy Jason Cordeira, Plymouth State University

The Landfall Tool displays the magnitude or probability and timing of AR conditions at each point on the map in a line along the U.S. West Coast or inland from the GEFS model over the next 7 or 16 days. The probability of AR conditions represents the number of ensemble members that predict IVT to be greater than the chosen threshold at the given location and time. To see how each forecast type has changed over the previous seven days click on dProp/dT. These plots are created by Jason Cordeira, Plymouth State Univeristy.

Select variable or threshold to be displayed, location, and forecast length to generate plot, click image to open in a new tab.

Type

Location

Forecast Length

dProg/dT




U.S. West Coast IVT Plume Diagrams Courtesy Jason Cordeira, Plymouth State University

The plume diagrams below represent the integrated water vapor transport (IVT) forecast for each of the 20 perturbed GFS ensemble models (thin gray lines), the unperturbed GFS control forecast (black line), the 20-member ensemble mean (green line), and the maximum ensemble value at that forecast hour (red line) and minimum ensemble value at that forecast hour (blue line). The white shading represents the +/- 1 standard deviation forecast from the ensemble mean. The red dot on the map indicates the location of the current plot.

Select forecast length of plot and coastal location to generate plot. Click image to open in new tab.

Forecast Length:  

Location:  



IVT Thumbnail and Probability Ensemble Plots Courtesy Jason Cordeira, Plymouth State University

Select forecast hour and domain to generate plot. Click image to open in new tab.

Forecast Hour:  

Domain:  

The above images display the 20 members of the GFS ensemble; each thumbnail shows IVT (kg m-1 s-1) magnitude shaded according to scale and IVT vectors.

The above images display the probability of IVT exceeding 250 kg m-1 s-1 based on the 20 members of the GFS ensemble and the IVT vectors from the control forecast.