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CW3E AR Landfall Tool Graphics

The purpose of this website is to catalog the different types of AR Landfall Tool forecast graphics produced by CW3E. The images below are all current forecast graphics with detailed figured captions.
1. Coastal 16-day AR Landfall Tool
This version of the AR Landfall Tool illustrates 3-h forecasts of the likelihood of AR conditions along the West Coast of North America out to 16 days. The likihood of AR conditions (shaded as a fraction from zero to one) is derived from the number of NCEP Global Forecast System (GFS) ensemble members with an IVT magnitude >250 kg/m/s *divided by* the total number of ensemble members. The NCEP-GFS Ensemble has 20 ensemble members, plus the control forecast. The left panel is set up as forecast time increasing *from right to left* along the x axis and latitude along the coast (shown by black dots in the right panel) increasing along the y axis. The bars in the right panel depict the number of confident hours any given latitude is forecasted to experience AR conditions: gray bars indicate the numbers of hours >50%, black bars indicate the number of hours >75%, and red bars indicate the number of hours >99%.

Alternate versions include: IVT>150 kg/m/s, IVT>500 kg/m/s, and IVT>750 kg/m/s.
Click image to enlarge.
2. Inland 16-day AR Landfall Tool
This version of the AR Landfall Tool is identical to the first version (#1 above), except the locations used to derive the likihood of AR conditions is located inland of the Cascade and Sierra Crest.

Alternate versions include: IVT>150 kg/m/s, IVT>500 kg/m/s, and IVT>750 kg/m/s.
Click image to enlarge.
3. Coastal and Inland 16-day IVT magnitudes
These versions of the AR Landfall Tool, for locations along the coast or inland, depict the IVT magnitude (kg/m/s; shaded) either from the NCEP-GFS Ensemble control forecast or from the NCEP-GFS ensemble mean forecast. Black bars in the right-most panel now depict the the total 16-d time-integrated IVT magnitude. The image shown at right is the NCEP-GFS control forecast.

Alternate versions include: Coastal Ensemble Mean, Inland Control, and Inland Ensemble Mean.
Click image to enlarge.
4. Coastal 16-day AR Landfall Tool with Skill Mask - *NEW*
This version of the AR Landfall Tool plots the likelihood of AR conditions along the coast (only) as a function of forecast lead time from the NCEP-GFS ensemble but applies a gray-shade mask to probability values that fail to meet a skill threshold at a particular latitude and lead time based on an analysis completed by J. Cordeira from data compiled during the 2016-2017 water year. The skill threshold is the 95th percentile of forecasted values during that water year at that latitude at that lead time specifically for days that verify with IVT >250 kg/m/s. This analysis helps answers the question: "Is this probability value at this lead time and at this latitude noteworthy? Should I pay attention to this value?" For additional questions, please write to J. Cordeira.
Click image to enlarge.
5. 7-day AR Landfall Tool
The AR Landfall Tool graphics are also generated for the 7-day forecast period. These graphics are included for both the coastal and inland transects, are only created for the probabilistic information (i.e., not the ensemble mean nor the control IVT magnitudes), and for coastal locations with a zoom in on California. The right-most panel of these graphics includes the same "number of hours with probabilities >50% ,>75%, and >99%" and also color-codes the dots along the coast (or inland) based on whether or not those number of hours is greater than 24 hours. The image shown at right is the 7-d AR Landfall Tool for coastal IVT probabilities >250 kg/m/s.

Alternate versions include:
Coastal 150, Coastal 500, Coastal 750,
Coastal CA 150, Coastal CA 250, Coastal CA 500, Coastal CA 750,
Inland 150, Inland 500, Inland 750.
Click image to enlarge.
6. Enhanced 7-day AR Landfall Tool
The Enhanced AR Landfall Tool describes the forecast time-coastal latitude evolution of atmospheric river (AR) conditions along the western coast of Canada, the U.S., and Mexico derived primarily from the NCEP GFS Ensemble dataset. These AR conditions include IVT direction, magnitude, likelihood, duration, time-mean aspects, and impacts related to quantitative precipitation forecasts (QPF). The latter is derived the NOAA Weather Prediction Center.

Panel (a) The likelihood of AR conditions is shown as colored arrows in the forecast time-coastal latitude framework (every 3 hours and every 0.5 degree of latitude) every 10% and is derived from the number of ensemble members with an IVT magnitude greater than 250 kg mÐ1 sÐ1 divided by the total number of members (plus the control; N=21). The direction of IVT is indicated by the arrows and is derived from the ensemble mean. The vectors are scaled slightly, but no reference vector is provided. The scaling is only provided for subjective analysis. The magnitude of IVT is indicated by thin black contours every 250 kg m-1 s-1 starting at 250 kg m-1 s-1 and is derived from the ensemble mean. The AR Category, a new method of scaling the intensity and duration of AR conditions, is provided as small numbers across the top of the panel and along the right-hand-side of the panel. Numbers across the top indicate the maximum AR Category at any latitude for a given forecast time, whereas numbers across the right-hand-side indicate the maximum AR Category at any forecast time for a given latitude. Combining the information can provide you with the AR Category for a given time and latitude. More information on the AR category will be published in BAMS, Ralph et al. 2018.

Panel (b) The duration of IVT magnitudes >250 kg m-1 s-1 (blue), >500 kg m-1 s-1 (green), >750 kg m-1 s-1 (red), and >1000 kg m-1 s-1 (black) is shown for each ensemble member and the ensemble mean. The duration is calculated as the integration of the number of 3-h forecast times that exceed each threshold during the 168-h forecast period. The duration curves collectively highlight those latitude locations expected to receive the most prolonged and intense AR conditions.

Panel (c) The 7-day time-mean IVT magnitude and direction of the ensemble-mean IVT vector is shown for the 168-h forecast period as a vector quantity with reference vector in the upper left of the panel. Dynamical frameworks consider the convergence of this vector field to associate with regions of most precipitation. The QPF during the 7-day period is shown (shaded with scale in lower left) provided by the NOAA Weather Prediction Center. The prior suggested dynamical relationship between time-mean IVT convergence and QPF is confirmed. Terrain is also provided (1-km ETOPO) as a gray-shaded quantity every 250 m without a scale and only meant for relatively spatial analysis.

Alternate versions include: Inland Enhanced Landfall Tool.
Click image to enlarge.
7. S2S AR Landfall Tool
The S2S AR Landfall Tool is similar to the regular AR lanfall tool graphic in #1 above, except that it extends the analysis into week 3 using the "Sub-X" dataset provided by EMC. This forecast-time, coastal latitude depiction of the likelihood of AR conditions is at 3-h resolution for the 0-to-7-day forecast period and transitions to daily resolution during week 2. The likelihood here is calculated as the NCEP GFS ensemble probability >250 kg/m/s at the 3-h interval (week-1) or during any the 8 3-h intervals (week-2). Week 3 is a weekly assessment of daily data from the SubX GFS Ensemble 850-hPa water vapor flux >50 g/g*m/s.
Click image to enlarge.