Information:
The image on the left illustrates bakward air parcel trajectories computed for a 72-hour period ending at the forecast time and altitude/pressure selected within regions with IVT magnitudes >500 kg/ms over the Northeast Pacific domain. Air parcel paths are shaded based on their elevation/pressure. Trajectories are calculated using a combination of spatial bilinear interpolation and log-p vertial interpolation, advected by the 3-d wind components from the one-hourly forecast GFS data. If parcels go backwards prior to t+0H, the four previous six-hour analyses are used, interpolating those to hourly.
The image on the right is a trajectory diagnostic that takes into account both 72-hour backward trajectories and 72-hour forward trajectories to identify structures similar to tropical moisture exports (TMEs) and similar to warm conveyor belts (WCBs). Emphasis on *similar*.
An air parcel within an AR at a given time is labeled as a pseudo TME if it has an origin <25N and is below 850 mb prior to its arrival in the AR.
An air parcel is labeled as a pseudo Sub(tropical)TME if it has an original <25N but is only below 850 mb outside of the tropics prior to its arrival in the AR. Note that TMEs have both a boundary layer origination component, a characteristic flux north of 35N that we are hand-waving in this analysis, and usually use a 5-day integration.
An air parcel within an AR at a given time is labeled as a psuedo WCB if it has ascended or will ascned 600 mb in any 48-hour period between t-72h and t+72 h. Note that actualy WCBs use +/-5-day trajectories to located 48-hour periods and WCBs must pass through a closed-low cyclone.
Method is incredibly computationally expensive and the process is "cut off" after a couple hours of processing time. If there are "a lot of trajectories" on any given day/forecast, it won't make all images.