What forecast models are being plotted?

• GFS - NCEP Global Forecast System
  
  • 1.0° resolution, 15-day forecast (T+12 to T+360h, 12-hourly steps)
  • Pressure levels: 500, 250, 100, 50, 30, 10 hPa
  • Updated twice daily at ~07:00 and ~19:00 UTC
• GEFS - NCEP Global Ensemble Forecast System
  
  • 31-member ensemble mean, 0.5° resolution, 15-day forecast in the same timesteps as above
  • Pressure levels: 500, 250, 100, 50, 10 hPa
    
  • Updated twice daily at ~08:00 and ~20:00 UTC
• ECMWF HRES - ECMWF Integrated Forecasting System
  
  • 0.25° resolution, 15-day forecast (T+12 to T+360h, 12-hourly steps)
  • Pressure levels: 500, 250, 100, 50, 10 hPa
  • Data via ECMWF Open Data (CC BY 4.0). Updated twice daily at ~09:00 and ~21:00 UTC

Climatology: NCEP/NCAR Reanalysis 1991-2020 daily long-term means, sourced from NOAA Physical Sciences Laboratory.

What plots are available?

Pressure level maps (select a level via the Pressure Levels menu):

• Height + Temperature Anomaly:
  Geopotential height contours overlaid on temperature anomaly shading relative to the 1991-2020 climatology. Warm colours indicate above-normal temperatures; cool colours indicate below-normal. Useful for identifying blocking patterns and tracking large-scale flow anomalies at a glance.
• Height + Temperature:
  Geopotential height contours overlaid on temperature shading with dashed isotherms. Shows the actual thermal structure rather than departures from normal. Most useful at 10 hPa for locating the polar vortex cold core and tracking its displacement.
• Height + Height Anomaly:
  Geopotential height contours overlaid on height anomaly shading relative to climatology. Red/orange indicates anomalously high heights (ridges, blocking); blue indicates anomalously low heights (troughs, vortex intensification). Provides the clearest signal of large-scale flow anomalies.
• Height + Wind Speed:
  Geopotential height contours overlaid on wind speed shading. At 10 hPa, a coherent ring of strong westerlies encircling the pole indicates a strong, stable polar vortex. It is also possible to observe the core of the tropospheric jet stream at 250 hPa.

Cross sections (fixed domain from surface to 1 hPa for GFS, 10 hPa for GEFS and ECMWF HRES):

• Zonal Mean Wind + YZ WAF:
  Latitude-pressure cross section of zonally-averaged zonal wind (shaded) with meridional/vertical wave activity flux vectors. Upward vectors show planetary wave energy propagating into the stratosphere. Easterly winds (reversal) above 60°N at 10 hPa are the defining dynamical signature of a Major Sudden Stratospheric Warming.
• Zonal GPH Anomaly + XZ WAF:
  Longitude-pressure cross section of geopotential height anomaly averaged over 40-80°N, with zonal/vertical wave activity flux vectors. Reveals planetary wave structure as a function of longitude and height. Upward-pointing vectors are a precursor to vortex disruption events.
• Zonal Mean Temperature:
  Latitude-pressure cross section of zonally-averaged temperature, shaded and contoured. A rapid warming above 60°N near 10 hPa, particularly approaching or exceeding 0°C, is one of the signatures of a SSW events.
• EP Flux:
  Latitude-pressure cross section of EP flux divergence with scaled EP flux vectors. Blue shading marks where planetary waves are breaking and decelerating the polar vortex. Vectors converging into the stratosphere from below are a important early diagnostic for SSW onset.

How to cite this work: If you use these plots in publications, posts, or presentations, please cite:
"Multi-Model Strato/Troposphere Hemispheric and Cross-Section Products, processed and visualized by Giuseppe Petricca. Data sources: NCEP NOMADS, ECMWF Open Data."
Including a link back to this page is appreciated.