June 14, 2017

GFS Forecast: analysis time: 18Z 2017-06-14 :: valid time: 04Z 2017-06-15 

  • Final update [2017/06/16]: Flight was further delayed due to hydraulics issues with one of the engine on 1701. Dropsondes launched around 04Z 2017-06-15. Here are the 10-hour GFS forecast for that time. 
  • Last updated: 05Z 2017/06/14 
  • Update [16Z 2017/06/13]: Flight delayed by one day due to a SAR mission. Maybe some low-level cloud near 76N.   
  • Update [06Z 2017/06/11]: The lower level is getting even drier. Likely to have good visibility for ocean drops.
  • Update [00Z 2017/06/11]: Similar to forecast by 18 hours ago. From 72N to 76N along 150W, it is very dry above 950 hPa (~600 m) and RH around 80% at 1000 hPa (~170m). Low-level winds are weak under the high pressure center.

 Sea ice edge is still close to the coast and ice concentration is high along 150W. May need to look at higher resolution products to find possible location for ocean drops. 

The Beaufort sea is dominated by high pressure. In the forecast using the analysis from 6 hours ago, there was a weak polar low around 73N and 145W and with its edge next to 150W line. In the current updated forecast, this polar low is moved toward northeast and further weakened.  At 700 hPa level, there is a strong wind jet stream extending from 80N, 160W to 75N, 130W. Around 150W, the air column is still cold due to the cold air advection from north.

In previous cycle, there was some low clouds north of 74N and a lot of mid- and high-level clouds around 150W, but no low- and mid-level clouds anymore. 

This is a high pressure, cold advection case. In general, it is cold and dry, similar to the state 1 in Liu and Schweiger (2017). The weak polar low to the northeast does make it more interesting.

  • Spatial maps


Sea ice concentration at analysis time

Mean sea leve pressure at valid time

700 hPa Geopotential Height

700 hPa temperature

700 hPa relative humidity

Geopotential Height on 2PVU surface

wind speed

700 hPa Wind speed

700 hPa U-wind

700 hPa V-wind

Low-level cloud cover

Mid-level cloud cover

High-level cloud cover


  • Transects along 150W