September 18, 2018

  GFS Forecast: analysis time: 12Z 2018-09-10 :: valid time: 00Z 2018-09-19 ( Alaska LT: Tue. 2018-09-18 16:00PM)

Links to plots Below

Sea ice contours: 15% (blue), 50% (black), 90% (red)

2-m temperature contour: -1.8 °C

U/V transect contour: 0 m/s 

Update [09:20PM, Sun. Sep. 16, 2018 PST]:  

Sea ice edge north of 77 °N. Surface visibility is over 5 miles. Easterly winds near coast and more southerly winds north of 72 °N. Low clouds clear up in GFS forecast, but WRF may tell a different story. The LLJ is close to the coast. Surface is warmer than -1.8 °C along 150 °W.  Waiting for ceiling height from WRF output. 

Btw, Seatac wifi is fast enough for me to remote desktop to office to update forecast and get the WRF forecast running. 

Update [17:00PM, Thur. Sep. 13, 2018 PST]:  

Sea ice edge at 77N. Visibility is still good at surface mostly. A band of cloud is over 150 °W, which is keep the ceiling height below 1000 ft. The cloud condition may change in the next forecast. LLJ moves further north and mostly southerly at surface as the surface high is positioned further east. 

Update [17:00PM, Thur. Sep. 13, 2018 PST]:  

Sea ice edge at 77 N. The high pressure center is further east compared to previous forecast. The winds are weak at 3 km and stronger at surface from the southeast on ice. Surface temperature is slight above -1.8 south of 75 °N. 

WRF runs: More extensive LLJ and low cloud. The surface visibility is still good but the ceiling dropped a little below 1000 ft between 72°N and 75°N. 

Update [09:40AM, Wed. Sep. 12, 2018 PST]:  

The high and low pressure centers move further east compared to previous forecasts. Now the high pressure is over the 150°W line. The winds are weak in general, northerly at 3 km and southerly at surface. Low clouds extend from 72°N to 77 °N. High surface visibility and surface temperature below -1.8°C north of 71°N. 

WRF run: Stronger and more extensive jet. The low clouds have low cloud base, but ceiling height is still above 1000 ft. Weak elevated temperature inversion south of 73.5°N at 1 km. 

Update [17:20PM, Tue. Sep. 11, 2018 PST]:  

Similar to previous forecast. The low to the east is weakened a little. The low level clouds clear up with clouds only present between 74 °N to 76 °N. 

Update [11:30AM, Mon. Sep. 10, 2018 PST]:  

Sea ice edge at 76.7 °N now. A high pressure to the west of 150°W and low pressure to the east. Northerly surface wind at the north and northeasterly close to the coast.  At 3 km, mostly weak northerly wind. Surface temperature drops below -1.8 °C north of 73 °N. Surface visibility is above 5 miles north of 72 °N. Low clouds at around 1 km north of 72 °N, no middle and high cloud above. Weak wind overall. Along 150 °N, cold air from the north dominates with only weak temperature inversion at 1.5 km from 74°N to 77°N. 

WRF runs have ceiling height at around 1500 ft. The wind speed is much stronger along the coast compared to GFS. 


    • Flight information

2018-09-18 14PM Alaska LT

2018-09-18 14PM Alaska LT

  • Pan-Arctic 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

700 hPa wind speed

Pressure on 2PVU surface

Pressure on 2PVU surface

Low-level cloud cover

Mid-level cloud cover


  • Beaufort and Chukchi seasonal ice zone (the map is centered at 150 °W)

Sea ice concentration at analysis time

Mean sea leve pressure at valid time

2-m air temperature

2-m relative humidty

low cloud fraction

middle cloud fraction


  • Transects along 150 °W


  • Flight conditions at different altitudes along 150 °W