Saturday, February 22, 2014

Strong Morning Inversion

A building ridge aloft is a good set-up for strong valley based inversions in the winter in Interior Alaska, as temperatures this Saturday morning illustrate. Here's the temperature trace from the lowest 1000 meters from the early morning sounding at the Fairbanks Airport.

As usual, most of the vertical temperature gradient is in the lowest 100 meter (-29C to -15C). The pressure gradient is increasing across the area this morning, with 10 to 20 mph east winds blowing at elevation, and the wind is starting to reach the valley floor in places. Surface temperatures from Fairbanks-land from 7 to 8am AST Saturday show a similar spread:

Goldstream Creek: -31F
Fort Wainwright RAWS: -30F
Woodsmoke CWOP: -30F (near North Pole)
Eielson AFB: -28F

UAF West Ridge -14F
Fairbanks Airport -15F (winds NE 5 mph)
Fort Wainwright Airport: -19F

Wickersham Dome: +10F (2200' MSL)
Caribou Peak RAWS: +10F (2500' MSL)
Keystone Ridge: +12F (1600' MSL)
Fox Ridge (CWOP)" +14F (2100' MSL)

A 40 degree spread is pretty impressive even by Fairbanks standards. Being two months past winter solstice, clear skies, and some wind I'd expect temperatures will rise dramatically at valley elevations today.


  1. A friend and I planned to go flying today. SW of Fairbanks to check on some fishing opportunities. Last eve the Delta Jct, Blair Lakes, and Nenana RAWS to the south showed the start of a breeze. We decided to wait and check WX this AM.

    Now (9AM) the ground wind chill to the west where we were going is -20 to -30F. That, the info I've learned here, and a warmer week ahead convinced us to stay put.

    This is March weather with the cool nights, daily wind, and increasingly sunny days that warm nicely.


  2. I slightly stronger inversion on this morning's sounding. Looks like 16°C in the lowest 100m.

  3. Nice daily temp swings happening in Fairbanks. Soon the March Madness breezes will commence, if we follow prior weather history. Watch the Tanana Jet for its daily appearances.

    Time to go camping and fishing!