Monday, October 25, 2010

SOLPEX IOP1 2030 UTC 25 Oct update

Radar imagery has been fairly quiet the past couple of hours. The latest shows some areas of orographic precipitation from Little Cottonwood to the UT-ID border.

We've opted to move forward with the optional 2100 UTC sounding for a couple of reasons.  The first is that the flows at the north end remain bizarre.  Note the southerly flow at Locomotive Springs.

I've seen this before in lake-effect events and its always been a head scratcher.  Trevor's model runs and observations thusfar today suggests perhaps some sort of wake effects in the lee of the Raft River range.  A single sounding ob might make this hard to nail down, but perhaps it will help.

The second is that we are starting to see an increase in cumulus convection over the lake.  In fact, todays visible satellite loop is really incredible.  Despite the persistent northwesterly flow at upper-levels, once cal clearly see what appear to be retrogressing mountain waves in the loop.

It appears, however, that the waves are becoming increasingly progressive in the last hour or two.  We'll see if this leads to anything or if the lake stays shut down as it often does in the afternoon.  The flow is so strong right now that I wonder if the thermally driven flows can even get going.


  1. I know nothing about the locomotive springs site, but can that anemometer be trusted? The wind direction seems out of whack and the last 24 hours of wind speed numbers look very suspicious. The highest gust recorded in the last 24 was 30mph at 12:30 AM and most readings seem too low ....

  2. I used to think it was flaky, but the north-end team has been observing some surprising flows, including a fairly deep layer of surface-based southeasterly flow at 1800 UTC. They report that more sustained northwesterly flow has recently developed and the mesonet stations around the Park Valley and at LMS are now westerly. As such, I'm wondering if the flakiness of the obs at LMS earlier reflects a wake downstream of the Raft River Range. Trevor has seen this in one lake-effect simulation.

  3. Should be different for southerly flow at such an exposed site though? Even during yesterday afternoon and evening the speed numbers were surprisingly low. I dont doubt that there are surprising flows I just wonder if the cups are sticky ...

  4. I can't confirm or deny that possibility ...