WX, weekend of 21/22 May 2016:
A strong low has moved on shore and will be over the Great Basin area. Circulation and compression around this low will bring strong SSW winds to the state on Saturday, stronger on Sunday. Moisture will fetch in on the flow as well with a bit of a dry slot east of the Divide on Saturday. Current winds aloft forecast for 0-12 Zulu (5pm Fri to 5am Sat) indicate mid 20 knots at 9&12K at Den and ALS; 12K at GJT in 30-35 knot range… As the low moves further east, we can anticipate these winds increasing throughout the day on Saturday and well into Sunday. In ortherwords, high winds this weekend; strong potential for squalls and OD west of the Divide on Saturday; squalls and OD more widespread over the mountains and state on Sunday. There is potential for shear issues (velocity rather than directional) aloft too so eastern plains may see a few cells approach severe levels over Friday through Sunday.
Midday gust differential in the mountains on Saturday will be on the order of 20+ when heating really influences things… With base surface winds in the 15 plus range, that means winds will vary between zero (thermal block) and 35+ (thermal downwind) and that means midday is not suitable for our wings. Since winds are forecast to increase throughout the day, evening flights are not likely either (if winds were forecast to ramp down, I would go for the evening in a heartbeat, but that ain’t happening this weekend).
To bad we don’t have a nice south facing ridge well east of Denver Metro area… And to bad we don’t have big old lake out there too 'cause kite boarding and sailing could be great!
It’s the Spring transition time. We would like to see the northern Jet transition to a track north of us and have the lows track further north rather than into the Great Basin track. As El Niño wanes and the tendency for a standing ridge (hot water pool = high pressure) in the Pacific diminishes, we should see things moving in that direction. Hopefully we will have a few weeks in late spring during this time before the monsoon begins to affect us… Sea surface temps off the coast of Baja and SoCal continue to be above average and this will likely contribute to the available moisture fetch when monsoon fires up. NAM Relative Humidity/Lifted Index data coupled with winds aloft data will be very useful when judging if it is prudent to mountain fly over the next 3 plus months. Forecasts will be difficult more than a couple days out from a flying day so watch trends in the forecast updates as the flying day approaches because the trends will clue you in on how fast/slow systems are moving and how they might affect where you would like to fly.
'hope this is of use.