Comments on the Red Rock PG Nationals

There are a few items I would like to comment on. First, I'd like to commend the organizers and meet director who made the Red Rock Nationals work so seamlessly. Their consideration for every detail paid off well.

We did start with "stellar" conditions for the first weekend of the comp, with Saturday and Sunday being very good soaring days (July 23-24). Monsoonal moisture crept into the area about 12 hours earlier for the next Monday, which put a lid on the flying, as expected. The drying trend did occur mid week as predicted by the GFS long range forecast for the Richfield region, but was still on the edge. There were a few days where XC flights could have been made with earlier launches, but the timing of official task starts made it impossible to get everyone safely on course before overdevelopment shut down the two parallel valleys. Conditions to the East and North were potentially soarable for solo XC some early afternoons, but unreachable for a competition with 60+ pilots at varied skill levels, plus the time it takes to set a task and start a race.

In the end, we had 2 valid tasks, a lot of sight-seeing of Utah's incredible national parks, plenty of mountain biking, bowling, beer drinking, a few matinee movies, and even a little tennis. Not to mention a performance by Miss Richfield at the awards dinner.

Looking directly above launch, Task 2.
Photo by Sarah Galli

Weather Review for July 29

Today presented a very challenging and frustrating situation on launch. The weak ridge surpressing moisture was aligned from SW to NE across the SW portion of Utah extending into central Utah. Monroe Peak was unfortunately on the moist side of this line by only 20 miles.

The task committee and meet director chose to close the launch within 3 minutes of the official open. This was due to a relatively shallow cumulus line developing directly on course line. Within 20 minutes, the line was dropping out in a somewhat benign fashion, but with a single lightening strike in the distance and the psychological factor of the sky just looking very border-line, the task remained on hold for another hour until the day was canceled.

The meet director deliberated on canceling the next day, given the forecast was for considerable more moisture and instability over the entire lower half of the state of Utah.

A conference call was initiated to incorporate the opinions of what would likely happen for Saturday, July 30. Those on the call were seasoned forecasters and a Professor of Atmospheric Science from the University of Utah, all who are familiar with reviewing and forecasting monsoonal conditions in the state. The consensus was that Saturday would not yield a soarable window from noon through 4pm, which would be the earliest a task window could be executed within.

Hence, the competition is officially over and the awards ceremony with commence a day early.

Closing thoughts to follow on another post.

Weather Outlook for July 29-30

The general weather outlook for July 29-30 in the Richfield.

Update on July 29, 7:45 am - cg
Notes from the morning discussion:
the elongated east-west upper ridge extending
across the Gulf Coast states through the desert SW has effectively
cut-off the deep layer to the south of Utah. The moisture that is
available across southern/cntrl/ern Utah will struggle to generate deep
convection again today. Subsidence associated with the near 700mb
high pressure across central Utah will inhibit convection outside of
the higher terrain where differential heating will come into play.

cg - The above says it all. The axis of the ridge that blocked moisture from yesterday is oriented in a way that will likely block the surge of moisture again today. This with a little high cirrus over the afternoon will likely suppress the triggering of deep convection, so TS will be more isolated and not scattered. Chance of TS is likely on the order of 10% for our region.


Friday Overview: The GFS model is showing considerably more moisture in the valleys surrounding Richfield tomorrow than the NAM does. The same was for Thursday, where conditions were by all means stellar for a task to the north with no overdevelopment within the area. This leads me to wonder about the validity of the moisture within the BL and aloft for Friday afternoon. To error on the conservative side, Friday will likely overdevelop by late afternoon within the region.

Saturday overview: Saturday is proving to be a difficult day to forecast. While NWS forecast discussions are stating that starting this weekend a surge of moisture will flow through southern and central Utah. However, there is indication that this may in fact be timed Sat night. Which leaves the early afternoon as a wild card. When these "pre monsoonal" conditions exist (if that's actually a real term) the spread of moisture aloft in stronger southerly flows, along with the destabilization within that flow, will allow for localized lines of overdevelopment as we have seen over this week, and then very widespread thunderstorms shortly beind. GFS shows strong southerly winds starting at 8am as low as 18k ft over 20 mph. This alone is perhaps enough reason to wright off Saturday as potentially taskable. This is also in line with the NWS discussion for the central Utah region.

** Saturday needs more consideration and review at this moment. **

The NWS synopsis:
Area forecast discussion
National Weather Service Salt Lake City Utah
341 PM MDT Thursday Jul 28 2011

Synopsis...a drier westerly flow will persist through tonight. The
very moist airmass to the south of Utah will begin to move north
through the state tomorrow before becoming well established
statewide this weekend. Deep moisture will remain in place into
middle week of next week.

Over Development & Precip

Friday will bring more moisture into the area as a south westerly flow aloft starts to set in above 500mb. This is not good news for our area in general, but as stated above, we may actually see usable conditions early afternoon before overdevelopment begins. Precipitable water will increase as wel (something on the order of .75 to 1.0) for this area. In a nut shell, this means that heavier rains will accompany and convective cells that drop out.

Winds 11 AM

Height	Direction	Speed	Notes as the day evolves
Surface	S	0-5 mph	SW throughout the San Pete valley
9000 ft	ESE	0-5 mph	Changing to light and variable for the afternoon
12000 ft	ESE	0-5 mph	Changing to light and variable for the afternoon
15000 ft	ESE	0-5 mph	Changing to light and variable for the afternoon
18000 ft	W	0-5 mph

East winds on launch in the morning may delay the start window or provide difficult launches until the west slopes can heat enough to block the morning flow.

Lift Potential & Clouds

• Cumulus clouds: widespread, bases from 15k up to 16k as the day evolves and deep cumulus develop.
  
• Top of lift: estimated at around 15,000 ft over the higher terrain, with valley climbs up to 12-13k.
• Cloud cover: cumulus with widespread mid stratus are likely for the afternoon. High clouds will increase throughout the day.
  

Even with a drier air mass aloft, the surface has retained tremendous moisture over the last 2 days and will contribute to deep cumulus development as well.

XC Skies 3 day Trends

Legend:

Red - Top of usable lift (1.2 m/s) Black - Thermal tops (TI~0)

White - Thermal top sensitivity(+2°C) Pink - Cu CCL (dew pt.)