OPEN CLASS NATIONALS /Pre-World Gliding Championships

UVALDE, TX; USAContest Day 3: Monday, August 8, 2011

World Class Soaring!Fly Safe ... and Enjoy!

South Texas Gulf Coast Sea Breezeat 1800 CDT

Uvalde Sky: SE Aspect0800 CDT

Uvalde Sky: SE Aspect1700 CDT

Del Rio12Z SundayMorning Post-BriefSounding

Unavailable: Briefing Time

Del Rio:By Sunday Afternoon

Visible Satellite (Sunday Afternoon)

500 mb Monday Afternoon Forecast

High Pressure Aloft

H

Water Vapor Satellite

Sunday Morning

TThis Morning

Increasing Low-LevelGulf Moisture

Low Cloud Base

Up 100-200 Feet

Infrared Satellite

Visible Satellite – Monday

850 mbModel Temp/Moisture

- 30 deg C Area- Sub-Tropical Moisture

Thunderstorm Outlook(To Right of Lines)

IncreasingThunderstormThreat Area

Surface Plot – 12Z

Pressure Gradient:2.7 mb(+1.0) Pressure Gradient:

2.3 mb (+0.5)

Del Rio Raob

Corpus ChristiRaob

Del Rio Raob24-Hr Comparison

Corpus Christi Raob24-Hour Comparison

Forecast Del Rio Sounding (5 PM CDT)

T/DP Trends

Soaring Graphics

Note: Altitudes are AGL Uvalde

XC-Skies: Top of Usable Lift (TI = -3)

Uvalde

San Angelo

Del Rio

Cotulla

Kerrville

XC-Skies: Boundary/Mixed Layer Tops

Uvalde

San Angelo

Del Rio

Cotulla

Kerrville

Trend: Down 500-1000Ft

XC-Skies: Average Thermal Updraft

Uvalde

San Angelo

Del Rio

Cotulla

Kerrville

Trend: Little Change

XC-Skies: Cloud Base

Uvalde

San Angelo

Del Rio

Cotulla

Kerrville

Lift Rates –BLIPMAP

Afternoon 21z(4 PM)

Boundary Layer Top

Afternoon 21z(4 PM)

Soaring Forecast (at pilot brief)• Delta-T 850-500: 27(NoChg) 850mb Temp: 22C(-1)

• K-Index, DRT: 33(No Chg)

• Launch: SCT 4500 Feet MSL

• Task: SCT 8000 Feet MSL (Lower 500 Feet … then

Go to FEW toward end of the afternoon.

• Maximum Temp 38.5C/101F .. (Little Change to -1F)

• Lift Rates: 650 FPM (Lower 100 FPM)

• Alt Max/Time: 8,000 Ft (blue) / 1700 CDT

• Trigger/Time: 32.5C(92F); 1230 CDT

• Winds: SE 10-17Kt (+2)

Monday Aug 8 2011- Temperature trends spot-on with readings through the late morning to mid-

afternoon running to the upper 90s by 1500 CDT. Biggest change was the earlier than anticipated onset of drying with dew points running 2-4 deg F. lower than 24-hours previous. This trend was anticipated more for the very late afternoon. Consequently the launch was conducted only under a few small cumulus rather than a full scattered sky condition of robust cumulus. Winds across South Texas running 10 to 17kts from S-SE.

- Tremendous variation in numerical forecast models this morning with the more pessimistic of the models showing 2000 feet less max altitude and lift rates 200 FPM less than the tremendous Sunday soaring conditions (Note the RASP Model referenced in the post-briefing slides). Several other numerical models and NWS forecasts reflected only what would amount to a small diminishing of the soaring conditions. PIREPS of flying representative of 7600 ft MSL…max altitudes above 8000 ft MSL. Lift rates initially worked 4-5kts with average rates mid-task of 4-6kts and day’s end at 5-7kts. Thermals chopped and not smooth. Several contestants chose to fly deeper into the turn-point circles to elongate the day to meet the 5-hour and 4-hour tasking.

- Essentially this soaring day was run in the “blue”with high-based FEW-SCT cumulus. The drying anticipated occurred early in the day instead of the latter part of the day with contestants running in the “blue” instead of classic Uvalde clouds.

- The sea breeze front crossed into the SE portion of the task area at Pleasanton just after 1800CDT seemingly responding per the increased onshore pressure gradient.

Added, Post-Brief RASP Meso-scale Model Evaluation: Thermal Updraft (Courtesy Alex Caldwell & John Glendening) Uvalde

Junction

Laredo

Added, Post-Brief RASP Meso-scale Model Evaluation: Boundary Layer (Courtesy Alex Caldwell & John Glendening) Uvalde

Junction

Laredo

Outook:Tuesday 1 PM CDT

H

FLIGHT RESTRICTIONS

Temporary Flight RestrictionsMonday: August 8, 2011

--- No V.I.P.s in Task Area (150mi radius)

--- No other unpublished restrictions (Could be “pop-up” Fire-Fight Restrictions)

OPEN CLASS NATIONALS /Pre-World Gliding Championships

UVALDE, TX; USA

World Class Soaring!Fly Safe ... and Enjoy!