THERMAL SOARING FORECASTING SkewT Plots, Boundary Layers BLIPMAPS, Models and Methods RICHARD KELLERMAN SATURDAY, FEBRUARY 21, 2004

YOU DON’T NEED TO BE A WEATHERMAN 1

YOU DON’T NEED TO BE A WEATHERMAN 2

CONTENT WHY BOTHER? WHAT I CAN DO WHAT I CAN’T DO

CONTENT (CONT’D) SKEWT’S BASIC BL PHYSICS BLIPMAPS AND THE RUC20 MODEL MAKING THE FORECAST EXAMPLES GETTING THE DATA

WHY BOTHER? BLIPMAPS DO IT ALL SOMETIMES BLIPMAPS EXEMPLIFY THE POWER OF COMPUTER GRAPHICS BLIPMAPS EXEMPLIFY THE LIMITATIONS ALSO WHAT’S UNDER THE HOOD? NOT DEPENDENT ON A SINGLE SOURCE

WHAT I CAN DO (WITHOUT BLIPMAPS) ANSWER THE FOLLOWING QUESTIONS: WHEN LIFT WILL START AND END? HOW HIGH? HOW STRONG? WILL THERE BE CU? WILL THERE BE SPREADOUT? WILL THERE BE CONVECTIVE O.D?

WHAT I CAN’T DO (WITH OR WITHOUT BLIPMAPS) HANDLE CIRRUS WELL LOOK GOOD IN THE VICINITY OF FRONTS ACCOUNT FOR MICRO-SCALE EVENTS DEAL WITH WAVE SUPPRESSION PREDICT STREETING BE PRECISE ABOUT LIFT STRENGTH QUANTIFY TERRAIN EFFECTS

WHAT ONLY BLIPMAPS CAN DO PROVIDE USEFUL INFORMATION OVER A LARGE AREA DEPICT BETTER AND WORSE CONDITIONS PROVIDE DETERMINISTIC LIFT STRENGTH PREDICTIONS DITTO FOR THE BUOYANCY/SHEAR RATIO

WHAT’S THIS?

SKEWT’S COMPACT DATA DISPLAY (GRAPHS) BALLOON SOUNDINGS MODEL SOUNDINGS CALCULATORS IDEAL FOR THERMAL SOARING FORECASTS RECAP

TEMPERATURE AND PRESSURE AXES

ADD DRY ADIABATS

ADD CONSTANT MIXING RATIO LINES “8 GM/KG” DETAILS (SLIDE 1) DETAILS (SLIDE 1)

MAKING CLOUDS

TEMPERATURE AND DEWPOINT LAPSE RATES TEMPERATURE LAPSE RATE ~5.3 F o /1,000 FT. DEWPOINT LAPSE RATE ~0.9 F o /1,000 FT CLOUDBASE = ((T – DP) / 4.4) * 1,000 FT

LAPSE RATES AND ADIABATS TEMPERATURE LAPSE RATE DEWPOINT LAPSE RATE DRY ADIABATIC LAPSE RATE SATURATED ADIABATIC LAPSE RATE T AND DP LAPSE RATES ARE DATA DALR’S AND SALR’S ARE CALCULATED THEY ARE RESPECTIVELY ~3C/1,000 FT AND ~2C/1,000 FT THE “SURFACE ADIABAT” IS THE (DRY) ADIABAT PASSING THROUGH THE SURFACE TEMPERATURE IN THE CONVECTIVELY MIXED BL: T LAPSE RATE = DALR

TEMPERATURE AND DP ALOFT

GOOD DAY WITH CU FORECASTS PM SOUNDING METHOD FORECASTS PM SOUNDING METHOD

GOOD DAY – NO CU SOARING FORECASTS PM SOUNDING METHOD SOARING FORECASTS PM SOUNDING METHOD

BAD DAY (MIFFLIN, /19)

SOARING FORECASTS “THERMAL INDEX/AM SOUNDING METHOD” (SLIDE 1) GET AM SOUNDING GET FORECAST SURFACE TEMPS CONSTRUCT SURFACE ADIABAT FOR TRIGGER CONSTRUCT OTHER SURFACE ADIABATS AS DESIRED

SOARING FORECASTS “THERMAL INDEX/AM SOUNDING METHOD” (SLIDE 2) TEMPERATURE EVOLUTION TEMPERATURE EVOLUTION

A DAY IN THE LIFE OF THE CONVECTIVE BL THE FOLLOWING SEQUENCE SHOWS WHAT ACTUALLY HAPPENED ON SEPTEMBER AT ABE IT ALSO MAKES VERY CLEAR ONE OF TWO FUNDAMENTAL PROBLEMS WITH THE AM SOUNDING/TI METHOD

8:00 AM

11:00 AM

2:00 PM

5:00 PM

TEMPERATURE EVOLUTION SOARING FORECASTS, “TI” METHOD (SLIDE 2) SOARING FORECASTS, “TI” METHOD (SLIDE 2)

DEWPOINT EVOLUTION

WHEN GOOD CLOUDS GO BAD, SLIDE 1

WHEN GOOD CLOUDS GO BAD, SLIDE 2

NUMERICAL MODELS RUC20/MAPS BLIPMAPS RUC VERSIONS

SOME OF WHAT THE RUC20 MODELS TERRAIN SOIL MOISTURE LAND USE INCLUDING VEGETATION COVER CLOUD PHYSICS RADIATIONAL FLUXES CONVECTION ADVECTION 3D PRESSURE

RUC20 VEGETATION CANOPY AND SOIL PHYSICS NOAA Forecast Systems Laboratory, RUC Development Group

RUC20 DATA INPUTS NOAA Forecast Systems Laboratory, RUC Development Group

SOME RUC20 ASSUMPTIONS 20 KM GRID 50 LAYER ATMOSPHERE

RUC20 TERRAIN RESOLUTION NOAA Forecast Systems Laboratory, RUC Development Group

RUC20 2M TEMPERATURE PERFORMANCE NOAA Forecast Systems Laboratory, RUC Development Group

RUC20 WIND FORECAST ERRORS NOAA Forecast Systems Laboratory, RUC Development Group

RUC20 RAOB VERIFICATION NOAA Forecast Systems Laboratory, RUC Development Group

RUC20 SCHEDULE

SOARING FORECASTS PM SOUNDING METHOD GET THE RUC20 PM SOUNDINGS CONSTRUCT THE SURFACE ADIABAT PASSING THROUGH THE (2M) SURFACE VIRTUAL TEMPERATURE DETERMINE HEIGHT OF LIFT ESTIMATE STRENGTH OF LIFT DETERMINE CLOUDBASE ASSESS THE CHANCE OF LATERAL OR VERTICAL OD ASSESS THE SENSITIVITY OF THE FORECAST TO DP AND/OR T ERRORS GOOD DAY – NO CU GOOD DAY – NO CU GOOD DAY WITH CU GOOD DAY WITH CU

MIFFLIN 2001 P2: FORECAST

MIFFLIN 2001 P2: WHAT HAPPENED (SLIDE 1) STRONG LIFT WITH CU AT 7,000 FT QV’S AND X’S DAY

MIFFLIN 2001 P2: WHAT HAPPENED (SLIDE 2) EVERYONE ELSE’S DAY HEAVY RAIN SHOWERS BROTHER UNABLE TO LAND 60 MPH GUST AT THE FIELD SPREADOUT DISGRUNTLED PILOTS

BLIPMAPS SUPPLEMENTS COMPLEMENTS PAINTS THE SOUNDING GRID DATA THERMAL STRENGTH IS DETERMINISTIC (NOT EMPIRICAL)

PREPARING THE FORECAST (SLIDE 1) 1. SURFACE ANALYSIS 2. FORECAST DISCUSSIONS 3. SATELLITE IMAGERY 4. SURFACE OBSERVATION

PREPARING THE FORECAST (SLIDE 2) 1. SKEWT PLOTS 2. BLIPMAP

DETAILS (SLIDE 1) VIRTUAL TEMPERATURE T V = T + W/6 VISIBILITY WIND SHEAR CIRRUS ADD CONSTANT MIXING RATIO LINES ADD CONSTANT MIXING RATIO LINES

SENSITIVITY ANALYSIS PRE-EMPTIVE EXCUSES HIGH INVERSION SURFACE DEWPOINT CLOSE TO CU/BLUE POINT SMALL T/DP SPREAD AT CLOUDBASE LITTLE OR NO INVERSION

SMALL T.I. – LOW INVERSION

SMALL T.I. – HIGH INVERSION

GLIDER PILOTS ARE A BIG PART OF THE PROBLEM FORECASTS DEAL IN AVERAGES GLIDER PILOTS FLY FROM ONE MICRO SCALE ANOMALY TO ANOTHER HOW TO FIND LIFT

SUMMARY WEATHER IS BASIC TO GLIDING UNDERSTANDING IT IS REWARDING UNDERSTANDING FORECAST LIMITATIONS HELPS YOU CAN AND SHOULD DO YOUR OWN FORECASTS