NWS Portland Aviation Forecast Operations Clinton Rockey Aviation Meteorologist

Forecast Office Overview 5 Lead Forecasters 12 Journey Forecasters 4 Hydro-meteorological Techs / Interns Responsible for southwest Washington and northwest Oregon Our Responsibilities include: Public Forecasts and Warnings Hydrologic Coastal Marine Wildfire and Land Management Aviation Our Staff include:

Aviation Operations Overview What We Do…  Terminal Aerodrome Forecasts (TAFs) 4 times per day, updated as needed Portland Eugene Hillsboro Salem Troutdale Astoria Newport  Route Forecasts (TWEBs) 4 times per day, updated as needed 367 Portland to Pendleton 371 Redmond to Portland 372 Portland to Eugene to Medford 373 Portland to Astoria  Soaring Forecast - daily  Monitoring and input to the FAs/Airmets and with McMinnville Flight Service Station - continuous

Terminal Aerodrome Forecast  Detailed weather forecast for the next 24 hours  Elements include Visibility, Cloud Heights and Winds, and Weather  TAF is good for a 5 mile radius around the airport  Issued 4 x day (00Z, 06Z, 12Z and 18Z  May include Low Level Wind is needed for the airport What is a TAF? Example: KPDX Z KT P6SM OVC060 FM KT P6SM SCT040 OVC070 TEMPO RA FM KT P6SM -RA BKN040 OVC070 FM KT P6SM -SHRA SCT025 OVC040 FM KT P6SM SCT025 BKN045 TEMPO SM –SHRA BR=

Transcribed Weather Broadcast (a.k.a. TWEB) What is a TWEB? Example: 367 TWEB KPDX-KDLS-KPDT. ALL HGTS MSL EXC CIGS AND BASES. KPDX-KCZK P6SM SCT070 BKN120 LCL -RA 14Z-18Z AREAS SFC WND 09025G35KT...23Z P6SM SCT060 BKN-OVC080 AREAS -RA. KCZK-K1S8 P6SM SCT080 BKN120 LCL -RA...18Z P6SM SCT200. K1S8-KPDT P6SM SCT070 BKN150.  12 Hour Forecast  Elements include Visibility, Cloud Heights and Weather. If significant, may include Winds.  TWEB is good for a 25 mile radius around anchor points, and 25 miles either side of the route center line (50 mile wide)

Transcribed Weather Broadcast (TWEBs) TWEB Route Synopsis Example: PDX SYNS SLY TO SWLY FLOW ALF OVR PAC NW THRU 02Z. STG SFC HIGH PRES OVR THE NRN ROCKIES WILL SHIFT EWD THRU 20Z...WKNG OFFSHORE SFC GRADS. DPNG UPR LOW IN ERN PAC WILL BE NR VRISL BY 20Z WITH FNT MOVG ACRS NW RTES THRU 20Z. AMS GNRLY STBL.  Overall weather picture for the next 12 to 18  Elements overall upper air flow, high and low pressure in the region, fronts and their movements during the forecast period and characteristics of the atmosphere.  One synopsis per state.

Daily Soaring Forecast LOCAL INDICES FOR SALEM THERMAL INDEX… MINUS SIGN IS UNSTABLE 5000 FT ASL……… FT ASL……… FT ASL……… FT ASL……… HEIGHT OF MINUS 3 INDEX…… 600 FT ASL TOP OF THE LIFT……………… FT ASL MAX TEMP AT SALEM………….. 53 DEG F FIRST USABLE LIFT…………….. 67 DEG F TOP OF THE LIFT……………… FT MSL SOARING INDEX………………… -126 FPM MAXIMUM LIFT………………… FPM AFTERNOON WINDS ALOFT FORECAST… 3000 MSL 180 DEG / 22 KT 6000 MSL 210 DEG / 41 KT / 1 DEG C  Winds aloft and thermal indices for next 12 hours  Tailored to needs of Local Pilot Briefers at the McMinnville Flight Service Station  Uses Salem and Medford Upper Air data Soaring Index

Local Hazards Ice & Snow January 2004 Winter Storm  Over 1300 flights cancelled  Thousands of dollars lost revenue  Portland Airport shut down for 2 ½ days

Local Hazards Strong Winds Famous Wind Storms October , November and 12 December 1995  Thousands of dollars lost revenue  Intense Crosswinds and Strong Gusts  Winds clocked at over 90 mph at PDX

Local Hazards Marine Stratus Mountain Obscurations

Local Hazards Thunderstorms

Tornadoes

Mountain Waves/Turbulence Danger? Vertical rises of over 15 per second with Mountain Waves

Low Level Wind Shear Danger? Stalls and abrupt landings  Vertical Wind Shear 10 kts or more per 100 feet in a layer at least 200 feet thick  Must be within 2000 feet of Ground  PIREP reporting non-convective wind shear causing an airspeed loss/gain of 20 kt (within 2000 feet of ground) What Is It? Common with…  South winds over the Willamette Valley, with strong east winds near the surface coming out of Columbia Gorge  Common to see Troutdale reporting LLWS around feet c

Other Local Hazards  Dense Fog (especially Oct – Dec)  Low Clouds and/or Visibility  Mountain Obscurations  Wind Shear near Troutdale In the Winter months… In the Summer months…  Marine Clouds  Low Clouds and/or Visibility  Thunderstorms, with hail and/or high winds  Wind Shear near Troutdale

Pilot Reports  Forecasters!  Fellow Pilots!  Anyone with flying interests  Often, PIREPs are the first sign of trouble, or weather that will affect the route and/or airport terminals  REMEMBER, your PIREP is extremely valuable. Who Needs Them? Example: CVO UA /OV CVO /TM 2246 /FL 150 /TP PAY2 /SK OVC-TOP012/ OVC160 /TA M07 /WV 23040KT /TB LGT OCNL MOD

AIRMETs  Areas of Moderate Turbulence  Areas of Moderate Icing and freezing levels  Areas of IFR Conditions and mountain obscurations  Strong Convective Areas  Volcanic Ash Tracks  Issued at 13 UTC, 19 UTC 01 UTC, and 07 UTC -- Updated as needed AIRMET SIERRA UPDT 3 FOR IFR AND MTN OBSCN VALID UNTIL AIRMET IFR...CA FROM RBL TO 60ESE CZQ TO 40SSE EHF TO 20N RZS TO OAK TO RBL OCNL CIGS BLW 010/VIS BLW 3SM BR/FG. CONDS CONTG BYD 03Z THRU 09Z.. AIRMET MTN OBSCN...WA OR CA FROM 40SE YDC TO LKV TO FOT TO 70WNW OED TO ONP TO HQM TO TOU TO BLI TO 40SE YDC MTNS OCNL OBSC IN CLDS/PCPN/BR. CONDS CONTG BYD 03Z THRU 09Z. Issued by National Aviation Center, in KCMO

SIGMETs  Thunderstorms greater than VIP level 4 (33 dbZ) affecting 40% or more of an area at 3000 square miles  Line(s) of Thunderstorms  Isolated Severe Thunderstorms (3/4” hail and/or 50 kt winds)  Tornadoes  Embedded Thunderstorms  Volcanic Ash  Issued when needed WSTW MKCW WST CONVECTIVE SIGMET...NONE OUTLOOK VALID TS ARE NOT EXPD. Issued by National Aviation Center, in KCMO

Weather and Accidents Source: NTSB chairman, Jim Hall’s testimony before the Committee on Transportation and Subcommittee on Aviation (22 July 1999) National Transportation Safety Board Statistics…  33% of all FATAL accidents are weather related  Of these, 40% occur within the TAF area of the airport  Low Ceilings and/or Visibilities  Icing  Thunderstorms, Lightning and/or Hail  Low Level Wind Shear Main Weather with these Crashes…

Where to Get Weather National Weather Service… weather.gov/portland

Questions?