Seattle-Tacoma International to Great Falls International SEA → GTF
444 nautical miles (511 statute miles) east on a straight line, true course 086°, about 070° magnetic at the departure end (variation 16E). At 120 knots that is 3 h 08 min at the quickest height in today's winds (34,000 ft, a 22-knot tailwind), arriving about 10:29 pm MDT (04:29 UTC), after sunset at the destination. Right now SEA is VFR, wind from the north (350°) at 11 knots; GTF is low IFR, wind from the north-northeast (020°) at 10 knots. For planning, not a briefing: the legal preflight briefing comes from Flight Service (1-800-WX-BRIEF) or the FAA's own tools. Airlines fly this pair: 726 flights in the DOT's last twelve reported months, the route's page.
The route the straight line, the warnings crossed, restrictions, pilot reports and the airports along the way · click a mark for its words
Green, blue, red and purple airport dots are the flying conditions reported there now (VFR, marginal VFR, IFR, low IFR); grey means no report. Red areas are SIGMETs, orange areas AIRMETs, hatched red areas temporary flight restrictions. Map tiles: OpenFreeMap, data © OpenStreetMap contributors.
Warnings the route crosses SIGMETs and AIRMETs whose area the line passes through or comes within 25 nm of
- AIRMET ZULU 2C: moderate icing up to 14,000 ft. Over the route from 118 to 355 nm out.
- AIRMET SIERRA 1E: mountains obscured by cloud (due to mountains obscured by clouds, precipitation, mist). Over the last 237 nm of the route.
- AIRMET SIERRA 4E: low cloud or poor visibility (IFR conditions) (due to ceilings below 1,000 ft, visibility below 3 miles, precipitation, mist). Over the last 187 nm of the route.
- AIRMET TANGO 4W: moderate turbulence above 18,000 ft from 18,000 ft to 36,000 ft. Over the last 177 nm of the route.
A SIGMET warns of weather hazardous to all aircraft; an AIRMET of weather that matters to small aircraft and to flying without instruments. "From 60 to 180 nm out" is measured along the route from SEA.
Pilot reports along the route within 50 nm of the line, last three hours, the serious ones first
- PC12 at 15,000 ft, 37 nm south, 5:42 pm PDT (00:42 UTC): remarks: zse. 30 nm along the route, 37 nm south of the line.
as filed, and in English
YKM UA /OV YKM270050/TM 0042/FL150/TP PC12/SK TOP130/RM -ZSE
- Report
- a routine report filed through YKM
- Where
- 50 nm west (270°) of YKM
- Time
- 00:42 UTC
- Height
- at 15,000 ft
- Aircraft
- PC12
- Sky
- TOP130
- Remarks
- zse
- PC12 at 13,000 ft, 37 nm south, 5:42 pm PDT (00:42 UTC): remarks: zse. 30 nm along the route, 37 nm south of the line.
as filed, and in English
YKM UA /OV YKM270050/TM 0042/FL130/TP PC12/SK TOP130/RM -ZSE
- Report
- a routine report filed through YKM
- Where
- 50 nm west (270°) of YKM
- Time
- 00:42 UTC
- Height
- at 13,000 ft
- Aircraft
- PC12
- Sky
- TOP130
- Remarks
- zse
- E75L descending, 44 nm north, 6:06 pm PDT (01:06 UTC): overcast above 4,000 ft. 325 nm along the route, 44 nm north of the line.
as filed, and in English
GPI UA /OV KGPI/TM 0106/FLDURD/TP E75L/SK OVC040
- Report
- a routine report filed through GPI
- Where
- over KGPI
- Time
- 01:06 UTC
- Height
- during the descent
- Aircraft
- E75L
- Sky
- overcast from 4,000 ft
- C25B at 4,100 ft, 40 nm south, 5:36 pm PDT (00:36 UTC): no icing, overcast above 4,100 ft, remarks: during the descent ils runway 12. 335 nm along the route, 40 nm south of the line.
as filed, and in English
MSO UA /OV MSO/TM 0036/FL041/TP C25B/SK OVC041/IC NEG/RM DURD ILS RY 12
- Report
- a routine report filed through MSO
- Where
- over MSO
- Time
- 00:36 UTC
- Height
- at 4,100 ft
- Aircraft
- C25B
- Sky
- overcast from 4,100 ft
- Icing
- none
- Remarks
- during the descent ils runway 12
Winds aloft along the route, and the time en route the forecast for use 20:00–03:00 UTC · at 120 knots true airspeed
The eastbound cruising heights for this course (VFR: odd thousands plus 500 ft; above 18,000 ft the forecast levels), with the wind averaged along the line from the 5 forecast points nearest it (SEA, YKM, GEG, GPI, GTF). A plus sign is a headwind, a minus sign a tailwind.
| Height | Average wind | Head- or tailwind | Temperature | Ground speed | Time en route | Arrival |
|---|---|---|---|---|---|---|
| 5,500 ft | 050° at 17 kt | +13 kt | -2 °C | 107 kt | 4 h 09 min | 11:30 pm MDT (05:30 UTC) |
| 7,500 ft | 060° at 15 kt | +13 kt | -5 °C | 107 kt | 4 h 09 min | 11:30 pm MDT (05:30 UTC) |
| 9,500 ft | 060° at 13 kt | +12 kt | -8 °C | 108 kt | 4 h 07 min | 11:28 pm MDT (05:28 UTC) |
| 11,500 ft | 060° at 7 kt | +6 kt | -9 °C | 114 kt | 3 h 54 min | 11:15 pm MDT (05:15 UTC) |
| 13,500 ft | 090° at 3 kt | +4 kt | -12 °C | 116 kt | 3 h 50 min | 11:11 pm MDT (05:11 UTC) |
| 15,500 ft | 150° at 5 kt | +3 kt | -16 °C | 117 kt | 3 h 48 min | 11:09 pm MDT (05:09 UTC) |
| 17,500 ft | 170° at 8 kt | +2 kt | -19 °C | 118 kt | 3 h 46 min | 11:07 pm MDT (05:07 UTC) |
| 18,000 ft FL180 | 180° at 9 kt | +2 kt | -20 °C | 118 kt | 3 h 46 min | 11:07 pm MDT (05:07 UTC) |
| 24,000 ft FL240 | 190° at 13 kt | −2 kt | -28 °C | 122 kt | 3 h 38 min | 10:59 pm MDT (04:59 UTC) |
| 30,000 ft FL300 | 210° at 34 kt | −15 kt | -37 °C | 135 kt | 3 h 17 min | 10:38 pm MDT (04:38 UTC) |
| 34,000 ft FL340 | 230° at 30 kt | −22 kt | -40 °C | 142 kt | 3 h 08 min | 10:29 pm MDT (04:29 UTC) |
| 39,000 ft FL390 | 240° at 23 kt | −20 kt | -42 °C | 140 kt | 3 h 10 min | 10:31 pm MDT (04:31 UTC) |
Based on data from the 11th at 18:00 UTC; valid on the 12th at 00:00 UTC for use 20:00 to 03:00 UTC; temperatures above 24,000 ft are below zero. Heights are above sea level; a height is left out when the forecast has no wind for it over most of the line (the ground is higher). Ground speed is the airspeed less the headwind; the time en route is for the straight line and ignores climb, descent and routing around weather.
The forecast points as issued
| Point | From | 3,000 | 6,000 | 9,000 | 12,000 | 18,000 | 24,000 | 30,000 | 34,000 | 39,000 |
|---|---|---|---|---|---|---|---|---|---|---|
| SEA | used from 0 nm out; 25 nm from the line | 360/9 | 350/10 1° | 010/10 -5° | 030/20 -11° | 020/60 -17° | 010/86 -26° | 360/90 -40° | 010/68 -42° | 360/31 -43° |
| YKM | used from 49 nm out; 58 nm from the line | 030/16 | 020/18 0° | 030/30 -8° | 030/23 -13° | 020/40 -23° | 010/73 -29° | 010/54 -36° | 360/29 -37° | 330/16 -40° |
| GEG | used from 99 nm out; 71 nm from the line | 050/18 -2° | 060/19 -8° | L/V -11° | 160/11 -24° | 190/17 -31° | 200/19 -35° | 220/14 -37° | 250/11 -41° | |
| GPI | used from 247 nm out; 70 nm from the line | 060/19 -3° | 110/11 -8° | 130/6 -8° | 200/40 -19° | 190/58 -28° | 200/101 -39° | 220/73 -43° | 230/41 -43° | |
| GTF | used from 394 nm out; 25 nm from the line | 070/21 | 080/18 -6° | 120/5 -5° | 180/30 -14° | 200/53 -24° | 210/80 -38° | 220/83 -44° | 230/68 -46° |
The weather now: both ends and the airports along the way public airports with a weather report within 25 nm of the line, one for each stretch
| Airport | Where | Conditions | Wind | Visibility | Ceiling | Elevation | Reported |
|---|---|---|---|---|---|---|---|
| SEA Seattle, WA | departure | VFR Sky: a few clouds at 5,000 feet | from the north (350°) at 11 knots | 10+ mi | none | 432 ft | 5:53 pm PDT (00:53 UTC) |
| ESW Easton, WA | 49 nm out, 15 nm south of the line | no report just now | 2,226 ft | ||||
| MWH Moses Lake, WA | 118 nm out, 21 nm south of the line, tower | VFR Sky: overcast at 10,000 feet | from the northeast (050°) at 13 knots, gusting to 18 | 10+ mi | 10,000 ft | 1,188 ft | 00:52 UTC |
| GEG Spokane, WA | 197 nm out, 4 nm northwest of the line, tower | VFR Sky: a few clouds at 4,500 feet, a broken layer at 5,500 feet, a broken layer at 10,000 feet | from the northeast (040°) at 15 knots | 10+ mi | 5,500 ft | 2,385 ft | 00:53 UTC |
| COE Coeur D'Alene, ID | 227 nm out, 11 nm north of the line | VFR Sky: overcast at 7,000 feet | from the north-northeast (030°) at 10 knots | 10+ mi | 7,000 ft | 2,320 ft | 00:56 UTC |
| THM Thompson Falls, MT | 286 nm out, 1 nm southwest of the line | no report just now | 2,467 ft | ||||
| CII Choteau, MT | 414 nm out, 19 nm north of the line | no report just now | 3,946 ft | ||||
| GTF Great Falls, MT | destination | low IFR Sky: a broken layer at 400 feet, overcast at 800 feet Weather: light snow, mist | from the north-northeast (020°) at 10 knots | 0.75 mi | 400 ft | 3,680 ft | 7:08 pm MDT (01:08 UTC) |
The highest airport on this list sits at 3,946 ft; the ground between airports is higher still. Check the sectional chart for the terrain and the minimum safe heights along the line.
At GTF when you get there the forecast at the estimated arrival, 10:29 pm MDT (04:29 UTC)
Wind from the north-northeast at 12 knots, visibility ¾ mile, light snow, mist, a broken layer at 500 feet, overcast at 1,200 feet low IFR
The whole forecast for GTF
- From Sun 6:00 pm MDT (00:00 UTC): wind from the north-northeast at 12 knots, visibility ¾ mile, light snow, mist, a broken layer at 500 feet, overcast at 1,200 feet
- At times between Mon 12:00 am MDT (06:00 UTC) and 3:00 am MDT (09:00 UTC): visibility 2 miles, light snow, overcast at 600 feet
- From Mon 3:00 am MDT (09:00 UTC): wind from the north at 9 knots, visibility 3 miles, light snow, mist, overcast at 500 feet
- From Mon 9:00 am MDT (15:00 UTC): wind light and variable, visibility 6 miles, light snow, mist, a broken layer at 800 feet, overcast at 1,500 feet
- From Mon 3:00 pm MDT (21:00 UTC): wind light and variable, visibility more than 6 miles, a broken layer at 2,500 feet
The forecast for SEA, the departure
- From Sun 5:00 pm PDT (00:00 UTC): wind from the north at 12 knots, gusting to 20, visibility more than 6 miles, a few clouds at 2,000 feet, a few clouds at 5,000 feet
- From Sun 8:00 pm PDT (03:00 UTC): wind from the northeast at 6 knots, visibility more than 6 miles, clear skies
- From Mon 3:00 am PDT (10:00 UTC): wind from the southeast at 4 knots, visibility more than 6 miles, patches of fog, clear skies
- From Mon 9:00 am PDT (16:00 UTC): wind from the south-southeast at 4 knots, visibility more than 6 miles, clear skies
- From Mon 11:00 am PDT (18:00 UTC): wind from the west at 6 knots, visibility more than 6 miles, clear skies
- From Mon 8:00 pm PDT (03:00 UTC): wind from the northwest at 5 knots, visibility more than 6 miles, scattered clouds at 25,000 feet
Temporary flight restrictions on the line or within 25 nm of it
No temporary flight restriction on or near this route right now.
Daylight
Sunset at SEA 6:27 pm PDT (01:27 UTC), at GTF 6:43 pm MDT (00:43 UTC) (civil twilight ends 7:14 pm MDT (01:14 UTC)). At 120 knots the arrival at GTF is after sunset there (6:45 pm MDT (00:45 UTC)).
Each restriction opens the FAA's own page with the exact area, heights and times. Ordinary notices to air missions (closed runways, lights out) are not shown: the FAA's notice search is not open to sites like this one at this time.
Radar and forecast charts for the regions crossed government pictures, the latest each time the page loads
Sources: the Aviation Weather Center's data service (SIGMETs, AIRMETs, graphical AIRMETs, pilot reports, winds and temperatures aloft, observations and terminal forecasts), the National Weather Service radar, the Weather Prediction Center's charts, the FAA's temporary flight restriction list and shapes, and the FAA's airport file for the positions, elevations and magnetic variation. Fetched when the page is viewed and kept a few minutes. Each leg is the straight line between its two airports; airways, terrain and airspace are not considered. The airports in detail: Seattle-Tacoma International, Great Falls International.