Missoula Montana Airport to Boeing Fld/King County International MSO → BFI
337 nautical miles (387 statute miles) west on a straight line, true course 279°, about 266° magnetic at the departure end (variation 13E). At 120 knots that is 2 h 36 min at the quickest height in today's winds (8,500 ft, a 10-knot tailwind), arriving about 8:29 pm PDT (03:29 UTC), after sunset at the destination. 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: 3 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 first 218 nm of the route.
- AIRMET TANGO 4W: moderate turbulence above 18,000 ft from 18,000 ft to 36,000 ft. Over the first 79 nm of the route.
- AIRMET SIERRA 1E: mountains obscured by cloud (due to mountains obscured by clouds, precipitation, mist). Over the first 139 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 route from 10 to 69 nm out.
- AIRMET TANGO 1W: moderate turbulence above 18,000 ft from 25,000 ft to 39,000 ft. Over the last 0 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 MSO.
Pilot reports along the route within 50 nm of the line, last three hours, the serious ones first
Not fetched just now.
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 westbound cruising heights for this course (VFR: even 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 (GPI, LWS, GEG, YKM, SEA). A plus sign is a headwind, a minus sign a tailwind.
| Height | Average wind | Head- or tailwind | Temperature | Ground speed | Time en route | Arrival |
|---|---|---|---|---|---|---|
| 4,500 ft | 040° at 15 kt | −8 kt | -2 °C | 128 kt | 2 h 38 min | 8:31 pm PDT (03:31 UTC) |
| 6,500 ft | 040° at 16 kt | −9 kt | -2 °C | 129 kt | 2 h 37 min | 8:30 pm PDT (03:30 UTC) |
| 8,500 ft | 040° at 17 kt | −10 kt | -6 °C | 130 kt | 2 h 36 min | 8:29 pm PDT (03:29 UTC) |
| 10,500 ft | 040° at 13 kt | −8 kt | -9 °C | 128 kt | 2 h 38 min | 8:31 pm PDT (03:31 UTC) |
| 12,500 ft | 040° at 8 kt | −5 kt | -12 °C | 125 kt | 2 h 42 min | 8:35 pm PDT (03:35 UTC) |
| 14,500 ft | 040° at 8 kt | −5 kt | -15 °C | 125 kt | 2 h 42 min | 8:35 pm PDT (03:35 UTC) |
| 16,500 ft | 040° at 7 kt | −5 kt | -19 °C | 125 kt | 2 h 42 min | 8:35 pm PDT (03:35 UTC) |
| 18,000 ft FL180 | 040° at 7 kt | −5 kt | -22 °C | 125 kt | 2 h 42 min | 8:35 pm PDT (03:35 UTC) |
| 24,000 ft FL240 | 360° at 10 kt | −1 kt | -29 °C | 121 kt | 2 h 47 min | 8:40 pm PDT (03:40 UTC) |
| 30,000 ft FL300 | 270° at 7 kt | +5 kt | -36 °C | 115 kt | 2 h 56 min | 8:49 pm PDT (03:49 UTC) |
| 34,000 ft FL340 | 270° at 11 kt | +10 kt | -38 °C | 110 kt | 3 h 04 min | 8:57 pm PDT (03:57 UTC) |
| 39,000 ft FL390 | 270° at 14 kt | +13 kt | -41 °C | 107 kt | 3 h 09 min | 9:02 pm PDT (04:02 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| GPI | used from 0 nm out; 82 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° | |
| LWS | used from 50 nm out; 64 nm from the line | 010/5 | 050/14 -2° | 040/12 -6° | 160/7 -10° | 190/30 -22° | 200/54 -27° | 200/48 -35° | 210/40 -37° | 230/32 -41° |
| GEG | used from 99 nm out; 31 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° | |
| YKM | used from 198 nm out; 65 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° |
| SEA | used from 297 nm out; 20 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° |
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 |
|---|---|---|---|---|---|---|---|
| MSO Missoula, MT | departure | no report just now | 3,205 ft | ||||
| GEG Spokane, WA | 149 nm out, 22 nm north of the line, tower | no report just now | 2,385 ft | ||||
| MWH Moses Lake, WA | 218 nm out, 11 nm south of the line, tower | no report just now | 1,188 ft | ||||
| ESW Easton, WA | 287 nm out, 14 nm south of the line | no report just now | 2,226 ft | ||||
| BFI Seattle, WA | destination | no report just now | 21 ft |
The highest airport on this list sits at 3,205 ft; the ground between airports is higher still. Check the sectional chart for the terrain and the minimum safe heights along the line.
At BFI when you get there the forecast at the estimated arrival, 8:29 pm PDT (03:29 UTC)
BFI has no terminal forecast; use the nearest airport that does.
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 MSO 6:54 pm MDT (00:54 UTC), at BFI 6:27 pm PDT (01:27 UTC) (civil twilight ends 6:58 pm PDT (01:58 UTC)). At 120 knots the arrival at BFI is after sunset there (6:29 pm PDT (01:29 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: Missoula Montana Airport, Boeing Fld/King County International.