Long Island Mac Arthur Airport to Montgomery County Airpark ISP → GAI
211 nautical miles (243 statute miles) southwest on a straight line, true course 244°, about 258° magnetic at the departure end (variation 14W). At 120 knots that is 1 h 41 min at the quickest height in today's winds (4,500 ft, a 5-knot tailwind), arriving about 6:41 am EDT (10:41 UTC), after sunset at the destination. Right now ISP is IFR, wind from the northeast (040°) at 11 knots; GAI is IFR, wind variable at 4 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: 2 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 SIERRA 3E: low cloud or poor visibility (IFR conditions) (due to ceilings below 1,000 ft, visibility below 3 miles, precipitation, mist, fog). Over the whole route.
- AIRMET TANGO 3W: moderate turbulence above 18,000 ft from 24,000 ft to 33,000 ft. Over the first 192 nm of the route.
- AIRMET TANGO 3W: moderate turbulence below 18,000 ft (due to mountain wave) up to 6,000 ft. Over the last 10 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 ISP.
Pilot reports along the route within 50 nm of the line, last three hours, the serious ones first
- C560 at 13,000 ft, 13 nm north, 2:38 am EDT (06:38 UTC): moderate turbulence, overcast above 19,000 ft, heavy rain, remarks: during the descent. 125 nm along the route, 13 nm north of the line.
as filed, and in English
PHL UA /OV 20 NW PHL/TM 0638/FL130 /TP C560/SK OVC190/WX +RA/TB MOD/RM DURD
- Report
- a routine report filed through PHL
- Where
- 20 northwest phl
- Time
- 06:38 UTC
- Height
- at 13,000 ft
- Aircraft
- C560
- Sky
- overcast from 19,000 ft
- Weather
- heavy rain
- Turbulence
- moderate
- Remarks
- during the descent
- K35R at 400 ft, 40 nm southeast, 3:45 am EDT (07:45 UTC): overcast above 40,000 ft. 144 nm along the route, 40 nm southeast of the line.
as filed, and in English
DOV UA /OV KDOV /TM 0745 /FL 004 /TP K35R /SK OVC004-TOPUNKN
- Report
- a routine report filed through DOV
- Where
- over KDOV
- Time
- 07:45 UTC
- Height
- at 400 ft
- Aircraft
- K35R
- Sky
- overcast from 400 ft, tops unknown
- B737 at 800 ft, 11 nm southeast, 3:30 am EDT (07:30 UTC): remarks: bases 800 ft. 192 nm along the route, 11 nm southeast of the line.
as filed, and in English
BWI UA /OV BWI/TM 0730/FL008/TP B737/RM BASES 008
- Report
- a routine report filed through BWI
- Where
- over BWI
- Time
- 07:30 UTC
- Height
- at 800 ft
- Aircraft
- B737
- Remarks
- bases 800 ft
Winds aloft along the route, and the time en route the forecast for use 08:00–15:00 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 3 forecast points nearest it (JFK, ACY, RIC). 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 | 350° at 14 kt | −5 kt | 125 kt | 1 h 41 min | 6:41 am EDT (10:41 UTC) | |
| 6,500 ft | 320° at 11 kt | +2 kt | 11 °C | 118 kt | 1 h 47 min | 6:47 am EDT (10:47 UTC) |
| 8,500 ft | 320° at 13 kt | +2 kt | 8 °C | 118 kt | 1 h 47 min | 6:47 am EDT (10:47 UTC) |
| 10,500 ft | 330° at 14 kt | +1 kt | 5 °C | 119 kt | 1 h 46 min | 6:46 am EDT (10:46 UTC) |
| 12,500 ft | 330° at 15 kt | +2 kt | 2 °C | 118 kt | 1 h 47 min | 6:47 am EDT (10:47 UTC) |
| 14,500 ft | 310° at 14 kt | +5 kt | -2 °C | 115 kt | 1 h 50 min | 6:50 am EDT (10:50 UTC) |
| 16,500 ft | 300° at 14 kt | +8 kt | -7 °C | 112 kt | 1 h 53 min | 6:53 am EDT (10:53 UTC) |
| 18,000 ft FL180 | 290° at 15 kt | +10 kt | -10 °C | 110 kt | 1 h 55 min | 6:55 am EDT (10:55 UTC) |
| 24,000 ft FL240 | 250° at 21 kt | +21 kt | -22 °C | 99 kt | 2 h 08 min | 7:08 am EDT (11:08 UTC) |
| 30,000 ft FL300 | 240° at 42 kt | +42 kt | -34 °C | 78 kt | 2 h 42 min | 7:42 am EDT (11:42 UTC) |
| 34,000 ft FL340 | 240° at 47 kt | +47 kt | -40 °C | 73 kt | 2 h 53 min | 7:53 am EDT (11:53 UTC) |
| 39,000 ft FL390 | 240° at 47 kt | +47 kt | -49 °C | 73 kt | 2 h 53 min | 7:53 am EDT (11:53 UTC) |
Based on data from the 12th at 06:00 UTC; valid on the 12th at 12:00 UTC for use 08:00 to 15:00 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| JFK | used from 0 nm out; 10 nm from the line | 020/25 | 290/9 12° | 300/12 7° | 320/14 3° | 290/17 -10° | 240/27 -21° | 240/44 -36° | 240/53 -41° | 240/51 -50° |
| ACY | used from 96 nm out; 47 nm from the line | 350/12 | 340/12 11° | 340/12 6° | 340/13 2° | 270/10 -10° | 240/17 -23° | 230/46 -33° | 230/46 -40° | 240/46 -49° |
| RIC | used from 192 nm out; 106 nm from the line | 350/34 | 340/27 12° | 340/36 8° | 330/31 3° | 310/32 -9° | 320/34 -21° | 300/37 -34° | 290/37 -39° | 290/42 -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 |
|---|---|---|---|---|---|---|---|
| ISP New York, NY | departure | IFR Sky: overcast at 700 feet Weather: mist | from the northeast (040°) at 11 knots | 6 mi | 700 ft | 98 ft | 4:56 am EDT (08:56 UTC) |
| FRG Farmingdale, NY | 19 nm out, 5 nm northeast of the line, tower | IFR Sky: overcast at 700 feet | from the north-northeast (020°) at 11 knots, gusting to 19 | 10+ mi | 700 ft | 81 ft | 08:53 UTC |
| EWR Newark, NJ | 48 nm out, 16 nm north of the line, tower | marginal VFR Sky: a few clouds at 800 feet, a broken layer at 1,100 feet, overcast at 1,600 feet | from the north (010°) at 9 knots | 10+ mi | 1,100 ft | 17 ft | 08:51 UTC |
| PNE Philadelphia, PA | 96 nm out, 2 nm west of the line, tower | IFR Sky: overcast at 900 feet | from the north (010°) at 11 knots | 10+ mi | 900 ft | 119 ft | 08:54 UTC |
| ILG Wilmington, DE | 134 nm out, 8 nm southeast of the line, tower | IFR Sky: a broken layer at 700 feet, overcast at 1,100 feet | from the north (350°) at 11 knots | 9 mi | 700 ft | 79 ft | 08:51 UTC |
| MTN Baltimore, MD | 173 nm out, 9 nm south of the line, tower | marginal VFR Sky: overcast at 1,100 feet Weather: light rain | from the north (350°) at 4 knots | 10+ mi | 1,100 ft | 22 ft | 08:55 UTC |
| GAI Gaithersburg, MD | destination | IFR Sky: overcast at 700 feet Weather: light rain | variable at 4 knots | 10+ mi | 700 ft | 538 ft | 4:56 am EDT (08:56 UTC) |
The highest airport on this list sits at 538 ft; the ground between airports is higher still. Check the sectional chart for the terrain and the minimum safe heights along the line.
At GAI when you get there the forecast at the estimated arrival, 6:41 am EDT (10:41 UTC)
GAI has no terminal forecast; use the nearest airport that does.
The forecast for ISP, the departure
- From Mon 5:00 am EDT (09:00 UTC): wind from the north-northeast at 12 knots, visibility 6 miles, mist, showers nearby, scattered clouds at 400 feet, overcast at 800 feet
- From Mon 8:00 am EDT (12:00 UTC): wind from the north at 12 knots, visibility more than 6 miles, a broken layer at 800 feet, overcast at 1,500 feet
- From Mon 11:00 am EDT (15:00 UTC): wind from the north at 11 knots, visibility more than 6 miles, a broken layer at 2,500 feet
- From Mon 2:00 pm EDT (18:00 UTC): wind from the north-northwest at 8 knots, visibility more than 6 miles, a few clouds at 2,500 feet, scattered clouds at 5,000 feet
- From Mon 10:00 pm EDT (02:00 UTC): wind light and variable, visibility more than 6 miles, a few clouds at 5,000 feet, a few clouds at 15,000 feet
Temporary flight restrictions on the line or within 25 nm of it
- 5/2811 NEW YORK, NY, Monday, October 20, 2025 through Tuesday, October 20, 2026 Local 15 nm from the route, 38 nm along the route · security · until 20 October · ZNY
- 6/8800 Baltimore, MD, Saturday, October 17, 2026 through Sunday, October 18, 2026 UTC 6 nm from the route, 182 nm along the route · drones kept away from a public gathering · starts Saturday 17 October · ZDC
- 4/9383 WASHINGTON, DC., USA 4 nm from the route, at the destination end · security · ZDC
- 6/8600 Sterling, VA, Monday, October 12, 2026 through Monday, October 12, 2026 Local 5 nm from the route, at the destination end · a VIP movement · today · ZDC
Daylight
Sunset at ISP 6:17 pm EDT (22:17 UTC), at GAI 6:34 pm EDT (22:34 UTC) (civil twilight ends 7:01 pm EDT (23:01 UTC)). At 120 knots the arrival at GAI is before sunrise there (7:15 am EDT (11:15 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: Long Island Mac Arthur Airport, Montgomery County Airpark.