TAF question

[troopernflight]

I was looking at this TAF for GMU and noticed the wind shear, 4th/5th lines down. I know the 1st one reads "wind shear, 2000ft/ 150 degrees at 30 kts". My question is, what exactly is that stating that you could encounter? Does it mean that the winds will change direction at 2000 ft from whatever the current winds aloft are to the noted direction and velocity? Is this something you would need to be very concerned about if you were expecting arrival during this time? Thanks.

KGMU 300310Z 3003/3024 05012KT 6SM -RA OVC015
TEMPO 3003/3005 05015G22KT 3SM RA BR BKN008 OVC015
FM300500 05012KT 3SM RA BR OVC008
FM300800 05007KT 3SM RA BR OVC006 WS020/15030KT
... FM301200 07005KT 3SM -SHRA BR OVC007 WS020/16040KT
FM301700 16010KT 3SM -SHRA BR OVC004

 

[Landis]

My understanding is that this is the wind you will encounter while climbing out. For your block indented above (12Z on the 30th) you'll have surface winds at 070 at 5 KTS and wind encountered at 2,000 AGL will be 160 at 40 KTS. If I was arriving I'd expect to be in the higher winds and a shear to decreasing winds at 90 degrees as I descend through 2,000 AGL.

From AviationWeather.gov:

Wind shear is the forecast of non-convective low level winds (up to 2000 feet) and is entered after the sky conditions when wind shear is expected. The forecast includes the height of the wind shear followed by the wind direction and wind speed at the indicated height. Height is given in hundreds of feet AGL up to and including 2,000 feet. Wind shear is encoded with the contraction WS followed by a three-digit height, slant character, and winds at the height indicated in the same format as surface winds. The wind shear element is omitted if not expected to occur.

 

[dustoff17]

I was looking at this TAF for GMU and noticed the wind shear, ............. Is this something you would need to be very concerned about if you were expecting arrival during this time? Thanks.

You should be concerned if you're arrival is around the time of the shear.

If you're on the RWY01 approach, you'll have have to correct for winds 100 degrees off your right (tailwind); maybe while IMC. Then you'll have to adjust your course correction as the winds "lighten" to 40 degrees off the right.

It's not impossible but you should plan for it to be a challenge and for it to be rather bumpy as you transition the shear altitude - (depending on what you're flying).

I wouldn't cancel a flight for this but the more information you have, the better prepared you are for what you're seeing on the approach. Knowing this ahead of time will help you justify the higher ground/approach speed and the correction angle.