Wind Shear on TAF
 

I am told that this TAF from last week indicates that, from 0000Z, there will be wind shear occurring at 2,000 with the wind forecast to be 160 at 50 knots. Presuming this is correct, is this 2,000 MSL or 2,000 AGL (I know it wouldn't matter at Kennedy). Also, I'm curious how they forecast wind shear that is expected to occur 17 hours out--and at 2,000? Thanks.

KJFK 300709Z 3007/0112 13005KT P6SM BKN008 FM301000 10008KT 5SM -SHRA BR OVC008 FM301200 10010KT 2SM RA BR BKN008 OVC015 FM301400 12013G22KT 2SM RA BR BKN008 OVC015 WS020/18040KT FM301900 13025G35KT 1SM RA BR OVC005CB WS020/17050KT FM010000 15024G35KT 1SM RA BR OVC004 WS020/16050KT FM010700 12015G25KT 3SM -RA BR OVC008

All details in a metar or taf involving vertical measurements are given in height, AGL in other words.
Met offices are getting smarter by the days, they calculate weather phenomena very accurate these days, given a basic wx situation (wind and velocity) they calculate the CBs position and moving direction, they calculate the base and soon you have the forecast as you see here for yourself.
Looking at the date it may fit actually into the seasonal wx condition, something serious which came up the Atlantic, not unusual.

Watch CNN or other wx broadcaster, their mathematical models are very precise about these occurrences.

Hi cf6-80c2b5f,

The MET forecaster have a pretty good idea about the expected ISO Bar pressure gradient with the passage of fronts etc. They can guesstimate the geostrophic wind speed at 1,000 m agl (3300ft) from the expected pressure gradient. The surface wind will be slowed down by friction, so there will be wind shear between the two levels and 2,000 feet is approximately half way between the two.

Thanks to both of you for the replies. Good thing they weren't using the Canarsie VOR to RW 13R that day.