OAT will decrease.
The wind that high is determined more by the temperature gradient than the surface pressure gradient - this is the thermal wind component. You are moving, as fullrich says, from high to low pressure, but aloft low pressure is largely caused by a column of air with low temperature. Constant pressure altitude so fullrich is wrong there; altitude is not affecting temperature, as this is related to pressure not true altitude.
That, at least, is my reading of it. Any Met instructors about?
Send Clowns
Nav & Flt Plng,
BCFT