Just a quick refresher of what density altitude is.....
Density altitude is defined as the altitude at which a given air density is found in the standard atmosphere. For a given altitude, density altitude changes with changes in pressure, air temperature, and humidity. An increase in pressure increases air density, so it decreases density altitude. An increase in temperature decreases air density, so it increases density altitude. An increase in humidity decreases air density, so it increases density altitude. Changes in pressure and temperature have the greatest effect on density altitude, and changes in humidity have the least effect.
With that information, you can see the effect of a temperature change on the aircraft altitude. Note also that entering a area of T/storms may well give rise to an increase in humidity thus an increase in density altitude.
KW 