function y=qwat_h(y)
%y=[tair rh p]
x=y(:,1);%air temp, C
rh=y(:,2);%rel hum, percent
p=y(:,3);%press, mb
es=6.112.*exp(17.502.*x./(x+241.0)).*(1.0007+3.46e-6*p);
e=rh/100.*es;
y=e*622./(p-.378*e);