Forecasting high temp vs low temp

[yeffy]

Hi john,
Is it more difficult to forecast the low temperature for a given day then the high temperature? I have no scientific proof or database of forecasted vs actual temps, but it seems to me that in general “Weather Men” seem to hit the high forecast more constantly then then the low temp.

 

[jd]

I would say that in general the low temps can be a bit more difficult to forecast for, especially in areas where there is some change in terrain. Overnight lows will be impacted by several things, including: Daytime high temperature the day before, any advection (transport) of warmer or colder air due to winds or fronts, sky cover and winds.

The terrain also plays a big role as cooler air will drain into the lowest of elevations. In fact, the errors you see in overnight lows might just be due to your location. Temps can be as much as 5-10 degrees different on an average night, due only to terrain. So keep in mind that when an overnight low temp is forecasted, it is more of an average for the region and on any given night temps can be 3-5 degrees different, with some nights even more variable.

-John

 

[yeffy]

Thanks John, I love your site!