Observations of mid-level moisture/RH in NUCAPS vs GFS...

Hi all!  Kris and Nadia here! 

So, we were looking to see how NUCAPS handled mid-level moisture in a pass today compared with a numerical weather model field...in this case, the GFS model.  The images are below.  Notice, there certainly is good overall agreement in the data (700-500 mb RH values). 

Image 1.  GFS 700-500 mb RH (left) and NUCAPS gridded 700-500 mb RH (right) at approx. 18Z 8 May 2018

Notice the plume of relatively dry mid-level air that extends northward from the Gulf of Mexico, across the TN/OH Valley regions and eventually into the Great Lakes region and the NE.  Next, I zoomed into a region with a relatively tight gradient of mid-level moisture in the mid-Miss Valley (Image 2). 

Image 2.  GFS 700-500 mb RH (left) and NUCAPS gridded 700-500 mb RH (right) at approx. 18Z 8 May 2018, same as above, but zoomed in over the mid-Mississippi Valley region

In Image 2, the NUCAPS indicates a tighter gradient in mid-level moisture especially in parts of southern Missouri.  I think these tighter gradients contained within the NUCAPS data may be important, and it makes sense that the observational data would show stronger gradients.  This type of observation can help the forecaster to adjust their mental or conceptual models of the atmosphere.  These gradients in the mid-levels can be important, but of course, they are much more important generally in the lower-levels of the troposphere.

That'll be next...

Kris W. and Nadia S.