Review of “A quasi-Lagrangian perspective on the role of dry and moist processes in the formation of blocked North Atlantic-European weather regimes” by Hauser et al. (2025)

This study looks at blocking in the North Atlantic-European sector from two different perspectives: an eulerian one, based on a well established weather regimes approach, and a lagrangian one, by tracking anticyclonic potential vorticity anomalies. The work highlights that several paths exist to create blocked regimes and a PV budget approach highlights the contributions of a range of different processes. I enjoyed reading the manuscript and learned a lot from it - I think it would be of interest to Weather andClimate Dynamics readers and the community at large. The manuscript is well reasoned and well written. I only have a few minor suggestions for the authors to consider.  

General comment

The manuscript is well written and well reasoned. However, I found some of the diabatic process links somewhat tenuous at times. Figures 6 and 7 perhaps make this case nicely. However, it is then argued that diabatics are important for retrogressive regimes, when most figures show the reverse.  For example, consider the critical role that moist processes play in retrogression pathways. However, the relevant figures do not always necessarily support that in my view (see 8 and Figure 11 for example). In addition, Figure 9 shows a different perspective from say Figures 6 and 7 on which diabatic processes are perhaps equally as important as boundary and baroclinicity (UP). Perhaps discussing this in some more detail will help to clarify for the reader. 

Specific comment for consideration 

• Line 57-58: Confusing sentence, consider rewording.  
• Lines 127: PVAs already defined above?
• Line 263-265: I know what you mean here but it reads fairly clunkily. Consider rewording this paragraph. 
• Lines 318-320: Where do I see the onset PVAs amplifying to day t+1? I am not sure which result you are referring to here? All amplifications in Figure 6 occur before the onset day. 
• Lines 321-323: DIVdiv is certainly the most positive contribution. But is it positive the entire pre-onset period? How long back do you need to go before it (and DIAG) become neutral? Additionally, DIAG amplifies in the days leading to onset (when the composite comes more into focus) without much movement in DIVdiv? Do diabatic processes explain this accelerated amplification? What are the major contributions to the increases? Can this be quantified? 
• Lines 339-340: Does the amplification of EuBL and AR over the high latitude regimes not also a reflection of their latitude? They would have easy access to low-PV tropospheric air as they are situated close to or the mean jet axis. Is this also related to their size? 
• Figure 7: I found the grey DIAG bar hard to see. Perhaps consider a grey line across the other bars to mark the height of the grey bar.
• Figure 8: I was perhaps surprised that the PV tendencies did not change on each dipole between the upstream and retrogression cases, given that they are both moving opposite directions. 
• Lines 365 - 367: How can two objects merge without increasing the overall size of the merged object? I was confused by this statement. 
• Lines 436 - 447: Would it be valuable to show how the positive and negative contributions of DIVdiv change with time in Figs 7/9? 
• Linked to Figure 11 in Lines 436 - 454, the discussion surrounds the importance of WCB and diabatic heating in retrogression of blocking, linking these statements to current and previous results. It was not clear to me from these results how this was the case. However, several results including Figure 7, 8 and 11 show that diabatic and WCB anticyclonic amplification are much more prominent in progressive regimes.