Quint et al. have produced a nice comparison of low-level jet occurrences and features based on simulations with and without offshore wind farms present. This study is of value to the wind energy community, especially in light of the extensive activity occurring offshore of the United States northeast region. The topic is deeply delved into by the authors, and the accompanying graphics are of high quality. I especially appreciated that the authors performed what validations they could, while acknowledging the limitations imposed by the vertical extent of available observations.

General comments

I have some concerns about the strength of the wording throughout the manuscript as it pertains to making bold physical statements based on simulations. Even the title would imply a well-documented observation-based study of offshore wind farms modifying LLJs instead of a comparison of simulations that lack extensive validation. There is still a lot of value in such a study, I just think care needs to be taken with the messaging.

There are extensive details that the reader must keep track of with not a lot of helpful reminders along the way. The phrase “the WF (wind farm) simulation” is used throughout the text, and it is easy to forget that you’re actually talking about three WF simulations being used to analyze five unique locations. And those five unique locations are reduced to two, with the other three placed in the appendices, but then the Conclusions section again discusses all five. In the Results section, Figure 7 presents five locations and is immediately followed by Table 5, which presents three locations, while most of the text in Section 4 discusses “both locations.” I recommend streamlining by picking the locations of greatest research value to you to focus the bulk of the paper on, and then briefly point to the additional details available in the appendices.

Many interesting findings are presented, but, in some cases, little to no physical suggestion or speculation accompanies the results. For example, the seasonal trends in wind veer reduction from the presence of wind farms presented in Section 4.6.4 are quite pronounced. Can you provide some comments in the text as to why those seasonal trends might exist in the simulations?

Check the intermingling of past versus present tense throughout the text. Lines 119-121 provide an example.

Specific comments

Line 10: It would be of interest to the reader to put some quantification here (percentage) on how many fewer LLJs occur in the wind farm simulations versus the no-wind-farm simulations.

Line 19: Citing BOEM’s website here would provide the reader with knowledge of the status of the lease areas at the time they read the manuscript.

Line 100: The Rosencrans paper does a nice job of discussing the validation, but it would be helpful here to reiterate at least some of the validating findings, particularly those that pertain to bias, in order to set expectations.

Line 102: “The period from 1 September 2019 00:00 UTC to 31 August 2020 23:50 UTC provides a temporal resolution of 10 minutes; we used hourly time steps for our analysis.” Why?

Section 3.1: It would be helpful here to remind readers that there are no consistently agreed upon numerical thresholds to define LLJs. Please consider explaining why you felt the selected LLJ definitions were the best ones for this analysis as opposed to the numerous other options in the literature.

Line 179: The authors should add references to other recent studies that classify modelled LLJs into hits, correct rejections, misses, and false alarms, namely, Hallgren et al. (2020), Kalverla et al. (2020), and Sheridan et al. (2024).

Line 204: Can the authors provide any speculations as to why one location had more LLJs and another had fewer?

Line 224: “Neutral conditions…” Suggest reformatting this sentence to follow the flow of the previous two for improved clarity. “Neutral conditions occur X%, and Y% of LLJs occurred during neutral conditions.”

Figure 12: Cropped at the lower extent

Line 298: This sentence is quite confusing. I think you mean that the trends are similar between ONEcent and southLA throughout the year, except for November and December. But the use of “with the exception of November and December at the southLA location, where the two simulations diverge” could also imply that the NWF and WF simulations are diverging from each other during these two months at this single location. Figure 22 indicates that it is the former assumption, not the latter, but this is another example where clarity is essential.

Line 302: “An extreme LLJ event was observed…” was it observed? Or did it appear in your simulations? If observed, please provide references to the data sources. If simulated, please rephrase the wording in Section 5 to indicate as such.

Line 359: Can you include the distances from the Martha’s Vineyard and Long Island sites from the wind farms alongside the distances between the sites you did analyze and the wind farms, for comparison value?

References:

Hallgren, C., Arnqvist, J., Ivanell, S., Körnich, H., Vakkari, V., and Sahlée, E.: Looking for an Offshore Low-Level Jet Champion among Recent Reanalyses: A Tight Race over the Baltic Sea, Energies, 13, 3670, https://doi.org/10.3390/en13143670, 2020.

Kalverla, P. C., Holtslag, A. A. M., Ronda, R. J., and Steeneveld, G.-J.: Quality of wind characteristics in recent wind atlases over the North Sea, Q. J. Roy. Meteorol. Soc., 146, 1498–1515, https://doi.org/10.1002/qj.3748, 2020.

Sheridan, L. M., Krishnamurthy, R., Gustafson Jr., W. I., Liu, Y., Gaudet, B. J., Bodini, N., Newsom, R. K., and Pekour, M.: Offshore low-level jet observations and model representation using lidar buoy data off the California coast, Wind Energ. Sci., 9, 741–758, https://doi.org/10.5194/wes-9-741-2024, 2024.

The study examines the impact of offshore wind farms on low-level jets (LLJs) along the east coast of the United States using Weather Research and Forecasting model simulations. The results indicate that wind farms reduce the frequency of LLJs and increase their height, with significant implications for regional meteorology.

The study is well-structured and written, and the results are clearly presented. My only concern is the lack of proper LLJ validation of the WRF by observation, as according to the WRF results 'LLJ nose heights' range from 328 m to 474 m and are well above the lidar range. This is addressed by the authors and cannot be resolved with the existing data set. For this reason, more care should be taken with the wording, and it should be made clear that the results are based on simulations, not real observations. For example, the title, passages in the abstract or the summary should be changed and phrased more appropriately.

I have only minor comments, and if these are considered, the study can be a very valuable contribution to the offshore wind energy community.

Specific comments:

Abstract: The abstract of the submitted manuscript does not correspond to the abstract of the revised one. Please clarify.

L.55 What is the Long-Ez aircraft ? Please explained

L. 74 Here you could add also a study about the stability by. Platis et al 2021:

Platis, A., Hundhausen, M., Lampert, A., Emeis, S., & Bange, J. (2021). The role of atmospheric stability and turbulence in offshore wind-farm wakes in the German bight. Boundary-Layer Meteorology, 1-29.

Fig. 4 Why do you see these line structures in the scatter plot? Does the ‘Calculated’ Data have a higher variability compared to RMOL of WRF ?

Sect. 3.4 What is the accuracy of the lidar measurements? Is it well above the 1m/s that you consider to be the LLJ criteria?

L 169 How long did a LLJ Event last? How did you consider this in the data analysis, also regarding Fig. 4 to calculate the percentage of LLJ ? How is the no. of LLJ related to the possible of 8784 hours (Fig.7) ? Please clarify.

Table 6: The sum of the NEbuoy stable, unstable and neutral is 100,1 % . Please correct this (probably a rounding error).

Sect. 4.2 Have you studied the dependency of stability on the wind direction?

Fig. 12 . Why does the overall wind speed around 10 m/s appear to be at hub height 5 % more often than at 230 m ?

Sect. 4.6.4 Why is the wind veer highest in the summer months? Please give an interpretation and/or discussion.

Sect. 5 What wind speeds did the lidar measure? Do they compare the modelled values?