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Abstract Hurricane Hilary brought extensive, record‐breaking precipitation to the Southwest United States in August 2023. Although tropical cyclones (TCs) are uncommon in this region, they can cause substantial damage, primarily through flooding. However, heat extremes associated with these TCs are understudied and could have significant impacts in populated coastal areas. This study examines the conditions that promoted the occurrence of 42 north‐reaching, northeastern Pacific TCs and quantifies how local temperatures responded to these storms. Using composite analysis, we find that there is significant warming along the coastal region of Southern California preceding a TC, particularly for storms that remain offshore. Three main mechanisms contribute to this warming pattern—adiabatic compression associated with downslope winds, warm air advection by the TC itself, and suppression of coastal upwelling. These compound heatwave‐TC events are an overlooked impact of TCs that will likely become more important as the climate warms.
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Tropical Cyclones’ Contribution to Seasonal Precipitation and Streamflow Over the Southeastern and Southcentral United States
Abstract Studies have quantified the contribution of tropical cyclones (TCs) toward seasonal precipitation, but limited analysis is available on TC contribution toward seasonal streamflow over the southeastern and southcentral (SESC) United States (U.S.). Using an extensive network of hydroclimatic data that consists of 233 TC tracks and daily precipitation and streamflow, we estimate TC contribution toward precipitation and streamflow during the hurricane season over the SESC U.S. We found that TCs account for 12% of seasonal streamflow and 6% of seasonal precipitation over the region. Florida, North Carolina, and Louisiana have the highest fractional occurrence of TC‐generated annual maximum precipitation (∼20%–32%) and streamflow (∼15%–27%). We also found the fractional occurrence of TCs associated with peak‐over threshold precipitation (streamflow) events ranges from 5% to 8% in coastal regions (10%–20% over FL and 5%–10% over coastal NC). Increased antecedent moisture results in increased TCs contribution to streamflow leading to different land‐surface responses for similar hurricane events.
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- Award ID(s):
- 1805293
- PAR ID:
- 10360031
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 48
- Issue:
- 15
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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