Tropical Storm Andrea (2025): A Retrospective Analysis of a Short-Lived Central Atlantic Cyclone
Issued by the Office of Senior Meteorological Analysis – Global Tropical Cyclone Review
Origin and Pre-Genesis Environment
Andrea’s roots were entirely non-tropical. Around 0000 UTC 22 June 2025, a weak area of low pressure developed along a decaying stationary front approximately 400 nautical miles east-southeast of Bermuda. The environment at that time featured:
- Moderately warm sea surface temperatures (SSTs) near 26–27°C.
- Low to moderate vertical wind shear (10–15 kt) — initially unfavorable for rapid organization.
- A broad, diffuse mid-level trough aloft providing weak upper-level divergence.
Over the next 24–30 hours, deep convection gradually aggregated near the circulation center. Satellite imagery from GOES-19 revealed episodes of disorganized thunderstorm activity, but the system lacked the persistent, deep convective core needed for immediate classification as a tropical cyclone.
The National Hurricane Center (NHC) first mentioned this disturbance in the Tropical Weather Outlook (TWO) approximately 30 hours before real-time genesis was declared. In post-analysis, however, the best track shifted the formation time earlier by 30 hours — a notable discrepancy highlighting the difficulty of capturing marginal tropical transitions.
Dissipation
After 1200 UTC 24 June, Andrea encountered a sharp increase in vertical wind shear (exceeding 25 kt) as an upper-level trough approached from the northwest. The deep convection rapidly sheared away from the low-level center. By 0000 UTC 25 June, the system had degenerated into a remnant low, and by 0600 UTC 25 June, the circulation had opened into a trough. No tropical storm force winds were observed after 1200 UTC 24 June.
|## Key Metrics Summary
| Parameter | Value |
||
| Storm name | Andrea (AL012025) |
| Basin | North Atlantic |
| Period of tropical cyclone | 23–24 June 2025 |
| Peak wind (1-min sustained) | 35 kt (40 mph / 18 m/s / 64 km/h) |
| Minimum central pressure | 1014 hPa |
| Peak intensity classification | Tropical Storm |
| Landfall | None |
| Direct fatalities | 0 |
| Damages | None reported |
| NHC best track reference | NHC Tropical Cyclone Report (12 Aug 2025) |
Final Assessment
Tropical Storm Andrea (2025) was a pedestrian, short-lived cyclone that neither threatened life nor property. Yet its genesis from a decaying front, its 24-hour plateau at 35 kt, and its compact structure provide rich material for researchers studying the lower end of the tropical cyclone intensity spectrum. The NHC’s post-analysis correction — moving genesis 30 hours earlier than real-time — serves as a reminder that even in the satellite era, borderline tropical systems test the limits of operational detection.
Andrea: small, short, and subtle. A storm that barely was, but was exactly what it needed to be.
Data sourced from: National Hurricane Center Tropical Cyclone Report AL012025 (Cangialosi, 2025); satellite imagery from NOAA/NESDIS/STAR; ASCAT from EUMETSAT/NOAA.