Tropical Upper Tropospheric Trough Forming?

GFS ENS Warm Forecast Bias in the West U.S.
07/13/2022, 12:19 pm EDT
Very Warm SSTA and Hot/dry East China Upper Ridge Risk Heading Into August
07/18/2022, 5:18 am EDT
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Highlight: TUTT forming? If so, TC season is delayed.

Fig. 1: Morning satellite view across the North Atlantic basin.

Discussion: A well-defined upper-level LOW has formed over Cuba and is established over most levels of the atmosphere in that zone. An upper-level LOW in this region will be difficult to remove. If the upper-level LOW elongates southwestward with time the configuration of this feature takes-on a trough-like pattern rather than a closed low as we have now. A tropical upper tropospheric trough (TUTT) is a tropical cyclone killer in the tropics due to the increase in attendant westerly shear. The axis of the upper-level shear pattern identifies the troughing pattern already starting to develop.

The developing upper trough which enhances dry air on the back side (Gulf of Mexico region) is the likely cause of a major rainstorm forecast for the northwest Gulf of Mexico earlier this week failing to evolve.