Q&A – Should Andrea Have Been Declared a Tropical Storm? – Driven By Braman Motorcars
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Today’s Entry: @brianmuddradio You sounded skeptical about Andrea. I'm interested to see what you have to say about it.
Bottom Line: What you detected earlier in the week from me was indeed skepticism regarding the naming of the extremely short-lived Tropical Storm Andrea. And not necessarily the decision by the National Hurricane Center to declare Andrea a tropical storm, but rather the timing of it. That’s for one very specific reason. The system in the northern Atlantic was not a tropical storm at the time it was declared. If that sounds like an oxymoron, because after all it isn’t it a judgement call by the Hurricane Center’s meteorologists as to when there’s named tropical storm? The answer is in name only.
As always there are two sides to stories and one side to facts, and the fact of the matter is that there are defined characteristics outlined by the National Weather Service for Tropical Depressions, Tropical Storms, Hurricanes and Major Hurricanes. They also have definitions for what are characterized as Tropical Waves, Tropical Disturbances, Tropical Cyclones, Potential Tropical Cyclones, Invest, Extratropical Cyclones, Post-Tropical Cyclones, Remnant Lows and Subtropical Cyclones. My point in mentioning all of what’s defined by the National Weather Service, is that weather characterizations aren’t subjective – they're extensively defined. For the purpose of this conversation, we’re talking about what qualifies as a Tropical Cyclone, defined as a Tropical Storm.
The definition of a Tropical Cyclone is:
- A warm-core non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center. Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temperature and heat export at the low temperatures of the upper troposphere. In this they differ from extratropical cyclones, which derive their energy from horizontal temperature contrasts in the atmosphere (baroclinic effects).
And Tropical Storm status is defined as:
- A tropical cyclone that has maximum sustained surface winds ranging from 39-73 mph (34 to 63 knots).
So again, the term tropical storm is a precise thing...this is science after all! So that takes us to the dynamic in play with Tropical Storm Andrea. The system in the north Atlantic wasn’t a tropical storm at the time the National Hurricane Center declared it to be a tropical storm. Specifically, at the time it was declared to be a tropical storm it failed to meet this standard: a closed surface wind circulation about a well-defined center (here’s a link of the radar to see for yourself). It’s inarguable. The rotation is clear, the convection is there, there were 40 mph winds, but a closed wind surface and well-defined center did not exist when the National Hurricane Center named Andrea.
Now, interestingly, you could have made the case up to two days prior that it did achieve one if ever-so-briefly. And that’s what’s in part confounding this system. Why, did the NHC wait until the system was less organized, and basically in the process of falling apart, to name this storm?
What I believe you will see happen is an eventual revision of the timing of this system. Do you remember the 2023 hurricane season when the National Hurricane Center, in late spring, came back and said that a subtropical storm had formed in January making it the first system of the season? A revision like that will almost certainly take place with Andrea to where they backdate when the tropical storm actually formed.
And on that note, this is where my semi-frustration comes into play. Unlike the subtropical January thing of a couple of years ago, you had a team of meteorologists watching this around the clock. It was such a borderline case that when it was at its apex – the forecaster(s) didn’t believe in that moment it met the requirements to be tropical storm but then later assessed it to be. That’s what didn’t/doesn’t sit well with me. It’s especially frustrating to me because A) Facts matter and should be the only thing that matters with forecasting at the NHC. B) I greatly respect the meteorologists at the NWS/NHC - they are on balance the best in the world at what they do.
The NHC is no place for agendas and the Andrea decision may not have been agenda driven, but the underlying facts of this situation do invite questions. One that probably only I will ask because it’s a career risk for any meteorologist to question the NWX/NHC. Andrea may well have technically classified it as a tropical storm for a hot minute or two, but if it did, it was not when they declared it to be.