Location - iCyclone.com

ICYCLONE CHASE REPORT
storm
Hurricane ERNESTO
location
Buena Vista, Quintana Roo, Mexico
date
07-08 August 2012
chasers
Josh Morgerman
author
Josh Morgerman
Location
I observed the passage of Hurricane Ernesto in the small town of Buena Vista, Quintana Roo,
Mexico, at 18.882N 88.244W. I rode out the storm at a patio restaurant on the side of Highway 307.
As per NHC advisory positions, this location was ~5 n mi N of Ernesto’s center (at its point of closest
approach)—however, BZE radar indicates it might have been closer.
I arrived at this location at around 9:30 pm CDT 07 August. I remained there during the approach and
passage of Ernesto’s inner core, departing the following morning, many hours after the cyclone passed.
The Chase Map shows my location (red marker) in relation to Ernesto’s center (blue markers), as
per NHC advisory positions. (Chase Map Detail is a closer view.)
Figure 1: Chase Map
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Figure 2: Chase Map Detail
Overview
Ernesto was a tightly-wound, extremely small hurricane—with a sharp pressure signature—that
came and went quickly.
Key observations (all times in this document CDT):
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Destructive winds didn’t last much more than about one hour.
The onset of strong winds was sudden, starting at around 12 midnight (08 Aug).
As the center neared, the air pressure fell as fast as ~0.5 mb/min.
The storm seemed to peak around 12:30 am—which was also the time of the lowest
pressure. (From here, the pressure rapidly recovered.)
Winds started to ease around 1 am, with another short velocity spike between 1:40 and 1:50
am.
The lowest pressure was 975.0 mb, measured at 12:34 am CDT, at which time the storm was reaching
its peak.
The instrument used to collect air-pressure data was a Kestrel 4500. The elevation where I kept the
instrument was ~51 ft, and the barometer was calibrated (for sea-level readings) using that value.
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Comments
Some comments Re: various aspects of the storm:
Dimensions
This was the smallest hurricane I've been in.
As the storm approached my location, strong winds didn't really kick up until the center was maybe 30
or 45 minutes away, and the worst of it was over within 30 minutes of the center's closest approach.
Destructive winds didn't last much more than about one hour at my location.
Looking at the damage afterward, there seemed to be little evidence of a storm once I got halfway up
the highway to Felipe Carrillo Puerto—approximately 20 n mi N of Buena Vista.
Path
Based on radar, the eye was extremely small—only a few miles wide—and the edge of it missed me to
the S by maybe a mile or two. This put me squarely in the intense N eyewall.
Pressure & Gradient
As mentioned above, my lowest pressure was 975.0 mb, measured at 12:34 am CDT.
Judging from the Barogram (below), the gradient was extremely steep. Since the pressure dropped as
fast as ~1 mb/2 min (0.5 mb/min), and the storm was moving ~15 mph at the time, this means the
gradient was probably ~2 mb/mi near the center.
Intensity
Assuming my pressure reading of 975.0 mb is accurate, the central pressure (~5 n mi away away)
would have been a few mb lower (assuming 2 mb/mi, as suggested by my pressure trace). Given this, a
central pressure in the low 970s seems reasonable.
Taking into account other key factors—the extremely small RMW (probably ~5 n mi), strengthening
trend at landfall, spectacular satellite presentation (with a distinct pinhole eye that lasted well inland),
solid eyewall as seen on BZE radar (despite distance and attenuation), and deep-tropical latitude—it
seems reasonable to suspect winds at landfall may have been higher than the operationally
assessed 75 kt.
Impact
It’s always hard to estimate winds, but I believe Ernesto inflicted a strong Cat-1 impact at my location,
which was well inland (~35 n mi from the open coast). It seemed more intense than all of the Cat 1s I've
chased—and even some of the Cat 2s. But that’s of course subjective.
Re: damage to my location… Some parts of the restaurant roof had been torn off and scattered across
the grounds. The metal signpost out front had been bent 45 degrees by strong NE winds. There were
downed wires and branches strewn around, and trees that had been full and lush the night before
looked burnt and wintery—they’d lost lots of foliage. All this having been said, the building was basically
intact.
As mentioned above, the hurricane's impact was quite localized. Heading back up the highway toward
Playa Del Carmen, I saw bent and broken signs within the first few miles, and the palms along the road
in Limones were all bent toward the W, suggesting strong E winds had occurred—but at about the
halfway point between Buena Vista and Felipe Carrillo Puerto, I could no longer see clear evidence of a
hurricane impact.
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Figure 3: iCyclone Location on Radar
Zoomed-in view of BZE radar at 0530Z, as Ernesto’s center was making its closest approach to the
iCyclone location in Buena Vista (marked with red diamond). At this time, Buena Vista was in the N
eyewall, experiencing its lowest pressure and probably strongest winds.
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Figure 4: Barogram
Video Footage
Everything described above can be seen in my 8-minute video summary of the event.
Find it on YouTube (http://youtu.be/8vXU44nXhIw) or on the iCyclone Website
(http://icyclone.com/chases/ernesto-2012.html).
All of the footage is timestamped in local time (CDT).
Questions or Feedback?
Get in touch:
Josh Morgerman
310.866.8400
[email protected]
[email protected]
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Additional Imagery
Roofing material strewn about the grounds of the patio restaurant.
Partially defoliated trees. (They were completely full and lush the night before.)
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Bent metal signpost.
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Additional Imagery (cont’d)
IR images at around the time Ernesto’s center was making its closest approach to Buena Vista
(~12:30 am CDT, or 0530Z). Note the distinct, pinhole eye was apparent hours after landfall.
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Additional Imagery (cont’d)
BZE radar image at around the time Ernesto’s center was making its closest approach to Buena Vista.
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