go up to 10,000 to 15,000 feet, it is already freezing. Now add
the ocean effect, which acts almost as a cool front with the sea
breeze. With the difference of the land in the 90s, the ocean in
the 80s, the sea breeze, the atmosphere in the 60s and lower,
you start to see this interaction, this instability, kick in. Across
most of the southeast, we have an atmosphere that almost
cries out for a thunderstorm.”
Predictability is a significant difference between the storms
we experience on the coast and what most of the rest of the
country sees. “In the Lowcountry,” Josh continued, “we know
when the conditions for a storm exists, but there is no way
of telling for sure whether rain will fall specifically in lower
Charleston County or on Kiawah or Seabrook. We don’t
have enough detail until the day of the activity. What we
can do is look at certain features in the atmosphere, the air
temperature, how much moisture is present, how much cool
air is aloft. All these variables allow thunderstorms to form.
We can see those conditions several days in advance, but
these air mass thunderstorms cannot be predicted as easily
or accurately as thunderstorms driven by cold fronts. Most
of our storms are ‘pop ups.’”
When asked about the “Kiawah Umbrella,” Josh laughed.
“Mt. Pleasant calls it the Mt. Pleasant Bubble. It’s just the
hit-and-miss nature of pop-up storms. You have to remember
the sea breeze can push inland before anything can really
develop. Over much of June of 2018, we were in a very
humid, tropical pattern. During this period the coasts didn’t
see much daytime rainfall, but it rained after midnight and
into the early morning hours. The reason for that was the sea
breeze helped stabilize the air near the coasts, dislocating the
unstable atmosphere. At night, this sea breeze would retreat
out to the ocean, and our air would become unstable again.
What happens is a called a land breeze, where the wind at the
lower levels of the atmosphere switches direction and heads
back towards the water, which is warmer than the land at that
hour. A boundary sets up just along the coasts, and you get
those pop-up showers and storms overnight.”
As difficult as it is to predict pop-up storms, technology
has improved the situation. Computer modeling has been
enhanced tremendously, and satellite data has become more
refined. “We have a computer model called Triple R (High-
Resolution Rapid Refresh Model, or HRRR-H, known as
‘Triple R’ to meteorologists). It runs about 15 hours out,
and it has such remarkable resolution that you can actually
see these little pop-up storms developing. On the satellite
front, NOAA’s GOES-16 has a 1KM resolution and updates
every minute. It provided us with images from Irma and
Maria beyond anything we could see previously, including
individual elements on the sidewalls. It was quite impressive.”
Our area has seen its share of storms over the past several
years, including the great flood of 2015, Hurricane Matthew,
and Hurricane Irma. These are the big newsworthy storms.
The more typical storms we contend with are almost daily
in nature during the summer. They give much-needed
water to our soil, while they also interrupt golf games and
outdoor activities. They will be with us regularly, whether
meteorologists can predict their exact arrival or not. NK
Editor’s Note: Special thanks to Josh Marthers for his comments
and insights.
Every spring the National Oceanic and Atmospheric
Administration (NOAA) issues their prediction for the
coming hurricane season. When asked how much faith we
should put into these predictions, Josh Marthers cautioned
that the public often misinterprets the numbers. The
public’s perception of the severity of a hurricane season
focuses more on landfall numbers and damage than on
the total number of named storms.
“NOAA’s focus is all about the number of storms, not
whether they will inflict damage. You can have 25 storms
develop in the Atlantic during the season without a single
one making landfall, and that’s considered an active storm
season. The next year if half that number form, but five
of them make landfall, the public thinks of it as an active
season, but by NOAA standards it may not be. The best
Predicting Hurricanes
example is 1992. Hurricane Andrew hit south Florida as
a Cat 5 hurricane, but 1992 is considered an inactive year
for total storms.”
“Overall, I have found NOAA’s predictions to be pretty
good when judged against the right criteria.”
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