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Coastal North Carolina Prepares for Outer Effects of Hurricane Maria
Bob
Henson
5
September, 2017
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Above: Infrared
GOES-16 satellite image of Hurricane Maria at 12:37 pm EDT Monday,
September 25, 2017. GOES-16 images are preliminary and
non-operational. Image credit: NASA/MSFC
Earth Science Branch. |
A
Tropical Storm Warning and Storm Surge Watch were up for much of
North Carolina’s Outer Banks on Monday as a weakening Hurricane
Maria headed
north at 7 mph. A mandatory evacuation was
ordered for
all visitors to Ocracoke Island and Hatteras Island.
Satellite
imagery on
Monday showed that Maria’s inner core had collapsed, and the
heaviest thunderstorm activity was on the east side of the storm,
away from where strong upper-level winds from the west were shearing
it. Maria’s weakening was primarily due to the storm’s passage
over the cool waters churned up by Hurricane Jose last week. The
Hurricane Hunters measured ocean temperatures of 24 - 26°C (75 -
79°F) near Maria’s center on Sunday night, and these
cool waters, combined with moderate wind shear of 15 knots, caused
the hurricane’s eyewall to collapse and the storm’s peak winds to
fall to Category 1 strength, 80 mph. Further weakening is likely, and
Maria is expected to be a strong tropical storm or low-end Category 1
hurricane on Wednesday, when it makes its closest approach to
North Carolina.
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Figure
1. GOES-16
view of large Hurricane Maria (left) and small Hurricane Lee (right) at 10:15 am EDT Monday, September 25, 2017. Image credit: NOAA/RAMMB. GOES-16 imagery is considered preliminary and non-operational. |
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Figure
2. The 11
am Monday NHC forecast for the probability of tropical-storm-force winds for the five days ending at 8 amSaturday, September 30, 2017. The Outer Banks of North Carolina were given about a 50% chance of tropical storm-force winds of 39+ mph, and the Norfolk, Virginia area, about a 20% chance. Image credit: NOAA/NWS/NHC. |
Intensity forecast for Maria
Maria
will continue to move across a region with cool sea surface
temperatures due to the passage of Hurricane Jose, and will continue
to experience moderate wind shear. Our top
intensity models predict that
a slow weakening of Maria will result, with the storm being a
tropical storm or low-end Categroy 1 hurricane with 60 - 75 mph winds
by Wednesdaymorning, when Maria is expected to make its closest
approach to North Carolina.
Track forecast for Maria
The
model forecasts for Maria have not changed much over the past day,
with all of our top models predicting that the hurricane will make
its closest approach to North Carolina on Wednesday, when it
will come within about 150 – 200 miles east of the Outer Banks. The
0Z Monday runs of the GFS model and European model had
fewer than 10% of their ensemble members showing a landfall in North
Carolina, and it is getting close to the time that we can dismiss the
possibility that Maria will make landfall there. By Thursday, a
trough of low pressure passing to the north of Maria will pull the
storm rapidly east-northeastward out to sea.
Tropical
storm-force winds extended about 185 miles to the northwest of
Maria’s center on Monday, and are predicted to maintain that
radius of coverage through Wednesday. Thus, it is likely that
the Outer Banks of North Carolina will experience sustained winds
near 35 - 40 mph on Wednesday, and about 1 – 2” of rain. The
counter-clockwise circulation of Maria, combined with its slow
motion, will be capable of driving a storm surge of 2 – 4’ to the
coast about 50 miles on either side of Cape Hatteras, North Carolina.
This may flood the only road into or out of the Outer Banks, NC 12,
and the potential severing of this lifeline to the islands
necessitated the evacuation order for Okracoke Island and visitors to
the Outer Banks. Last week, waves and storm surge from Hurricane Jose
washed over the road and damaged the dunes protecting it.
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Figure
3. Views
of Puerto Rico and the Virgin Islands at night, before and after Hurricane Maria, from the day-night band of the VIIRS instrument on the Suomi satellite. Power restoration has a long way to go in the wake of the hurricane. Image credit: NASA. |
Puerto Rico radar destroyed by Hurricane Maria
The
U.S. territory of Puerto Rico continues
to grapple with destruction, dislocation, and suffering in
the aftermath of Hurricane Maria, with the power grid still decimated
and water and cellphone service both scarce. “The devastation in
Puerto Rico has set us back nearly 20 to 30 years,” said Puerto
Rico’s nonvoting representative in Congress, Jenniffer
Gonzalez.
The damage assessment extends to the world of meteorology, as new
photos on Sunday revealed. Both the radar dish and the surrounding
radome were scoured clean from the pedestal of the National Weather
Service’s TJUA radar. Winds of 145 mph were measured before the
radar went down, according
to weather.com’s Jonathan Belles.
What a NWS radar normally looks like from the exterior, versus @NWSSanJuan radar now after Hurricane #Maria.
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Figure
4.
Hurricane Lee at 9:45 am EDT Monday, September 25, 2017. Image credit: NOAA/NESDIS. |
Lonesome Lee could become a bit stronger this week
Far
out in the central North Atlantic, almost 900 miles east of
Bermuda, Hurricane
Lee isn’t
bothering any land areas, though it’s steadily adding to this
season’s already-hefty pileup of accumulated cyclone energy (ACE).
Let’s keep in mind that if the definition of ACE took into account
storm size as well as peak winds, Lee wouldn’t be contributing
much. Its tropical-storm-force winds extended no more than 35 miles
from its center as of Monday morning, and hurricane-force winds
extended out a mere 10 miles. However, Lee’s top winds were holding
near 90 mph at 11
am Monday,
which kept it a high-end Category 1 storm. As is typical of small,
higher-latitude hurricanes, Lee has a distinct eye embedded in
lower-topped showers and thunderstorms, a result of its relatively
cool atmospheric environment.
Lee
remains in a supportive regime for growth, and its tiny size will
allow for potentially rapid, hard-to-predict shifts in strength.
Vertical wind shear will remain on the light to moderate side—around
10 knots—through Wednesday, as Lee drifts mainly westward over SSTs
of 27-28°C (81-82°F), close to 1°C above average. The main
impediments to Lee’s strength through midweek are its poky motion,
which is allowing cooler water to be churned up, and intrusions of
dry air (mid-level relative humidity this week will be around 40 –
50% in Lee’s environment). If Lee can overcome these threats, it
could surge to Category 2 strength in short order. The 06Z Monday run
of our top intensity model, HWRF, has Lee peaking as a low-end Cat 2.
Later in the week, wind shear will increase, and Lee is expected to
accelerate northeast over cooler water.
Is this fall at all? Heat records dropping faster than leaves in the Midwest and Northeast
Large
swaths of the U.S. Midwest and Northeast, along with southeast
Canada, continued to bake on Monday in some of the region’s highest
temperatures ever recorded after the autumnal equinox. The heat is a
product of the same sprawling zone of upper-level high pressure
that’s slowed the northward treks of Hurricanes Jose and Maria.
Meanwhile, it’s been quite chilly across the western U.S., but
continent-wide, there have been far more heat records than cold
records. One reason: a cloudy, chilly air mass can easily keep
daytime highs 20°F or more below average in the arid West, but it’s
more difficult to push early-autumn temperatures 20°F or more above
average in the more temperate East. Moreover, the clouds and moisture
out West have tended to keep nighttime temperatures from plummeting,
whereas rich atmospheric moisture has kept nighttime lows back East
close to summertime levels.
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Figure
5. Temperature
departures from average (in degrees Celsius) at 2 pm EDT Sunday,
September 24, 2017, as analyzed by the GFS model. Parts of the
U.S. Midwest and Northeast and adjacent Canada were running 12 –
20°C (22 – 38°F) above average, while parts of the Rocky
Mountains and Great Basin were 12 – 20°C (22 – 38°F) below
average. The most impressive records associated with this pattern
have been heat records, though. |
Traverse
City, MI, had
a trio of 95°F highs on Fri, Sat, and Sun. These are the first-ever
days topping 90°F during astronomical autumn in Traverse City, where
records go back to 1896. Several other locations in upper Michigan
also set records for early-autumn heat on each day Friday through
Sunday, including Sault Ste. Marie (87°F, 90°F, 89°F; records
begin 1888) and Gaylord (88°F, 87°F, 89°F; records begin 1893). At
Houghton Lake, the streak of record highs goes back to Thursday
(88°F, 92°F, 91°F, 91°F; records begin 1913).
Madison, WI, set daily records on Wed (91°F), Fri (91°F), Sat (92°F), and Sun (89°F). Milwaukee saw its warmest high (95°F on Friday) and warmest low (73°F on Saturday) ever recorded during autumn, in records going back to 1871.
Madison, WI, set daily records on Wed (91°F), Fri (91°F), Sat (92°F), and Sun (89°F). Milwaukee saw its warmest high (95°F on Friday) and warmest low (73°F on Saturday) ever recorded during autumn, in records going back to 1871.
Burlington,
VT, hit
91°F on Sunday, the hottest reading ever observed so late in the
year by a full 6°F. Burlington's records go back to 1883. In Maine,
Caribou (85°F) and Houlton (87°F) had their warmest readings so
late in the year on Sunday. Records go back to 1939 in Caribou and
1849 in Houlton.
In
Canada’s largest city—Toronto,
Ontario, where
weather records go all the way back to 1840—Sunday was the hottest
day ever notched after the autumnal equinox, with a sweltering high
of 33.6°C (92.5°F). This compares to an average high for the date
of 19.0°C (66.2°F). Sunday was also Toronto’s hottest day of the
entire year (so far).
The
chilly pattern in the West produced only a few scattered record lows,
but there was an impressive three-day cluster of record-cold highs
around Utah’s Wasatch Range. Provo,
UT (Brigham
Young University) had a daytime high of just 42°F on Sunday, which
was its coldest day ever notched during September in records going
back to 1916. Spanish
Fork, UT, also
set a monthly record for coldest daily maximum, with 43°F (records
begin in 1909).
Alta,
UT, got
a head start on ski weather, with 3.4” of snow on Friday, 3” on
Saturday, and 11” on Sunday along with daily highs of 34°F, 35°F,
and 31°F on Friday, Saturday, and Sunday. Sunday was the earliest
day in autumn that Alta has remained below freezing in records going
back to 1906.
September 24th with an older TWC umbrella @Snowbird via my friend Jodi Saeland
Dr.
Jeff Masters co-wrote this post.
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