"Have
we already arrived at the time of perpetual storms?"
--Kevin
Hester
JOSE
UPDATE/HURRICANE WATCHES/LEEWARD ISLANDS
BPEarthWatch
Dangerous
TD 15 headed for Eastern Caribbean; Hurricane Jose Headed Towards New
England
Dr.
Jeff Masters ·
Above: MODIS view of Potential Tropical Cyclone 15 (later to become TD 15) on Saturday morning, September 16, 2017. Image credit: NASA.
September
16, 2017, 11:46 AM EDT
Tropical
Depression Fifteen formed on Saturday afternoon in the waters east of
the Lesser Antillies Islands, and tropical storm watches were hoisted
for the islands of St. Lucia, Martinique, Guadeloupe, Barbados, St.
Vincent and the Grenadines, and Dominica. TD 15 has the potential to
be a hurricane by the time it passes through the Lesser Antilles
Islands on Tuesday morning.
TD
15 had very favorable conditions for development on Saturday
afternoon. Wind shear was light, 5 - 10 knots, SSTs were a very warm
29 – 29.5°C (84 - 85°F), and relative humidity at mid-levels of
the atmosphere (as analyzed by the 12Z Saturday run of the SHIPS
model) was moderately moist--about 60%. Satellite loops showed that
TD 15 had a good deal of spin, and heavy thunderstorm activity was
steadily increasing and growing more organized, with several curved
low-level spiral bands forming. The first hurricane hunter aircraft
is scheduled to investigate TD 15 on Sunday afternoon.
PTC
15 forecast
Figure
1. The 20 track forecasts for TD 15 (formerly Invest 96L) from the 0Z
Saturday, September 16, 2017 GFS model ensemble forecast. Image
credit: CFAN.
PTC
15 forecast
Figure
2. The 50 track forecasts for TD 15 (formerly Invest 96L) from the 0Z
Saturday, September 16, 2017 European model ensemble forecast. The
operational European model for TD 15 is the red line, adjusted by
CFAN using a proprietary technique that accounts for storm movement
since 0Z Saturday. The track of the average of the 50 members of the
European model ensemble is the heavy black line. Image credit: CFAN.
Track
forecast for TD 15
The
model forecasts on Saturday morning were in better agreement than on
Friday, predicting that TD 15 would be steered west-northwest at
speeds ranging from 10 – 20 mph through Thursday, bringing the
storm through the Lesser Antilles Islands on Tuesday morning, to the
vicinity of the Virgin Islands and Puerto Rico by Wednesday morning,
and near the Dominican Republic by Thursday morning. Beyond Thursday,
the path of TD 15 will depend, in part, upon what Jose is up to. If
Jose is still wandering off the U.S. New England coast, this will
create a weakness in the ridge of high pressure steering TD 15 to the
west-northwest, and TD 15 will turn more toward the northwest or
north-northwest. If Jose is out of the picture, the ridge could keep
TD 15 rolling west-northwestward. In either case, it is possible that
TD 15 will approach the U.S. East Coast more than a week from now. A
strong autumn-like upper-level trough will be moving across the
western and central U.S. late in the week. This will tend to pump up
a ridge toward the northeast U.S. and northwest Atlantic, which could
end up blocking TD 15 from moving out to sea.
Intensity
forecast for TD 15
The
12Z Saturday run of the SHIPS model predicted that TD 15 would have
very favorable conditions for development over the next five days.
Wind shear will be low, TD 15 will have very warm SSTs near 29.5°C
(85°F), and there will be moist conditions at mid-levels of the
atmosphere. These conditions should allow for strengthening of TD 15.
On Saturday morning, our top intensity models—the HWRF, COAMPS-TC,
DSHIPS, LGEM, and HMON—all predicted steady intensification of TD
15 into a hurricane by Tuesday, when the storm is expected to be
moving through the Lesser Antilles. Further strengthening is likely
through Thursday, until TD 15 potentially gets disrupted by passage
over Puerto Rico and/or Hispaniola. Note that the official NHC
forecast of a Category 1 hurricane on Tuesday and Wednesday is
conservative; the 12Z Saturday runs of the HWRF and HMON models show
TD 15 attaining Category 3 hurricane status by Tuesday afternoon.
That may be too aggressive, but I would not be surprised to see TD 15
become a major hurricane by Wednesday, given how Hurricane Irma
exploded into a major hurricane under similar conditions and in a
similar location. The next name on the list of Atlantic storms is
Maria.
 |
Jose
Figure
3. GOES-16 view of Hurricane Jose at 11 am EDT September 16, 2017.
Image credit: NOAA/RAMMB. GOES-16 data is considered preliminary and
non-operational.
Hurricane
Jose headed towards New England
Hurricane
Jose was headed northwest at 9 mph towards North Carolina on Saturday
morning, but is expected to turn to the north by Saturday night and
pass several hundred miles east of the North Carolina coast on
Monday. Jose's tropical storm-force winds cover a large area of
ocean, extending out 150 miles to the northeast of the center. This
wind field is expected to expand to 160 miles to the northeast of
Jose’s center on Monday, then 230 miles on Tuesday. These winds are
generating large swells that are bringing rough surf and the risk of
rip currents to Bermuda, The Bahamas, the northern coasts of
Hispaniola and Puerto Rico, and the U.S. east coast. Jose may bring
up to 1” of rain to North Carolina’s Outer Banks on Monday, and
heavier rains of 2 – 4” to Eastern Massachusetts beginning on
Tuesday. The U.S. coast from Long Island, New York to Maine is at the
edge of Jose’s 5-day cone of uncertainty.
Satellite
images on Saturday morning showed that Jose had plenty of intense
heavy thunderstorm activity that was well-organized, with a hint of
an eye. The storm was less developed on its northwest side, where
strong upper-level winds out of the west-northwest were tearing into
the hurricane. An Air Force hurricane hunter aircraft will
investigate Jose on Saturday afternoon.
Track
forecast for Jose
A
high-pressure system to the northeast of Jose will steer the storm
mostly to the north over the remainder of the weekend, putting Jose a
few hundred miles east of North Carolina’s Outer Banks on Monday.
In their 11 am Saturday Wind Probability Forecast, NHC gave Cape
Hatteras, North Carolina a 28% chance of seeing tropical storm-force
winds from Jose. Jose is then expected to turn to the east-northeast
and pass close to the coast of southeast Massachusetts on Wednesday.
NHC gave Nantucket, Massachusetts a 50% chance of seeing tropical
storm-force winds from Jose by Thursday morning. The large waves from
the storm will be capable of causing high surf and considerable beach
erosion along the shores of the mid-Atlantic and New England coasts
during this period. Jose’s fate beyond Wednesday is coming into
better focus, with the Saturday morning runs of the GFS and European
models predicting that a trough of low pressure passing to Jose’s
north continue to pull Jose to the east-northeast, out to sea.
However, it is still possible that the trough of low pressure passing
to Jose’s north will not be strong enough to do this, leaving Jose
wandering in an area of weak steering currents a few hundred miles
southeast of Massachusetts late in the week. This was the solution of
the 0Z Saturday run of the UKMET model.
Jose
forecast
Figure
4. The 20 track forecasts for Jose from the 0Z Saturday, September
16, 2017 GFS model ensemble forecast. Jose is a potential landfall
threat along the coast from Long Island, New York to Southeast
Massachusetts, according to these forecasts. Image credit: CFAN.
Jose
forecast
Figure
5. The 0Z Saturday September 16, 2017, track forecast by the
operational European model for Jose (red line, adjusted by CFAN using
a proprietary technique that accounts for storm movement since 0Z
Saturday), along with the track of the average of the 50 members of
the European model ensemble (heavy black line), and the track
forecasts from all 50 members of the ensemble. The European model
ensembles show less of a threat to New England than the GFS model
ensembles. Image credit: CFAN.
Intensity
forecast for Jose
Jose
was under high wind shear of 20 – 25 knots Saturday morning. But
with sea surface temperatures (SSTs) near 29.5°C (85°F), Jose
should be able to maintain hurricane status though Sunday morning.
Higher wind shear of 30 – 35 knots is expected to affect Jose on
Sunday and Monday, which should cause weakening, perhaps to a strong
tropical storm with 70 mph winds, by Wednesday. Wind shear will
likely fall to the moderate range again on Tuesday and Wednesday, but
the waters beneath Jose will be steadily cooler as the storm heads
north, discouraging any strengthening. SSTs are about 28°C (82°F) a
few hundred miles off the coast of North Carolina, where Jose will be
on Monday. Once Jose moves north of about 37°N (the latitude of
Washington D.C.), the storm will be beyond the warm waters of the
Gulf Stream, making it difficult for Jose to intensify. Water
temperatures within about 400 miles of the coast, from New Jersey to
Maine, are generally below 26°C (79°F). Most of the intensity
models show Jose as a strong tropical storm with 60 – 70 mph winds
throughout its closest approach to the New England coast, Tuesday and
Wednesday.
 |
Lee
Figure
6. Visible image of Lee at 10:45 am EDT Saturday, September 16,
2017. Image credit: NOAA/NESDIS.
TD
14 develops into Tropical Storm Lee, but not expected to be a threat
TD
14 developed into Tropical Storm Lee at 11 am EDT Saturday, becoming
the 12th named storm of this ferociously active Atlantic hurricane
season. We are just 5 days past the climatological mid-point of the
Atlantic hurricane season, and have already had a full season’s
worth of activity: 12 named storms, 6 hurricanes, and 3 intense
hurricanes. An average season has 11 named storms, 6 hurricanes, and
2 intense hurricanes by the end of November.
Lee
is expected to continue rolling westward at about 12 mph on Saturday,
with a gradual turn toward the west-northwest by Monday. Our top
track models agree that an upper-level trough should pull Lee
northwestward long before it has a chance to reach the Lesser
Antilles, and high wind shear from strong upper-level winds
associated with this trough should be able to destroy Lee by
Thursday. Lee is not expected to be a threat to any land areas.
Bob
Henson contributed to this post.
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