Hurricane
Ophelia Heads To Ireland
Enormous
consequences of abrupt climate change are coming home to roost. Here
I discuss the latest strangeness in our Climate Casino, namely
Hurricane Ophelia that is making a beeline towards Ireland & the
UK.
Very
high ocean temperatures are allowing hurricanes like Ophelia to move
farther northward and maintain their strength. Slower and wavier jet
streams are stalling hurricanes (Harvey), and huge atmospheric energy
release are causing very large & powerful superstorms (Irma,
Maria). All because of abrupt climate change greatly warming the
Arctic.
Please
support my website and teaching videos with a donation at
http://paulbeckwith.net
Category
2 Hurricane Ophelia Headed Towards the Azores and Ireland
Dr.
Jeff Masters ·
Above: MODIS satellite image of Ophelia on Friday morning, October 13, 2017. At the time, Ophelia was a Category 2 storm with 100 mph winds. Image credit: NASA.
October
13, 2017, 1:28 PM EDT
Category
2 Hurricane Ophelia was headed east-northeast at 12 mph late Friday
morning towards the Azores Islands, and is likely to bring tropical
storm-force winds and heavy rains to the Azores on Saturday, and to
Ireland on Monday. Ophelia continued to look impressive on satellite
imagery on Friday afternoon, with a distinct eye surrounded by a
moderately intense area of heavy thunderstorms. Ophelia had favorable
conditions to maintain hurricane strength, with moderate wind shear
near 15 knots and sea surface temperatures (SSTs) a marginally warm
26°C (79°F)--about 1°C above average for mid-October.
Ophelia’s
impact on the Azores
Ophelia
will become caught in the prevailing westerlies this weekend, which
will accelerate the storm to the east-northeast and then northeast.
Sea surface temperatures will gradually drop and wind shear will rise
on Saturday and Sunday, weakening the storm. However, Ophelia will
begin to derive energy from non-tropical (baroclinic) processes this
weekend, and should be able to maintain Category 1 strength until
Monday, when it is expected to transition into a powerful
post-tropical (mid-latitude) storm with winds of hurricane strength.
On
Ophelia's expected course, the storm will track just south of Santa
Maria, the southeastern-most island of the Azores, on Saturday night.
The 12Z Friday run of the GFS model brings Ophelia within about 60
miles of Santa Maria. This track would put the island on the weaker
left-hand side of Ophelia, where maximum sustained winds of 40 – 50
mph will be likely. In NOAA’s historical hurricane database, which
extends back to 1851, only 11 hurricanes have passed within about 200
miles of the Azores (as noted by weather.com). Every one of those
occurred in August or September—except for strikingly unseasonal
Hurricane Alex, which struck the islands in January 2016 just after
weakening to tropical-storm strength.
Ophelia
wind forecast
Figure
1. Wind forecast from the 0Z Friday run of the European model, valid
at 18Z Monday, October 16, 2017. Sustained tropical storm-force winds
of 65 kph (40 mph) were predicted along much of the southwestern
coast of Ireland.
Ophelia’s
impact on Ireland
Ophelia
is expected to complete the transition to an extratropical storm just
off southwest Ireland on Monday morning. As this process unfolds, the
wind field of Ophelia will expand, and Ophelia promises to be a
damaging wind event for Ireland. Expect widespread tree damage and
uprooted trees, damaged roofs, power blackouts, mobile phone coverage
interruptions, and flying debris. The Irish weather service has
issued a Yellow Alert for Monday.
Winds
will begin to strengthen in Ireland on Monday morning, but the real
impact will be Monday afternoon and evening. Expect sustained
southeasterly winds of 55 – 65 kph (34 – 40 mph) for coastal
southwest Ireland (Munster province) and southeast Ireland (Leinster
province.) Along the south Munster coast (south Cork and south
Waterford), sustained winds of 65 - 75 kph (40 – 46 mph) are
likely, and winds could be higher along exposed headlands and over
the Wicklow Mountains. Up to 2” of rain can be expected over higher
terrain from Ophelia. One concern for Ophelia’s impact on Ireland
may be the potential for the ex-hurricane to develop a “sting jet.”
This is a current of extra-strong jet stream winds that start out
about 3 – 4 km above the surface, then descend over a 3 – 4 hour
period. Rain falling into the jet evaporates and cools, causing the
winds in the sting jet to accelerate as they reach the ground.
Storm
surge
According
to storm surge expert Hal Needham, extra-tropical cyclones sometimes
cause substantial storm surges in high latitudes. For example,
Pacific typhoons have become extra-tropical and generated storm
surges of 12 feet in Western Alaska. Although Ophelia will maintain
hurricane-force wind speeds close to the coast of Ireland, the storm
will be moving with a forward speed near 30 mph on Monday. Such fast
movement will reduce the ability of Ophelia to generate widespread
storm surge. However, we still may see surge impacts where strong
onshore winds blow into inlets or bays.
Hurricane
history of the UK and Ireland
We
don’t often talk about Europe when discussing hurricanes, and
Ophelia is likely to be one of the top ten most notable Atlantic
ex-hurricanes to affect Europe over the past 50 years. Hurricanes
that transition to powerful extratropical storms hit the UK or
Ireland several times per decade, on average. Some recent examples:
The
extratropical version of Hurricane Katia skirted the northern coast
of Scotland on September 12, 2011, two days after transitioning from
a hurricane to an extratropical storm south of Newfoundland, Canada.
According to Wikipedia, a maximum wind gust of 158 km/h (98 mph) was
recorded on Cairn Gorm, Scotland as Katia impacted the region, with a
peak gust of 130 km/h (81 mph) observed at a non-mountain station in
Capel Curig, Wales; these observations marked the strongest impact
from a tropical cyclone since Hurricane Lili in 1996. Waves up to 15
meters (49 ft) battered the western coastline of Ireland, and fallen
power lines temporarily disrupted DART services. Approximately 4,000
households were left without power across the country. A catering
marquee was blown into the air on a set for the television series
Game of Thrones, causing one injury. In County Durham, United
Kingdom, a man was killed after a tree fell on the minivan he was
driving. Damage estimates in the United Kingdom alone topped £100m
($157 million 2011 USD). The remnants of Katia produced damage as far
east as Estonia and Russia. In St. Petersburg, wind gusts up to 45
mph (75 km/h) damaged buildings and left roughly 1,500 residents
without power.
Extratropical
storm Bill of 2009, which hit Ireland on August 25 with sustained
winds of 45 mph, had been a Category 4 hurricane northeast of the
Lesser Antilles five days prior. Bill brought heavy rain and severe
gales to the UK.
Extratropical
Storm Alberto of 2006, which had been a strong tropical storm that
hit the Florida Panhandle, hit northern Ireland and Scotland as an
extratropical storm with 35 mph winds.
Extratropical
Storm Gordon hit Ireland on September 21, 2006, with sustained winds
of 65 mph. Gordon brought record warm temperatures as tropical air
pushed north across the UK, and also strong winds that brought down
power lines in Northern Ireland. Wind gusts to 60 mph (97 km/h)
occurred in the Isles of Scilly off the southwest coast, and 81 mph
(130 km/h) on the mainland.
Extratropical
Storm Helene hit Northwestern Ireland on September 27, 2006, with
sustained winds of 45 mph.
Extratropical
Storm Lili moved across Britain on October 28 – 29, 1996.
Ex-Hurricane Lili brought gusts in excess of 90 mph, and caused
widespread impacts across the UK and significant disruption.
As
we discussed in yesterday’s post, there is officially one fully
tropical hurricane that has hit Europe: Hurricane Debbie of 1961,
which tracked through the western Azores as a Category 1 hurricane,
then arced northeast and brushed the west coast of Ireland on
September 16, also as a Category 1 hurricane. However, there is
evidence that Debbie transitioned from tropical to post-tropical
(extratropical) cyclone before hitting Ireland (see also this
discussion at Irish Weather Online.) Debbie passed close enough to
Ireland to produce major destruction. Wind gusts reached 106 mph at
Ballykelly and 104 mph at Tiree and Snaefill, and coastal radio
stations reported the airwaves were jammed with calls for help from
small ships and fishing craft. Eleven people were killed and 50
injured in the storm. The only other tropical cyclone recorded to
have hit Europe since 1851 was Hurricane Vince of 2005, which hit
southern Spain as a tropical depression on October 11, 2005.
Historical documents also suggest a hurricane hit Spain on October
29, 1842.
Sunday,
October 15, 2017 is the 30th anniversary of one the most talked-about
weather events in UK history, the ‘Great Storm’ of 1987. See the
UK Met Office article on this weather event, whose 100 mph winds
gusts killed 22 people and caused around £1 billion worth of damage.
It has gone down in history as one of the worst UK storms since 1703
and will obviously be remembered for Michael Fish’s now-legendary
television broadcast.
Figure
2. Visible satellite image of 92L as seen on Friday, October 13,
2017. GOES-16 data is considered preliminary and non-operational.
Image credit: NOAA/RAMMB.
92L
east of the Leeward Islands may affect Bermuda next week
A
broad area of low pressure was located about 250 miles east of the
Leeward Islands early Friday morning, and was headed west-northwest
at 15 – 20 mph. This system was designated 92L by the National
Hurricane Center early Friday afternoon, and has the potential to
develop into a tropical depression early next week as it moves
northwards towards Bermuda. No other land areas are likely to be
impacted by 92L, though the storm will bring some heavy rain showers
and gusty winds to the Leeward Islands, Virgin Islands, and Puerto
Rico over the weekend, as it passes to the north.
92L
was under high wind shear of 20 - 25 knots on Friday morning, but had
ocean temperatures warm enough for development: 28°C (82°F).
Relative humidity at mid-levels of the atmosphere as analyzed by the
12Z Friday run of the SHIPS model was favorable for development,
about 65%. Satellite loops showed that 92L had a modest area of heavy
thunderstorms that were poorly organized, though a surface
circulation was attempting to form just west of the area of heaviest
thunderstorms.
Forecast
for 92L
The
0Z Friday runs of our top three models for predicting tropical
cyclone genesis--the European, UKMET and GFS model--had two of them,
the UKMET and European models, forecasting that 92L might develop
into a tropical depression by Tuesday. Approximately 25% of the 70
members of the 0Z GFS and European model ensemble forecast showed
development of 92L. The 12Z Friday run of the SHIPS model predicted
that wind shear would remain high, 20 – 30 knots, over the next
five days, which should keep development slow, and limit the
potential for 92L to become anything more than a weak tropical storm.
In their 2 pm Friday Tropical Weather Outlook, NHC gave 92L 2-day and
5-day odds of development of 10% and 30%, respectively. The most
likely time frame for 92L’s closest approach to Bermuda will be
Monday evening through Tuesday morning.
No comments:
Post a Comment
Note: only a member of this blog may post a comment.