Hurricane Harvey

star gazer · 25-08-2017 10:42am #1

Hurricane Harvey looks set to be the first Major Hurricane to make landfall in the United States in over a decade and one of the most worrying aspects of it is the forecast for Harvey not to move very far for days after making that landfall, meaning a lot of rain will fall over a large section of the Texas coastal area for an extended period. 400mm to 650mm of rain could fall in a large area of the Texas coast and up to 900mm in isolated parts with storm surges of 1 to 3.5 meters. At the moment Minimum Central Pressure is 967mb with max sustained winds of 165km/h 105mph making it a Category two Hurricane. It is due to strengthen to a Category 3 Major Hurricane today and make landfall some time late Friday local time. Houston is forecast to get huge rainfall with actual landfall likely to be made somewhere near Corpus Christi.
NHC advisory 20 Wunderground

A report from the weather channel warning that it's the water (storm surge and rainfall flooding) that causes the most fatalities in these natural disasters:
https://twitter.com/weatherchannel/status/900838671775133696
The first rain bands are affecting land already. Donegal saw what can happen with a large amount of rain in a short space of time, Such a large amount of rain over an extended period will be an enormous test of communities and of their emergency response services.

ronnie3585 · 25-08-2017 4:06pm

Strong words from the NHC, looks like this could be devastating;

At 1000 AM CDT (1500 UTC), the eye of Hurricane Harvey was located
by an Air Force Reserve Hurricane Hunter aircraft and NOAA Doppler
radar near latitude 26.7 North, longitude 96.0 West. Harvey is
moving toward the northwest near 10 mph (17 km/h), but its forward
speed is expected to decrease significantly during the next couple
of days. On the forecast track, Harvey will make landfall on the
middle Texas coast tonight or early Saturday. Harvey is then likely
to meander near or just inland of the middle Texas coast through the
weekend.

Maximum sustained winds are near 110 mph (175 km/h) with higher
gusts. Some strengthening is possible, and Harvey is forecast to
become a major hurricane before it reaches the middle Texas coast.

Hurricane-force winds extend outward up to 35 miles (55 km) from the
center, and tropical-storm-force winds extend outward up to 140
miles (220 km). A buoy located about 40 miles east of South Padre
Island recently reported sustained winds of 42 mph (68 km/h) and a
gust to 54 mph (86 km/h).

The minimum central pressure based on data from the Air Force plane
is 947 mb (27.97 inches).

HAZARDS AFFECTING LAND
RAINFALL: Harvey is expected to produce total rain accumulations
of 15 to 25 inches and isolated maximum amounts of 35 inches over
the middle and upper Texas coast through next Wednesday. During
the same time period Harvey is expected to produce total rain
accumulations of 5 to 15 inches in far south Texas and the Texas
Hill Country over through southwest and central Louisiana. Rainfall
of this magnitude will cause catastrophic and life-threatening
flooding.

STORM SURGE: The combination of a dangerous storm surge and the
tide will cause normally dry areas near the coast to be flooded by
rising waters moving inland from the shoreline. The water is
expected to reach the following heights above ground if the peak
surge occurs at the time of high tide...

N Entrance Padre Island Natl Seashore to Sargent...6 to 12 ft
Sargent to Jamaica Beach...5 to 8 ft
Port Mansfield to N Entrance Padre Island Natl Seashore...5 to 7 ft
Jamaica Beach to High Island...2 to 4 ft
Mouth of the Rio Grande to Port Mansfield...2 to 4 ft
High Island to Morgan City...1 to 3 ft

The deepest water will occur along the immediate coast near and to
the northeast of the landfall location, where the surge will be
accompanied by large and destructive waves. Surge-related flooding
depends on the relative timing of the surge and the tidal cycle, and
can vary greatly over short distances. For information specific to
your area, please see products issued by your local National Weather
Service forecast office.

WIND: All last-minute preparations should be rushed to completion
since tropical storm conditions are likely just beginning in
portions of the hurricane and tropical storm warning areas.
Hurricane conditions are likely to begin within the hurricane
warning area later today or tonight. Tropical storm conditions are
likely to persist along portions of the coast through at least
Sunday.

SURF: Swells generated by Harvey are affecting the Texas,
Louisiana, and northeast Mexico coasts. These swells are likely to
cause life-threatening surf and rip current conditions. Please
consult products from your local weather office.

TORNADOES: A few tornadoes are possible later today through
Saturday near the middle and upper Texas coast.

M.T. Cranium · 25-08-2017 6:16pm

Track the eye ...

https://radar.weather.gov/radar.php?rid=crp&product=NCR&overlay=11101111&loop=no

Itssoeasy · 25-08-2017 8:28pm

The hurricane has strengthened to a category 3 one. And having watched the mayor of corpus Christi earlier and the governor of Texas, it's clear they are worried.

star gazer · 25-08-2017 8:31pm

"Catastrophic flooding" seems the best quick sum up of this, though there are other dangers.
It's been upgraded to a Major Hurricane, Category 3, 195km/h, 120mph, min central pressure down to 943mb.
The storm surge has begun near Corpus Christy. Potential storm surge map.
Tornado warnings going out.
I haven't seen similar Hurricanes talked about that lingered as long as Harvey is forecast to, does anyone know of any like that historicaly?

dfx- · 25-08-2017 8:33pm

Doesn't a European model have it stalling, then coming back out into the Gulf and restrengthening before a final move NE?

Rock Lesnar · 25-08-2017 8:36pm

Watching CNN at the minute, its completely mad that people would still stay and try stick it out considering the warnings about how bad its gonna be

Rock Lesnar · 25-08-2017 8:43pm

Upto to 36 and possibly more inches of Rain forecast :eek:

Akrasia · 25-08-2017 8:45pm

I heard some officials telling people to leave, that they should go visit friends or family, or just head to higher ground.

It's possible there are lots of people who don't have anywhere to go and no way of getting there.

I hope they have shelters and transport for people to get out of the path of this storm. They probably do for the mandatory evacuations, but what about those places where it's voluntary but strongly advised?

star gazer · 25-08-2017 8:58pm

dfx- wrote: »

Doesn't a European model have it stalling, then coming back out into the Gulf and restrengthening before a final move NE?

Yeah the NHC forecast has it doing that as well, Friday to Monday going in land slowly, doubling back around the same area, able to partially feed off the Gulf for some of the time and remaining around the Texas coast for another couple of days after that, moving North East.
It's a long time to be raining on parts of Texas. Anyone know of a Hurricane Precedent?

Meteorite58 · 25-08-2017 9:13pm

https://ruc.noaa.gov/tracks/

NOAA ESRL Demo -- Tropical Cyclone Tracks from Experimental Forecast & Ensemble Models

Looking very slow moving atm.

NOAA recon plane in #Harvey's eye continues to find stronger winds and lower central pressure than previous passes. Strengthening continues.

EjhkSc6.jpg?1

https://twitter.com/TropicalTidbits/status/901163522587021320

https://twitter.com/TropicalTidbits/status/901158647434227716

star gazer · 25-08-2017 9:54pm

It's 110km East-Southeast from Corpus Christi now, moving North West at 17 km/h.
Nice link Meteorite58, thanks.
Houston is inside the 500mm (20 inches) total rainfall area:
https://twitter.com/NWS/status/901165176908648449
There are a few Tornadado warnings out now (plus Galveston County):
https://twitter.com/weatherchannel/status/901184490927603717

25-08-2017 10:17pm

4 PM CDT discussion. Staying near the coast is going to delay the decline of this system, leading to serious rainfall totals.

Hurricane Harvey Discussion Number
22 NWS National Hurricane Center Miami FL
AL092017 400 PM CDT Fri Aug 25 2017

Despite its concentric eyewall structure, Harvey's winds have increased during the day. NOAA and Air Force Reserve Hurricane Hunter planes have measured maximum flight-level winds of 129 kt and SFMR winds to 102 kt. Based on these data, Harvey's maximum surface winds are estimated to be 110 kt. Harvey's central pressure has also continued to fall, and the latest estimate based on dropsonde data is 941 mb. Harvey still has not slowed down, and the initial estimate is 325/9 kt.

Based on the forecast track, Harvey is expected to make landfall along the middle Texas coast tonight. After that, the track models insist that the hurricane will slow down considerably during the next 24 hours, and it is likely to move very little between 36 and 120 hours. In fact, there has been a somewhat notable change in the guidance, with very few of the models showing Harvey lifting out toward the northeast by the end of the 5-day forecast period. As a result, the NHC track forecast has been pulled back a bit and keeps Harvey near or just inland of the Texas coast through the middle of next week.

This slow motion only exacerbates the heavy rainfall and flooding threat across southern and southeastern Texas. Harvey may continue to strengthen during the 6-12 hours it has before landfall, but regardless it is expected to make landfall at major hurricane strength. Gradual weakening is anticipated after the center moves inland, but Harvey's slow motion will keep a significant portion of its circulation over water, which may slow the weakening rate. As a result, the NHC intensity forecast leans closer to the global model guidance instead of the statistical- dynamical guidance, which seems to weaken Harvey too fast. Harvey could maintain tropical storm strength for the entire 5-day forecast period due to its proximity to the northwestern Gulf of Mexico.

Key Messages: 1. Harvey will make landfall tonight, bringing life-threatening storm surge, rainfall, and wind hazards to portions of the Texas coast. Tropical-storm-force winds have moved onshore in portions of the warning areas and conditions will continue to deteriorate as the eye of Harvey approaches the middle Texas coast tonight.
2. A Storm Surge Warning is in effect for much of the Texas coast. Life-threatening storm surge flooding could reach heights of 6 to 12 feet above ground level at the coast between the north entrance of the Padre Island National Seashore and Sargent. For a depiction of areas at risk, see the Storm Surge Watch/Warning Graphic at hurricanes.gov. Due to the slow motion of Harvey and a prolonged period of onshore flow, water levels will remain elevated for several days.
3. Catastrophic and life-threatening flooding is expected across the middle and upper Texas coast from heavy rainfall of 15 to 30 inches, with isolated amounts as high as 40 inches, through Wednesday. Please refer to products from your local National Weather Service office and the NOAA Weather Prediction Center for more information on the flooding hazard.

FORECAST POSITIONS AND MAX WINDS INIT

25/2100Z 27.5N 96.5W 110 KT 125 MPH 12H
26/0600Z 28.2N 97.0W 100 KT 115 MPH...INLAND 24H
26/1800Z 28.8N 97.5W 75 KT 85 MPH...INLAND 36H
27/0600Z 28.9N 97.8W 60 KT 70 MPH...INLAND 48H
27/1800Z 28.6N 97.8W 50 KT 60 MPH...INLAND 72H
28/1800Z 28.1N 96.9W 40 KT 45 MPH...INLAND 96H
29/1800Z 28.5N 96.0W 40 KT 45 MPH...OVER WATER 120H
30/1800Z 29.5N 95.5W 35 KT 40 MPH...INLAND

Gaoth Laidir · 25-08-2017 10:41pm

Latest TCHP shows just about 90 kJ/cm2 in the area where Harvey intensified. This value is seen as the threshold for rapid intensification. With some cold upwelling likely the longer Harvey hangs around this may actually limit its potential over the following days.

ronnie3585 · 25-08-2017 10:42pm

Been watching this guy all evening - fascinating footage;

https://www.pscp.tv/Jeff_Piotrowski/1rmxPqngkaDKN

star gazer · 25-08-2017 10:42pm

By not moving far from where it makes landfall and with all the flooding and damage, it could be a long time before it's possible to get help to many people affected. It was very fast to strengthen in the last 36 hours.
With a little time left over water, there's still a chance it becomes a Category 4 Hurricane. 95km from Corpus Christi, still moving at 17km/h.

BillyBobBS · 25-08-2017 10:48pm

Wow just seen a report there on NBC and the weather reporter basically said anyone who hasn't evacuated better make preparations for their own funeral. Talk about pulling no punches!!

25-08-2017 11:19pm

Heres an image of Harvey taken from the new GOES 16 satellite launched last November. Its a big step up quality wise from the older GOES birds. While not yet fully operational (will be at 75 degrees W in Nov) the images can be seen here: https://www.aos.wisc.edu/weather/wx_obs/GOES16.html

25-08-2017 11:30pm

From the full resoulution CONUS image. Really has matured as a system.

Meteorite58 · 25-08-2017 11:32pm

Making it's presence felt...

https://twitter.com/iCyclone/status/901200087761682432

Close to a Cat 4

https://twitter.com/ReaganMatt/status/901202658404560900

EDIT: About to make landfall. Max sustained winds 125mph / 201 km/h

Meteorite58 · 25-08-2017 11:47pm

live

This guy is going to get himself killed !

https://twitter.com/BrandonCatteneo/status/901213050426060800

https://twitter.com/ReedTimmerAccu/status/901212568592797697

star gazer · 26-08-2017 12:02am

Category 4, slowing down to 13km/h, 70km East of Corpus Christi.
NHC

Hurricane Harvey Tropical Cyclone Update
NWS National Hurricane Center Miami FL AL092017
600 PM CDT Fri Aug 25 2017

...6 PM CDT POSITION AND INTENSITY UPDATE...
...HARVEY BECOMES A CATEGORY FOUR HURRICANE...
...SUSTAINED HURRICANE-FORCE WINDS SPREADING ONTO THE MIDDLE TEXAS
COAST...

Air Force Reserve Reconnaissance aircraft data indicate that Harvey
has become a category 4 hurricane with maximum sustained winds of
130 mph (215 km/h).

A station at Aransas Pass run by the Texas Coastal Observing
Network recently reported a sustained wind of 74 mph (119 km/h) with
a gust to 96 mph (154 km/h).

SUMMARY OF 600 PM CDT...2300 UTC...INFORMATION
LOCATION...27.7N 96.7W
ABOUT 45 MI...70 KM E OF CORPUS CHRISTI TEXAS
ABOUT 50 MI...85 KM SSW OF PORT OCONNOR TEXAS
MAXIMUM SUSTAINED WINDS...130 MPH...215 KM/H
PRESENT MOVEMENT...NW OR 325 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...941 MB...27.79 INCHES

I do wonder if it may have been better to have (had) mandatory evacuations on a vast scale in the 500mm-plus rainfall area given how flooding could cut much of the area off and the rising waters' threat to peoples safety. The expected area of heavy rain is so large. Of course it's tough to forecast exactly where Hurricane Harvey will go and where the worst flooding will be and what that does to normal river drainage and other channels. And forcing a lot of people out is a huge ask socially, particularly with the late notification.

Tropical Storm Alison lingered for a number of days.

Itssoeasy · 26-08-2017 12:16am

It's been confirmed as a CAT 4 hurricane. Sweet Jaysus this is going to cause some damage when it makes landfall.

uck51js9zml2yt · 26-08-2017 12:19am

Itssoeasy wrote: »

It's been confirmed as a CAT 4 hurricane. Sweet Jaysus this is going to cause some damage when it makes landfall.

When is it supposed to hit land?

Meteorite58 · 26-08-2017 12:26am

https://twitter.com/mikeseidel/status/901220679730778112

About 45 miles East of Corpus Christi, winds 130 mph/ onshore 100mph , travelling at 8 -10 mph

https://twitter.com/ChrisShadrock/status/901220257800622083

Itssoeasy · 26-08-2017 12:31am

CBS news are reporting that a mayor in Texas is saying to residents have haven't evacuated at this stage to write their social security numbers on their arms. Now that sounds bad.

star gazer · 26-08-2017 12:37am

Wynter Nutty Desert wrote: »

When is it supposed to hit land?

It should be in the coming few hours but it is also slowing down moving NW. Moving slower now means longer/more storm surge, potential to pick up more moisture at sea and dump more rain on land.

La.de.da · 26-08-2017 1:46am

Meteorite58 wrote: »

live

This guy is going to get himself killed !

https://twitter.com/BrandonCatteneo/status/901213050426060800

https://twitter.com/ReedTimmerAccu/status/901212568592797697

He's watching an electricity pole sparking very near a petrol station, wow! Stupidity.

Hope those who needed too evacuated. Looks terrifying.

PokeHerKing · 26-08-2017 8:16am

Itssoeasy wrote:

It's been confirmed as a CAT 4 hurricane. Sweet Jaysus this is going to cause some damage when it makes landfall.

Still Cat 3

Gaoth Laidir · 26-08-2017 8:31am

PokeHerKing wrote: »

Still Cat 3

It was Cat 4 earlier

http://www.nhc.noaa.gov/archive/2017/al09/al092017.update.08260358.shtml?

...11 PM CDT POSITION UPDATE... ...EYE OF CATEGORY 4 HARVEY NOW OVER ARANSAS BAY TEXAS...
A station at Aransas Pass run by the Texas Coastal Observing Network recently reported a sustained wind of 102 mph (165 km/h) with a gust to 132 mph (213 km/h).
A station at Aransas Wildlife Refuge run by the Texas Coastal Observing Network recently reported a sustained wind of 75 mph (120 km/h) with a gust to 99 mph (159 km/h).
A station at Rockport, Texas, reported a pressure of 945 mb (27.92 in.) on the western side of the eye.
SUMMARY OF 1100 PM CDT...0400 UTC...INFORMATION
LOCATION...28.1N 97.0W NEAR ROCKPORT TEXAS ABOUT 40 MI...70 KM WSW OF PORT OCONNOR TEXAS
MAXIMUM SUSTAINED WINDS...130 MPH...215 KM/H
PRESENT MOVEMENT...NW OR 325 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...938 MB...27.70 INCHES $$
Forecaster Cangialosi/Zelinsky

BillyBobBS · 26-08-2017 9:02am

So made landfall as a Cat 4, wow that's going to hurt. Hard to feel sorry for anyone who decided to wait it out despite all the warnings. Some people are just stupid and will never change.

Hurricane Harvey

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