ATL: HARVEY - Post-Tropical - Discussion

[tolakram]

You are looking high into the storm from this range and it's tilted with height due to the 10 to 15 kts of shear. I'm not sure where the talk of ERC started but unless the NHC mentions it I doubt it's happening. It's simply the fact Harvey is not in an absolute perfect environment. Unfortunately while winds will be some of the story it's the rain aftermath that's going to cause most of the issues. I hope everyone in the path is aware it may be raining for a week.

[cycloneye]

Hurricane Harvey Local Statement Advisory Number 20
National Weather Service Corpus Christi TX AL092017
436 AM CDT Fri Aug 25 2017

This product covers SOUTH TEXAS

**HURRICANE HARVEY DANGEROUSLY APPROACHING THE TEXAS COAST**


NEW INFORMATION
---------------

* CHANGES TO WATCHES AND WARNINGS:
- None

* CURRENT WATCHES AND WARNINGS:
- A Storm Surge Warning and Hurricane Warning are in effect for
Aransas, Calhoun, Kleberg, Nueces, Refugio, San Patricio, and
Victoria
- A Tropical Storm Warning is in effect for Duval and McMullen
- A Hurricane Warning is in effect for Bee, Goliad, Jim Wells,
and Live Oak

* STORM INFORMATION:
- About 185 miles south-southeast of Port Oconnor TX or about 180
miles southeast of Corpus Christi TX
- 25.9N 95.4W
- Storm Intensity 105 mph
- Movement Northwest or 320 degrees at 9 mph

SITUATION OVERVIEW
------------------

Hurricane Harvey is expected to continue to strengthen as it moves
toward the Texas Coast through Friday. Harvey is a Category
2 hurricane, with sustained winds of 105 mph. Harvey is expected to
reach Category 3 status prior to landfall. Tropical storm force winds
are expected to reach coastal areas of the Coastal Bend as early as
later this morning. Hurricane force winds will be possible as early as
this afternoon.

Heavy rainfall is expected through much of the area with rainfall
totals of 20 to 30 inches near, north and east of a line from near
Port Aransas to near Goliad. Outside that area, amounts of 10 to
20 inches are expected from near and east of a Loyola Beach to near
George West line. Lesser amounts are expected further west and
southwest. These numbers and locations are subject to change depending
on the exact location of landfall along the Texas coast, as well as how
long Harvey meanders over South Texas. These high rainfall amounts
will likely produce devastating and life threatening flash flooding.
The heaviest rains are expected to occur from late Friday afternoon
through Saturday night, and quite possibly into early next week
depending on how long Harvey remains over the area.

Peak Storm surge inundation is generally expected to be 6 to 12 feet
above ground level from near Mustang Island to Port O'Connor. South of
Mustang Island storm surge is generally expected to be 4 to 6 feet
above ground level. Impacts would be felt along the Barrier Islands
and into the inland bays and waterways. Isolated locations could see
slightly higher inundation.

Tornadoes and waterspouts are possible as rainbands move onshore early
this morning through Saturday, especially north and east of the center
of Harvey.

Mandatory evacuations have been issued for the following areas:
- The city of Port Aransas
- Aransas County
- Refugio County
- San Patricio County
- Victoria County
- Calhoun County
- Eastern Kleberg County (Baffin Bay, Loyola
Beach and Rivera Beach and areas east)

CHRISTUS Spohn Health System to close certain locations:
- CLOSED: Robstown, Northside, Westside, Padre Island, Freer,
Beeville, Dr. Hector P. Garcia, and Memorial Quick Care (Reopen
Monday, August 28).
- CLOSED: CHRISTUS Physician Group physician practices.
- ABBREVIATED WORK SCHEDULE: Promptu Clinics will operate a shortened
schedule on Friday, August 25.

POTENTIAL IMPACTS
-----------------

* SURGE:
Prepare for life-threatening surge having possible devastating impacts
across the Middle Texas Coast and Barrier Islands. Potential impacts in
this area include:
- Widespread deep inundation, with storm surge flooding greatly
accentuated by powerful battering waves. Structural damage to
buildings, with many washing away. Damage greatly compounded
from considerable floating debris. Locations may be
uninhabitable for an extended period.
- Near-shore escape routes and secondary roads washed out or
severely flooded. Flood control systems and barriers may become
stressed.
- Extreme beach erosion. New shoreline cuts possible.
- Massive damage to marinas, docks, boardwalks, and piers.
Numerous small craft broken away from moorings with many lifted
onshore and stranded.

* WIND:
Prepare for life-threatening wind having possible devastating impacts
across essentially all of the Coastal Bend and Victoria Crossroads
area. Potential impacts in this area include:
- Structural damage to sturdy buildings, some with complete roof
and wall failures. Complete destruction of mobile homes. Damage
greatly accentuated by large airborne projectiles. Locations
may be uninhabitable for weeks or months.
- Numerous large trees snapped or uprooted along with fences and
roadway signs blown over.
- Many roads impassable from large debris, and more within urban
or heavily wooded places. Many bridges, causeways, and access
routes impassable.
- Widespread power and communications outages.

Also, prepare for life-threatening wind having possible significant
to extensive impacts across McMullen and Duval Counties.

* FLOODING RAIN:
Prepare for life-threatening rainfall flooding having possible
devastating impacts across he Coastal Bend and Victoria Crossroads
area. Potential impacts include:
- Extreme rainfall flooding may prompt numerous evacuations and
rescues.
- Rivers and tributaries may overwhelmingly overflow their banks
in many places with deep moving water. Small streams, creeks,
canals, and ditches may become raging rivers. Flood control
systems and barriers may become stressed.
- Flood waters can enter numerous structures within multiple
communities, some structures becoming uninhabitable or washed
away. Numerous places where flood waters may cover escape
routes. Streets and parking lots become rivers of raging water
with underpasses submerged. Driving conditions become very
dangerous. Numerous road and bridge closures with some weakened
or washed out.

Prepare for life-threatening rainfall flooding having possible
limited to extensive impacts across the remainder of South Texas.

* TORNADOES:
Prepare for a tornado event having possible limited impacts across
areas near and east of a Corpus Christi to Beeville line. Potential
impacts include:
- The occurrence of isolated tornadoes can hinder the execution
of emergency plans during tropical events.
- A few places may experience tornado damage, along with power
and communications disruptions.
- Locations could realize roofs peeled off buildings, chimneys
toppled, mobile homes pushed off foundations or overturned,
large tree tops and branches snapped off, shallow-rooted trees
knocked over, moving vehicles blown off roads, and small boats
pulled from moorings.

Elsewhere across SOUTH TEXAS, little to no impact is anticipated.

PRECAUTIONARY/PREPAREDNESS ACTIONS
----------------------------------

* EVACUATIONS:
For those under evacuation orders, leave as soon as practical with a
destination in mind. Gas up your vehicle well ahead of time. Be sure
that you take all essential materials from your emergency supplies kit.
Let others know where you are going and when you intend to arrive.

If evacuating the area, stick to prescribed evacuation routes. Look
for additional traffic information on roadway smart signs and listen to
select radio channels for further travel instructions. Drivers should
not use cell phones while operating vehicles.

If you are exceptionally vulnerable to wind or water hazards from
tropical systems, consider voluntary evacuation, especially if being
officially recommended. Relocate to a predetermined shelter or safe
destination.

* OTHER PREPAREDNESS INFORMATION:
When making safety and preparedness decisions, do not focus on the
exact forecast track as there are inherent forecast uncertainties which
must be taken into account.

If you live in a place that is particularly vulnerable to high wind,
such as a mobile home, an upper floor of a high rise building, or on
a boat, plan to move to safe shelter. Take enough supplies for you
and your family for several days.

When securing your property, outside preparations should be conducted
as soon as possible before conditions deteriorate. The onset of strong
gusty winds and heavy rain can cause certain preparedness activities to
become unsafe.

Closely monitor NOAA Weather Radio or other local news outlets for
official storm information. Listen for possible changes to the
forecast.

* ADDITIONAL SOURCES OF INFORMATION:
- For information on appropriate preparations see ready.gov
- For information on creating an emergency plan see getagameplan.org
- For additional disaster preparedness information see redcross.org

NEXT UPDATE
-----------

The next local statement will be issued by the National Weather
Service in Corpus Christi TX around 730 AM CDT, or sooner if
conditions warrant.

$$

[tolakram]

[Thetxhurricanemaster]

I'm still in corpus christi 5 miles from the bay it's raining now with gusts of about 30 MPh

[forecasterjack]

Certainly looking powerful as ever on Satellite. Building a ring of <-80C cloud tops. That's pretty wild. https://weather.us/satellite/921-w-267- ... .html#play

[Exalt]

You are looking high into the storm from this range and it's tilted with height due to the 10 to 15 kts of shear. I'm not sure where the talk of ERC started but unless the NHC mentions it I doubt it's happening. It's simply the fact Harvey is not in an absolute perfect environment. Unfortunately while winds will be some of the story it's the rain aftermath that's going to cause most of the issues. I hope everyone in the path is aware it may be raining for a week.

I'm going to have to politely disagree, you can see the old eyewall begin to decay with the second eyewall starting to strengthen ln radar. At the rate it's bombing it would completely make sense for an EWRC to occur considering it's a borderline Cat 3 and it isn't unheard of for a Cat 2 to undergo a slight EWRC.

Edit: Also IIRC I believe recon found two eyewalls.

[Fishing]

Going to ride it out in Victoria

Godspeed to you. You may want to give that some careful reconsideration.

[MaineWeatherNut]

112300 2620N 09548W 6968 02700 9466 +176 +091 091010 012 022 001 03
112330 2621N 09546W 6976 02686 9466 +168 +122 107021 028 028 002 00

946mb this pass... Add 3mb so 949mb yet another 4 or 5 mb drop in the last hour...

[NDG]

You are looking high into the storm from this range and it's tilted with height due to the 10 to 15 kts of shear. I'm not sure where the talk of ERC started but unless the NHC mentions it I doubt it's happening. It's simply the fact Harvey is not in an absolute perfect environment. Unfortunately while winds will be some of the story it's the rain aftermath that's going to cause most of the issues. I hope everyone in the path is aware it may be raining for a week.

If it would had not been at fairly perfect environment we would had not seen yet another 20 mb drop during the night. I have to question that shear map, clearly there's an anticyclone on top of it, unless the shear is more in the mid levels.

[xironman]

Perhaps an outer eyewall beginning to form, good and bad news I guess.

Not really,,,

The inner eye wall is quickly merging with the outter. This could allow for a very quick ewrc and this thing within 6 hours from now could be bombing once again.

The bad news is it is quite rare for another ewrc to occur within 18-24 hours after a successful one is complete. This increases the odds that this won't weaken before landfall.

We can get an idea from the recon if a secondary wind maximum starts developing outside the eyewall, time will tell.

This, there is no real sign of a major double max in the recon data.

[Exalt]

112300 2620N 09548W 6968 02700 9466 +176 +091 091010 012 022 001 03
112330 2621N 09546W 6976 02686 9466 +168 +122 107021 028 028 002 00

946mb this pass... Add 3mb so 949mb yet another 4 or 5 mb drop in the last hour...

If it's bombing out like this during an EWRC, I don't think there's anything stopping it now..

[Hypercane_Kyle]

Looks to me Harvey's being hit by 10-15 knots of shear (look at visible for further confirmation, note the squashed look to the CDO).

EDIT: Agree that no EWRC taking place. Lack of double wind max.

[tolakram]

You are looking high into the storm from this range and it's tilted with height due to the 10 to 15 kts of shear. I'm not sure where the talk of ERC started but unless the NHC mentions it I doubt it's happening. It's simply the fact Harvey is not in an absolute perfect environment. Unfortunately while winds will be some of the story it's the rain aftermath that's going to cause most of the issues. I hope everyone in the path is aware it may be raining for a week.

If it would had not been at fairly perfect environment we would had not seen yet another 20 mb drop during the night. I have to question that shear map, clearly there's an anticyclone on top of it, unless the shear is more in the mid levels.

If it was in a perfect environment we would be staring at a cat 4 at this point, no other negatives besides shear to slow it down IMO.

Latest recon, pressure still lower if I read this correctly.

112300 2620N 09548W 6968 02700 9466 +176 +091 091010 012 022 001 03
112330 2621N 09546W 6976 02686 9466 +168 +122 107021 028 028 002 00

946mb

[WeatherGuesser]

On this page: https://www.tropicaltidbits.com/storminfo/#09L

Hmmm, hard to say from those, but it looks like a possibility a week or so out..

[jaguars_22]

We are boarded up and staying in a interior room... how much wind would you say Victoria should get???

[tolakram]

Latest recon, pressure still lower if I read this correctly.

112300 2620N 09548W 6968 02700 9466 +176 +091 091010 012 022 001 03
112330 2621N 09546W 6976 02686 9466 +168 +122 107021 028 028 002 00

946mb

951mb reported.

[Texas Snowman]

Good morning everyone. Long, tense, busy day coming up for a lot of folks today. My thoughts and prayers for those on the Texas Coast.

Thought this would be a good time to encourage everyone to follow forum rules, to be cordial, and to remain on topic today.

Here's how our Pro Met / Moderator AJC3 put it yesterday afternoon:

"Gang,

Please keep the OT chit chat stuff confined to the chat room, PMs, or some other outlet, and not the forums. The mods/admins are pretty much in "storm mode" right now, meaning the chaff posts are being deleted without notice.

Thanks."

[NDG]

You are looking high into the storm from this range and it's tilted with height due to the 10 to 15 kts of shear. I'm not sure where the talk of ERC started but unless the NHC mentions it I doubt it's happening. It's simply the fact Harvey is not in an absolute perfect environment. Unfortunately while winds will be some of the story it's the rain aftermath that's going to cause most of the issues. I hope everyone in the path is aware it may be raining for a week.

If it would had not been at fairly perfect environment we would had not seen yet another 20 mb drop during the night. I have to question that shear map, clearly there's an anticyclone on top of it, unless the shear is more in the mid levels.

If it was in a perfect environment we would be staring at a cat 4 at this point, no other negatives besides shear to slow it down IMO.

Latest recon, pressure still lower if I read this correctly.

112300 2620N 09548W 6968 02700 9466 +176 +091 091010 012 022 001 03
112330 2621N 09546W 6976 02686 9466 +168 +122 107021 028 028 002 00

946mb

It takes a while for winds to reflect pressure drops, it does not happen in an instance.
A lot of people were calling for Harvey to level off at Cat 2 before landfall because of that shear map, I remember the NHC mentioning last night that Harvey is in a low shear environment, otherwise they would had not said that if those 15 knots of shear over Harvey would had been true.

[GCANE]

[Hypercane_Kyle]

Dropsonde doesn't support a 946mb pressure.