ATL: HARVEY - Post-Tropical - Discussion

[tropicwatch]

Once it pulls away from Yucatan, it should start to look better convection wise.

[RL3AO]

How confident are we that this will only be a strong TS or very weak Hurricane?

I can't speak for the NHC, but I'd say lower than average confidence. A period of rapid intensification before landfall is a real possibility.

[hohnywx]

How confident are we that this will only be a strong TS or very weak Hurricane?

I don't think anyone is confident of that...the first forecast out from the NHC has it at hurricane strength making landfall. Continue to watch the forecast and model trends today.

[HouTXmetro]

Convection exploding near COC per latest satellite imagery

[slamdaddy]

With the G-IV flight yesterday, hunters down there now and another G-IV flight today (I think), and all the WFOs we have...should there not be good confidence in at least 3 days out ? That's a lot of data coming from different assets.

[KWT]

Yeah the forecast Harvey from the NHC does say they expect it to be a hurricane before landfall but the timings are uncertain with regards to how quickly it takes off once it is a little more organised.

Going to be a most interesting 72hrs, and obviously the flooding is probably going to be the biggest story unless this one really goes great guns...

[stormreader]

Well, I posted last night that to my untrained eye I thought the center was organizing around a point 50 miles or so N and E of where the official plot had the storm and where models are initializing. Storm hasn't moved much since then, but I think its clear (to me at least) the the obvious organization of the new depression is in fact north of the points where models had storm location. Its well north of Yucatan, whereas models last night and official plot had it in the BOC. Don't know if that will make a difference in the track.

[hohnywx]

With the G-IV flight yesterday, hunters down there now and another G-IV flight today (I think), and all the WFOs we have...should there not be good confidence in at least 3 days out ? That's a lot of data coming from different assets.

At 72 hours out, the NHC forecast has a forecast error of 107 mi. Meaning the storm should be within 107 mi of the forecast point. Track forecasting, while better than intensity forecasting, is still not an exact science:

http://www.nhc.noaa.gov/aboutcone.shtml

[Portastorm]

Well, I posted last night that to my untrained eye I thought the center was organizing around a point 50 miles or so N and E of where the official plot had the storm and where models are initializing. Storm hasn't moved much since then, but I think its clear (to me at least) the the obvious organization of the new depression is in fact north of the points where models had storm location. Its well north of Yucatan, whereas models last night and official plot had it in the BOC. Don't know if that will make a difference in the track.

Okay it is time to stop posts like these. The National Hurricane Center has issued its first set of advisories and named the center of the system. You can think what you want, but it doesn't make it official.

For persons in the potentially impacted areas and who are reading this ... please pay attention to the advisories and information from the National Hurricane Center. Outside of blue tags on this forum, the rest of us are just regular joes and josephinas sharing our opinions.

[tropicwatch]

How confident are we that this will only be a strong TS or very weak Hurricane?

I don't think anyone is confident of that...the first forecast out from the NHC has it at hurricane strength making landfall. Continue to watch the forecast and model trends today.

Forecast cone does not show a landfalling hurricane.

[ronyan]

Read the discussion. Those points are deceptive because one is over water and one is over land.

[cycloneye]

Tropical Depression Harvey Local Statement Advisory Number 12
National Weather Service Houston/Galveston TX AL092017
1024 AM CDT Wed Aug 23 2017

This product covers Southeast Texas

**HARVEY REGENERATES INTO A TROPICAL DEPRESSION**


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

* CHANGES TO WATCHES AND WARNINGS:
- A Storm Surge Watch and Hurricane Watch have been issued for
Brazoria, Jackson, and Matagorda
- A Tropical Storm Watch has been issued for Austin, Colorado,
Fort Bend, Liberty, Waller, and Wharton
- A Storm Surge Watch and Tropical Storm Watch have been issued
for Chambers, Galveston, and Harris

* CURRENT WATCHES AND WARNINGS:
- A Storm Surge Watch and Hurricane Watch are in effect for
Brazoria, Jackson, and Matagorda
- A Tropical Storm Watch is in effect for Austin, Colorado, Fort
Bend, Liberty, Waller, and Wharton
- A Storm Surge Watch and Tropical Storm Watch are in effect for
Chambers, Galveston, and Harris

* STORM INFORMATION:
- About 560 miles south-southeast of Galveston TX or about 540
miles south-southeast of Matagorda TX
- 21.5N 92.5W
- Storm Intensity 35 mph
- Movement Northwest or 310 degrees at 9 mph

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

Harvey has regenerated into at Tropical Depression this morning. TD
Harvey is expected to continue to strength into a tropical storm or
hurricane in the next couple of days. The primary impact from Harvey is
expected to be heavy rainfall and flooding, but there will still be a
threat for tropical storm to hurricane force winds and storm surge
along the coast.

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

* FLOODING RAIN:
Prepare for locally hazardous rainfall flooding having possible
limited impacts across Southeast Texas. Potential impacts include:
- Localized rainfall flooding may prompt a few evacuations.
- Rivers and tributaries may quickly rise with swifter currents.
Small streams, creeks, canals, arroyos, and ditches may become
swollen and overflow in spots.
- Flood waters can enter a few structures, especially in usually
vulnerable spots. A few places where rapid ponding of water
occurs at underpasses, low-lying spots, and poor drainage
areas. Several storm drains and retention ponds become
near-full and begin to overflow. Some brief road and bridge
closures.

* SURGE:
Prepare for life-threatening surge having possible significant
impacts across the whole Upper Texas Coast. Potential impacts in
this area include:
- Areas of inundation with storm surge flooding accentuated by
waves. Damage to several buildings, mainly near the coast.
- Sections of near-shore escape routes and secondary roads become
weakened or washed out, especially in usually vulnerable low
spots.
- Major beach erosion with heavy surf breaching dunes. Strong and
numerous rip currents.
- Moderate damage to marinas, docks, boardwalks, and piers.
Several small craft broken away from moorings, especially in
unprotected anchorages.

Also, prepare for locally hazardous surge having possible limited
impacts across northern Galveston Bay and Trinity Bay.

Elsewhere across Southeast Texas, little to no impact is anticipated.

* WIND:
Prepare for dangerous wind having possible significant impacts across
the Upper Texas Coast mainly near Matagorda. Potential impacts in this
area include:
- Some damage to roofing and siding materials, along with damage
to porches, awnings, carports, and sheds. A few buildings
experiencing window, door, and garage door failures. Mobile
homes damaged, especially if unanchored. Unsecured lightweight
objects become dangerous projectiles.
- Several large trees snapped or uprooted, but with greater
numbers in places where trees are shallow rooted. Several
fences and roadway signs blown over.
- Some roads impassable from large debris, and more within urban
or heavily wooded places. A few bridges, causeways, and access
routes impassable.
- Scattered power and communications outages, but more prevalent
in areas with above ground lines.

* TORNADOES:
Conditions will be favorable for isolated tornadoes across much of
Southeast Texas.

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

* EVACUATIONS:

WATCH/WARNING PHASE - 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:
Now is the time to check your emergency plan and take necessary
actions to secure your home or business. Deliberate efforts should be
underway to protect life and property. Ensure that your Emergency
Supplies Kit is stocked and ready.

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.

If you live in a place particularly vulnerable to flooding, such as
near the ocean or a large inland lake, in a low lying or poor
drainage area, in a valley or canyon, or near an already swollen
river, plan to move to safe shelter on higher ground

Always heed the advice of local officials and comply with any orders
that are issued. Do not needlessly jeopardize your life or the lives
of others.

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.

Be sure to let friends and other family members know of your
intentions and whereabouts for surviving the storm. For emergency
purposes, have someone located away from the threatened area serve as
your point of contact. Share vital contact information with others.
Keep cell phones handy and well charged.

Be a Good Samaritan and check on those who may not be fully aware of
the situation or who are unable to make personal preparations.

Visitors to the area should become familiar with nearby surroundings.
If you are a visitor, know the name of the county or parish in which
you are located and where it is relative to current watches and
warnings. If staying at a hotel, ask the management staff about their
onsite disaster plan. Listen for evacuation orders, especially
pertaining to area visitors.

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 Houston/Galveston TX around 430 PM CDT, or sooner if
conditions warrant.

[cycloneye]

Tropical Depression Harvey Local Statement Advisory Number 12
National Weather Service Corpus Christi TX AL092017
1029 AM CDT Wed Aug 23 2017

This product covers SOUTH TEXAS

**TROPICAL DEPRESSION HARVEY MOVING TOWARD THE TEXAS COAST**

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

* CHANGES TO WATCHES AND WARNINGS:
- A Hurricane Watch has been issued for Bee, Goliad, Jim Wells,
Live Oak, and Victoria
- A Storm Surge Watch and Hurricane Watch have been issued for
Aransas, Calhoun, Kleberg, Nueces, Refugio, and San Patricio

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

* STORM INFORMATION:
- About 520 miles southeast of Port Aransas TX or about 540 miles
south-southeast of Port Oconnor TX
- 21.5N 92.5W
- Storm Intensity 35 mph
- Movement Northwest or 310 degrees at 9 mph

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

Hurricane hunter aircraft have found a closed circulation in what
was the remnants of Harvey, and have found strong enough winds to
categorize Harvey as a tropical depression. Harvey is expected to
continue to strengthen as it approaches the Texas coast Thursday into
Friday. Tropical storm force winds could approach coastal areas in the
Coastal Bend as early as Thursday night or Friday morning.

Heavy rainfall is expected through much of the area with rainfall
totals of 6 to 12 inches possible along the middle Texas coast and
Victoria Crossroads. Lesser amounts are expected further west. These
numbers and locations are subject to change depending on the exact
point of landfall along the Texas coast. Flash flooding is possible
with these high rainfall totals. The heaviest rains will occur
Thursday night through Saturday.

Storm surge inundation of up to 4 to 6 feet is possible along the islands
and into the bays. Isolated locations could see slightly higher inundation.

Tornadoes are possible as rainbands move onshore Thursday night
through Saturday.

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

* WIND:
Prepare for dangerous wind having possible significant impacts across
the Coastal Bend and middle Texas coast. Potential impacts in this area include:
- Some damage to roofing and siding materials, along with damage
to porches, awnings, carports, and sheds. A few buildings
experiencing window, door, and garage door failures. Mobile
homes damaged, especially if unanchored. Unsecured lightweight
objects become dangerous projectiles.
- Several large trees snapped or uprooted, but with greater
numbers in places where trees are shallow rooted. Several
fences and roadway signs blown over.
- Some roads impassable from large debris, and more within urban
or heavily wooded places. A few bridges, causeways, and access
routes impassable.
- Scattered power and communications outages, but more prevalent
in areas with above ground lines.

* FLOODING RAIN:
Prepare for locally hazardous rainfall flooding having possible
impacts across SOUTH TEXAS. Potential impacts include:
- Localized rainfall flooding may prompt a few evacuations.
- Rivers and tributaries may quickly rise with swifter currents.
Small streams, creeks, canals, and ditches may become swollen
and overflow in spots.
- Flood waters can enter a few structures, especially in usually
vulnerable spots. A few places where rapid ponding of water
occurs at underpasses, low-lying spots, and poor drainage
areas. Several storm drains and retention ponds become
near-full and begin to overflow. Some brief road and bridge
closures.

* SURGE:
Prepare for life-threatening surge having possible significant
impacts across the middle Texas coast including the barrier islands.
Potential impacts in this area include:
- Areas of inundation with storm surge flooding accentuated by
waves. Damage to several buildings, mainly near the coast.
- Sections of near-shore escape routes and secondary roads become
weakened or washed out, especially in usually vulnerable low
spots.
- Major beach erosion with heavy surf breaching dunes. Strong and
numerous rip currents.
- Moderate damage to marinas, docks, boardwalks, and piers.
Several small craft broken away from moorings, especially in
unprotected anchorages.

* TORNADOES:
Little to no impacts are anticipated at this time across South Texas.
Tornado threats are expected to increase Thursday night through Saturday.

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

* EVACUATIONS:
If you are exceptionally vulnerable to wind or water hazards from
tropical systems, consider voluntary evacuation. Relocate to a
predetermined shelter or safe destination. If evacuating away from
the area or relocating to a nearby shelter, leave early before
weather conditions become hazardous.

* OTHER PREPAREDNESS INFORMATION:
Now is the time to check your emergency plan and take necessary
actions to secure your home or business. Deliberate efforts should be
underway to protect life and property. Ensure that your Emergency
Supplies Kit is stocked and ready.

If you live in a place particularly vulnerable to flooding, such as
near the ocean or a large inland lake, in a low lying or poor
drainage area, in a valley or canyon, or near an already swollen
river, plan to move to safe shelter on higher ground

Always heed the advice of local officials and comply with any orders
that are issued. Do not needlessly jeopardize your life or the lives
of others.

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 4 PM, or sooner if conditions warrant.

[hohnywx]

How confident are we that this will only be a strong TS or very weak Hurricane?

I don't think anyone is confident of that...the first forecast out from the NHC has it at hurricane strength making landfall. Continue to watch the forecast and model trends today.

Forecast cone does not show a landfalling hurricane.

Although not explicitly forecast below, we are anticipating Harvey being a hurricane at landfall after the 48 hour forecast point.

Please read the discussions...do not just look at a map:

http://www.nhc.noaa.gov/text/refresh/MI ... 1450.shtml

[HurricaneBrain]

Per the forecast discussion:

Although not explicitly forecast
below, we are anticipating Harvey being a hurricane at landfall
after the 48 hour forecast point.

How confident are we that this will only be a strong TS or very weak Hurricane?

I don't think anyone is confident of that...the first forecast out from the NHC has it at hurricane strength making landfall. Continue to watch the forecast and model trends today.

Forecast cone does not show a landfalling hurricane.

[LearnedHat]

With the G-IV flight yesterday, hunters down there now and another G-IV flight today (I think), and all the WFOs we have...should there not be good confidence in at least 3 days out ? That's a lot of data coming from different assets.

At 72 hours out, the NHC forecast has a forecast error of 107 mi. Meaning the storm should be within 107 mi of the forecast point. Track forecasting, while better than intensity forecasting, is still not an exact science:

http://www.nhc.noaa.gov/aboutcone.shtml

since 12 hours ago a cone would have included South Padre to Lafayette, 107 miles either side seems pretty good.

[ronyan]

The 107 mi is mean error correct?

[jasons2k]

Be careful using the 72-hour rule. The margin of error is higher with an initial forecast - also mentioned in the discussion.

[jasons2k]

The other thing to note is with intensifying systems approaching the Texas coast at this trajectory, forecast adjustments tend to shift right/east.

[CycloneGuru]

The other thing to note is with intensifying systems approaching the Texas coast at this trajectory, forecast adjustments tend to shift right/east.

Agree 100%, I think its just a matter of time before it starts making a more easterly shift. It's a waiting game now.