October 2015 - Severe Storms/Moderate Risk Excessive Rainfal

[ticka1]

Hopefully Jeff's update answered all the SE Texas folks questions. I'll be away for a while after some minor surgery. Great job everyone in keeping those updates coming.

We will miss you srainhoutx - get well quickly.

[srainhoutx]

Update from Jeff:

Increasing confidence that SE TX is going to have some significant impacts over the weekend from a developing storm along the TX coast helped by the remains hurricane Patricia.

Main threats will be excessive rainfall and high coastal tides both of which will likely cause some degree of flooding.

Rainfall:
Confidence that heavy rainfall axis will end up somewhere across SE TX from midday Saturday to late Sunday evening or even Monday morning. Rainfall totals widespread of 5-7 inches with isolated amounts of 10-12 inches will be possible. Where exactly the heavy rain falls is still a question, but models have been trending toward the US 59 corridor including Harris County. It is still possible that the heaviest rains could remain offshore or to the NW of Harris County.

Rainfall of the expected magnitude will cause flooding even with the dry grounds. Of concern is the potential for hourly rainfall rates of 2-4 inches and this type of rainfall continuing in training bands for a few to several hours. Watersheds can handle several inches of rainfall due to the dry conditions, but amounts toward the higher end of the expect totals will likely cause some problems.

A Flash Flood Watch is in effect from Saturday morning until Monday morning.

Tides:
Still expecting tides of 4.0-5.0 ft above MLLW Saturday afternoon and evening into Sunday morning. Water levels of this heights will have impacts around Clear Lake including Nassau Bay and Clear Lake Shores as well as portions of Kemah and Seabrook. This will mainly result in street flooding and flooding under elevated structures.

Minor flooding will also be possible in Shoreacres along Taylor’s Bayou and near the Battleship Texas and the Lynchburg Ferry Landing. Elevated tides will also push northward up the lower portion of the San Jacinto River.

Any increase in the intensity of the surface low forming over the TX coastal waters will only increase these expected tides levels a little more and values of 45.0-6.0 ft are possible.


A coastal Flood Watch has been issued by the NWS to cover the possible flooding at times of high tide and this will likely be upgraded to a warning on Saturday.

HCFCD Actions:

· Clear Creek Second Outlet Gates will be opened this afternoon which will help expedite storm run-off out of Clear Lake.

· HCFCD Flood Operations Team will move to Stand By Mode at 200pm Saturday.

· HCFCD Flood Operations staff will be at Transtar effective at 200pm and at HCFCD offices effective at 600pm Saturday (possibly sooner based on conditions). 12-hr shifts will be in effect until Monday.

· Myself and Kim Jackson will support media operations at HCOEM and Karen Hastings will be helping in the JIC

· 3 HCFCD crews will be deployed at 200pm Saturday to check coastal water levels and possible flooding impacts in SE Harris County.

· HCFCD Phone Bank will be established at 600pm Saturday and can be reached at 713-684-4000

[srainhoutx]

Updated 5 Day QPF graphic has been issued.

[Rip76]

Watch out if that number verifies.

[DoctorMu]

Updated 5 Day QPF graphic has been issued.

Thanks - get well quickly!

[sau27]

Based on what the models are continuing to show and based on the updates from pro-mets this weekend we are for all intents and purposes looking at a weak (relative to wind) tropical storm, even though it wont technically meet the criteria to be classified as such.
Given the expected timing of this low moving by Saturday night, is it out of the question to think about a core-rain event taking place? Its not a term you hear very often but I know it can happen at night with dying tropical systems.

[Katdaddy]

Wow, what a historic weather day with CAT 5 Patricia being the most intense hurricane on record in the W Hemisphere. Unreal maximum winds of sustained at 200 with gust to 245 MPH earlier today. Patricia's extreme eyewall is nearing the SW MX Coast currently at 190G235MPH. Hold on tight and stay safe iCyclone Josh Morgerman. Cant imagine what you will experience during the next few hours.

For the upcoming SE TX weather this weekend the Houston-Galveston NWS state it very well "Dangerous Major Storm Event To Move Through Southeast Texas This Weekend". Patricia's energy will combine with a surface low along the TX Coast resulting in flooding rains with high rainfall rates, coastal flooding, and winds that may reach TS force in gusts along the coast. Rainfall totals forecast to average 9-12" S of I-10 to the coast with higher amounts possible. This will be a non-tropical low but it will feel like a TS. This has all the parameters in place to be a very significant event. Very heavy flooding rains will be possible across STX, S Central TX, Central TX including the Hill Country, N Central TX, NTX, ETX, NW TX, and SW LA. NTX has already seen flooding today with Flash Flooding Warning's currently in effect. This is "Turn Around Don't Drown Weekend". More info through the weekend. Stay tuned and be weather aware.

[srainhoutx]

As Dr. Neil will tell you, it's usually not a good thing when KHOU brings him back for the local newscast. Always good to see one of this online weather community biggest supporter. Turn on Channel 11/KHOU to get the latest.

[srainhoutx]

Update from Jeff:

Potentially dangerous and life threatening Flash Flood Event heading for SE TX.

Much advertised flash flood event is underway across TX. Since early this afternoon 11.6 inches of rainfall has fallen in Corsicana, TX. This clearly shows the capability of this air mass the produce “incredible” rainfall totals.

Latest guidance is now is pretty good agreement that rainfall maximum will be over SE TX and recent WPC graphics now paint an astounding maximum of 13.0 inches just south of Houston in 48 hours. A larger area of 8-12 inches includes nearly all of Harris County. Rainfall of this magnitude if it occurs as currently suggested will produce significant flash flooding and creek/bayou flooding.

Event shall commence early Saturday morning NW parts of SE TX and begin to affect the central areas in the early afternoon hours with conditions becoming hazardous and dangerous into the early and overnight hours.

Meteorologist will likely not be any more certain than now on exactly where the heavy rainfall will fall until the event is underway, but given the general decent model agreement now…much of SE TX is going to likely see some very significant totals.

No changes to tides or coastal flooding impacts at this time.

[Andrew]

Just a reminder that the track of the coastal low will determine where the heaviest rain will setup. We could see a rather sharp gradient, but wherever the banding features setup flooding will become an issue fast.

[Paul Robison]

2 questions.

1. Will the aftermath of these rains be similar to the Ike aftermath? You know, millions of households left in the dark, roads completely impassable, etc?


2. This is hypothetical:

What if Hurricane Patricia were a gulf of Mexico storm (not pacific) and it was heading towards Houston/Galveston instead of Manzanillo, Mex right now. How would city officials respond? What would residents be instructed to do?

[Andrew]

2 questions.

1. Will the aftermath of these rains be similar to the Ike aftermath? You know, millions of households left in the dark, roads completely impassable, etc?


2. This is hypothetical:

What if Hurricane Patricia were a gulf of Mexico storm (not pacific) and it was heading towards Houston/Galveston instead of Manzanillo, Mex right now. How would city officials respond? What would residents be instructed to do?

1. No

2. Similar to Rita or Ike I would presume. Luckily this is not the case.

[davidiowx]

As Dr. Neil will tell you, it's usually not a good thing when KHOU brings him back for the local newscast. Always good to see one of this online weather community biggest supporter. Turn on Channel 11/KHOU to get the latest.

Darn I missed it. Hope there is a video I can see..

[srainhoutx]

Update from Jeff regarding Patricia:

At 615pm the center of Hurricane Patricia crossed the coast of Mexico at Cuixmala or 55 miles WNW of Manzanillo , MX. The hurricane made landfall with sustained winds of 165mph and a central pressure of 920mb…the inner eyewall appeared to collapse as the center neared the coast which is not surprising given how difficult it is to maintain such an intense hurricane to landfall as land friction comes into play. With that said…those locations in the eyewall of this hurricane are experiencing catastrophic damage. Video posted to Twitter just outside the eyewall wind maximum was easily sustained at over 100mph based on the howling nature.

A US hurricane intercept chase team appears to have been located very near or possibly at the landfall point, but there has been no contact with them since about mid afternoon.


(I will add that the chaser Jeff mentioned is not Josh. Josh did catch the eyewall, but is safe and communicating with Scott747 and providing updates on The Weather Channel).

[unome]

do you know what chasers he was talking about?

[srainhoutx]

do you know what chasers he was talking about?

No, I do not know. Perhaps Jeff will answer your question. He has been dropping in several times a day. Although tomorrow afternoon onward I am sure he will be very busy. I will try and get a message to him tomorrow on NWSchat.

[Paul Robison]

A possible light in the tunnel? A possible saving grace? HGX says:

IF THE TRACK ENDS UP FURTHER OFFSHORE THAN MOST MODELS ARE INDICATING...THEN
THE HEAVIEST RAINFALL COULD END UP OVER THE OPEN GULF WATERS. THIS
STORM SYSTEM ALSO HAS THE POTENTIAL FOR LOTS OF ISSUES ALONG THE
COAST (INCLUDING HIGH TIDES AND STRONG ONSHORE WINDS AS THE SYSTEM
MOVES INTO THE AREA SATURDAY NIGHT AND SUNDAY...AND THEN LOWERING
TIDE LEVELS AND STRONG OFFSHORE WINDS AS THE SYSTEM EXITS OFF TO
THE EAST SUNDAY NIGHT INTO MONDAY). 42

I've heard that during an El Nino year, the forecast models do a LOUSY job with tracking low-pressure disturbances, so I don't think this is out of the question.

[Scott747]

Wow. That's interesting. When Jeff says 'intercept team' it sounds like an organized group and my first thought was the Texas Tech research team but I'm not aware of them being in the area. And we would have heard about any of the handful of potential American chasers.

There really wasn't many options in the eventual landfall area. We were gonna have Josh move up towards Costa Careyes but it didn't sound like it was worth the risk. Not sure if the resort up there was open. There might have been a chaser there who would have taken a good hit.

Steve.. Get with Jeff if he knows who it is and if he doesn't turn up I'll see if Josh and Erik can inquire about him before they head out.

[cperk]

A possible light in the tunnel? A possible saving grace? HGX says:

IF THE TRACK ENDS UP FURTHER OFFSHORE THAN MOST MODELS ARE INDICATING...THEN
THE HEAVIEST RAINFALL COULD END UP OVER THE OPEN GULF WATERS. THIS
STORM SYSTEM ALSO HAS THE POTENTIAL FOR LOTS OF ISSUES ALONG THE
COAST (INCLUDING HIGH TIDES AND STRONG ONSHORE WINDS AS THE SYSTEM
MOVES INTO THE AREA SATURDAY NIGHT AND SUNDAY...AND THEN LOWERING
TIDE LEVELS AND STRONG OFFSHORE WINDS AS THE SYSTEM EXITS OFF TO
THE EAST SUNDAY NIGHT INTO MONDAY). 42

I've heard that during an El Nino year, the forecast models do a LOUSY job with tracking low-pressure disturbances, so I don't think this is out of the question.

I have saw no modeling to indicate the low tracking further offshore.

[Paul Robison]

A possible light in the tunnel? A possible saving grace? HGX says:

IF THE TRACK ENDS UP FURTHER OFFSHORE THAN MOST MODELS ARE INDICATING...THEN
THE HEAVIEST RAINFALL COULD END UP OVER THE OPEN GULF WATERS. THIS
STORM SYSTEM ALSO HAS THE POTENTIAL FOR LOTS OF ISSUES ALONG THE
COAST (INCLUDING HIGH TIDES AND STRONG ONSHORE WINDS AS THE SYSTEM
MOVES INTO THE AREA SATURDAY NIGHT AND SUNDAY...AND THEN LOWERING
TIDE LEVELS AND STRONG OFFSHORE WINDS AS THE SYSTEM EXITS OFF TO
THE EAST SUNDAY NIGHT INTO MONDAY). 42

I've heard that during an El Nino year, the forecast models do a LOUSY job with tracking low-pressure disturbances, so I don't think this is out of the question.

I have saw no modeling to indicate the low tracking further offshore.

That's right. There is no modeling.
BUT.....
Remember, they said if the track ends up further offshore THAN MOST MODELS ARE INDICATING. The models are NOT indicating it, true. But HGX seems open to that possibility. And, when I say forecast models don't handle lows during El Nino years, I'm quoting Accuweather's Henry Margusity.