Beta is now off to the east. As of 10:30 am on 9/23/2020, the East and West Forks are well within their banks. So are the lesser tributaries with the exception of Cypress Creek. Lake Conroe is still below 200 feet. And Lake Houston, thanks to a pre-release, is only about a tenth of an inch above normal so far, though it is rising this morning.
4-Day Rainfall Total for Storm
The radar image below shows the total rainfall accumulations across the Houston Area for the duration of the storm, starting at 2:37p.m. on 9/19/2020. This was a story of selective drenching. The south and southwest sides of the city received four times as much rain as Kingwood, Crosby and Atascocita. And more than twice as much rain as Humble. They got caught under a training feeder band; we missed it.
Source: RadarScope Pro
Here are the totals associated with the different colors above:
Light green = 2 inches
Dark green = 3 inches
Light purple = 4 inches
Dark purple = 5 inches
Light blue = 6 inches
Dark blue = 7 inches
Yellow = 8 inches
Orange = 10 inches
Red = 12 inches
Brown = 15 inches
Harris County Flood Warning System Shows Slightly Higher Totals
The radar image may understate the totals. The four-day-rain totals from Harris County Flood Control District gages mirror the pattern above, but show slightly higher numbers. For instance, the radar image shows 3-4″ for Kingwood, but the gages show 4-5″. I live in Kingwood and my personal weather station recorded 4.92 inches for the same four-day period.
Regardless, those caught under training feeder bands on the south and southwest sides got drenched. The Lake Houston Area escaped the worst of the rains.
While these totals are within the ranges predicted at the start of the storm, they definitely fall on the low side. Why?
Space City Weather offered this. “We had two big allies over the last week; moderate wind shear to prevent Beta from strengthening, and dry air over the state from a weak front that disrupted its circulation and prevented the formation of several, thick bands of rainfall. Instead, if you watched the radar closely, there was only ever really one strong band that was perhaps 10 to 15 miles across. This just happened to set up over Houston on Monday and Monday night…”
The Lessons of Beta
Even the heaviest rains we received were about one fourth of what Harvey dropped (40-60 inches). Beta was not unusual. As Space City Weather offered, “A tropical storm that brings a range of 5 to 15 inches rain across Houston, with rainfall rates below 2 inches per hour, is a fairly common event.”
Yet some areas still flooded. In my opinion, this underscores the need for:
HCFCD to continue and accelerate (if possible) its work.
All governments in the region to adopt higher regulations for new developments that reflect Atlas-14 rainfall tables.
People at all levels of government (Federal, State, Counties, Cities) to work together and make flood mitigation a top priority.
Leaders throughout the region to realize that we are all in this together. Slowing floodwater down in one area while speeding it up in another is a losing battle that undermines the economic heart of the region.
Posted by Bob Rehak on 9/23/2020
1121 Days after Hurricane Harveyand 370 after Imelda
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/09/Total-Accumulation-Beta.jpg?fit=1200%2C812&ssl=18121200adminadmin2020-09-23 10:52:472020-09-23 10:57:30Lake Houston Area Lucked Out With Beta
The center of Beta is currently near Bay City and moving ENE. For the next 24 hours, the National Hurricane Center (NHC) forecasts maximum winds at 30 mph.
If any readers in the Lake Houston Area felt left out by Beta, tonight could be your night. According to the NHC, Harris County Meteorologist Jeff Lindner and Space City Weather, models continue to show that a heavy band of rainfall will begin to develop over the next few hours across the northern portions of Harris County.
Beta Tuesday evening at 5PM, courtesy of RadarScope. The bands are moving from SE to NW. But the forward motion of the storm is perpendicular, from SW to NE. That could push new feeder bands into the Lake Houston Area later tonight.
Current Radar Trends Show Storm Moving Toward Northeast Harris County
“Current radar trends show what may be the start of this banding feature from Downtown Houston to Jersey Village to Waller where a broken band of heavy to excessive rainfall is forming,” said Lindner at 4pm today.
He continued, “Models show this band continuing well into the evening and overnight hours across much of northern and northeastern Harris County into Liberty County. Training of heavy rainfall is likely with this banding along with flash flooding.”
Additional rainfall of 4-7 inches will be possible over the northern portions of Harris County into Liberty County and possibly southern Montgomery County with isolated totals of 10-12 inches possible.
JEFF LINDNER, HARRIS COUNTY METEOROLOGIST
(Update At 9:10 PM) The radar image above looked like this and heavy rain had started in Kingwood.
Source: RadarScope
However, in the upper San Jacinto Watershed, the expected rainfall amounts will likely produce flooding only on Cypress and Little Cypress Creeks.
In other parts of Houston, the following streams could flood:
Greens Bayou
Halls Bayou
Hunting Bayou
White Oak Bayou tributaries
Cedar Bayou
Gum Gully
Langham Creek
Horsepen Creek
South Mayde Creek
Bear Creek
The largest threat at this point is street flooding. So move your cars out of the street tonight.
West Fork Still At Normal Level
At 4PM CDT Tuesday, the West Fork San Jacinto at US59 is still nearly seven feet from coming out of its banks.
Flood Warning System Shows Effects of Heavy Training
The high rainfall gradient across Harris County should the effects of heavy training by Beta’s feeder bands during the last 48 hours. Places under the bands received 12 to 14 inches of rains. Meanwhile, the Lake Houston Area received only around an inch so far.
Beta’s heaviest rainfall until now focused on SW Harris County. Figures shown represent last 48 hours.Source: Harris County Flood Warning System.Note 13.44 inches on HW288!
Worst Likely Over for SW Harris County
Some heavy rainfall is still possible in already hard-hit southern and southwestern Harris County. However, where and potentially how much may fall in that area is uncertain.
Beta Continuing to Weaken
High-resolution visible satellite imagery, surface observations, and NOAA Doppler weather radar data from San Antonio and Houston, Texas, indicate that Beta has continued to weaken.
Cloud tops only extend up to 25,000- 30,000 ft, mainly near and northeast of the center. However, they are quite prodigious rain-producers. Rainfall totals of 13-14 inches having been measured across portions of the Houston metropolitan area thus far.
The Future of Beta
Since Beta should remain inland throughout the forecast period, the cyclone is not expected to regain tropical storm status. Beta should degenerate into a remnant low within 36 hours and dissipate over Mississippi or Alabama in 96 hours, if not sooner.
At 4 p.m. Tuesday, September 22, 2020, the National Hurricane Center (NHC) issued its last update on Beta.
Said Space City Weather, “The good news is that this mess will begin to clear our of here by Wednesday morning, if not sooner for some areas. The bad news is that we’ve got to get through later today and tonight.”
Posted by Bob Rehak on 9/22/2020 based on data from HCFCD, NHC and Space City Weather
1120 Days after Hurricane Harvey and 369 since Imelda
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/09/Screen-Shot-2020-09-22-at-5.15.09-PM.jpg?fit=1200%2C759&ssl=17591200adminadmin2020-09-22 17:19:482020-09-22 21:18:04Lake Houston Area Could Be in Beta’s Crosshairs Tonight
At 10 a.m. CDT, the National Hurricane Center (NHC) downgraded Tropical Storm Beta to a tropical depression. The NHC also cancelled the tropical storm and storm surge warnings that were in effect. However, flash flood warnings remain in effect for large parts of the seven-county Houston region, especially the southern part. A flash flood watch remains in effect for the entire region.
RadarScope split image. Left half shows track of active storms as of 9:06AM CDT. Right half shows total rainfall accumulation for Beta. Note band of extreme rainfall near Sugar Land and sharp drop-off near Kingwood.
Flash Flood Warnings and Watches
A flash flood warning means that flooding is in progress. A Flash Flood Watch means that conditions may develop that lead to Flash Flooding.
Source: National Weather Service. Updated at 10:29 a.m. 9/22/2020. Reddish area = Flash flood warning. Green = Flash flood watch.
Lake Conroe/Lake Houston Within Banks
Neither Lake Conroe, nor Lake Houston have yet been adversely affected by Beta.
The level of Lake Conroe stands at 199.63 feet. Normal conservation pool equals 201.
According to the Coastal Water Authority, Lake Houston is at:
Lake Houston Area Lucked Out With Beta
Beta is now off to the east. As of 10:30 am on 9/23/2020, the East and West Forks are well within their banks. So are the lesser tributaries with the exception of Cypress Creek. Lake Conroe is still below 200 feet. And Lake Houston, thanks to a pre-release, is only about a tenth of an inch above normal so far, though it is rising this morning.
4-Day Rainfall Total for Storm
The radar image below shows the total rainfall accumulations across the Houston Area for the duration of the storm, starting at 2:37p.m. on 9/19/2020. This was a story of selective drenching. The south and southwest sides of the city received four times as much rain as Kingwood, Crosby and Atascocita. And more than twice as much rain as Humble. They got caught under a training feeder band; we missed it.
Here are the totals associated with the different colors above:
Harris County Flood Warning System Shows Slightly Higher Totals
The radar image may understate the totals. The four-day-rain totals from Harris County Flood Control District gages mirror the pattern above, but show slightly higher numbers. For instance, the radar image shows 3-4″ for Kingwood, but the gages show 4-5″. I live in Kingwood and my personal weather station recorded 4.92 inches for the same four-day period.
Sheer, Dry Air Result in Low-Side of Predictions
While these totals are within the ranges predicted at the start of the storm, they definitely fall on the low side. Why?
Space City Weather offered this. “We had two big allies over the last week; moderate wind shear to prevent Beta from strengthening, and dry air over the state from a weak front that disrupted its circulation and prevented the formation of several, thick bands of rainfall. Instead, if you watched the radar closely, there was only ever really one strong band that was perhaps 10 to 15 miles across. This just happened to set up over Houston on Monday and Monday night…”
The Lessons of Beta
Even the heaviest rains we received were about one fourth of what Harvey dropped (40-60 inches). Beta was not unusual. As Space City Weather offered, “A tropical storm that brings a range of 5 to 15 inches rain across Houston, with rainfall rates below 2 inches per hour, is a fairly common event.”
Yet some areas still flooded. In my opinion, this underscores the need for:
Posted by Bob Rehak on 9/23/2020
1121 Days after Hurricane Harvey and 370 after Imelda
Lake Houston Area Could Be in Beta’s Crosshairs Tonight
The center of Beta is currently near Bay City and moving ENE. For the next 24 hours, the National Hurricane Center (NHC) forecasts maximum winds at 30 mph.
If any readers in the Lake Houston Area felt left out by Beta, tonight could be your night. According to the NHC, Harris County Meteorologist Jeff Lindner and Space City Weather, models continue to show that a heavy band of rainfall will begin to develop over the next few hours across the northern portions of Harris County.
Current Radar Trends Show Storm Moving Toward Northeast Harris County
“Current radar trends show what may be the start of this banding feature from Downtown Houston to Jersey Village to Waller where a broken band of heavy to excessive rainfall is forming,” said Lindner at 4pm today.
He continued, “Models show this band continuing well into the evening and overnight hours across much of northern and northeastern Harris County into Liberty County. Training of heavy rainfall is likely with this banding along with flash flooding.”
(Update At 9:10 PM) The radar image above looked like this and heavy rain had started in Kingwood.
However, in the upper San Jacinto Watershed, the expected rainfall amounts will likely produce flooding only on Cypress and Little Cypress Creeks.
In other parts of Houston, the following streams could flood:
West Fork Still At Normal Level
At 4PM CDT Tuesday, the West Fork San Jacinto at US59 is still nearly seven feet from coming out of its banks.
Flood Warning System Shows Effects of Heavy Training
The high rainfall gradient across Harris County should the effects of heavy training by Beta’s feeder bands during the last 48 hours. Places under the bands received 12 to 14 inches of rains. Meanwhile, the Lake Houston Area received only around an inch so far.
Worst Likely Over for SW Harris County
Some heavy rainfall is still possible in already hard-hit southern and southwestern Harris County. However, where and potentially how much may fall in that area is uncertain.
Beta Continuing to Weaken
High-resolution visible satellite imagery, surface observations, and NOAA Doppler weather radar data from San Antonio and Houston, Texas, indicate that Beta has continued to weaken.
Cloud tops only extend up to 25,000- 30,000 ft, mainly near and northeast of the center. However, they are quite prodigious rain-producers. Rainfall totals of 13-14 inches having been measured across portions of the Houston metropolitan area thus far.
The Future of Beta
Since Beta should remain inland throughout the forecast period, the cyclone is not expected to regain tropical storm status. Beta should degenerate into a remnant low within 36 hours and dissipate over Mississippi or Alabama in 96 hours, if not sooner.
At 4 p.m. Tuesday, September 22, 2020, the National Hurricane Center (NHC) issued its last update on Beta.
Said Space City Weather, “The good news is that this mess will begin to clear our of here by Wednesday morning, if not sooner for some areas. The bad news is that we’ve got to get through later today and tonight.”
Posted by Bob Rehak on 9/22/2020 based on data from HCFCD, NHC and Space City Weather
1120 Days after Hurricane Harvey and 369 since Imelda
Beta Downgraded to Tropical Depression
At 10 a.m. CDT, the National Hurricane Center (NHC) downgraded Tropical Storm Beta to a tropical depression. The NHC also cancelled the tropical storm and storm surge warnings that were in effect. However, flash flood warnings remain in effect for large parts of the seven-county Houston region, especially the southern part. A flash flood watch remains in effect for the entire region.
Flash Flood Warnings and Watches
A flash flood warning means that flooding is in progress. A Flash Flood Watch means that conditions may develop that lead to Flash Flooding.
Lake Conroe/Lake Houston Within Banks
Neither Lake Conroe, nor Lake Houston have yet been adversely affected by Beta.
The level of Lake Conroe stands at 199.63 feet. Normal conservation pool equals 201.
According to the Coastal Water Authority, Lake Houston is at:
USGS shows that even though the lake has received about 1.75 inches of rainfall to date…
…the lake level has been dropping, no doubt due to a preemptive release.
Posted by Bob Rehak at 10:50 on 9/22/2020 based on NHC, NWS, and RadarScope data
1120 Days since Hurricane Harvey and 369 since Imelda