Flash Floods Kill 3 in Colorado; Dangerous 93L Developing in Gulf of Mexico

By: Dr. Jeff Masters , 3:06 PM GMT on September 12, 2013

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Devastating flash floods swept though numerous canyons along the Front Range of Colorado's Rocky Mountains Wednesday night and Thursday morning, washing out roads, collapsing houses, and killing at least two people. The floods were triggered by widespread torrential rains of 4 - 6" that fell in less than twelve hours, thanks to a flow of extremely moist air from the southeast that pushed up against the mountains. These sort of upslope rain events are so-named because as the air flows uphill, it expands and cools, forcing the moisture in it to fall as rain. Balloon soundings from Denver last night and this morning recorded the highest levels of September moisture on record for the station. The total precipitable water (PW), which is how much water would fall at the ground if the entire amount of water vapor through the depth of the atmosphere was condensed, was 1.33" at 12Z (8 am EDT) on September 12, and 1.31" at 00Z September 12. The previous September record was 1.23", set on September 10, 1980. Balloon soundings began in 1948. Wednesday night's rainfall was heaviest near Boulder, Colorado, where a flash flood watch continues through Thursday evening. Though rainfall amounts today are not expected to be as great as on Wednesday, the soils are saturated, and additional flash flooding will occur today as an upper-level low centered over the southern Great Basin continues to pull a moist southeasterly surface flow of air across Eastern Colorado. A map of Boulder flood zones and detailed history of previous floods in the area may be found here.


Figure 1. Flooding in Boulder, Colorado on Wednesday evening, September 11, 2013. Photo posted by brandish on Instagram @photogjake.


Figure 2. Radar-estimated rainfall for the Colorado's Front Range from the September 11 - 12 flash flood event. Rainfall amounts of 6 - 8" (dark rad colors) were indicated near Boulder (circle with a "+" symbol), and confirmed by rain gauge measurements.


Video 1. Flooding in Boulder, Colorado at 36th and Colorado Street on Wednesday night, September 11, 2013.

Dangerous 93L developing in the Gulf of Mexico
A low pressure system (Invest 93L) over the Southwestern Gulf of Mexico's Bay of Campeche is generating heavy rains over the Yucatan Peninsula and adjacent waters as it moves west-northwest at about 5 mph. Radar loops from Mexico show that 93L has a pronounced rotation and is developing low-level spiral bands, and there is a strong possibility that the Air Force hurricane hunter plane scheduled to investigate 93L Thursday afternoon will find that a tropical depression has formed. Satellite loops show only a modest area of heavy thunderstorms, but these are steadily growing in intensity and areal coverage. The atmosphere is unusually moist, ocean temperatures are a very warm 29 - 29.5°C (84 - 85°F), and wind shear is a moderate 10 - 15 knots. These favorable conditions for development are expected to continue through Monday, according to the latest SHIPS model forecast. The computer models predict a landfall location along the Mexican coast between Veracruz and a location a few hundred miles south of the Texas/Mexico border by early next week. The storm is expected to maintain a forward speed of about 5 mph during the coming five days, and this slow motion will potentially allow 93L enough time to intensify into a hurricane before landfall. The high levels of moisture and slow motion of 93L make it a very dangerous rainfall threat, and I expect rainfall amounts of 5 - 10 inches will affect portions of the Mexican coast between Veracruz and Brownsville, Texas over the next five days. An added danger is the presence of tropical disturbance 90E in the Eastern Pacific Ocean, on the other side of Mexico. If 93L intensifies sufficiently, it could draw in the moisture from 90E across Southern Mexico, resulting in torrential rains on both the Pacific and Atlantic sides of Southern Mexico. In their 8 am EDT Thursday Tropical Weather Outlook, NHC gave 2-day odds of development of 60% and 5-day odds of 80%.


Figure 3. Latest satellite image of Tropical Depression Ten.

Humberto peaks in intensity
Hurricane Humberto is headed northwards over the far Eastern Atlantic, and has likely peaked in strength, with 85 mph winds. Humberto is listed in NHC's preliminary Best-Track data repository as having achieved hurricane strength at 8 am EDT on September 11, which would tie it with Hurricane Gustav of 2002 for latest appearance of the season's first hurricane since 1941. Satellite loops show that Humberto is well-organized hurricane with a distinct eye, but the storm has moved over waters cooler than 26°C, and wind shear has risen to 20 knots, which will likely cause weakening over the next few days. Humberto is not expected to be a threat to any land areas.

Gabrielle heads towards Canada
Tropical Storm Gabrielle is headed northwards to Canada after bringing 40 mph winds and just over an inch of rain to Bermuda on Tuesday night. Satellite loops show that wind shear has ripped up Gabrielle, leaving the storm with almost no heavy thunderstorms, and exposing the low level circulation to view. Wind shear is expected to rise to an extremely high 45 - 70 knots on Friday as Gabrielle encounters a trough of low pressure, which will likely destroy the storm. Gabrielle's remnants will likely bring heavy rain to the Canadian Maritime Provinces on Friday and Saturday.

Jeff Masters

After the Rain (mtnwoman67)
Lots of rain in Colorado for weeks. Last evening's setting sun gave us a great show east of us.
After the Rain

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1899. dabirds
3:58 PM GMT on September 13, 2013
And doesn't the Front Range drain into the MO river basin? lots of help for CO river lakes?

Beautiful day in S C IL - 74 high, good sleeping next two nights mid 40s tonite, 50 Sat nite. Then Sun, a 1 in 95 chance to win a Sportster thanks to KSHE 95! Drawing at Grafton, so at the very least a nice day on the River Road!
Member Since: August 23, 2011 Posts: 0 Comments: 745
1898. AussieStorm
3:46 PM GMT on September 13, 2013
Quoting Neapolitan:
Yeah, I thought about that nonsense comment when I saw it. The thing is, extreme drought with massive fires that destroy homes and take lives in an area, followed just a few months later by massive floods that destroys homes and takes lives in that same area, isn't really "balanced". In fact, it's no more "balanced" than a guy whose left leg swells to twice its normal size due to gets elephantiasis, and who simultaneously loses his right leg in an accident.


Climate whip-lash

Btw, got a storm here right now, I'll put my time-lapse camera on and record it, I'll have a look at it in the morning.

Goodnight all
Member Since: September 30, 2007 Posts: 9 Comments: 15938
1897. bappit
3:45 PM GMT on September 13, 2013
Quoting 1891. LAbonbon:


Yeah, but what a great tune it is :)

It was the death of rock.
Member Since: May 18, 2006 Posts: 10 Comments: 6061
1896. redwagon
3:44 PM GMT on September 13, 2013
Quoting 1871. MrMixon:
One of our "friends" above suggested that this storm perfectly balances the drought in Colorado, ending our problems and putting things right back to the perfect balance which nature always achieves.

Hogwash.

This...


Won't be fixed by this...


Indeed - the areas that needed this rain the least have gotten the most. Southern Colorado has barely been touched by the storm. So, the drought will persist for them.


There might be a silver lining of popcorn showers for some time with all the moisture? Redistributing the rain y'all got?
Member Since: August 4, 2007 Posts: 0 Comments: 3275
1895. daddyjames
3:44 PM GMT on September 13, 2013
Quoting 1886. redwagon:


This track.. is just about perfect, and Avila just wrote it 30 mins ago. He did caution about errors for track, but this looks beautiful.


To all the others, take this into the context from his local perspective.
Member Since: June 25, 2011 Posts: 2 Comments: 3733
1894. WunderAlertBot (Admin)
3:43 PM GMT on September 13, 2013
JeffMasters has created a new entry.
1893. bappit
3:43 PM GMT on September 13, 2013
Quoting 1873. CybrTeddy:


Are you sure you're not looking at an old advisory of Gabrielle?

No. The current discussion mentions the shear. It has been obvious for a couple days.
Member Since: May 18, 2006 Posts: 10 Comments: 6061
1892. Waltanater
3:43 PM GMT on September 13, 2013
Quoting 1889. Waltanater:
"For behold, I will bring a flood of waters upon the earth to destroy all flesh in which is the breath of life under heaven. Everything that is on the earth shall die." Ah ha ha ha!
For those who don't know that was another band called Genisis - 617 or something. have no fear, that flood already happened, so we are safe now. LOL
Member Since: May 16, 2010 Posts: 0 Comments: 1472
1891. LAbonbon
3:41 PM GMT on September 13, 2013
Quoting 1890. daddyjames:


Ya know, now I have that tune stuck in my head :P


Yeah, but what a great tune it is :)
Member Since: June 26, 2013 Posts: 0 Comments: 1817
1889. Waltanater
3:39 PM GMT on September 13, 2013
"For behold, I will bring a flood of waters upon the earth to destroy all flesh in which is the breath of life under heaven. Everything that is on the earth shall die." Ah ha ha ha!
Member Since: May 16, 2010 Posts: 0 Comments: 1472
1888. Thundercloud01221991
3:39 PM GMT on September 13, 2013
Can we get some rain in east Texas?
Member Since: August 1, 2006 Posts: 28 Comments: 3716
1887. bryanfromkyleTX
3:38 PM GMT on September 13, 2013
Quoting 1861. bappit:
Another sheared system. TS by the hair of it's chinny chin chin.


Named the storm to justify funding, ONCE AGAIN!!!!!
Member Since: April 15, 2013 Posts: 0 Comments: 97
1886. redwagon
3:38 PM GMT on September 13, 2013
Quoting 1856. FunnelVortex:
South Texas should still be on the lookout for TS conditions from Ingrid.



This track.. is just about perfect, and Avila just wrote it 30 mins ago. He did caution about errors for track, but this looks beautiful.
Member Since: August 4, 2007 Posts: 0 Comments: 3275
1885. daddyjames
3:37 PM GMT on September 13, 2013
Quoting 1866. Waltanater:
Well, I guess it's time to listen to GOD and build that ARK then! LOL!!


And I always thought that was Bill Cosby . .
Member Since: June 25, 2011 Posts: 2 Comments: 3733
1884. GatorWX
3:36 PM GMT on September 13, 2013
The "Rain-maker".


Member Since: January 1, 2008 Posts: 0 Comments: 3389
1883. Sfloridacat5
3:35 PM GMT on September 13, 2013
Tropical Atlantic has - Tropical Storm Ingrid


Sep. 13, 2013 12:00 Z (Friday)



Coordinates:

19.7N 94.5W



Wind Speed:

35 kts (40.3 mph, 64.8 km/h, 18 m/s)



MSLP:

1000 mb (29.53 inHg, 1000 hPa)



Storm Direction:

W (270°)



Storm Speed:

3 kts (3.5 mph, 5.6 km/h)



System Depth:

Medium



Last closed isobar press.:

1008 mb (29.77 inHg, 1008 hPa)



Last closed isobar radius:

180 nm (207.1 miles, 333.4 km)



Radius of Max Winds:

30 nm (34.5 miles, 55.6 km)
Member Since: September 16, 2007 Posts: 0 Comments: 7321
1882. TropicalAnalystwx13
3:33 PM GMT on September 13, 2013
@NBCNews: Photo: Seaside Heights, N.J. following Sandy and today (following fire) http://t.co/Uww7cvHCVx
Member Since: July 6, 2010 Posts: 113 Comments: 32261
1881. Neapolitan
3:33 PM GMT on September 13, 2013
Quoting 1871. MrMixon:
One of our "friends" above suggested that this storm perfectly balances the drought in Colorado, ending our problems and putting things right back to the perfect balance which nature always achieves.

Hogwash.

This...


Won't be fixed by this...


Indeed - the areas that needed this rain the least have gotten the most. Southern Colorado has barely been touched by the storm. So, the drought will persist for them.
Yeah, I thought about that nonsense comment when I saw it. The thing is, extreme drought with massive fires that destroy homes and take lives in an area, followed just a few months later by massive floods that destroys homes and takes lives in that same area, isn't really "balanced". In fact, it's no more "balanced" than a guy whose left leg swells to twice its normal size due to gets elephantiasis, and who simultaneously loses his right leg in an accident.
Member Since: November 8, 2009 Posts: 4 Comments: 13549
1880. daddyjames
3:33 PM GMT on September 13, 2013
Oops wrong storm.

Member Since: June 25, 2011 Posts: 2 Comments: 3733
1879. hurricanehanna
3:32 PM GMT on September 13, 2013
1871. MrMixon

How are you doing this am ? What are things like in your area ?
Member Since: September 5, 2007 Posts: 0 Comments: 3488
1878. Patrap
3:32 PM GMT on September 13, 2013
BOULDER COUNTY Fire and EMS Channel

Denver
NEXRAD Radar

Storm Total Surface Rainfall Accumulation ° Elevation
Range 124 NMI

Member Since: July 3, 2005 Posts: 426 Comments: 128639
1877. hydrus
3:31 PM GMT on September 13, 2013
Quoting 1864. Patrap:
Think about
Think about how many times I have fallen
Spirits are using me larger voices callin'
What Heaven brought you and me cannot be forgotten



Great song. Southern Cross 1982 release C.S.&N..
Member Since: September 27, 2007 Posts: 1 Comments: 21414
1875. daddyjames
3:31 PM GMT on September 13, 2013
Quoting 1871. MrMixon:
One of our "friends" above suggested that this storm perfectly balances the drought in Colorado, ending our problems and putting things right back to the perfect balance which nature always achieves.

Hogwash.

This...


Won't be fixed by this...


Indeed - the areas that needed this rain the least have gotten the most. Southern Colorado has barely been touched by the storm. So, the drought will persist for them.


Mr. M

How are things by you? Still ok - relatively speaking?
Member Since: June 25, 2011 Posts: 2 Comments: 3733
1874. GatorWX
3:29 PM GMT on September 13, 2013
Quoting 1855. daddyjames:


Southern Texas may not be entirely pleased either - a little too much, too quickly perhaps.


"After nine days I let the horse run free
'Cause the desert had turned to sea
There were plants and birds and rocks and things
there was sand and hills and rings
The ocean is a desert with it's life underground
And a perfect disguise above"
Member Since: January 1, 2008 Posts: 0 Comments: 3389
1873. CybrTeddy
3:29 PM GMT on September 13, 2013
Quoting 1861. bappit:
Another sheared system. TS by the hair of it's chinny chin chin.


Are you sure you're not looking at an old advisory of Gabrielle?
Member Since: July 8, 2005 Posts: 259 Comments: 24167
1872. redwagon
3:29 PM GMT on September 13, 2013
Quoting 1829. calkevin77:


Well if 10 comes in across the North Mexican/South Padre Coast we could see some precip from the upper right quadrant outer rain bands. I'll take anything at this point :) It just really depends on how much moisture this thing picks up over the water and how far North it goes before turning inland. Either way its the best chance a significant part of TX has had for any decent rain in a while.


Avila just put landfall about 250-300miles S of the border, but tracking straight, so more chance of approach to the RGV at 55kts, then and Ern turn. That's better for us than the cone o' doom was last time I looked..
Member Since: August 4, 2007 Posts: 0 Comments: 3275
1871. MrMixon
3:29 PM GMT on September 13, 2013
One of our "friends" above suggested that this storm perfectly balances the drought in Colorado, ending our problems and putting things right back to the perfect balance which nature always achieves.

Hogwash.

This...


Won't be fixed by this...


Indeed - the areas that needed this rain the least have gotten the most. Southern Colorado has barely been touched by the storm. So, the drought will persist for them.
Member Since: March 26, 2006 Posts: 44 Comments: 1520
1870. FunnelVortex
3:29 PM GMT on September 13, 2013
Quoting 1865. hydrus:
Friday the 13th, and we have an I storm..Hopefully the Pacific system will remove some energy from Ingrid.


It wont matter either way, the other storm will make landfall.
Member Since: October 20, 2012 Posts: 7 Comments: 2873
1869. VAbeachhurricanes
3:29 PM GMT on September 13, 2013
Ripped to shreds, poor Humberto...


Member Since: September 6, 2007 Posts: 0 Comments: 6593
1868. Tazmanian
3:28 PM GMT on September 13, 2013
Quoting 1852. sunlinepr:
Interesting "fence" around TD10 blocking access into Conus..... But Tx is still exposed....




TD 10 has a name now
Member Since: May 21, 2006 Posts: 5091 Comments: 115235
1867. daddyjames
3:28 PM GMT on September 13, 2013
Quoting 1863. FunnelVortex:


Plus the OTHER TC coming in from the other side.

As I said yesterday, I expect this to be Boulder, CO x1000


All feeding moisture into the same area - Mexico! The only exception being the Baja region.
Member Since: June 25, 2011 Posts: 2 Comments: 3733
1866. Waltanater
3:28 PM GMT on September 13, 2013
Quoting 1524. trunkmonkey:
God bless all of those involved in the floods of Colorado.

I'm going to post again what my old TV weatherman Bob McClain stated, mother nature has a way of evening things out.
Lake Mead and Lake Powell are way below normal water heights, unfortunately those water levels will rise, due to the current floods
Hate to see it happen this way.
Well, I guess it's time to listen to GOD and build that ARK then! LOL!!
Member Since: May 16, 2010 Posts: 0 Comments: 1472
1865. hydrus
3:27 PM GMT on September 13, 2013
Friday the 13th, and we have an I storm..Hopefully the Pacific system will remove some energy from Ingrid.
Member Since: September 27, 2007 Posts: 1 Comments: 21414
1863. FunnelVortex
3:27 PM GMT on September 13, 2013
Quoting 1860. daddyjames:


This looks like a possible nationwide catastrophe for Mexico.


Plus the OTHER TC coming in from the other side.

As I said yesterday, I expect this to be Boulder, CO x1000
Member Since: October 20, 2012 Posts: 7 Comments: 2873
1862. VR46L
3:27 PM GMT on September 13, 2013
Quoting 1832. Tazmanian:
not evere day you get a TS and a TD hiting MX at the same time


Err neither have yet...





Member Since: March 1, 2012 Posts: 0 Comments: 6927
1861. bappit
3:26 PM GMT on September 13, 2013
Another sheared system. TS by the hair of it's chinny chin chin.
Member Since: May 18, 2006 Posts: 10 Comments: 6061
1860. daddyjames
3:25 PM GMT on September 13, 2013
Quoting 1850. CybrTeddy:


I don't. I'd rather it be a small wind event than a massive rain event.


This looks like a possible nationwide catastrophe for Mexico.
Member Since: June 25, 2011 Posts: 2 Comments: 3733
1859. RGVtropicalWx13
3:25 PM GMT on September 13, 2013
Quoting 1848. CaribBoy:


ALL of these systems are boring.

Umm no they aren't!!!!
Member Since: May 30, 2013 Posts: 0 Comments: 564
1858. barbamz
3:25 PM GMT on September 13, 2013
National Guard begins rescuing residents of flood-besieged Lyons, Colorado
By Ed Payne and Ana Cabrera, CNN
September 13, 2013 -- Updated 1501 GMT

Boulder, Colorado (CNN) -- After more than a day of isolation, help has arrived for flood-besieged Lyons, Colorado.

The Colorado National Guard began evacuating the entire town of about 2,000 at daybreak, Gov. John Hickenlooper said.

The rescue undoubtedly comes as good news for the residents, who have been facing what Fire Chief J.J. Hoffman called a "very large disaster" -- flash flooding from more than half a foot of rain that washed out roads, damaged dams, flooded homes and left the city entirely cut off from the outside.

Not even National Guard helicopters -- grounded by poor weather -- could reach the residents Thursday.
...

Whole article see link above.

Member Since: October 25, 2008 Posts: 55 Comments: 6013
1857. sunlinepr
3:25 PM GMT on September 13, 2013
Member Since: August 2, 2010 Posts: 21 Comments: 9821
1856. FunnelVortex
3:25 PM GMT on September 13, 2013
South Texas should still be on the lookout for TS conditions from Ingrid.

Member Since: October 20, 2012 Posts: 7 Comments: 2873
1855. daddyjames
3:24 PM GMT on September 13, 2013
Quoting 1847. GatorWX:


Mexico says they don't like the rain-maker!


Southern Texas may not be entirely pleased either - a little too much, too quickly perhaps.
Member Since: June 25, 2011 Posts: 2 Comments: 3733
1854. hurricanehanna
3:24 PM GMT on September 13, 2013
Quoting 1853. Patrap:
..Thursday I don't care about you, it's Friday I'm in Love




and yet again, another storm in the GOM on Friday....well, it's a pattern
Member Since: September 5, 2007 Posts: 0 Comments: 3488
1853. Patrap
3:23 PM GMT on September 13, 2013
..Thursday I don't care about you, it's Friday I'm in Love


Member Since: July 3, 2005 Posts: 426 Comments: 128639
1852. sunlinepr
3:23 PM GMT on September 13, 2013
Interesting "fence" around TD10 blocking access into Conus..... But Tx is still exposed....

Member Since: August 2, 2010 Posts: 21 Comments: 9821
1851. daddyjames
3:23 PM GMT on September 13, 2013
Quoting 1832. Tazmanian:
not evere day you get a TS and a TD hiting MX at the same time


Actually two forecast tropical storms hitting. :(
Member Since: June 25, 2011 Posts: 2 Comments: 3733
1850. CybrTeddy
3:22 PM GMT on September 13, 2013
Quoting 1841. taco2me61:


Yelp and not a one may end up being no more than a "Rain Maker" :o)

Which I like "Very Much"

Taco :o)


I don't. I'd rather it be a small wind event than a massive rain event.
Member Since: July 8, 2005 Posts: 259 Comments: 24167
1849. hurricanehanna
3:22 PM GMT on September 13, 2013
Quoting 1844. VR46L:


LMAO



I'm impatient...what can I say.
Member Since: September 5, 2007 Posts: 0 Comments: 3488

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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