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

Share this Blog
58
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1799 - 1749

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38Blog Index

Quoting 1788. barbamz:




Hi, Daddy. Uneventfull, quite chilly weather at my place near Frankfurt. Heater isn't on yet, and the housekeeper, who could do that, is on holidays in Scottland - where they (whole UK) are experiencing
their first autumn storm. Ireland as well, I think.


VR was saying something about rain the other day ;)

Quiet is good, you all had enough action earlier this year. Cold, blah. :)
Member Since: Posts: Comments:
Quoting 1780. Torito:
DANG Humberto is gone now. Naked swirl is all that is left.



It'll be back in a few days, stronger than ever if the models are right.
Member Since: Posts: Comments:
1797. Torito
Quoting 1789. VR46L:


Got a be selfish .. I am relieved that he is not building up to be a major on the outer border of the tropical Atlantic ...


Yea, I doubt he will get back to hurricane status once he loses it later today.
Member Since: Posts: Comments:
Quoting 1656. help4u:
Joe b nailed Sandy 8 days out when everyone said out to sea,he was within 30 miles at landfall.Went to maps of other storms that had impacted area years earlier and based forcast off that and not a super computer that had it going out to sea.Weather repeats itself, nothing new under the sun.Also remember the drought mantra in Colorado that many were hyping,mother nature wins again.It alaways balances out,has for hundreds of years and will continue to do so.Has nothing to do with global warming or anything else,it's just the weather.


When Katrina was forecast to hit Florida as a Cat1 days before it was ever forecast to come to New Orleans, JB kept saying it was going farther west and that New Orleans needed to watch out. Thats when I really started paying attention to him. He is not right all of the time and some of his forecasts are flat out WRONG... But when it matters and when its something big, he is almost always right!
Member Since: Posts: Comments:
Quoting 1784. VR46L:


True but the Atlantic is getting a barren dessert look again..



Yeah, but it has been a BOC/GOM kinda year. Contrary to what everyone was thinking

A pattern not necessarily what one would want to see going into October.

Models have everything quiet for the next week or so, guess we will have to wait and see.
Member Since: Posts: Comments:
Quoting 1779. RGVtropicalWx13:
1774: nope and btw it's a she!!! Get it right!!!


My Austin chances are starting Sunday 20,50,70,80,60,20 - almost a week of rain, unheard of - and they've been this way for 6 days, way before Ingrid crossed the BOC.

Somebody, somewhere is sure of a near TX/MX landfall.
Member Since: Posts: Comments:
1793. Torito
HAMweather says that TD 10 will be a TS by the next advisory.

Member Since: Posts: Comments:
1792. barbamz
Quoting 1773. GatorWX:
Afternoon over there Barb!


Hi, Josh. Already excited because of your trip to Spain? Weather forecast for Barcelona for the next week is very fair and pleasant. Dry, warm, but not too hot :)
Member Since: Posts: Comments:
Reinforcements on the way to the gulf, from the Epac..?
Member Since: Posts: Comments:
1790. Patrap
There is no debate, only a perceived one.

Even NOAA Knows dat.



Sip, ahhhhh'

Global Climate Change Indicators


Member Since: July 3, 2005 Posts: 414 Comments: 125503
1789. VR46L
Quoting 1780. Torito:
DANG Humberto is gone now. Naked swirl is all that is left.



Got a be selfish .. I am relieved that he is not building up to be a major on the outer border of the tropical Atlantic ...
Member Since: March 1, 2012 Posts: 0 Comments: 6613
1788. barbamz
Quoting 1772. daddyjames:


Good afternoon barbmz. The pattern here in the US seems to be semi-stuck. How are things in NoEU?




Hi, Daddy. Uneventfull, quite chilly weather at my place near Frankfurt. Heater isn't on yet, and the housekeeper, who could do that, is on holidays in Scottland - where they (whole UK) are experiencing
their first autumn storm (edit: or will at Sunday). Ireland as well, I think.


Winds at Sunday.

Member Since: Posts: Comments:
1787. 7544
hmm 3 stroms g,h,i,in the first two weeks of sept not a bad track record tropics are going to play catch up time with the numbers . could get 2 more before the end of this month imo closer to home .
Member Since: Posts: Comments:
1786. GatorWX
Please no CC/GW/AGW stuff. C'mon, seriously? It's an argument and never a discussion. Let's just agree to disagree. You can't win a debate by arguing your point anyway. You'll just bolster the other's opinion, especially when you quote them and respond directly.
Member Since: January 1, 2008 Posts: 0 Comments: 2386
Hi everyone I usually lurk and enjoy all the useful info given here. We really had a downpour this morning from about 1:00 am. Lots of lightning and thunder. Never heard thunder like that before. Many folks flooded out in Diego Martin, Trinidad. Some roads including the Diego Martin Highway under slosh and water. KFC in Diego also flooded out and there is a Senior Citizen Home not too far from KFC, that got flooded as well. Right now some members of the defence force and other emergency agencies are assisting folks whose homes have been flooded out. Today looks as though we will get some more rain as well.
Member Since: Posts: Comments:
1784. VR46L
Quoting 1776. daddyjames:


First half yes, and it looks as if the game is lost - but there have been remarkable comebacks in the 2nd.

At least in sports ;)


True but the Atlantic is getting a barren dessert look again..

Member Since: March 1, 2012 Posts: 0 Comments: 6613
1783. hydrus
Quoting 1769. pensacolastorm:


I'm hoping that is an ULL.
It is, but it is gradually working down. It showing up well at 500 mb..
Member Since: Posts: Comments:
Quoting 1778. PensacolaDoug:




Dry! For a change!


LOL - well you all did need a break, to say the least.
Member Since: Posts: Comments:
Quoting 1771. GatorWX:


It's essentially a Fujiwhara-type effect, no? That's my thought anyway. The tug from two strong vorticies close to one another.


No. they're too weak
Member Since: Posts: Comments:
1780. Torito
DANG Humberto is gone now. Naked swirl is all that is left.

Member Since: Posts: Comments:
1774: nope and btw it's a she!!! Get it right!!!
Member Since: Posts: Comments:
Quoting 1663. daddyjames:


Good morning PD - I see you disagree - how are things in the panhandle?




Dry! For a change!
Member Since: Posts: Comments:
Central Caribbean is an ULL ,but there is strong vorticity at mid levels , which could quite easily work itself down to the surface
Member Since: Posts: Comments:
Quoting 1770. VR46L:


Give it up ... this season may have had many clouds named . Humberto is going to save the Ace figures slightly which are frankly laughable, at the moment, 8 Storms with Ace is around 17 ...

Definite Bust first half of a season...


First half yes, and it looks as if the game is lost - but there have been remarkable comebacks in the 2nd.

At least in sports ;)
Member Since: Posts: Comments:
Quoting 1763. SouthernIllinois:

No, that is not correct. Bastardi AND Dr. Master's both do not have degrees in climatology Scott. To say that one has more experience than the other is simply unsubstantiated.


I'm sure that Dr. Masters would love to know he's being compared to Jo. Bastardi!
Member Since: Posts: Comments:
Looks like Ingrid may just kill himself by crashing into Southern Mehico
Member Since: Posts: Comments:
1773. GatorWX
Afternoon over there Barb!
Member Since: January 1, 2008 Posts: 0 Comments: 2386
Quoting 1768. barbamz:


And besides the trough, more rain developing on the way to drenched Colorado. Good morning over there, folks.


Good afternoon barbmz. The pattern here in the US seems to be semi-stuck. How are things in NoEU?
Member Since: Posts: Comments:
1771. GatorWX
Quoting 1764. Funication:
Watch from way up here



It's essentially a Fujiwhara-type effect, no? That's my thought anyway. The tug from two strong vorticies close to one another.
Member Since: January 1, 2008 Posts: 0 Comments: 2386
1770. VR46L
Quoting 1734. Neapolitan:
Definitely too early. I'm not in any way claiming that 2013 will equal 2010's prodigious output, but the former is at the moment very closely tracking the latter:

2013


Give it up ... this season may have had many clouds named . Humberto is going to save the Ace figures slightly which are frankly laughable, at the moment, 8 Storms with Ace is around 17 ...

Definite Bust first half of a season...
Member Since: March 1, 2012 Posts: 0 Comments: 6613
Quoting 1761. hydrus:
Morning Gator..I believe the spin over the Central Caribbean has potential after the gulf system moves inland...Any thoughts.?


I'm hoping that is an ULL.
Member Since: Posts: Comments:
1768. barbamz


And besides the trough, more rain developing on the way to drenched Colorado. Good morning over there, folks.
Member Since: Posts: Comments:
1767. GatorWX
Quoting 1761. hydrus:
Morning Gator..I believe the spin over the Central Caribbean has potential after the gulf system moves inland...Any thoughts.?


Morning Chris,

I don't. Maybe (big one) 98L, but central Caribbean low is way up high in the sky.

Member Since: January 1, 2008 Posts: 0 Comments: 2386
Seems like the center could be relocating in the deeper convection? Just look at the difference between the best track and recons. More northeast.
Member Since: Posts: Comments:
Quoting 1759. HurricaneCamille:


It's going to come close to category 1 status.


Agree that is possible - but only if it does not wander onto the coast . . . it is pretty close right now.

If it does, I'm willing to wager this will be two days from now.
Member Since: Posts: Comments:
Watch from way up here
Quoting 1742. GatorWX:
This makes me think it may not go north.



Needs disconnection from 90E.

Member Since: Posts: Comments:
Quoting 1714. calkevin77:


Well TB has a AOI slated for a Cat-5-Martin forecasted so we shall see :)


And a shunned and shamed former captain of an imitation quarterback...good luck with that.
Here in God's country its 82 with a light north east Brees, probably blow a football 450 yards
Member Since: Posts: Comments:
1761. hydrus
Quoting 1757. GatorWX:


However, the doughnut shape is characteristic, as Levi pointed out and to those who watched, of the surface trof which 10 developed from. His theory and reasoning is the surface trough will wrap around Ingrid before it makes landfall, thus tugging it that direction, northwest to north-northwest. It seems quite far south at this point for a TX/MEX landfall, imo.



Morning Gator..I believe the spin over the Central Caribbean has potential after the gulf system moves inland...Any thoughts.?
Member Since: Posts: Comments:
Quoting 1755. SouthernIllinois:

Nah. Cuz with that logic, perhaps Dr. Masters should stick with what he started out with -- tropical weather.

No, it doesn't. The claim was that Bastardi can successfully predict the tracks of some hurricanes. We already know that Bastardi has difficulty with scientific concepts fundamental to climate change, including the laws of thermodynamics. This suggests that his should stick with the science topics that he has experience and success in (supposedly hurricanes).

Contrast this with Dr. Masters, who has experience in understanding the tropics and climate change. There is not a record of Dr. Masters misunderstanding basic physics concepts. As such, he can be considered an authoritative source to blog about both.
Member Since: Posts: Comments:
Quoting 1752. daddyjames:


My comment was in regards to the track.

Yes, it bumped up what - 5-10 mph. RI this is not.


It's going to come close to category 1 status.
Member Since: Posts: Comments:
1758. hydrus
Quoting 1754. VirginIslandsVisitor:
Good morning everyone

Sitting here doing up invoices for fish sales right now. Yellowtail and Rainbow Runner for sale. Any takers? ;)

Lovely day here on the island.

Lindy
I,m in for Yellowtail...Seasoned and pan fried with sauteed onions....fries....ice cold Fresca...life is good.
Member Since: Posts: Comments:
1757. GatorWX
Quoting 1742. GatorWX:
This makes me think it may not go north.



Needs disconnection from 90E.


However, the doughnut shape is characteristic, as Levi pointed out and to those who watched, of the surface trof which 10 developed from. His theory and reasoning is the surface trough will wrap around Ingrid before it makes landfall, thus tugging it that direction, northwest to north-northwest. It seems quite far south at this point for a TX/MEX landfall, imo.



Member Since: January 1, 2008 Posts: 0 Comments: 2386
Good morning everyone

Sitting here doing up invoices for fish sales right now. Yellowtail and Rainbow Runner for sale. Any takers? ;)

Lovely day here on the island.

Lindy
Member Since: Posts: Comments:
Quoting 1747. JNTenne:
Vera Cruz MX webcam


Nasty weather, but what a gorgeous city!
Member Since: Posts: Comments:
Quoting 1748. HurricaneCamille:


Open your eyes man, the thing is down there intensifying I type this.


My comment was in regards to the track.

Yes, it bumped up what - 5-10 mph. RI this is not.
Member Since: Posts: Comments:
Quoting 1742. GatorWX:
This makes me think it may not go north.



Needs disconnection from 90E.


Systems that far south in the BOC almost always end up south of Veracruz in this steering pattern. It's just way too close to land and too far west to gain much more latitude.
Member Since: Posts: Comments:
Quoting 1739. daddyjames:


I don't think so, it looks as if the trough/front to the north is not going to penetrate as far south and west into Texas as originally forecast. The ridge will build back in and start pushing this towards Mexico, around Tampico.


Hard to be sure either way, entirely possible it will shift.
Member Since: Posts: Comments:
Quoting 1745. ILwthrfan:
Is there any way that the Mountains of Mexico could contribute dry air to Ingrids circulation? As the circulation grows stronger and more expansive I would imagine wind pulling in from the west would be compressing and drying as moves downslope of the mountains, maybe keeping Ingrid in check somewhat? Something to keep an eye on as it is very close land as it is.


Too much moisture in region right now for that to occur. If anything, moisture from the Pacific will amplify things.
Member Since: Posts: Comments:

Viewing: 1799 - 1749

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38Blog Index

Top of Page

About JeffMasters

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