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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Quoting 1195. CaribBoy:


I would say.... no.

XD
I disagree... I am sure I read a few sighs of satisfaction at the rain u got before Gabrielle fell apart the first time.... lol
Member Since: Posts: Comments:
Quoting 1193. GatorWX:
It does look ominous doesn't it?



It is warm indeed!


The NHC agrees. Can't get any more blunt than this:

000
WTNT35 KNHC 122335
TCPAT5

BULLETIN
TROPICAL DEPRESSION TEN INTERMEDIATE ADVISORY NUMBER 1A
NWS NATIONAL HURRICANE CENTER MIAMI FL AL102013
700 PM CDT THU SEP 12 2013

...TROPICAL DEPRESSION MOVING SLOWLY WESTWARD...
...LIFE-THREATENING FLOODING EXPECTED OVER PARTS OF EASTERN
MEXICO...

Member Since: June 25, 2011 Posts: 2 Comments: 3733
1197. GatorWX
Sounds better than warm lager.
Member Since: Posts: Comments:
1196. pottery
Quoting BahaHurican:
Even inside it's been ridiculous ... got home and got into the a/c with a long cold drink of something [not saying what lol] WITH ICE....

I'm not saying we're going to end up with a hyperactive season, but this weirdness is just.... ominous.

Agreed.

Makes you wonder what is going to happen next.
Ominous yes.
Member Since: Posts: Comments:
Quoting 1031. TropicalAnalystwx13:

Do you do anything other than complain?



I would say.... no.

XD
Member Since: October 6, 2007 Posts: 0 Comments: 6455
1194. pottery
Quoting GatorWX:
Watcha hydrating with Pott? Anything good?

Just the usual. :):))

But I have to admit to doing ''a Baha'' earlier.
Lager & Ice? Why not ?

heheheheh
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1193. GatorWX
It does look ominous doesn't it?



It is warm indeed!
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1192. GatorWX
Watcha hydrating with Pott? Anything good?
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Quoting 1188. pottery:


Yeah, exhausting weather,
. Especially since I got to spend the day outside in the sun.
Just trying to re-hydrate now.......
Even inside it's been ridiculous ... got home and got into the a/c with a long cold drink of something [not saying what lol] WITH ICE....

I'm not saying we're going to end up with a hyperactive season, but this weirdness is just.... ominous.
Member Since: Posts: Comments:
1190. pottery
Quoting GatorWX:


All these ull's and the presence of the epac disturbance is going to stack up a lot of moisture. This could be a really big time rain event and not just for MX.

Yeah
Thats a big area with loads of moisture involved.

Could get nasty.
Member Since: Posts: Comments:
1189. GatorWX
Quoting 1186. Tazmanian:



is it me or dos TD 10 seem too be having a backword spin too it


There is anticyclonic spin above 10. The surface is spinning the right direction. Well ventilated, let's just say that.
Member Since: Posts: Comments:
1188. pottery
Quoting daddyjames:


LOL pot, Good evening, how are you?

Edit: Corrected a couple of errors, including the one pointed out :D

Doing very well, considering...


Quoting BahaHurican:

Been saying that since May. It barely got to 90 here... cloudy/hazy all day... stifling in the afternoon...


Yeah, exhausting weather,
. Especially since I got to spend the day outside in the sun.
Just trying to re-hydrate now.......
Member Since: Posts: Comments:
Quoting 1166. allancalderini:
90E looks poised to become a td in the Epac.Mexico may get a double hit after all.


I haven't followed the EPAC as I should - mesmerized by TD10 - did 99L/TD8 become one of the systems we're talking about after crossing over to the EPAC? Is it one of that train just SW of TD10?
Member Since: August 4, 2007 Posts: 0 Comments: 3280
Quoting 1182. GatorWX:


All these ull's and the presence of the epac disturbance is going to stack up a lot of moisture. This could be a really big time rain event and not just for MX.



is it me or dos TD 10 seem too be having a backword spin too it
Member Since: May 21, 2006 Posts: 5091 Comments: 115454
1185. GatorWX


Worse before it gets better it appears.
Member Since: Posts: Comments:
Quoting 1139. tramp96:
More evidence that GW is a crock heck even the good doctor has slowed waaaay down on the amount of GW articles.

Link


Going to Fox News for scientific information is like going to see Krusty the Clown for open brain surgery.

That being said, that news article is not referencing a study. It is referencing an op-ed in the journal (the opinions and comments section). The articles appearing in the opinion and comments section are not peer reviewed research.

The opinion article in no way comes to the conclusion the AGW is a crock. In fact, it is exploring several different ways to improve the modeling of the Earth's climate to better capture intermediate variability (i.e. make models more accurate).

Anyway, the tropics are finally looking alive. Seems like 93L will get a chance to intensify into the next named storm.

Member Since: Posts: Comments:
0z SHIPS makes 10L a Category 1 hurricane prior to landfall somewhere near 96 hours out.

V (KT) LAND 30 33 36 38 40 45 50 54 60 65 67 47 33
Member Since: July 6, 2010 Posts: 113 Comments: 32853
1182. GatorWX


All these ull's and the presence of the epac disturbance is going to stack up a lot of moisture. This could be a really big time rain event and not just for MX.
Member Since: Posts: Comments:
Quoting 1173. pottery:
Good evening all.

Hot and breathless day here.
Winds were Calm and occasionally Westerly.
Strange, unless there is a Low east of here which there wasn't.

Where are the Trades ?????
This is a Weird season, man.
Been saying that since May. It barely got to 90 here... cloudy/hazy all day... stifling in the afternoon...
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Quoting 1176. pottery:


I'm glad I'm not one of them.

:):))


LOL pot, Good evening, how are you?

Edit: Corrected a couple of errors, including the one pointed out :D
Member Since: June 25, 2011 Posts: 2 Comments: 3733
Quoting 1167. moonlightcowboy:
Good evening, weathergeeks! ;)

Y'all got TD10 figured out yet? Is DOOM imminent? ')


Seems like mostly rain related DOOM for the MX... x2 if u count the EPac system that also seems 2 be ramping up...
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1178. GatorWX
Quoting 1170. Levi32:
Good evening.

Blog update:

Thursday Evening Video Discussion on Tropical Depression #10


Very good video Levi! Could not agree with you more.
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Quoting 1151. GeoffreyWPB:


He voted no for Sandy aid...here is his release...and it is weather related...I post...You decide...

U.S. Sen. Ted Cruz Statement on the Disaster Relief Act of 2013


Contact: press@cruz.senate.gov / (202) 228-7561
Monday, January 28, 2013


Emergency relief for the families who are suffering from this natural disaster should not be used as a Christmas tree for billions in unrelated spending, including projects such as Smithsonian repairs, upgrades to National Oceanic and Atmospheric Administration airplanes, and more funding for Head Start.

Two thirds of this spending is not remotely “emergency”; the Congressional Budget Office estimates that only 30% of the authorized funds would be spent in the next 20 months, and over a billion dollars will be spent as late as 2021.
.
I guess his district doesn't get hit by hurricanes...
Member Since: Posts: Comments:
1176. pottery
Quoting daddyjames:


We (other bloogers and I) had this discussion earlier - I said there was shear to the north, and it looked as if it would hang around impeding any opportunity for 10L to significantly strengthen. Others disagreed.

Right now, I see the ULL to the north sheering off any convection. The center is moving 4 mph in circles.

Regardless, this is going to be remembered for rain, not for winds, so it doesn't matter if it strengthens appreciably. If it does get named, depending upon its impact on Mexico, it may be one of the rare tropical storms that has its name retired.


I'm glad I'm not one of them.

:):))
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It would be helpful if a ASCAT pass is made to see how the structure of TD TEN is.
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Should be the strongest storm thus far in my stay here in Asheville...

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1173. pottery
Good evening all.

Hot and breathless day here.
Winds were Calm and occasionally Westerly.
Strange, unless there is a Low east of here which there wasn't.

Where are the Trades ?????
This is a Weird season, man.
Member Since: Posts: Comments:
1172. GatorWX
Quoting 1167. moonlightcowboy:
Good evening, weathergeeks! ;)

Y'all got TD10 figured out yet? Is DOOM imminent? ')




It's gonna rain!
Member Since: Posts: Comments:
1171. will40
the ignore feature works well . just saying
Member Since: Posts: Comments:
1170. Levi32
Good evening.

Blog update:

Thursday Evening Video Discussion on Tropical Depression #10
Member Since: Posts: Comments:
Out of respect for the rest of the bloggers here I will refrain from entering into a political debate, even though I have strong views on the subject of Ted Cruz, Hillary Clinton, Rand Paul, Joe Biden and a host of others...and I have a Political Science degree. Please demonstrate the same respect and keep your political views off this board, if you don't mnid.

Thank you in advance.
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It's nearly impossible to go one day without drama on WU these days...
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Good evening, weathergeeks! ;)

Y'all got TD10 figured out yet? Is DOOM imminent? ')


Member Since: Posts: Comments:
90E looks poised to become a td in the Epac.Mexico may get a double hit after all.
Member Since: October 15, 2011 Posts: 0 Comments: 4467
Quoting 1158. jascott1967:


He legally gave up his Canadian citizenship this past summer. Constitutionally, he can run and he probably will.

PS - I don't normally comment on political subjects on this board unless I see something false.


If you minus blog-derailing non-wx narcissistic political comments 10 times, they disappear from your view and don't return when you hit refresh. You're free of them forever, whichever camp you reside in. Then if that narcissist decides to make a wx-related post, you won't have ignored him and will see it.
Member Since: August 4, 2007 Posts: 0 Comments: 3280
Quoting 1160. GatorWX:


The Republican Party certainly seems to b headed down that path.

It's too bad they can't get a real libertarian. They don't need Cruz, lol.

4 ULLs, just in the Caribbean wv sat. All seemingly converging on 10. Should be well ventilated if it can avoid wind shear from them. That seems rather inevitable.



Unless that convection mass isn't actually indicative of the llc (sheared some), it doesn't seem to be moving much at all. 4 mph always seems generous. CIMSS shows 20-25 kts, GFS was initialized with essentially none.




We (other bloggers and I) had this discussion earlier - I said there was shear to the north, and it looked as if it would hang around impeding any opportunity for 10L to significantly strengthen. Others disagreed.

Right now, I see the ULL to the north sheering off any convection (edit: on the north side of 10L). The center is moving 4 mph in circles.

Regardless, this is going to be remembered for rain, not for winds, so it doesn't matter if it strengthens appreciably. If it does get named, depending upon its impact on Mexico, it may be one of the rare tropical storms that has its name retired.
Member Since: June 25, 2011 Posts: 2 Comments: 3733


Still some sort of circulation associated with ex98L



Pressures still quite low



850mb vort still looks impressive.
Member Since: Posts: Comments:
Another enlightening and interesting spell on the blog! Keep safe and dry, all of you in CO, NM, and along the East Coast.

MrMixon - thank you for all of your updates today. And stay out of the kayak, no inner tubes, and no playing in drainage ditches or flooded roadways. Yes, I've been listening to emergency dispatch all day; I know what some of you Coloradoans get up to... :)

Good night, all.
Member Since: June 26, 2013 Posts: 0 Comments: 1893
1160. GatorWX
Quoting 1148. daddyjames:


Apparently, he still qualifies as his mother was a US citizen when he was born . . . H

He's the male version of Sarah Palin. But should not necessarily be underestimated.


The Republican Party certainly seems to b headed down that path.

It's too bad they can't get a real libertarian. They don't need Cruz, lol.

4 ULLs, just in the Caribbean wv sat. All seemingly converging on 10. Should be well ventilated if it can avoid wind shear from them. That seems rather inevitable.



Unless that convection mass isn't actually indicative of the llc (sheared some), it doesn't seem to be moving much at all. 4 mph always seems generous. CIMSS shows 20-25 kts, GFS was initialized with essentially none.


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Quoting 1144. GatorWX:


I just found out he was Canadian, lol. So much for him being prez.


He legally gave up his Canadian citizenship this past summer. Constitutionally, he can run and he probably will.

PS - I don't normally comment on political subjects on this board unless I see something false.
Member Since: Posts: Comments:
Quoting 1154. GatorWX:


Another plume.



Still reminds me of Stan.

The ULL seems to have come a bit more south - and I still say - inducing sheer on the northern part of 10L. If it starts tracking more to the west, it'll start ventilating 10L better.
Member Since: June 25, 2011 Posts: 2 Comments: 3733
Humberto...

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Quoting 1151. GeoffreyWPB:


He voted no for Sandy aid...here is his release...and it is weather related...I post...You decide...

U.S. Sen. Ted Cruz Statement on the Disaster Relief Act of 2013


Contact: press@cruz.senate.gov / (202) 228-7561
Monday, January 28, 2013



WASHINGTON, DC -- U.S. Sen. Ted Cruz (R-TX) made the following statement on the Disaster Relief Act of 2013:

Hurricane Sandy inflicted devastating damage on the East Coast, and Congress appropriately responded with hurricane relief. Unfortunately, cynical politicians in Washington could not resist loading up this relief bill with billions in new spending utterly unrelated to Sandy.

Emergency relief for the families who are suffering from this natural disaster should not be used as a Christmas tree for billions in unrelated spending, including projects such as Smithsonian repairs, upgrades to National Oceanic and Atmospheric Administration airplanes, and more funding for Head Start.

Two thirds of this spending is not remotely “emergency”; the Congressional Budget Office estimates that only 30% of the authorized funds would be spent in the next 20 months, and over a billion dollars will be spent as late as 2021.

This bill is symptomatic of a larger problem in Washington – an addiction to spending money we do not have. The United States Senate should not be in the business of exploiting victims of natural disasters to fund pork projects that further expand our debt.



Don't mistake my statement as support for him. He is what the Tea party wants.
Member Since: June 25, 2011 Posts: 2 Comments: 3733
1154. GatorWX


Another plume.



Still reminds me of Stan.
Member Since: Posts: Comments:
Quoting 1150. TropicalAnalystwx13:
TD10 should get going later tonight with the help of diurnal maximum, especially with it being in the Bay of Campeche.
I agree. Shouldn't take long at all to get Ingrid.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
00z Best Track for Humberto stays at 75kts.

AL, 09, 2013091300, , BEST, 0, 231N, 294W, 75, 980, HU
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Quoting 1148. daddyjames:


Apparently, he still qualifies as his mother was a US citizen when he was born . . . H

He's the male version of Sarah Palin. But should not necessarily be underestimated.


He voted no for Sandy aid...here is his release...and it is weather related...I post...You decide...

U.S. Sen. Ted Cruz Statement on the Disaster Relief Act of 2013


Contact: press@cruz.senate.gov / (202) 228-7561
Monday, January 28, 2013



WASHINGTON, DC -- U.S. Sen. Ted Cruz (R-TX) made the following statement on the Disaster Relief Act of 2013:

Hurricane Sandy inflicted devastating damage on the East Coast, and Congress appropriately responded with hurricane relief. Unfortunately, cynical politicians in Washington could not resist loading up this relief bill with billions in new spending utterly unrelated to Sandy.

Emergency relief for the families who are suffering from this natural disaster should not be used as a Christmas tree for billions in unrelated spending, including projects such as Smithsonian repairs, upgrades to National Oceanic and Atmospheric Administration airplanes, and more funding for Head Start.

Two thirds of this spending is not remotely “emergency”; the Congressional Budget Office estimates that only 30% of the authorized funds would be spent in the next 20 months, and over a billion dollars will be spent as late as 2021.

This bill is symptomatic of a larger problem in Washington – an addiction to spending money we do not have. The United States Senate should not be in the business of exploiting victims of natural disasters to fund pork projects that further expand our debt.
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TD10 should get going later tonight with the help of diurnal maximum, especially with it being in the Bay of Campeche.
Member Since: July 6, 2010 Posts: 113 Comments: 32853
Quoting 1145. daddyjames:


LOL - I just got it!


Haha, I am old!

Come on TD 10, momma needs rain! (on topic comment)
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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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