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: 1699 - 1649

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

1698. hydrus
Member Since: Posts: Comments:
1697. GatorWX
NO, no! TB goin' to straight CRUSH!

Member Since: January 1, 2008 Posts: 0 Comments: 2983
Quoting 1670. 7544:


agree looks ;like a 40 mph ts right now !
Recon has found 50 mph winds enough that i think it could jump to 50 on the next update
Member Since: Posts: Comments:
Quoting 1683. CybrTeddy:


Ingrid it is! 9-1-0.


What is the least recorded ACE of the first 9 storms of any season that meets that criteria? I wonder if this season has the lowest?
Member Since: Posts: Comments:

SevereStudios ‏@severestudios 2 m
Loveland, CO-- RT @mikeseidel: Big Thompson River is now flowing across I-25 shutting it down in both directions. Link
Member Since: Posts: Comments:
1692. hydrus
Member Since: Posts: Comments:
Quoting 1674. clwstmchasr:
It's simple:

You believe GW is not a fact, watch FOX news, you are in JB's camp.

You believe that GW is fact and based on real scientific data and watch CNN, you are not in JB's camp.

It has nothing to do with his forecasting ability.

Ok, now to my second bowl of Lucky Charms.


I am in my own camp.
I simply do not like snobs.
=)
Member Since: Posts: Comments:
1690. Patrap
Quoting 1680. TampaSpin:


Touche'

I try to keep an open mind....but you liberals close if fast with your forced agenda!



You missed the Friday uber Liberal Skype confernce call.

Still a strong "Brees" forecasted for Tampa Sunday.

JB jus tweeted it.
Member Since: July 3, 2005 Posts: 424 Comments: 128273
Paul Revere was an alarmist...

just sayin...
Member Since: Posts: Comments:
Obvious TS on the recon, flight level winds maxed out at 51mph, SFMR was around 42 uncontaminated. Ingrid is here.
Member Since: July 8, 2005 Posts: 259 Comments: 24018
Member Since: June 11, 2013 Posts: 20 Comments: 2933
Quoting 1675. Neapolitan:
AL, 10, 2013091312, , BEST, 0, 197N, 945W, 35, 1000, TS, 34, NEQ, 30, 0, 0, 30, 1008, 180, 30, 0, 0, L, 0, , 0, 0, INGRID, M,


So we have Ingrid now. Bringing our Total for the season to 9-1-0.

Member Since: Posts: Comments:
Quoting 1675. Neapolitan:
AL, 10, 2013091312, , BEST, 0, 197N, 945W, 35, 1000, TS, 34, NEQ, 30, 0, 0, 30, 1008, 180, 30, 0, 0, L, 0, , 0, 0, INGRID, M,


Ingrid it is! 9-1-0.
Member Since: July 8, 2005 Posts: 259 Comments: 24018
Ingrid is Born!!!
Member Since: Posts: Comments:
1681. GatorWX


Tides?



They rise and fall. End of story.

I agree with good ole JB this is probably a TS right now. It looks that way on satellite.

Dvorak says 996mb and 33kts. Meh!
Member Since: January 1, 2008 Posts: 0 Comments: 2983
Quoting 1642. ihave27windows:


I do not find left leaning news organizations to be credible. I watch Fox News, and I don't give a rat's behind what you think. Ugh! You are a snob, and you are officially disliked, and IGNORED.


Touche'

I try to keep an open mind....but you liberals close if fast with your forced agenda!
Member Since: Posts: Comments:
1678. Patrap
Member Since: July 3, 2005 Posts: 424 Comments: 128273
1676. help4u
Enjoy the weather it is the only weather you got!Forgot to tell you he nailed Gabby too.
Member Since: Posts: Comments:
AL, 10, 2013091312, , BEST, 0, 197N, 945W, 35, 1000, TS, 34, NEQ, 30, 0, 0, 30, 1008, 180, 30, 0, 0, L, 0, , 0, 0, INGRID, M,
Member Since: Posts: Comments:
Quoting 1669. calkevin77:
Good morning all from Austin. I thought I'd share this. My boss showed me this site that is pretty much everything tropical. Not the prettiest but it sure has a lot of stuff in one screen. Enjoy:

http://www.spaghettimodels.com/

great...now I'm hungry for spagetti...bad enought GT was showing us ice cream yesterday afternoon... lol neat site
Member Since: September 5, 2007 Posts: 0 Comments: 3487
1671. Patrap



Member Since: July 3, 2005 Posts: 424 Comments: 128273
1670. 7544
Quoting 1664. hurricanehanna:
I'm thinking upgrade on TD10


agree looks ;like a 40 mph ts right now !
Member Since: Posts: Comments:
Good morning all from Austin. I thought I'd share this. My boss showed me this site that is pretty much everything tropical. Not the prettiest but it sure has a lot of stuff in one screen. Enjoy:

http://www.spaghettimodels.com/
Member Since: Posts: Comments:
Gabby is exploding in size along the cold front coming off the East Coast, very interesting stuff.  This is similar to what caused Sandy to explode last year, though Sandy was much stronger/bigger when her metamorphosis occurred. 

Gabby is going to bring some rough oceans in the Gulf of Maine and shouldnt be taken lightly by our northern friends in Canada.  She's been a trooper.



Member Since: Posts: Comments:
1666. help4u
AGREE DR. Masters has no political motives,just a global warming agenda and the money and influence and power it gives the politicians to control our life.Other than that nothing to worry about,i like politicians don't you.
Member Since: Posts: Comments:
Quoting 1642. ihave27windows:


I do not find left leaning news organizations to be credible. I watch Fox News, and I don't give a rat's behind what you think. Ugh! You are a snob, and you are officially disliked, and IGNORED.


People should always see viewpoints of all sides, not just one. The more viewpoints the more accurate you can deduct accurate information. Thats why I always use multiple sources, not ones based on my political ideologies, because every media ever created always has and always will have a bias.
Member Since: Posts: Comments:
I'm thinking upgrade on TD10
Member Since: September 5, 2007 Posts: 0 Comments: 3487
Quoting 1654. PensacolaDoug:




Analysis in 140 characters or less?
It's twitter. Get a grip!


Good morning PD - I see you disagree - how are things in the panhandle?
Member Since: Posts: Comments:
1662. GatorWX
Quoting 1646. Neapolitan:
This was posted a while ago, but thought it worth showing again. It's the hydrograph of the North Fork of the Big Thompson River at Drake. The previous record high flood stage of 9.3' occurred during the 1976 Big Thompson Canyon floo that killed 144 people. The river crested at 10.55' a few hours ago, and will slowly drop during the day as the hills feeding the watershed continue to drain down:

bt

The bulk of the rainfall has thankfully shifted off to the east. However, there's still ample monsoonal moisture flowing north, so the Boulder area could be in for at least another few hours of light to moderate rainfall before the worst of it moves off.


That's about a foot and a half above the forecasted crest isn't it?
Member Since: January 1, 2008 Posts: 0 Comments: 2983
1661. KEEPEROFTHEGATE (Mod)
Member Since: Posts: Comments:
19.667N 95.233W 959.4 mb
(~ 28.33 inHg) 376 meters
(~ 1,234 feet) 1001.7 mb
(~ 29.58 inHg) - From 84 at 45 knots
(From the E at ~ 51.7 mph) 21.5C*
(~ 70.7F*) 21.4C*
(~ 70.5F*) 45 knots
(~ 51.7 mph)
Member Since: September 5, 2007 Posts: 0 Comments: 3487
1659. Patrap
JB has to "tweet" his thoughts cuz no one pays for them over there that's fer sure.

Ironic is the fact that all you JB folks are here, dontcha think?

LOL


Member Since: July 3, 2005 Posts: 424 Comments: 128273
I think we are seeing some Rapid strengthening with TD 10

here is ADT

CI# /Pressure/ Vmax
2.9 / 999.0mb/ 43.0kt


Final T# Adj T# Raw T#
2.9 3.2 3.5

Center Temp : -70.6C Cloud Region Temp : -62.3C

Scene Type : UNIFORM CDO CLOUD REGION

and here is what recon just found

13:37:30Z 19.650N 95.233W 959.7 mb
(~ 28.34 inHg) 371 meters
(~ 1,217 feet) - - From 84° at 44 knots
(From the E at ~ 50.6 mph) 20.8°C*
(~ 69.4°F*) -* 45 knots
(~ 51.7 mph) 43 knots
(~ 49.4 mph) 0 mm/hr
(~ 0 in/hr) 42.0 knots (~ 48.4 mph)
Tropical Storm 95.6%
13:38:00Z 19.667N 95.233W 959.4 mb
(~ 28.33 inHg) 376 meters
(~ 1,234 feet) 1001.7 mb
(~ 29.58 inHg) - From 84° at 45 knots
(From the E at ~ 51.7 mph) 21.5°C*
(~ 70.7°F*) 21.4°C*
(~ 70.5°F*) 45 knots
(~ 51.7 mph) 41 knots
(~ 47.1 mph) 1 mm/hr
(~ 0.04 in/hr) 41.0 knots (~ 47.1 mph)
Tropical Storm 91.1%
13:38:30Z 19.700N 95.233W 959.2 mb
(~ 28.33 inHg) 380 meters
(~ 1,247 feet) 1002.0 mb
(~ 29.59 inHg) - From 84° at 44 knots
(From the E at ~ 50.6 mph) 21.5°C
(~ 70.7°F) 20.8°C
(~ 69.4°F) 45 knots
(~ 51.7 mph) 39 knots
(~ 44.8 mph) 2 mm/hr
(~ 0.08 in/hr) 38.1 knots (~ 43.9 mph)
Tropical Storm 86.7%
13:39:00Z 19.717N 95.233W 959.4 mb
(~ 28.33 inHg) 381 meters
(~ 1,250 feet) 1002.3 mb
(~ 29.60 inHg) - From 85° at 43 knots
(From the E at ~ 49.4 mph) 21.2°C*
(~ 70.2°F*) 21.0°C*
(~ 69.8°F*) 44 knots
(~ 50.6 mph) 39 knots
(~ 44.8 mph) 1 mm/hr
(~ 0.04 in/hr) 38.1 knots (~ 43.8 mph)
Tropical Storm 88.6%
13:39:30Z 19.750N 95.233W 959.4 mb
(~ 28.33 inHg) 383 meters
(~ 1,257 feet) 1002.6 mb
(~ 29.61 inHg) - From 90° at 45 knots
(From the E at ~ 51.7 mph) 21.4°C
(~ 70.5°F) 21.0°C
(~ 69.8°F) 46 knots
(~ 52.9 mph) 45 knots
(~ 51.7 mph) 9 mm/hr
(~ 0.35 in/hr) 44.0 knots (~ 50.6 mph)
Tropical Storm 97.8%
13:40:00Z 19.767N 95.233W 959.0 mb
(~ 28.32 inHg) 388 meters
(~ 1,273 feet) 1003.1 mb
(~ 29.62 inHg) - From 91° at 42 knots
(From the E at ~ 48.3 mph) 21.2°C*
(~ 70.2°F*) -* 45 knots
(~ 51.7 mph) 47 knots
(~ 54.0 mph) 10 mm/hr
(~ 0.39 in/hr) 43.9 knots (~ 50.4 mph)
Tropical Storm 104.4%
13:40:30Z 19.800N 95.233W 960.4 mb
(~ 28.36 inHg) 375 meters
(~ 1,230 feet) 1003.2 mb
(~ 29.62 inHg) - From 93° at 43 knots
(From the E at ~ 49.4 mph) 21.0°C*
(~ 69.8°F*) -* 45 knots
(~ 51.7 mph) 44 knots
(~ 50.6 mph) 9 mm/hr
(~ 0.35 in/hr) 42.0 knots (~ 48.4 mph)
Tropical Storm 97.8%
13:41:00Z 19.817N 95.233W 959.1 mb
(~ 28.32 inHg) 391 meters
(~ 1,283 feet) 1003.3 mb
(~ 29.63 inHg) - From 93° at 40 knots
(From the E at ~ 46.0 mph) 21.9°C*
(~ 71.4°F*) -* 42 knots
(~ 48.3 mph) 41 knots
(~ 47.1 mph) 4 mm/hr
(~ 0.16 in/hr) 39.0 knots (~ 44.9 mph)
Tropical Storm 97.6%
13:41:30Z 19.850N 95.233W 959.3 mb
(~ 28.33 inHg) 389 meters
(~ 1,276 feet) 1003.4 mb
(~ 29.63 inHg) - From 94° at 42 knots
(From the E at ~ 48.3 mph) 21.4°C
(~ 70.5°F) 21.4°C
(~ 70.5°F) 42 knots
(~ 48.3 mph) 40 knots
(~ 46.0 mph) 8 mm/hr
(~ 0.31 in/hr) 40.0 knots (~ 46.0 mph)
Tropical Storm 95.2%
13:42:00Z 19.867N 95.233W 959.4 mb
(~ 28.33 inHg) 390 meters
(~ 1,280 feet) 1003.2 mb
(~ 29.62 inHg) - From 96° at 42 knots
(From the E at ~ 48.3 mph) 21.9°C*
(~ 71.4°F*) -* 43 knots
(~ 49.4 mph) 38 knots
(~ 43.7 mph)
Member Since: Posts: Comments:
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.
Member Since: Posts: Comments:
1655. 7544
wait till oct goin to be a busy caribiean month stay tuned
Member Since: Posts: Comments:
Quoting 1601. daddyjames:


His tweets - such as stating that 10L could be a cat 2-3 before landfall, and that Gabby should not be downgraded to a TD are proffered without analysis, or any reasoning to back it up.

They, directly and indirectly, demonstrate contempt of those at the NHC.

JB brings it on himself. His statements are designed to draw attention, and to drum up business. But they are extremely unprofessional criticisms of his colleagues, and cause the public to question the statements of the NHC serving no one but himself.




Analysis in 140 characters or less?
It's twitter. Get a grip!
Member Since: Posts: Comments:
1653. Patrap
FOX taught me everything I know about the Tides, thanx Bill.


Member Since: July 3, 2005 Posts: 424 Comments: 128273
1652. Patrap
A alarmist?

I think your kinda tossing around words that you dont understand.

Dr. Masters is a realist when it comes to Data, any data he use's on anything is well presented, and you wont find him en meshed in Politics that's fer sure.

Your statement is not only factually incorrect, it says a lot about why your here Dawlin'

Member Since: July 3, 2005 Posts: 424 Comments: 128273
Quoting 1643. SouthernIllinois:

True. Doc Masters is an alarmist. But that doesn't give me a reason or even desire to mock him or degrade his credentials. I guess that's just to Nat in me...I see the good out of everyone.


Well,except those of us convinced of AGW . . . :P
Member Since: Posts: Comments:

Viewing: 1699 - 1649

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

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