Boulder's 1-in-100 Year Flood Diminishing; Ingrid a Dangerous Flood Threat for Mexico

By: Dr. Jeff Masters , 3:43 PM GMT on September 13, 2013

Colorado's epic deluge is finally winding down, as a trough of low pressure moves across the state and pushes out the moist, tropical airmass that has brought record-breaking rainfall amounts and flooding. 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 three people. The flood that swept down Boulder Creek into Boulder, Colorado was a 1-in-100 year event, said the U.S. Geological Survey. A flash flood watch continues through noon Friday in Boulder. According to the National Weather Service, Boulder's total 3-day rainfall as of Thursday night was 12.30". Based on data from the NWS Precipitation Frequency Data Server, this was a greater than 1-in-1000 year rainfall event. The city's previous record rainfall for any month, going back to 1897, was 9.59", set in May 1995. Some other rainfall totals through Thursday night include 14.60" at Eldorado Springs, 11.88" at Aurora, and 9.08" at Colorado Springs. These are the sort of rains one expects on the coast in a tropical storm, not in the interior of North America! The rains were due to a strong, slow-moving upper level low pressure system to the west of Colorado that got trapped to the south of an unusually strong ridge of high pressure over Western Canada. This is the same sort of odd atmospheric flow pattern that led to the most expensive flood disaster in Canadian history, the $5.3 billion Calgary flood of mid-June this summer. The upper-level low responsible for this week's Colorado flood drove a southeasterly flow of extremely moist tropical air from Mexico that pushed up against the mountains and was lifted over a stationary front draped over the mountains. As the air flowed uphill and over the front, it expanded and cooled, forcing the moisture in it to fall as rain. Balloon soundings from Denver this morning continued to show levels of September moisture among the highest on record for the station, as measured by 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. Four of the top eight all-time September highs for Precipitable Water since records began in 1948 have been recorded over the past two days:

1.33" 12Z September 12, 2013
1.31" 00Z September 12, 2013
1.24" 12Z September 13, 2013
1.23" 12Z September 10, 1980
1.22" 00Z September 2, 1997
1.21" 00Z September 7, 2002
1.20" 00Z September 13, 2013

Wunderground weather historian Christopher C. Burt discusses how this year's flood compares to previous Colorado floods in his latest post.

A map of Boulder flood zones and detailed history of previous floods in the area may be found here.


Figure 1. A torrent of water rushes alongside a swamped house following flash flooding near Left Hand Canyon, south of Lyons, Colo., Sept 12, 2013. (AP Photo/Brennan Linsley)



Figure 2. Observed rainfall for the Colorado's Front Range from the September 11 - 13 rain event. Rainfall amounts greater than 10" (pink colors) were indicated near Boulder. Image credit: NWS Denver.

Tropical Storm Ingrid a Dangerous Rainfall Threat for Mexico
Tropical Storm Ingrid, the ninth named storm of the 2013 Atlantic hurricane season, has formed in the Southwestern Gulf of Mexico's Bay of Campeche. Ingrid is the most dangerous Atlantic tropical cyclone of 2013 thus far, due to its rainfall potential. Ingrid is embedded in an exceptionally moist environment, and is already bringing heavy rains to the Mexican coast in Veracruz state, as seen on Mexican radar. Satellite loops show that Ingrid is not well-organized, and has only a modest area of heavy thunderstorms. However, the Friday morning hurricane hunter mission found 45 mph winds, prompting NHC to upgrade Ingrid. Moderate wind shear of 15 - 20 knots is interfering with development, but ocean temperatures are a very warm 29 - 29.5°C (84 - 85°F).


Figure 3. Percent chance of receiving more than 16" of rain during a five day period, from the Friday 2 am EDT run of the experimental GFDL ensemble model for Tropical Storm Ingrid. More than 16" of rain are predicted for the Oaxaca and Tampico areas of Mexico. Image credit: NOAA/GFDL.

Forecast for Ingrid
The soils along the Mexican Gulf Coast are already saturated from the rains of Tropical Depression Eight and Tropical Storm Fernand, and it won't take much additional rain to generate dangerous flash floods and mudslides. An added danger is the presence of tropical disturbance 90E in the Eastern Pacific Ocean, on the other side of Mexico. If Ingrid 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. Ninety-E represents a threat to develop into a tropical depression in its own right; in their 8 am EDT Friday Tropical Weather Outlook, NHC gave 2-day odds of development of 70% for the disturbance, and predicted a north to northwest motion of the storm towards the coast. This morning's 2 am EDT run of the experimental GFDL ensemble model predicted that a some areas of Mexico are at high risk of 16+ inches of rain due to the combined effects of Ingrid and 90E. The greatest danger is on the Pacific side in Oaxaca state, where the combined effects of the circulations of Ingrid and 90E will pull a flow of very moist air upwards over the mountains, creating torrential rains. All of the models predict a west-northwest to northwest track for Ingrid into Mexico, but heavy rains of 2 - 4" may also affect extreme South Texas by early next week.

Today is the 25th anniversary of the intensification of Hurricane Gilbert into the strongest hurricane ever observed in the Atlantic (at the time.) I was on the hurricane hunter flight into Gilbert that day, and will be posted an account of the mission later today.

Jeff Masters

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Humberto is forecast to degenerate into a remnant low and become a hurricane again by day 5.
Member Since: July 6, 2010 Posts: 128 Comments: 35640
Bill Nye just attributed Boulder floods to climate change because Boulder is downhill and bridges are washed out."

Member Since: September 30, 2007 Posts: 9 Comments: 16088
BULLETIN
TROPICAL STORM HUMBERTO ADVISORY NUMBER 22
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092013
1100 PM AST FRI SEP 13 2013

...HUMBERTO CONTINUES TO WEAKEN AS IT MOVES WESTWARD...
...EXPECTED TO BECOME A REMNANT LOW ON SATURDAY...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...24.8N 33.0W
ABOUT 840 MI...1355 KM NW OF THE CAPE VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES
Member Since: Posts: Comments:
Quoting 929. Tazmanian:




read what I this said I said no all ready has I don't live in CO LOL


I was not aware that Colorado was the only state that could have flooding
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TROPICAL STORM MANUEL DISCUSSION NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL EP132013
800 PM PDT FRI SEP 13 2013

CONVENTIONAL AND MICROWAVE SATELLITE IMAGES INDICATE THAT MANUEL HAS
CONTINUED TO BECOME BETTER ORGANIZED. BANDING FEATURES HAVE
IMPROVED IN ALL QUADRANTS EXCEPT TO THE NORTHWEST...AND RECENT
PASSIVE MICROWAVE IMAGES HAVE REVEALED A SMALL LOW- TO MID-LEVEL
EYELIKE FEATURE. FIXES FROM TAFB AND SAB...ALONG WITH ADT ESTIMATES
ARE AROUND 35 KT. HOWEVER...THE INTENSITY HAS BEEN INCREASED TO 40
KT BASED ON THE 15-20 NMI DIAMETER EYELIKE FEATURE. THE 34-KT WIND
RADII WERE EXPANDED...ESPECIALLY TO THE NORTHEAST...BASED ON WIND
REPORTS FROM SHIP DFZB2.

IT APPEARS THAT MANUEL HAS SLOWED DOWN AND IS NOW NEARLY STATIONARY.
MANUEL IS EMBEDDED WITHIN A LARGER SYNOPTIC-SCALE CYCLONIC GYRE
THAT EXTENDS FROM THE EASTERN NORTH PACIFIC NORTHEASTWARD ACROSS
MEXICO AND INTO THE GULF OF MEXICO...WHICH INCLUDES TROPICAL STORM
INGRID LOCATED OVER THE BAY OF CAMPECHE. MOST OF THE NHC MODEL
GUIDANCE IS FORECASTING THE ENTIRE GYRE COMPLEX TO SHIFT SLOWLY
NORTHWARD TO NORTHWESTWARD OVER THE NEXT FEW DAYS...WHICH SHOULD
RESULT IN MANUEL GRADUALLY ASSUMING A NORTHWARD TO NORTHWESTWARD
MOTION BEGINNING EARLY SATURDAY AND CONTINUING UNTIL LANDFALL
IN 36-48 HOURS. THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE
PREVIOUS ADVISORY TRACK AND LIES TO THE LEFT OF THE TVCE
MULTI-MODEL CONSENSUS.

AS MENTIONED IN THE PREVIOUS FORECAST DISCUSSION...MANUEL HAS A
SMALL RADIUS OF MAXIMUM WINDS...WHICH IS SUPPORTED BY RECENT TRMM
AND SSMIS MICROWAVE IMAGERY INDICATING AN EYELIKE FEATURE. SINCE
THE SHEAR IS FORECAST TO DECREASE TO LESS THAN 10 KT AFTER 18-24
HOURS...MANUEL HAS A GOOD CHANCE TO INTENSIFY...AND THE NHC
INTENSITY FORECAST REMAINS A LITTLE ABOVE THE INTENSITY CONSENSUS
MODEL ICON. HOWEVER...IF INNER-CORE DEEP CONVECTION DEVELOPS SOONER
THAN CURRENTLY EXPECTED...THEN MANUEL COULD BE NEAR HURRICANE
STRENGTH WHEN IT MAKES LANDFALL.

FORECAST POSITIONS AND MAX WINDS

INIT 14/0300Z 15.3N 102.5W 40 KT 45 MPH
12H 14/1200Z 16.0N 102.7W 45 KT 50 MPH
24H 15/0000Z 17.0N 102.9W 50 KT 60 MPH
36H 15/1200Z 18.1N 103.3W 55 KT 65 MPH
48H 16/0000Z 19.1N 103.9W 30 KT 35 MPH...INLAND
72H 17/0000Z...DISSIPATED

$$
FORECASTER STEWART
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night all


am getting out of here be for I de rail the blog and I don't want too de rail the blog and its getting late in CA any ways


bye
Member Since: May 21, 2006 Posts: 5101 Comments: 118560
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Quoting 926. Patrap:


The Gom and Caribbean are open for Business well into November.

Hurricane Juan


Formed October 26, 1985

Dissipated November 1, 1985

Highest winds 1-minute sustained:

85 mph (140 km/h)

Lowest pressure 971 mbar (hPa); 28.67 inHg

Fatalities 24 direct, 50 indirect

Damage $2.8 billion (1985 USD)

(Includes indirect losses)

Areas affected Louisiana, Mississippi, Alabama, Florida Panhandle

Part of the 1985 Atlantic hurricane season






Don't forget Ida in 2009, Pat.
Member Since: March 7, 2007 Posts: 626 Comments: 22810
Everything wants to stop moving.

Now forecast to near hurricane intensity before landfall on Sunday.

BULLETIN
TROPICAL STORM MANUEL ADVISORY NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL EP132013
800 PM PDT FRI SEP 13 2013

...MANUEL NEARLY STATIONARY...
...EXPECTED TO TURN NORTH-NORTHWESTWARD ON SATURDAY...


SUMMARY OF 800 PM PDT...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...15.3N 102.5W
ABOUT 190 MI...300 KM S OF LAZARO CARDENAS MEXICO
ABOUT 280 MI...455 KM SSE OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...SW OR 225 DEGREES AT 3 MPH...6 KM/H
MINIMUM CENTRAL PRESSURE...996 MB...29.41 INCHES
Member Since: July 6, 2010 Posts: 128 Comments: 35640
Quoting 925. yoboi:


do ya have flood insurance????




read what I this said I said no all ready has I don't live in CO LOL
Member Since: May 21, 2006 Posts: 5101 Comments: 118560
Quoting 921. YUCATANCHICXULUB:



hey! I live in Yucatan, do you feel is gong back to Yucatán lol.



No.
Member Since: September 10, 2007 Posts: 0 Comments: 12796
Today is the 25th anniversary of the intensification of Hurricane Gilbert into the strongest hurricane ever observed in the Atlantic (at the time.) I was on the hurricane hunter flight into Gilbert that day, and will be posted an account of the mission later today.


I think dr m for got lol
Member Since: May 21, 2006 Posts: 5101 Comments: 118560


The Gom and Caribbean are open for Business well into November.

Hurricane Juan


Formed October 26, 1985

Dissipated November 1, 1985

Highest winds 1-minute sustained:

85 mph (140 km/h)

Lowest pressure 971 mbar (hPa); 28.67 inHg

Fatalities 24 direct, 50 indirect

Damage $2.8 billion (1985 USD)

(Includes indirect losses)

Areas affected Louisiana, Mississippi, Alabama, Florida Panhandle

Part of the 1985 Atlantic hurricane season




Member Since: July 3, 2005 Posts: 449 Comments: 141905
Looks like Ingrid is trying to make a run for a hurricane.
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Intense convection going off over Ingrid's low-level center as it backtracks to the east-northeast.

Member Since: July 6, 2010 Posts: 128 Comments: 35640
Quoting 917. yoboi:



well johnny come lately do you have flood insurance???



I don't live in CO LOL
Member Since: May 21, 2006 Posts: 5101 Comments: 118560
Quoting 909. scott39:
Ingrid is going back to the Yucatan! Lol



hey! I live in Yucatan, do you feel is gong back to Yucatán lol.

Member Since: August 16, 2013 Posts: 0 Comments: 130
Looking back over the past 100-years or so, most of the Hurricanes if not all which hit the state of Florida during the month of October have originated in the Western Caribbean and not the Gulf of Mexico or the Atlantic. Hurricane Inez of 1966 would be an exception. It is very possible for a major Hurricane such as a cat. 3 or 4 develop and move North or Northeast out of the Caribbean Sea and strike somewhere over the Sunshine State. So people in Florida, don't let your guard down.
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Quoting 903. winter123:

I saw it. I think people put too much faith in computer models, NHC included. Computer models should be used as a guide, not an absolute truth. A category 2 in the north Atlantic is a pretty low possibility for a naked swirl strongly sheared from the southwest. NHC forecasts Humberto making it back to a 75mph hurricane as of the previous advisory, but I expect that to be lowered in about 35 minutes.


There's a point where one should use your eyes instead of the models, I agree with that. But I don't agree with the idea that Humberto is done for. If all of the models are showing significant strengthening with Humberto while accurately portraying the weakening (the ECMWF and GFS both bring it down to a 1010mb remnant low), they simply cannot be thrown out. If this was a situation where the models were completely confused, then you should throw them out the window. However, they're all virtually unanimous on Humberto weakening, perhaps to a remnant low, then coming back with full fury.

It's not like this hasn't happened before.. recall Ophelia in 2011.
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Really interested in the 11pm Humberto discussion by the NHC.

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well I hop evere one in CO learn a lesson form this flooding and get flood insurance
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Quoting 909. scott39:
Ingrid is going back to the Yucatan! Lol


It's heading for Florida! And worse yet, my house!

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Quoting 907. yoboi:



do you???;)
Hurricane Kate occurred in November of 1985, not in October!
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Quoting 907. yoboi:



do you???;)


No, lol.

But I know the Atlantic hurricane database like the back of my hand!
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Quoting 906. BRWeatherGeek:
A lil funk top green



AND starting to get all shrimp-like on us too...
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910. flsky
Quoting 877. Funication:



Have you seen the animated wind graphic on TWC. Pretty interesting.
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Ingrid is going back to the Yucatan! Lol
Member Since: June 13, 2009 Posts: 0 Comments: 7218
Quoting 886. unknowncomic:
Maybe I should recomment. I have a feeling we have escaped another Andrew type storm this year in Florida. We may still get a cat1 or 2 from the gulf or Caribbean but not a catostrophic one.


This is like Caesar saying the Ides of March have come
and then failing to acknowledge

"Aye but they have not gone"


We have 45% of the season left. It ain't over till its over (actually December has some risk too) Remember Wilma. I wasn't there in 2005 but I remember Kate in late November 1985 in TLH and that gave me my lifetime fill of hurricanes, thanks and no sir I will not have another!


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A lil funk top green

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Quoting 902. KoritheMan:


Louisiana and Alabama can still get hurricanes well into October. It's rare, but it does happen. Remember Juan and Kate in 1985?
Oh yea!
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Quoting 901. scott39:
Fantasy Model support, time of the season, and my big fat Gut!


nuff said lol
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Quoting 834. CybrTeddy:


Read post 802.

I saw it. I think people put too much faith in computer models, NHC included. Computer models should be used as a guide, not an absolute truth. A category 2 in the north Atlantic is a pretty low possibility for a naked swirl strongly sheared from the southwest. NHC forecasts Humberto making it back to a 75mph hurricane as of the previous advisory, but I expect that to be lowered in about 35 minutes.
Member Since: July 29, 2006 Posts: 28 Comments: 1845
Quoting 897. scott39:
I would guess anywhere from the last week of September until the first week of October is our window.


Louisiana and Alabama can still get hurricanes well into October. It's rare, but it does happen. Remember Juan and Kate in 1985?
Member Since: March 7, 2007 Posts: 626 Comments: 22810
Quoting 899. SuperStorm093:
Why do you believe that? What reasons
Fantasy Model support, time of the season, and my big fat Gut!
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Quoting 886. unknowncomic:
Maybe I should recomment. I have a feeling we have escaped another Andrew type storm this year in Florida. We may still get a cat1 or 2 from the gulf or Caribbean but not a catostrophic one.


Well considering how rare an Andrew type storm is, I think it's safe to say you're probably in the clear from that in any given year.
Member Since: March 7, 2007 Posts: 626 Comments: 22810
Quoting 897. scott39:
I would guess anywhere from the last week of September until the first week of October is our window.
Why do you believe that? What reasons
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Quoting GeoffreyWPB:


Congrats on 15,000 Aussie!


I only realized I had passed 15,000 when I read you had passed 10,000. Congrats on your 10,000.
Member Since: September 30, 2007 Posts: 9 Comments: 16088
Quoting 893. KoritheMan:


Oh I know you're grasping. That much was obvious, lol.

I'm as ready as ever. Just don't know when it'll be.
I would guess anywhere from the last week of September until the first week of October is our window.
Member Since: June 13, 2009 Posts: 0 Comments: 7218
Friday, Sept. 13, 2013

G-IV: Is tasked by HRD and are flying a Tail Doppler Radar Experiment into Tropical Storm Ingrid. They took off at 1300 UTC (9AM Eastern) for an eight hour flight. No HRD scientists are on this flight. DONE

NOAA43: Is tasked by EMC are flying a Tail Doppler Radar Experiment into Tropical Storm Ingrid. They took off at 1814 UTC (2:14PM Eastern). Two HRD scientists and an HRD intern are on this flight. DONE

Saturday, Sept. 14, 2013

NOAA42: Is tasked by EMC to fly a Tail Doppler Radar Experiment into Tropical Storm Ingrid. Take off time is scheduled for 0600 UTC (2AM Eastern). Three HRD scientists will be on this flight. NEXT

G-IV: Is tasked by HRD to fly a Tail Doppler Radar Experiment into Tropical Storm Ingrid. Take off time is scheduled for 1300 UTC (9AM Eastern). No HRD scientists will be on this flight.

NOAA43: Is tasked by EMC to fly a Tail Doppler Radar Experiment into Tropical Storm Ingrid. Take off time is scheduled for 1800 UTC (2PM Eastern). Two HRD scientists and an HRD intern will be on this flight.
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Quoting 888. AussieStorm:


And no one congratulated me on #15000 comments. LOL


Congrats on 15,000 Aussie!
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Quoting 890. scott39:
Ingrid is going to play games with us.
Not really, pretty much going to either Mexico or south texas.
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Quoting 885. scott39:
Just grasping! Lol It is moving E though. Are you ready for the big one??


Oh I know you're grasping. That much was obvious, lol.

I'm as ready as ever. Just don't know when it'll be.
Member Since: March 7, 2007 Posts: 626 Comments: 22810
@HRD_AOML_NOAA: #NOAA43 aircraft completed pattern into Tropical Storm #Ingrid. On way home. Up next: #NOAA42 aircraft takeoff 2AM.
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891. beell
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Ingrid is going to play games with us.
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Quoting 885. scott39:
Just grasping! Lol It is moving E though. Are you ready for the big one??
Might not be a big one, who knows.
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Quoting rudyinpompano:


Congrats on comment #10,000, cool...


And no one congratulated me on #15000 comments. LOL
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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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