Red River rising: 18th consecutive year of flooding--why?

By: Dr. Jeff Masters , 3:08 PM GMT on March 19, 2010

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The Red River at Fargo, North Dakota continues to rise, with a peak expected Sunday at the 4th highest flood level observed in the past century. "Major" flood level is 30 feet, which the river surpassed on Wednesday, and the river is expected to crest near 38 feet on Sunday, just 2.8 feet below the record set last year. Flood stage is eighteen feet, and the Red River has now reached flood stage at Fargo for eighteen consecutive years, according to the U.S. Army Corps of Engineers. Prior to this remarkable stretch of flooding (which began in 1993), the river flooded in just 29 of 90 years. This year's flood is rated as somewhere between a 50-year and 100-year flood. Last year's record flood was a 100-year flood. The U.S. Army Corps of Engineers lists the 10-year flood level for the Red River at Fargo to be 10,300 cubic feet per second. A 10-year flood, historically, has a 10% chance of occurring in a given year. In the last twenty years, the Red River has had eight 10-year floods--one every 2.5 years, on average. This year is the fourth year out of the past five with a 10-year flood. Clearly, flooding has increased significantly along the Red River over the past twenty years.


Figure 1. Current and forecast flood stage for the Red River of the North at Fargo, ND. You can access images like these using our wundermap for Fargo with the "USGS River" layer turned on. Click on the icon for USGS station 05054000, then hit the "click for graph" link.

Reasons for flooding: landform factors
According the U.S. Geological Survey, the unique landform characteristics of the Red River Valley make it highly susceptible to flooding. These factors include:

1) A relatively shallow and meandering river channel--a shallow channel holds less water and the meandering can cause flow to slow down as the channel makes its turns, causing over-bank flooding.

2) A gentle slope (averaging 0.5 to 1.5 feet per mile) that inhibits channel flow and encourages overland flooding or water "ponding" (especially on even, saturated ground) in the basin.

3) The northerly direction of flow--flow in the Red River travels from south (upstream) to north (downstream). The direction of flow becomes a critical factor in the spring when the southern (upstream) part of the Red River has thawed and the northern (downstream) part of the channel is still frozen. As water moves north toward the still frozen river channel, ice jams and substantial backwater flow and flooding can occur.


Figure 2. Peak flow of the Red River at Fargo, North Dakota through time. The two largest flow rates occurred last year (2009), and in 1997. The projected crest for Sunday (red circle) would be fourth greatest flood since reliable records began in 1901. Image credit: U.S. Geological Survey.

Reasons for this year's flood: highly unfavorable weather conditions
The USGS also cites five weather factors that can act to enhance flooding along the Red River. All five of these factors occurred to a significant degree this year:

1) Above-normal amounts of precipitation in the fall of the year that produce high levels of soil moisture, particularly in flat surface areas, in the basin. North Dakota had its 22nd wettest fall in the 115-year record in 2009.

2) Freezing of saturated ground in late fall or early winter, before significant snowfall occurs, that produces a hard, deep frost that limits infiltration of runoff during snowmelt. Fargo had a November that was much warmer than average, followed by a sudden plunge to below-zero temperatures by the second week of December. This froze the saturated ground to a great depth.

3) Above-normal winter snowfall in the basin. North Dakota had a top 15% winter for precipitation, with the period December 2009 - February 2010 ranking 15th wettest in the past 115 years.

4) Above-normal precipitation during snowmelt. Precipitation for March 1 - 18 has been 1.41", compared to the average of 0.61".

5) Above-normal temperatures during snowmelt. High temperatures in Fargo have averaged 6°F warmer than normal for March 1 - 18.

Urbanization increases flooding
Urbanization has had a major impact on increasing flooding not only along the Red River, but in every river basin in the U.S. Many cities and developed areas are located in flood plains next to major rivers and their tributaries. Highways, streets, parking lots, sidewalks, and buildings now cover large areas of the ground that used to absorb excess rain water and slow the rate at which run-off from precipitation and melting snow reached rivers. By developing large portions of our flood plains, run-off now reaches rivers more quickly, generating higher floods.

Building levees and flood defenses increases flood peaks
Defending ourselves against floods has made floods worse. Every time a new levee is built, or an old floodwall raised in height to prevent overtopping, more and more water is forced into the river bed, which raises the height of the flood. Flood waters that used to be able to spread out over their natural flood plains are now forbidden from spilling out over newly developed land in flood plains. For example, proposed improvements to the flood defense system in Fargo could cause a 4 - 10 inch rise in floods immediately downstream from the city, according to the Army Corps of Engineers.

Precipitation is increasing
As the climate warms, evaporation of moisture from the oceans increases, resulting in more water vapor in the air. According to the 2007 IPCC report, water vapor in the global atmosphere has increased by about 5% over the 20th century, and 4% since 1970. Satellite measurements (Trenberth et al., 2005) have shown a 1.3% per decade increase in water vapor over the global oceans since 1988. Santer et al. (2007) used a climate model to study the relative contribution of natural and human-caused effects on increasing water vapor, and concluded that this increase was "primarily due to human-caused increases in greenhouse gases". This was also the conclusion of Willet et al. (2007). This increase in water vapor has very likely led to an increase in global precipitation. For instance, over the U.S., where we have very good precipitation records, annual average precipitation has increased 7% over the past century (Groisman et al., 2004). Precipitation over the Red River drainage basin increased by about 10 - 20% during the 20th Century (Figure 3.) The same study also found a 14% increase in heavy (top 5%) and 20% increase in very heavy (top 1%) precipitation events over the U.S. in the past century. These are the type of events most likely to cause flooding. Kunkel et al. (2003) also found an increase in heavy precipitation events over the U.S. in recent decades, but noted that heavy precipitation events were nearly as frequent at the end of the 19th century and beginning of the 20th century, though the data is not as reliable back then.


Figure 3. Change in precipitation over the U.S. between 1900 - 2000, from the U.S. Cooperative network. Precipitation in the Red River drainage area increased by 10 - 20% over the 20th century. Image credit: Contemporary Changes of the Hydrological Cycle over the Contiguous United States: Trends (Groisman et al., 2002).

The future of flooding
As the population continues to expand, development in flood plains and construction of new levees and flood protection systems will continue to push floods to higher heights. With global warming expected to continue and drive ever higher precipitation amounts--falling preferentially in heavy precipitation events--it is highly probable that flooding in the Red River Valley--and over most of the northern 2/3 of the U.S. where precipitation increases are likely--will see higher and more frequent floods. With these higher and more frequent floods comes the increased risk of multi-billion dollar disasters, when a record flood event overwhelms flood defenses and inundates huge areas of developed flood plains. Obviously, we need to make smart decisions to limit development in flood plains to reduce the cost and suffering of these future flooding disasters.

References
Kunkel, K. E., D. R. Easterling, K. Redmond, and K. Hubbard, 2003, "Temporal variations of extreme precipitation events in the United States: 1895.2000", Geophys. Res. Lett., 30(17), 1900, doi:10.1029/2003GL018052.

Groisman, P.Y., R.W. Knight, T.R. Karl, D.R. Easterling, B. Sun, and J.H. Lawrimore, 2004, "Contemporary Changes of the Hydrological Cycle over the Contiguous United States: Trends Derived from In Situ Observations," J. Hydrometeor., 5, 64.85.

Milly, P.C.D., R.T. Wetherald, K.A. Dunne, and T.L.Delworth, Increasing risk of great floods in a changing climate", Nature 415, 514-517 (31 January 2002) | doi:10.1038/415514a.

Santer, B.D., C. Mears, F. J. Wentz, K. E. Taylor, P. J. Gleckler, T. M. L. Wigley, T. P. Barnett, J. S. Boyle, W. Brüggemann, N. P. Gillett, S. A. Klein, G. A. Meehl, T. Nozawa, D. W. Pierce, P. A. Stott, W. M. Washington, and M. F. Wehner, 2007, "Identification of human-induced changes in atmospheric moisture content", PNAS 2007 104: 15248-15253.

Trenberth, K.E., J. Fasullo, and L. Smith, 2005: "Trends and variability in column-integrated atmospheric water vapor", Climate Dynamics 24, 741-758.

Willett, K.M., N.P. Gillett, P.D. Jones, and P.W. Thorne, 2007, "Attribution of observed surface humidity changes to human influence", Nature 449, 710-712 (11 October 2007) | doi:10.1038/nature06207.

Links
A good way to track the flooding event is to use our wundermap for the Red River with the USGS River layer turned on.

The Fargo Flood webpage of North Dakota State University, Fargo, has some excellent links.

I'll have a new post on Monday or Tuesday.

Jeff Masters

Red River Flood 2006 (mw25)
The water level of the Red River when I took this photo was 47.2 feet, 19.2 feet above flood stage and the 6th highest level in Grand Forks' history. The river is expected to crest at 47.4 feet on Wednesday morning. Luckily, no homes have been lost in the Grand Forks area as of yet due to the flooding.
Red River Flood 2006
Fargo Flood 2009 - Elm & 15th Ave. N. (tliebenow)
Picture says it all. Clay dike built to contain the Red River in North Fargo.
Fargo Flood 2009 - Elm & 15th Ave. N.

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Quoting Hurricanes101:


Heh, looks like my eyeball forecast was right. Just look at it and see what it wants to do. I'm going to be an eyeball-caster this year! :D


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Despite no storms, insurers say they've been battered
Despite four years without a South Florida hurricane, insurance companies say they can't turn a profit. On the table: rate deregulation.


BY BEATRICE E. GARCIA
bgarcia@MiamiHerald.com

After four hurricane-free years in South Florida, insurance companies should have been raking in the profits. All that premium money pouring in -- and no big catastrophe claims checks going out.

Not so. Most of the state's insurance companies report they are losing money. If the numbers are valid, the next big storm could not only destroy your home but also the company that insures it.

Based on insurers' 2009 annual reports, 50 of out 70 Florida-based companies posted losses on their insurance business for the year; 31 of the companies reported a drop in reserves -- the money insurers set aside to pay claims.

These Florida-based companies, many of them small, write about 52 percent of the residential homeowners insurance in the state. The rest is written by Citizens Property Insurance, the state-run company, State Farm Florida Insurance, the largest private carrier and several dozen companies based outside of Florida.

The dreary financial reports coincide with a push in Tallahassee to pass legislation that would free up insurance companies to raise their rates at will -- as much as 5 percent initially and as much as 15 percent in the future. Right now, any rate increase requires state approval.

Some are puzzled at how insurers can be doing so poorly during a time when hurricanes have bypassed Florida.

``Our insurance companies ought to be making good profits,'' said Alex Sink, the state's chief financial officer and a candidate for governor. Sink has asked Insurance Commissioner Kevin McCarty for a status report on the financial health of Florida-based insurers. It's due Wednesday.

The companies aren't alone in issuing dire warnings about the industry.

Demotech, a Columbus, Ohio,-based rating agency, withdrew positive ratings on 10 Florida companies over the past year, including Magnolia Insurance, Edison Insurance and two insurers operated by Northern Capital Group.

A.M. Best, another rating agency, downgraded five Florida-based insurers -- different ones -- because they didn't meet capitalization or other requirements.

And yet, in a move likely to fuel skepticism about insurance company losses, one company, Southern Oak, was just slapped by the state for overpaying a sister company to perform routine paperwork, pay agents and resolve claims.

It made Southern Oak' bottom line look worse than it actually was.

If insurance companies are as bad off as they say they are, South Florida residents are especially at risk. In Miami-Dade, Broward and Palm Beach Counties, about 776,404 -- nearly 55 percent of the 1.4 million insured homes -- are covered by smaller firms that collect less than $200 million in annual premiums.

WHAT INSURERS SAY

If a homeowner's insurer goes belly up, the state's guaranty fund will pay up to $500,000 -- which might not cover all of the homeowner's losses. Those payments could result in additional taxes for Floridians if the guaranty fund runs out of money to pay losses and needs to raise more.

Insurers say they have been left vulnerable by a combination of factors, including:

• The state's determination to hit the brakes on rate increases. Numerous rate hike requests have been whittled down or rejected.

• The rise in the cost of ``reinsurance'' -- backup insurance that companies buy to limit their exposure in the event of a disaster.

• The state's schedule of wind mitigation discounts, which grants major rate cuts to homeowners who buy shutters and pay for other improvements to make their homes more hurricane-ready. Companies complain that the discounts are overly generous.

• The reopening of Hurricane Wilma claims as policyholders put in for additional losses -- often at the insistance of public adjusters, who represent homeowners.

• As in the case of Southern Oak, the payment of overly-generous commissions to affiliated companies that drain revenue from the insurer and leave it with little income or sometimes even losses.

Regulators and lawmakers have started to focus on this last problem.

Last week, Rep. Alan Hays called for an investigation, noting some company executives are paid big bonuses and generous commissions go to sister companies at the same the insurer is agitating for higher rates.

Some remedies are emerging in Tallahassee. One is a massive insurance bill that would require each property insurer operating in Florida to boost its reserves to $15 million; the current requirement: just $4 million.

It would also allow insurers to increase rates to offset those mitigation credits. While good for insurance companies, that would cost homeowners big money.

Meantime, for the first time in three years, rate hikes are winning approval from the state. Over the past 10 months, regulators have OK'd 75 rate increases -- some for more than 20 percent -- for insurers selling home and windstorm coverage. Insurers say it's not enough and that still higher increases are needed so companies can sock away revenue to pay future claims.

A 14 PERCENT INCREASE

The state's largest insurer State Farm, which won a 14.9 percent rate increase last year, says it had an underwriting loss of $463.9 million in 2009. In conjunction with the rate hike, the company got permission to drop 125,000 Florida policies.

State Farm and other Florida insurers say they have been undermined by a 2007 law that required insurers to lower rates if they purchased reinsurance from the state's catastrophe fund at lower than the going rate in the private market. Savings had to be passed on.

The same 2007 law froze the rates charged by Citizens Property Insurance, the state-run insurer, through 2009 and freed the company to compete head-on with private carriers. Locking in the rates at Citizens put the private insurers at a disadvantage, those companies say.

There was a time when Citizens was mandated to have the highest rates. No longer.

John Rollins, who runs Rollins Actuarial Services in Newberry, Fla., says traditionally insurers will build up their reserves in years when hurricanes veer away from Florida. He contends flat rates have prevented that from happening.

According to Rollins, 40 cents out of every $1 of premium collected by Florida property insurers is spent on backup insurance; 25 cents is spent on non-catastrophe claims such as fire and theft; and another 30 cents covers underwriting expenses, which include the cost of servicing claims, agents' commissions, administrative costs and premium taxes.

WHAT'S LEFT OVER

That leaves about five cents profit for an insurer that can run efficiently and contain its expenses.

``The average company isn't achieving [that five-cent profit] because it can't charge a premium large enough to cover all those costs,'' he says.

Southern Oaks, the company ordered to slash what it pays to the sister company -- called a managing general agent -- is not the only insurer facing closer scrutiny these days. Several are being examined, said a spokesman for the Office of Insurance Regulation. The office would not identify those companies.

Not everyone is down on selling insurance in Florida.

American Integrity, a company based in Tampa, and New York based-Privileged Underwriters Reciprocal Exchange have added capital in the past 12 months and are poised to grow.

Robert Ritchie, American Integrity's president, says the company will be writing new policies throughout the state and is interested in taking over some of the 125,000 policies State Farm won't be renewing in the next 12 months.

American Integrity won approval for a 14.8 percent rate hike in late 2009.

``I'm not happy that homeowners will see rate increases,'' says Ritchie. ``[But] we need to do a better job overall explaining the need for rate increases and why the pain is being felt this year when actually it has been building over the past three years.''

Read more: http://www.miamiherald.com/2010/03/20/1539837/despite-no-storms-insurers-say.html#ixzz0iqJKjZq0


Member Since: July 3, 2005 Posts: 423 Comments: 127804
Quoting winter123:
98W is a monster storm for march. Looks like its having problems organizing still. What do models say for this storm? Just eyeballing it looks like a recurve near the phillipenes... probably not over TS strength.


WU front page says it is now TD 2W
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98W is a monster storm for march. Looks like its having problems organizing still. What do models say for this storm? Just eyeballing it looks like a recurve near the phillipenes... probably not over TS strength.
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Dueling weather services: Was either right?



Reality fell far short of dire predictions. But even the low end of the forecast was wrong
February 26, 2010|By Daniel Patrick Sheehan | and Brian Callaway OF THE MORNING CALL Reporters Frank Warner and Scott Kraus contributed to this story.

For the Lehigh Valley, it's hard to say who came out ahead in the forecasting duel: the flamboyant AccuWeather or the conservative National Weather Service.

Though both agencies predicted a significant storm, AccuWeather, a for-profit forecasting agency based in State College, had touted it as a blockbuster in the making, a hurricane with snow, a paralyzing blizzard, a blast of historic proportions. The government-run weather service had suggested that AccuWeather was abusing the thesaurus.

In any case, many school districts decided on Wednesday to cancel Thursday classes; emergency officials hauled out the emergency plans one more time; the National Guard geared up for another round of snow patrol.
Member Since: July 3, 2005 Posts: 423 Comments: 127804
Quoting Skyepony:
The dynamic models want to go really cold & quicker..


It is pouring here now..

Hmm. A cliffhanger-plunge...

Could be that we go into La Nina...rough possible severe wx season next year.
Member Since: August 16, 2007 Posts: 6 Comments: 12461
Just randomly saw Bastardi says big widespread snow event for Friday and Saturday for the northeast. I see nothing even close to that on this model though. Thoughts???
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MESOSCALE DISCUSSION 0202
NWS STORM PREDICTION CENTER NORMAN OK
0215 PM CDT SUN MAR 21 2010

AREAS AFFECTED...PORTIONS OF CENTRAL/SOUTHERN FL PENINSULA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 211915Z - 212045Z

A SEVERE THREAT MAY DEVELOP/INCREASE THROUGH 20-21Z ACROSS PORTIONS
OF THE SOUTH CENTRAL/EAST CENTRAL FL PENINSULA. A WATCH IS NOT
CURRENTLY ANTICIPATED...BUT CONVECTIVE TRENDS WILL CONTINUE TO BE
MONITORED.

A RELATIVE MAXIMA OF SURFACE PRESSURE FALLS ARE NOTED COINCIDENT
WITH RECENT CLOUD BREAKS ACROSS THE SOUTH CENTRAL FL
PENINSULA...SOUTH OF A NORTHEAST-SOUTHWEST ORIENTED/CONVECTIVE LINE
INDUCED RAIN-COOLED EFFECTIVE BOUNDARY. AHEAD OF THE AFOREMENTIONED
CONVECTIVE LINE...SOME QUASI-DISCRETE CELLULAR DEVELOPMENT HAS BEEN
NOTED OVER THE PAST HOUR IN THE GENERAL VICINITY OF SEBRING/AVON
PARK. WHILE A WARM LAYER ALOFT AROUND 700-800 MB NOTED PER A 16Z XMR
OBSERVED RAOB/MORE RECENT ACARS SOUNDINGS MAY STILL BE CAPPING MUCH
OF THE WARM SECTOR...NEAR SURFACE CINH CONTINUES TO GRADUALLY ERODE
GIVEN CLOUD BREAKS COINCIDENT WITH THE CONTINUED STEADY NORTHWARD
DEVELOPMENT OF UPPER 60S/AROUND 70 F SURFACE DEWPOINTS ACROSS THE
SOUTHERN HALF OF THE FL PENINSULA. AN INCREASINGLY WARM/MOIST
BOUNDARY LAYER...AND SUFFICIENT LOW LEVEL/STRONG DEEP LAYER WIND
PROFILES PER MLB/TBW DERIVED WSR-88D VWP DATA...SUPPORTS SOME
POSSIBILITY FOR AN INCREASING DAMAGING WIND/TORNADO RISK OVER THE
NEXT HOUR OR TWO...AT LEAST IN AN ISOLATED SENSE. THIS WOULD BE VIA
QUASI-DISCRETE DEVELOPMENT AHEAD OF/STORM MERGERS WITH THE
CONVECTIVE LINE AND/OR LINE-EMBEDDED TYPE CIRCULATIONS CAPABLE OF
DAMAGING WINDS/POSSIBLY A TORNADO...PERHAPS MOST LIKELY AS STORMS
INTERACT WITH THE EAST COAST VICINITY SEA BREEZE.

..GUYER.. 03/21/2010
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Good afternoon.
Interestingly, the 'wave' we were looking at yesterday has managed to pull some moisture into it,(per the WV Images, mid level), and at the same time the very dry air to it's north has shifted further north.
The feature is at 30w-35w. There is an area of heavy rain/cloud just exiting the coast of Africa, will probably follow the one above. Can this second one remain intact?
Stay tuned.......
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899. xcool






Member Since: September 26, 2009 Posts: 2 Comments: 15648
what could a neutral ENSO with a cold bias mean for the atlantic hurricane season?
Member Since: August 7, 2009 Posts: 0 Comments: 251
It's wonderful here right now, BTW... mare's tails and puffy whites, and lots of sunshine and cool breezes and 81 deg F.... in fact, it's the first genuinely "March-like" day so far.... pity it won't last....
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Quoting Skyepony:
The dynamic models want to go really cold & quicker..


It is pouring here now..
Not impossible, but seems a bit precipitious.... wonder what they're "seeing" to make them react that way....
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sure hope I don't have to drive 2 work in this 2morrow a.m.....
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894. Skyepony (Mod)
The dynamic models want to go really cold & quicker..


It is pouring here now..
Member Since: August 10, 2005 Posts: 162 Comments: 37803
893. Skyepony (Mod)
Quoting Jeff9641:


Possible rotating storms heading your way SKY.


Yes..it's just beginning. Hope that vorticy slides south or better yet disapates.. Here's my weather station. Lightning is getting worse. Hadn't heard cloud to ground in a while..

Member Since: August 10, 2005 Posts: 162 Comments: 37803
ENSO neutral with a cold bias by July:

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.."Something WUnderful is going to Happen"..

David Bowman, 2010


Member Since: July 3, 2005 Posts: 423 Comments: 127804
889. Skyepony (Mod)
Levi~I think the original questions questioned if it was reactionary or was there Kelvin waves. I think I established there were waves & you gave a good explination of reactionary. Which may be more a discription of the process than an offical definition, kelvin waves & all.

As for the SOI..I think that has given great uncertanty to the 6th month forecast..it just bottomed a few weeks ago...little up but the overall trend still by outside chance has the chance to go lower. Like Storm said, going into this El Nino signs were everywhere. Now not so, atleast in my opinion. I like El Nino through spring. We will see how the forecasts for aug/sept do.
Member Since: August 10, 2005 Posts: 162 Comments: 37803
Sunday 21st March 2010
Eyjafjoll volcano, Iceland
An eruption began under the Eyjafjallajökull glacier on 21st March 2010. Locals reported lava fountaining and a lava flow from the glacier. Residents were evacuated. The eruption was limited to an area with little ice, so the threat of a flood was reduced. All flights to and from Iceland have been cancelled because of the eruption. There is a 120 mile radius no fly zone around the volcano.

from john seach

hi guys!
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Quoting StormW:


However, this one started out with lack of precipitation over the Indian Ocean, below average convection (before the Equatorial Pacific began turning warm). There was one more clear signal, but I don't remember at the moment.


ESPN taking over MNF was it I believe Chief..
Member Since: July 3, 2005 Posts: 423 Comments: 127804
Quoting bappit:
Bordonaro, did this get DFW to a new record snowfall?

edit: for this winter


I don't believe so! I think we're about 0.5" below the record

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
1137 AM CDT SUN MAR 21 2010

...SPRING SNOW FOR DFW...

DFW AIRPORT RECORDED 1.2 INCHES OF SNOW ON MARCH 20TH. THIS BREAKS
THE PREVIOUS DAILY RECORD FOR MARCH 20TH OF 0.4 INCHES SET IN 1970.
AN ADDITIONAL 0.1 OF AN INCH OFFICIALLY FELL ON MARCH 21ST AND THE
EVENT TOTAL IS 1.3 INCHES.

THE ADDITIONAL 1.3 INCHES BRINGS THE 2009-2010 WINTER TOTAL TO 17.1
INCHES. THIS RANKS SECOND OF ALL TIME AND CAME 0.5 INCHES SHY OF
TYING THE ALL-TIME RECORD OF 17.6 INCHES SET IN 1977-1978.

THIS SNOW EVENT WAS UNSEASONABLY LATE IN THE YEAR. THE LAST TIME AN
INCH OR MORE FELL AT DFW LATER THAN MARCH 20TH WAS WHEN 2 INCHES
FELL ON MARCH 29TH IN 1937.

--------------------------------------------------------------------

DALLAS/FORT WORTH - SNOWIEST SEASONS

1 17.6 1977-78
2 17.1 2009-10*
3 15.3 1963-64
4 13.5 1923-24
5 10.4 1976-77
6 9.5 1909-10
7 9.2 1916-17
8 8.8 1947-48
9 8.1 1937-38
10 7.3 1965-66
7.3 1941-42
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872. Levi32

One could also argue that the start of warming in the NINO 1+2 region in Jan 09 "flipped" the oscillation from Nina to Nino, thus ocean induced. There are valid arguments on both sides, forever a chicken and egg discussion.
Member Since: September 23, 2005 Posts: 14 Comments: 11053
Here's Typhoon Tip of 1979, one that was slightly larger than Nida (and the largest tropical cyclone on record):



...and the first hurricane of the Atlantic hurricane season the following year (Hurricane Allen):

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879. Ighuc
Just spent the weekend in Fargo helping with the sandbagging efforts. Although the waters are still rising, Fargo is far more prepared this year compared to last. As long as the water stays at the projected crest, disaster will surely be averted as well despite another historic flood. Last years mood was in the extremes (either panic or apathy), this year the community really came together and got things taken care of.

Well done Fargo!
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The real "trigger" of the El Nino Modoki going into "strong" mode was likely Super Typhoon Nida, at the end of November 2009.

Here's Nida at maximum size:

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Member Since: July 15, 2006 Posts: 170 Comments: 53517


The former nor'easter, now in the Eastern Atlantic, is leaving behind another trail of low-level vorticies. The Midwest/Florida storm is just behind its tracks, so I seriously think that we could have hurricanes taking tracks like that this season.
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Member Since: July 15, 2006 Posts: 170 Comments: 53517
It is thundering here pretty good right now in St Petersburg
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<
Member Since: July 15, 2006 Posts: 170 Comments: 53517
Quoting Skyepony:


Ain't that about right.. My lively ENSO debate with StormW lastnight ended with my bookmarks disabled & with this page in one window & a NASA one in another..I've got to suspect here. Not like they won't be restored or like I don't have this lappy with them on it too ..only the lappy has no spell check.. so enjooy.. may just spend the season from it..

I'd still like to see an offical definition of a reactionary El Nino.. Only thng google takes me too is some random blog where the guy says.."I believe that this El Nino is more reactionary to the overall cooling cycle of the Pacific." while refuring to this el nino when it was in it's beginning..he had also thought it would never be a strong one either..hhmm. Though the definition varies slightly from the one I've seen here.

Off to play before it rains..


Well Skye I can't find a paper either but when you use common sense you know they have to exist. The ENSO is an atmospheric-oceanic relationship, and we know from the Walker Circulation that the atmosphere can start things in motion and cause the SSTs to change, rather than the SSTs starting things and causing the atmosphere to change. There are some meteorologists that simply started calling an atmospheric-driven El Nino a "reactionary" El Nino, reacting to the atmosphere.

Now how can we know if it's reactionary? We look at the atmosphere of course. Our best method of determining what the atmosphere is doing in relation to the ENSO is the SOI. So if we look back at the beginning of this El Nino, we see that the weak La Nina of the '08-'09 winter peaked in January 2009.



Now it turns out that the SOI, which had been positive all winter, took its first dive in late February, which lasted through late March and ended up just below zero.



Notice how after this downward dive in the SOI started in late February, the SSTs rose just barely, bringing the ONI average for February up by 0.1C, marking the end of the peak of the La Nina. During March it rose a little bit more due to the SOI continuing downward and causing some Kelvin Waves to form and move eastward:

Wind speed and directional vector anomalies for March, 2009:



The SOI went back up from its spike in April, but peaked lower than before, and then took another, larger dive downward during May and early June, taking it well into negative territory. The ONI followed suit and started rising steadily, taking us into a weak El Nino in June of 2009.

How do we know for sure which was the dog and which was the tail? Yes it's hard, but then again not so much if we use common sense. The ONI barely went up at all during February, and not much in March either, while the SOI made a major nose-dive, definitely not low-profile. This alone would seem to suggest that it was the atmosphere making a big change and forcing the SSTs to start warming up slightly from the La Nina peak.

Also, compare the SSTs from late February 2009, when the SOI dive started, with nearly a month later in mid-March, when the SOI had fallen steadily and rapidly for 25 days, and was then nearly down to zero.

February 23rd, 2009:



March 16th, 2009:



Not much change is there, and in fact the cool tongue off of South America in the eastern Pacific is actually colder than it was before! It is obvious that the SOI went down much more significantly than the SSTs went up, and one can see the atmosphere started changing in February before the ocean did, making the atmosphere the factor which turned the ENSO around and started the process of forming an El Nino during 2009.

More evidence presents itself when the El Nino peaked and started going down in January of this year. The SOI had started going up in November, 2009, an entire 2 months before the SSTs reacted and started to fall off their December peak.

It also makes sense to think of it as "reactionary" to the PDO going cold. The road downward into the cold cycle of the PDO isn't going to be all smooth, and reactionary spikes in the ENSO on the way down are to be expected. Back when this El Nino formed it seemed like this was likely one of those spikes, but due to the PDO, probably wouldn't last very long. And here we are indeed seeing this start to die as soon as the peak of winter passes. You can't get a much shorter El Nino than that.

Member Since: November 24, 2005 Posts: 635 Comments: 26594
Hard to find a Tropical Wave in the N Atlantic in March...

WAVETRAK - Tropical Wave Tracking
Product Descriptions | 7-Day Image Archive


N Atlantic,Latest Available
Member Since: July 3, 2005 Posts: 423 Comments: 127804
Quoting Bordonaro:
Can someone lend the DFW, TX area a warm 75F day PLEASE!! Today's high is supposed to be 45F!!


I am sure glad we don't have those cold temps way up North here... the Golfing is great right now :)

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AOI

AOI

AOI

AOI

Humor in Comments
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US minimum 2m temperature tonight (map)
Link
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828

I saw one of the (many, many) maps posted on here showing that the wave was part of the ITCZ. As long as its in the ITCZ I don't think it qualifies as an easterly wave though it certainly is a wave, trough of some kind. Did look like the ITCZ was abnormally far north.

Sometimes I wish people would just give a link.
Edit: to the original graphic, not something they stashed and who knows whether it is the original.
Member Since: May 18, 2006 Posts: 10 Comments: 5998
hail reports northwest of tampa...should be a interesting next couple of hours in swfl as the wx charges east at over 30mph,a severe wx watch should be issued in the next hr,IMO
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Bordonaro, did this get DFW to a new record snowfall?

edit: for this winter
Member Since: May 18, 2006 Posts: 10 Comments: 5998
Member Since: July 15, 2006 Posts: 170 Comments: 53517
NEXRAD Radar
Tampa, Velocity Azimuth Display Wind Profile Range 124 NMI

Member Since: July 3, 2005 Posts: 423 Comments: 127804
Quoting cchsweatherman:


Don't know about you, but there appears to be rotation developing within the thunderstorms directly west of Tampa on radar.



MESOSCALE DISCUSSION 0201
NWS STORM PREDICTION CENTER NORMAN OK
1032 AM CDT SUN MAR 21 2010

AREAS AFFECTED...FL PENINSULA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 211532Z - 211700Z

AT LEAST AN ISOLATED SEVERE THREAT MAY DEVELOP MAINLY ACROSS THE
CENTRAL FL PENINSULA THROUGH THE EARLY/MID AFTERNOON HOURS. A
CONVECTIVE WATCH IS NOT CURRENTLY ANTICIPATED...BUT TRENDS WILL
CONTINUE TO BE CLOSELY MONITORED THROUGH THE AFTERNOON.

NORTHEAST-SOUTHWEST ORIENTED/FAST MOVING CONVECTIVE LINE...WITH SOME
EMBEDDED BOWS EVIDENT OFFSHORE...WILL CONTINUE TO MOVE INLAND ACROSS
THE WEST-CENTRAL FL PENINSULA THROUGH THE EARLY/MID AFTERNOON HOURS.
WHILE CLOUD COVER IS PLENTIFUL ACROSS MUCH OF THE PENINSULA AT THIS
TIME...MODEST CLOUD BREAKS/SURFACE HEATING COUPLED WITH A NORTHWARD
ADVANCING WARM FRONT...WITH ATTENDANT 60S F SURFACE
DEWPOINTS...COULD FAVOR A BIT OF AN UPSWING IN TSTM VIGOR/SEVERE
POTENTIAL INLAND ACROSS THE CENTRAL FL PENINSULA THROUGH THE
EARLY/MID AFTERNOON HOURS. DAMAGING WINDS WOULD APPEAR TO BE THE
PRIMARY SEVERE RISK...ALTHOUGH AN ISOLATED TORNADO THREAT CANNOT BE
RULED OUT. QUESTIONS REGARDING THE MAGNITUDE/EXTENT OF THE SEVERE
RISK WILL PRECLUDE A WATCH ISSUANCE IN THE SHORT TERM...BUT
DEVELOPMENTAL TRENDS WILL CONTINUE TO BE MONITORED THROUGH THE
AFTERNOON.

..GUYER.. 03/21/2010


ATTN...WFO...MLB...TBW...JAX...

LAT...LON 28118280 29018223 29208148 28868111 27668100 26908174
26758229 28118280
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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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