Parkersburg tornado an EF-5; major flooding in Central America likely from 90E
The tornado that devastated Parkersburg, Iowa on Sunday has now been rated an EF-5 by the National Weather Service. An EF-5 is the strongest possible classification a tornado can receive, and is only given to those tornadoes with estimated winds over 200 mph. The winds in the Parkersburg tornado were estimated at 205 mph. At those wind speeds, total destruction of homes occurs. Even those sheltering in basements are not safe--several of the six deaths from the Parkersburg tornado were from people sheltering in basements.
The Parkersburg tornado cut a path 43 miles long and between 3/4 miles and 1.2 miles wide across Iowa, killing six people, completely destroying 350 buildings in Parkersburg, and injuring 70 people. It was only the second EF-5 tornado this decade in the U.S. The other EF-5 occurred in May 2007, when much of Greensburg, Kansas got leveled. The Parkersburg tornado was the first F5 or EF5 tornado in Iowa since the Jordan, Iowa tornado of June 13, 1976, and was the second deadliest in Iowa since official record-keeping began in 1950. Iowa's deadliest tornado hit Charles City on May 15, 1968, killing 13 while producing F5 damage.
Figure 1. EF-5 damage from the May 25, 2008 Parkersburg tornado. At EF-5 winds speeds (over 200mph), homes are completely destroyed or removed from their foundations. Image credit: Iowa Helicopter. The NWS Des Moines office has posted ground damage photos from their damage survey.
Major flooding likely in Central America from 90E
An area of low pressure (90E) in the Eastern Pacific off the coast of Costa Rica, near 10N 88W, is steadily organizing and appears likely to develop into a tropical depression later today or tomorrow. The National Hurricane Center is currently assigning a "High" probability (>50% chance) that this will be a tropical depression, in its new experimental Tropical Weather Outlook. Satellite loops show that the low has developed a very large and expanding circulation. This circulation is likely to expand across Central America into the Western Caribbean, allowing the storm to tap moisture from the Atlantic and Pacific. Storms that are able to tap the moisture sources of both oceans can be extremely dangerous rainmakers, even if they are weak tropical depressions. Already, 90E is generating very heavy rains in excess of six inches per day near its center. The storm is expected to move northeastward over Costa Rica or Nicaragua by Thursday or Friday, and should being dangerous flooding rains of 5-10 inches to those nations and Panama. Most of the computer model guidance suggests that the storm will then track to the north, spreading very heavy rains across Guatemala, El Salvador, Honduras, Belize, and southern Mexico by Saturday. These heavy rains will cause life-threatening flash flooding, particularly in mountainous regions.
Since 90E is beginning to dominate the circulation pattern of the region, it appears unlikely that a tropical depression will form in the Western Caribbean in the coming week, as some computer models have been predicting. It is possible that 90E could cross Central America and pop out in the Western Caribbean near the Yucatan Peninsula, or in the Gulf of Mexico's Bay of Campeche. However, the crossing of Central America will severely disrupt the storm, and the odds of 90E becoming a depression in the Atlantic basin are low.
Figure 2. Observed precipitation for the 24 hours ending at 12Z (8am EDT) Wednesday May 28, 2008. Rainfall amounts in excess of 2000mm (eight inches, yellow colors) occurred near the center of disturbance 90E off the Pacific coast of Costa Rica. Image credit: U.S. Navy Monterey.
I'll have an update Thursday morning.
Jeff Masters
Reader Comments
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1) Invest 90E will make landfall within the next 24 to 36 hours, thus collapsing the system and no longer an inhibiting factor for the Caribbean low.
2) There has been a remarkable moisture surge over the past 24 hours in the Caribbean that looks to continue northward as a stationary boundary (from the cold front that moved through South Florida Sunday) is moving back north.
3) The upper-level high that has developed over Invest 90E continues to expand northeastward and has now started to fight back the high wind shear in the Northwest Caribbean. Given 48 to 72 hours, this high wind shear will likely be gone as forecasted by Wunderground and some computer models.
4) There will be a tropical wave meeting this Caribbean low within the next 48 to 72 hours that will add extra vorticity and energy to the system which could act like a sparkplug.
5) Troughs have continued to dig into the Southeast United States creating weaknesses in the Atlantic ridge. This pattern does not look to stop anytime soon, so I expect more troughs to continue moving through. It seems quite reasonable that one can expect a trough at the time a potential system would reach the Northwest Caribbean due to the frequency of the troughs.
With 90E so close to land one wonders whether it will actually achieve TD status before going ashore. Interaction with land is almost certainly interfering with the N and E quadrants of the circulation. Meanwhile, the low in the Caribbean continues to show deep convection with the cirrus canopy expanding now into the NW Caribbean, just hanging around and waiting.
Quite a match going on there LOL
Perhaps there is more than meets the eye - perhaps not.
Keep the wisdom coming.
A weak 1007 mb surface low pressure coupled with
the presence of the tropical wave along 80w are producing a
broad area of dense cloudiness with scattered showers and
embedded thunderstorms S of 17n W of 72w over the SW Caribbean
Sea...N Colombia and Central America.
2008 could set records for tornado deaths
I've heard all this before, I think on STL's blog...
Good look here and you can see a second swirl off the coast of Nicaragua, but some of the energy is still being sucked in by 90E. Ivan's observations are spot-on there at the coast lines. Will it survive? Not likely, imo, especially with higher shear to its north.
That together with the broad circulation means slow (if any) development in spite of impressive upper level divergence, very favorable wind shear and warm SSTs.
the convection in SW carribean has winds more than 40knots
28/1745 UTC 10.0N 86.3W T1.5/1.5 90E
This wave is pretty linear meridionally...no wave breaking genesis likely...more of an enhancement of convergence with the preexisting weak low.
I'd say there is a fair chance (maybe 20%) of development in around 72 hours from this interaction. Large scale low level vorticity advection from 90E could help the genesis process as well...though the large scale steering of 90E isn't well resolved by the models.
PS!I will say this convection has been on a steady increase in the carribean.SEE HERE
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