The 2008 Memorial Day Weekend tornado outbreak will continue to hammer the U.S. today, even as residents from Iowa and Minnesota clean up from the devastating tornadoes that killed eight people Sunday afternoon. A mile-wide tornado plowed through Parkersburg, Iowa between 5pm and 6pm CDT yesterday, killing five people in that city, and two in nearby New Hartford. It was the deadliest tornado in Iowa in more than 40 years. The tornado passed just north of the airport in Waterloo, Iowa, which recorded sustained winds of 64mph, gusting to 94 mph at 5:37pm CDT. Damage appeared to be at least EF-4 in photos I saw, and possibly EF-5 (over 200 mph). In Minnesota, another powerful twister killed at least one person and injured 9 in the Minneapolis suburb of Hugo.
Figure 1. Satellite image of the supercell thunderstorms that spawned the Parkerburg, Iowa and Hugo, Minnesota tornadoes on May 25, 2008.
The slow-moving low pressure system responsible for all the mayhem began in Colorado on Thursday, when the Storm Prediction Center (SPC) recorded 48 reports of tornadoes, including the EF-3 mile-wide twister that killed one person in Windsor, Colorado. On Friday, an additional 63 tornado reports occurred, mostly in Kansas. The tornado that hit Quinter, Kansas on Friday was the eighth violent EF-4 tornado of the year. Also on Friday, two people were killed in Cairo, Kansas when a tornado smashed a car trying to flee the storm. If you want to see why one should not try to escape a tornado in a car, take a look at what the tornado did to the car. Saturday was relatively quiet, with only 13 tornado reports, but Sunday's tally of 43 brought the 4-day total from the 2008 Memorial Day weekend outbreak to a remarkable 157 tornado reports. Some of these tornado reports are undoubtedly of the same tornado, so the actual number of tornadoes for the 4-day outbreak may be less than 150. BBC has some awesome aerial footage of the weekend tornadoes.
Figure 2. Radar reflectivity image (top) of the May 25, 2008 Parkersburg, Iowa tornado. The position of Parkersburg is marked by a circle with a cross in the middle. Bottom: Doppler velocity image of the tornado, showing a small core of red and blue colors right next to each other, denoting strong winds towards and away from the radar, the classic signature of a tornado vortex.
Figure 3. Radar reflectivity image (top) of the May 25, 2008 Hugo, Minnesota tornado. The position of Hugo is marked by a circle with a cross in the middle. Bottom: Doppler velocity image of the tornado, showing a small core of red and blue colors right next to each other, denoting strong winds towards and away from the radar, the classic signature of a tornado vortex. We've also saved a 12-frame radar animation of the Hugo cell, thanks to wunderground member Todd S.
Tallying up the numbers
The death toll from Sunday pushes this year's tornado deaths to 111, the most since 1998, when 130 were recorded. Assuming that the Parkersburg, Iowa tornado was an EF-4 or EF-5, there have been nine violent EF-4 or EF-5 tornadoes this year. This is the most since 1999, when 13 such twisters were recorded. The total number of tornadoes this year is approaching 1100, and we may challenge the all time record for tornadoes in a year of 1817, set in 2004. Could this be a sign of climate change? No, I don't think so, and I'll explain why in a blog later this week.
Severe weather forecast
Severe weather will pound the U.S. again this Memorial Day, with the main action expected to stretch more than halfway across the country--from Texas to New York. NOAA's Storm Prediction Center has placed much of Kansas, Oklahoma, and the Texas Panhandle under its "Moderate Risk" category for severe weather, one step below its highest level of concern, "High Risk". Yesterday was also a "Moderate Risk" day in Iowa and Minnesota. The Weather Underground Severe Weather page and Tornado page are good places to go to follow the severe weather. Also, tune in to the chase accounts and awesome storm photos from Wunderblogger Mike Theiss. After today, it appears the severe weather outbreak will finally diminish, with only a slight risk of severe weather expected Tuesday, and no severe weather expected Wednesday.
Possible development in the Western Caribbean or Eastern Pacific late this week
For the past 3-6 days, our most reliable global computer weather forecast models have been predicting the development of a low pressure system near or over Central America by Friday of this week. Given the persistence in the models in developing this low, we need to be alert to the possibility of a tropical depression forming in either the Western Caribbean or Eastern Pacific, on either side of Costa Rica and Nicaragua. It is uncertain which ocean basin such a storm might form in, and whether or not there will be a tropical wave around to help kick off development. It may be that the low pressure region will stay anchored over land south of the Yucatan Peninsula, preventing any development. This is the solution preferred by the ECMWF model in its last few runs. However, the GFS, NOGAPS, and Canadian models all predict a tropical depression might form in the Western Caribbean near Mexico's Yucatan Peninsula. In contrast, the UKMET shows development in the Eastern Pacific, on the Pacific side of Central America. Climatologically, May tropical storms are much more common in the Eastern Pacific than the Western Caribbean, so we should not discount the UKMET solution, even though it is an outlier. All five models predict that the Central American low pressure area will move northward towards the Gulf of Mexico, and wind shear may fall enough to allow a tropical depression to form should the low's center emerge over water. I'll be posting daily updates on the situation this week.
Jeff Masters
A large and violent wedge tornado near Quinter, Kansas. Photo Copyright Mike Theiss
Photo of a wallcloud crossing road near lacrosse, Kansas on May 25, 2008. Photo copyight Mike Theiss
These are pictures taken of the storm that went through Forest Lake / Hugo, MN. The tornado passed 3 miles south of us, but we got a pretty vicious shot of hail for about 15 minutes straight. The pictures of bldg damage are west of the worst tornado damage, probably where the funnel cloud was just about to reach the ground.
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ASCAT validation with buoy and QuikSCAT data
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For global scales, the quality of ASCAT data is investigated using .... ASCAT and QuikSCAT data coherency is also investigated based on the approach ...
www.ocean-sci-discuss.net/5/77/2008/osd-5-77-2008.pdf - Similar pages
Link
I'm home today so should get a chance to check in and out during the day. Hope Dr master's sets up a new thead soon.
So an invest yet??? (will go read back now) LOL
QuikSCAT now has help. An important new source of QuikSCAT-like data has been made available by the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT). They launched their first polar-orbiting satellite, Metop-A, in October 2006, and declared the satellite ready for routine operations as of May 2007. This satellite carries a scatterometer called ASCAT which, like QuikSCAT, measures the winds at the ocean surface. ASCAT doesn't "see" the Earth's surface as well as QuikSCAT can--ASCAT sees chunks of the surface 25 km by 25 km, while QuikSCAT has a resolution twice as good--12.5 km. In addition, ASCAT only sees 60% of what QuikSCAT sees of the Earth's surface--QuikSCAT sees a swath of ocean 1800 km wide, while ASCAT sees two parallel swaths 550 km wide, separated by a 720 km gap. I found it frustrating to use ASCAT much this hurricane season, since it seemed that the passes missed the center of circulation of a storm of interest about 75% of the time.
Terra.
Yeah scott brings up a good point. THe 850 vort on the SW Caribbean low doesnt show up well so im not entirely convinced its hit the surface yet. The elongated low in the EPac on the other hand does.
Thanks.
SJ only has the Quickscat page linked. I'm looking for Ascat data. Thanks anyway.
This will lift the entire system out from the Southwest Caribbean and Eastern Pacific and into the Northwest Caribbean and over Central America.
If the "system" does not get better organized over the next 24 hours, isn't also possible that it could just be swept to the NE by the lifting trof; just as a band of unorganized clouds?
1340. cchsweatherman 9:02 AM CST on May 27, 2008
This will lift the entire system out from the Southwest Caribbean and Eastern Pacific and into the Northwest Caribbean and over Central America.
If the "system" does not get better organized over the next 24 hours, isn't also possible that it could just be swept to the NE by the lifting trof?
That could be true. I don't even know why I keep calling it a "system" when a system is an organized weather feature. I should be calling this a feature, not a system or a disturbance until it gets organized.
By the way, scottsvb, you are correct that there is no surface low right now. I should have stated that a surface low is developing. I was wrong in saying that there is a surface low down there. Too bad QuikSCAT is having problems right now because we all want to see a QuikSCAT for the area.
You can see one forming over the EPac low here. Look at the pinkish lines and the direction they flow in over the low:
12UTC GFS 00Hours
Regarding model generation of tropical low from western Caribbean
Sea next week...the models continue to flip-flop on this solution
with GFS now showing some energy meandering over Yucatan Peninsula
while a separate low peels off and deepens while moving into the
Florida Peninsula next week. European model (ecmwf) shows a similar split but then
decays both circulations rather quickly with little fanfare. This
appears to be the start of a season of model idiosyncracies in the
tropical latitudes of the model domain. These solutions...given
the distance in time...are being discounted beyond Monday.
thanks Michfan.
Plenty of dry air still.
Anything exiting Brewing - or are Models Predicting Willy-Nilly?
: )
Jesse
The 12UTC GFS drops the low at 78 hours out. Wonder if that will be all she wrote for the system forecasted by the GFS.
Look again at 108 hours.
Here is a view of the area.
Go HERE for RAMSDIS floaters.
Gets a little something going down on the Yuc Late in the week.
OK...so does this mean I was right when I said we would have something form before the end of May? Either way...I hope this is not another signal of a busy season this year....
God we need Ascat....
but it just didn't cover over it...
can it make it into the gulf?
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