TornadoVideos.net

Posted At: August 30, 2008 @ 5:31 PM

Posted By: Reed Timmer

Hurricane Gustav is currently just west of Havana, Cuba as a strong category 4 hurricane, likely causing extensive damage with 150 mph sustained winds and a 20+ foot storm surge.  The concave shape of the southern coastline of Cuba southwest of Havana is a recipe for disaster with a category 4-5 storm surge, as this increases the water levels even more due to the funneling effect.  Hopefully loss of life will be minimized, but this is a very bad situation for Cuba.  As seen in the loop below, a stadium effect is clearly evident on visible satellite, with a textbook, cloudless eye 20-25 nm in diameter.  I would give anything to have been on the Isle of Youth earlier this afternoon, as the west side of the eye passed right along the east side of the island.   A tornado watch is also in effect for the entire Florida Keys where water spouts/tornadoes will be common this evening and overnight.  Gustav is expected to intensify to category 5 status in the next few hours, after which eye wall replacement cycles will lead to intensity fluctuations between cat 4 and 5.  This is a worst case scenario for New Orleans, where Mayor Nagin is forcing residents and vacationers to leave. 

Check out the forum for links to radar loops, live cams, model forecast pages, and news updates  throughout this event.  TVN will also be streaming live from the south Louisiana Coast beginning on Monday.  Stay tuned for updates.

Posted At: August 30, 2008 @ 12:50 PM

Posted By: Reed Timmer

Hurricane Gustav has intensified rapidly overnight and today, and now has maximum sustained surface winds of 145 mph as measured by Hurricane Hunter Aircraft!  Interestingly, the minimum pressure was measured at 942 mb, which is relatively high for a category 4 hurricane.  Typically the pressure drop precedes the wind increase in a rapidly intensifying hurricane, so this could mean that Gustav has much more strengthening to do before reaching a maximum.  The eye is currently over the eastern side of the Isle of Youth - we should have made the trip!


Here is the special advisory issued by the National Hurricane Center a short time ago:

Posted At: August 29, 2008 @ 9:49 AM

Posted By: Reed Timmer

The early morning GFDL is predicting a landfall near New Orleans on Monday with winds of category 3 strength (see figure below), which is an absolute worst case scenario track for Hurricane Gustav.  The few days before landfall as predicted by the GFDL looks eerily similar to that of Katrina, with the western eyewall passing right over New Orleans, and the eastern eyewall over the MS Gulf Coast.  It should also be realized that these dynamical models are often conservative in their intensity forecasts, as they often under-forecast the strength of rapidly intensifying storms, and this explosive strengthening appears likely over the next few days with Gustav.  The official NHC forecast has the storm making landfall in the swamplands south of New Orleans Monday evening with a slow-down is expected just prior to landfall.  It must be realized that substantial error exists in tropical cyclone forecast this far in advance, so there is still major uncertainty in any forecast.  TVN is planning an intercept of Hurricane Gustav and will be leaving this weekend for a target somewhere along the central Gulf Coast.  Stay tuned for updates    

Posted At: August 28, 2008 @ 1:56 PM

Posted By: Reed Timmer

Different than model consensus, Tropical Storm Gustav moved west-southwest over night toward Jamaica in association with a convective explosion near and southwest of the center.  Mesoscale forcing mechanisms such as this are very hard to predict, and add to the difficulty in forecasting of hurricane tracks.  The recent model runs predict Gustav will move westward for a day or so before turning to the northwest into the central Gulf of Mexico.  However, the same few models that accurately predicted last night's track of Gustav have the storm moving westward into the northern Yucatan Peninsula, which seems like a very real possibility based on climatology.  Even if Gustav grazes the northern Yucatan, it will likely become a major hurricane in the Gulf of Mexico despite increasing wind shear.  Stay tuned for updates..

Posted At: August 26, 2008 @ 11:25 AM

Posted By: Reed Timmer

Hurricane Gustav is strengthening rapidly in the warm ocean waters south of Hispaniola today, with maximum sustained winds of 90 mph and a minimum surface pressure of 982 mb indicated in the 11:00 am advisory.  The only factor that could contribute to Gustav weakening is a passage over the center of Cuba, which is not being forecast by any of the models, so this storm is almost guaranteed to become a monster.


As seen below, a majority of the models take Gustav on a slow northwestward track toward southwest Cuba by Wednesday, with a turn to the west/southwest for a few days thereafter.  If this turn occurs, then Gustav will avoid the orography of Cuba, and will likely be un-phased by land.  This would be a bad scenario for the U.S. Gulf Coast, as Gustav would likely make landfall somewhere between Mobile, AL and the Mexico Gulf Coast as a major hurricane.  This could be a very dangerous and life threatening situation not only for the U.S., but also for Cuba.  Stay tuned for updates..

Posted At: August 26, 2008 @ 12:47 AM

Posted By: Reed Timmer

Tropical Storm Gustav is very close to becoming a hurricane, if not already.  Satellite imagery has indicated the presence of a closed low-level eyewall, and the next Hurricane Hunter Aircraft will likely find Gustav as a minimal hurricane.  The forecast track has been shifted southward slightly, now forecast to past over western Cuba late this week into the weekend.  Gustav will then enter the warm waters of the Gulf of Mexico where rapid strengthening is a definite possibility.  TVN will likely intercept this storm if it makes landfall anywhere as a cat 3 or higher storm...  Stay tuned for updates...Residents along the Gulf Coast should definitely keep an eye on the forecast.

Posted At: August 24, 2008 @ 9:05 PM

Posted By: Reed Timmer

Photogenic land spouts touched down today east of Denver, CO between 2330 and 00 UTC in Douglas, Elbert, and Arapahoe Counties, as merging outflow boundaries interacted with airmass storms/brief supercells across the CO High Plains.  The outflow boundaries were clearly evident on Denver radar, with the tornadoes touching down as the outflow boundaries collided with the storms.  Given the very weak low- and deep layer shear across Colorado, it is highly unlikely that these tornadoes were associated directly with a mesocyclone.  Here is a link to Channel 7 news in Denver for pictures:

http://www.thedenverchannel.com/slideshow/weather/17120420/detail.html Here is video Dick found on Youtube:

Posted At: August 24, 2008 @ 2:18 PM

Posted By: Reed Timmer

Tornadoes are possible today in the eastern outer bands of Tropical Depression Fay, as substantial breaks in the clouds have developed over eastern MS into AL, allowing for sufficient instability to develop for convection.  Tornadoes typically occur in the right-front quadrant of land-falling tropical cyclones, especially when being "picked-up" by a mid-latitude trough (which enhances the deep-layer shear and supercell potential).  Tropical Depression Fay is in a very stagnant upper pattern, so conditions are not ideal for a widespread outbreak of tornadoes as occurred with Hurricane Ivan as it moved through the Mid-Atlantic while embedded in the westerlies.  Still though, brief tornadoes are possible given the very strong low-level shear to the east and northeast of the center of circulation.

Posted At: August 23, 2008 @ 4:06 PM

Posted By: Reed Timmer

Check out "Raging Nature" tonight on Discovery Channel at 8:00 pm EDT...The Manchester, SD video will be shown, along with an interview of Chuck Doswell.   The complete schedule for this series can be found at the link below.  It's going to be an active year for television tornado specials!

http://dsc.discovery.com/tv-schedules/series.html?paid=1.14619.25808.35906.1

Posted At: August 21, 2008 @ 11:19 AM

Posted By: Reed Timmer

Tropical Storm Fay has basically been sitting in the same spot for over 12 hours now, but should drift slowly westward over northern Florida over the next few days, before possibly re-emerging over the northeast Gulf of Mexico Friday night.  On satellite, Fay is a very large storm but appears to be pulling in dry continental air from the north and west, as expected.  The NHC reported a minimum pressure of 994 mb and maximum sustained winds of 50 knots in their latest advisory, but this will likely be the peak intensity unless Fay takes a more southern track than forecast.  Stay tuned for updates as this HISTORIC tropical cyclone surges west!

Posted At: August 19, 2008 @ 9:15 AM

Posted By: Reed Timmer

Thankfully for the residents of South Florida, Tropical Storm Fay did not intensify much before making landfall this morning.  Hurricane Hunter aircraft recording a max surface wind of 49 knots with a dropsonde, with max flight level winds of 61 knots.  The satellite image was actually quite impressive at landfall, but the wind and pressure measurements did even come close to hurricane strength.  In the end, it looks like it was a good decision for us not to intercept -- although in 6 months we'll be chasing everything worldwide!

Posted At: August 16, 2008 @ 4:18 PM

Posted By: Reed Timmer

Check out this incredible video of a tornado hitting a bus in Poland during a tornado outbreak late last week!  Thanks to Volker for bringing this to our attention once again!
Here is a link for video of wedges during the same Poland tornado outbreak:

http://www.youtube.com/watch?v=_EPXh32sQKA

Posted At: August 16, 2008 @ 11:43 AM

Posted By: Reed Timmer

After an explosion of convection overnight just south of Hispaniola, it appears that Tropical Storm Fay is struggling to organize due to the orography of Haiti despite favorable atmospheric conditions.  Still though, all the models show Fay making landfall somewhere between the northeast Gulf Coast and South Florida, with the track trending east with each advisory.  The current NHC advisory forecasts Fay to make landfall as a strong category 1 hurricane over southwest Florida, however, the high oceanic heat content and lack of shear are creating an environment favorable for explosive intensification.

The visible satellite loop below shows the decline of the convective burst this morning, as expected with the diurnal cycle...   When I first pulled up the infra-red image this morning, I just about destroyed my computer because it looked like a cat 5 hurricane (not quite), but then realized that a majority of the convection was well south of the center, and likely due to orographic lift over Hispaniola.  How Fay handles the mountainous terrain over Cuba will determine it's strength at landfall, and whether we decide to chase.  We'll know for sure tomorrow, and if it appears Fay will make landfall as a cat 2 or higher hurricane -- we'll likely mobilize!  Stay tuned for updates..

Posted At: August 14, 2008 @ 8:21 PM

Posted By: Matthew Van Every

Simply put, this wave is trying so hard!!!!!!!!!!!

The environment looks very favorable for continued development over the next 72 hours.

Latest IR satellite loop shows the beginnings of what could be a well-developed high pressure within the next day or so. If this high matures then there will be huge potential for an explosion of development as soon as the system moves away from the islands. The islands can both help and hurt the development of this storm. If the center moves to close then the mountains and land friction will significantly hinder development because the low will try to fill. On the other hand if the circulation is able to say far enough north of the main islands then the storm will be helped by the enhanced daytime convection that land daytime heating provides; simultaneously not being affected by land friction. This is the best case for rapid development.

 

 

A few days down the road...

It looks like there will be a jet streak off the Atlantic Coast that could pull the storm to the north causing a probable landfall near South Carolina. This jet has the potential to do some interesting things to the tropical wave... depending on locations. If the storm meets the streak near the middle, where the winds are the strongest, then the storm will show some development just before being sheared apart, and carried out to sea. If the storm aligns with the right entrance region of the jet steak, then fireworks could happen.

 

 

Why? The right entrance region is a region of enhanced lift; this will lift air in the storm causing extreme rapped development due to intense convection. This could cause the storm to easily skip categories between NHC's standard advisories!

Posted At: August 14, 2008 @ 9:47 AM

Posted By: Reed Timmer

A classic northwesterly-flow MCS pattern will prevail today and tomorrow across the Southern High Plains, with a subtle disturbance ejecting from the Rocky Mountains this afternoon.  CAPE values across the TX Panhandle, southwest KS, southeast CO, and Northeast NM will be in the 2000-3000 J/kg range by 21z, with supercells developing shortly thereafter.  Given insanely weak low-level shear, these supercells will likely be non-tornadic in nature (although a freak accident is not out of the question), and should merge into a squall line by 00z before diving to the south.  Stay tuned for updates..

Posted At: August 12, 2008 @ 10:02 PM

Posted By: Matthew Van Every

The National Hurricane Center has downgraded the western tropical wave due to a lack of convection. Also, a Hurricane Hunter mission flew out today and determined that the system was not a Tropical Depression quite yet.

The latest IR satellite imagery suggest that the environment for both the west and east wave are still favorable for slow development. This is apparent with the anticyclonic rotation of high level clouds (storm's exhaust), and cyclonic rotation of low and mid level clouds (storm's inflow). The convection must pick up on both waves with in the next 2 to 3 days so that the storms can change their environment; the environment looks like it might be less hospitable in a few days.

 

 

The latest Water Vapor satellite imagery also suggests that the west wave has a good amount of moisture surrounding it that should contain plenty of potential energy. I am puzzled why this wave is having such a hard time turning that potential energy to kinetic energy. The east wave has what could be a significant problem when looking at WV satellite imagery. There seems to be a huge plume of dry air in the path of the wave and to the north.

 

Stay tuned!

 

Posted At: August 12, 2008 @ 12:32 AM

Posted By: Matthew Van Every

The wave in the Atlantic is still small but continues to have active deep convection as it moves west north west. There will be a low over New England for the next several days, this will most likely pull this tropical wave more northernly with time, so the main threat (if it develops) will most likely be on the east coast rather than Mexico or the Gulf. The second wave is very large and therefore has more energy release available therefore it has a good chance too.



Both systems seem to be in an environment favorable for slow development, however the GFS is suggesting that this environment will contain some shear as the storm gets closer to the Islands. If the wave is not developed by then, then it could get ripped apart before making landfall on the US.

Posted At: August 10, 2008 @ 2:49 PM

Posted By: Reed Timmer

Check out these photos taken by Mike Rurak (mikeR on the forum) in Red Deer, Alberta a few days ago.  AMAZING photos...

Posted At: August 10, 2008 @ 2:37 PM

Posted By: Matthew Van Every

 

Posted At: August 8, 2008 @ 6:01 PM

Posted By: Matthew Van Every

Posted At: August 6, 2008 @ 8:19 PM

Posted By: Reed Timmer

This looks very real...

Posted At: August 6, 2008 @ 10:34 AM

Posted By: Reed Timmer

Here is a video showing the components of the TVN tornado probe, and the deployment process (with a few bad re-enactments).  We'll be designing a page dedicated entirely to the probe, including this video, pictures, probe footage archive, and the wind data collected during successful intercepts.  In a few months, we'll begin mass-producing these tornado probes for the 2009 season so that each of the stream teams will have the ability to deploy -- and this should increase our success rate dramatically... 

Posted At: August 5, 2008 @ 10:30 AM

Posted By: Reed Timmer

Tropical Storm Edouard made landfall this morning at around 12z in the McFaddin National Wildlife Refuge between High Island and the Louisiana Border, packing winds of 55 knots.  The center was difficult to locate at times, and was likely changing locations slightly as convection pulsed.  Most of the convection and intense rain bands were on the west side of the storm, indicating that wind shear was likely still a problem, and inhibited Edouard from becoming a hurricane.  Shown below is a radar image from just after landfall: 


While isolated convective elements in the rain bands outside of the inner core of Edouard were scarce this morning, thus limiting the tornado threat, there is a possibility that the tornado chances could increase this afternoon with the heating of the day.  The SPC has issued a mesoscale discussion for more of east Texas and western Louisiana for this afternoon, where a tornado watch will likely be issued if convective elements begin to initiate in the rain bands of the front-right quadrant of the tropical cyclone.  Stay tuned for updates..

Posted At: August 4, 2008 @ 9:45 AM

Posted By: Reed Timmer

The maximum sustained winds have been lowered to 40 knots in the latest advisory on Tropical Storm Edouard, because Hurricane Hunter aircraft could not find a wind observation to support a 45 knot intensity.  The latest discussion mentioned 45 knots at 850 mb on the way back from the storm, and that was the maximum wind observation.  Still though, convection has been trying to develop near the center overnight, but still looks relatively weak and disorganized coming into an unfavorable time in the diurnal cycle. 


The official NHC forecast calls for Edouard to make landfall near the Houston, TX area on Tuesday as a strong tropical storm or even a weak hurricane.  The GFDL model, for example, is showing Edouard becoming a weak hurricane, while a majority of the other models are showing strong tropical storm at landfall.  If this storm RAPIDLY intensifies over the next 12 hours, we may consider chasing it..  but right now it looks like Edouard will be weaker than our minimum threshold for deployment..

Posted At: August 3, 2008 @ 10:56 PM

Posted By: Matthew Van Every

Sunday morning at around 4:30 A.M. CDT, Sioux Falls, SD reached an "Africa Hot" temperature of 101F after being in the 70s just 10 minutes prior! Why? The cause was a convective heat burst created by a collapsing thunderstorm 10 to 20K feet above ground level. These heat burst exist where rain from storms falls through a dry air mass. This dry air mass allows the rain to evaporate which cools the air and allows it to fall faster. As the air falls to Earth it warms at about 10C per 1KM due to compressional heating. If the falling air builds enough momentum it will reach the ground and cause a heat spike of up to about 30F in just a few minutes. Below is the RUC forecast sounding for Sioux Falls, SD valid 4 A.M. (courtesy of NOAA NWS).

 

 

These heat bursts are not rare; nevertheless it is "cool" when it happens. Below is the temperature and dewpoint timeline for the automated surface observation system (ASOS) at Joe Foss Field (provided by NOAA NWS). Notice the rapid temperature rise and and the plummeting dew point.

 

IN OTHER NEWS...

Keep watching the tropics; we now have Tropical Storm Edouard just off the Gulf Coast. He is moving very slow with warm waters and there is a strong high-pressure system just to the north, don't be surprised if Edorado makes hurricane status by landfall in Texas. Also note that Edorado has the potential to affect a huge number of off shore drilling wells, if Edorado were to become an intense storm then we can expect gas prices to jump up at the pump.

 

Posted At: August 3, 2008 @ 3:01 PM

Posted By: Reed Timmer

Check out this video of the Whitedeer, TX tornado on May 29, 2001, shot by Joel Taylor from close range.  This tornado was rated an F3, but likely would have been rated even higher had it not remained over rural areas - thankfully.  Notice the very sporadic rain curtains wrapping around the tornado when they are in the "notch". 

While nothing even close to the Whitedeer Tornado is anticipated today, there could be some supercells with very large hail in Southern Minnesota this evening if the cap can break along an outflow boundary/pseudo-warm front.  The SPC has just issued an MD for this area, as extreme CAPE is building in from the south...

Posted At: August 1, 2008 @ 9:22 PM

Posted By: Matthew Van Every

Well, the easterly wave that moved off of Africa's coast a few days ago is still trying to develop, but it is struggling to exist. Satellite IR imagery has shown weak thunderstorm development near the surface low. In fact thunderstorm activity has been pulsing and at times non-existent (see bellow). This is a problem because the wave is in an environment unfavorable for development and without thunderstorms the wave cannot change its environment for the better... essentially the wave is being choked out.

 

One thing that might give the wave one last chance to develop is the warm waters in front of its path (see below). These warm waters will release extra energy that the wave can use to create more storms, which could eventually make the environment favorable for further development.

 

 

It will be interesting to see how this wave evolves over the next few days... if it survives at all!

Posted At: August 1, 2008 @ 4:35 PM

Posted By: Reed Timmer

Severe thunderstorm watches have been issued for most of the western Great Lakes region, mainly for the threat of strong straight-line winds and marginally severe hail.  Many of these storms are forming along lake breeze fronts and outflow boundaries, with the storms likely congealing into one or more MCSs by this evening.  0-1 and 0-3 km helicity values are under 50 m2/s2 for the entire region, so the tornado threat is almost non-existent.  Tomorrow could be very interesting in Manitoba!  Check out the forecasting thread in the forum for updates.