TornadoVideos.net

Posted At: October 30, 2006 @ 11:16 AM

Posted By: Reed Timmer

A nice case study of the October 26, 2006 cold-core tornado outbreak is presented by Jon Davies at the URL below.  John Davies has published several articles concerning the typical synoptic and mesoscale features of cold-core tornado events, including Davies and Guyer (2004). 

http://members.cox.net/jondavies6/102606swks/102606swks.htm

Many of the tornadoes observed on October 26 appear to be non-supercell tornadoes or landspouts, which are those not associated with a deep persistent mesocyclone.   Landspouts are typically much weaker than supercell tornadoes, and form via the stretching by an updraft (from a cumulus cloud or thunderstorm) of pre-existing vorticity or rotation associated with surface boundaries.  

Posted At: October 26, 2006 @ 3:36 PM

Posted By: Reed Timmer

As of 4:30 pm CDT, two brief tornadoes have been reported in southwest Kansas in Gray County in association with the cold core vorticity maximum.  While these tornadoes are usually brief and weak as compared to tornadoes in the warm sector, they are often very photogenic.  The storms that produce these tornadoes also rarely look impressive on radar, and often show very small areas of brief rotation.  The image below shows the Dodge City, KS radar image at around the time of the tornado.
                   

Posted At: October 25, 2006 @ 10:22 AM

Posted By: Reed Timmer

The Wednesday morning forecast models are still predicting favorable conditions for tornadoes tomorrow over central and eastern OK.  Each successive model run continues to slow down the system, so I would not be surprised if we're even chasing in western OK tomorrow.  The moisture will be very high with dewpoints in the mid-60s, resulting in very good instability for this time of year.  A potent upper-level storm system will also induce an intense low-level jet over the area, resulting in extreme low-level wind shear.  The 12z Wed WRF model output for dewpoint, 850 mb, and 500 mb for Thursday evening are displayed below.
                 

Posted At: October 24, 2006 @ 10:15 PM

Posted By: Reed Timmer

An intense upper storm system will sweep across the Southern Plains on Thursday, pumping tropical moisture northward from the Gulf of Mexico and enhancing the low-level shear in the warm sector.  This event appears to be a textbook bulging dry line setup, with 2000+ J/kg CAPE and nicely backed surface winds over eastern OK by Thursday afternoon (as forecast by the 00z WRF Tuesday night).  If this forecast verifies, we will definitely be chasing this event Thursday, so stay tuned to the live tracker.  Shown below are the forecast CAPE and 500 mb flow for Wednesday evening.
          

Posted At: October 23, 2006 @ 1:01 AM

Posted By: Reed Timmer

Hurricane Paul has strengthened during the day Sunday into a strong category 1 hurricane, with maximum sustained winds of 75 knots as of 8:00 pm PDT Sunday evening.  An eye has appeared on satellite imagery, and the convection around the center remains intense.  Paul is expected to strengthen slightly over the next day before making landfall near the tip of the Baja Peninsula in 24-48 hours.  If Hurricane Paul strengthens more than expected, and could make landfall as a major hurricane (cat 3 or higher), we may have to buy a last minute plane ticket to Cabo tomorrow once again!
         

Posted At: October 15, 2006 @ 5:46 PM

Posted By: Reed Timmer

A tornado was reported at 6:22 pm CDT in east-central Reeves Countey, TX, or 17 miles SE of Pecos, TX, right in the heart of the Pecos Valley.  As can be seen in the previous post, this supercell moved into an area with very favorable 0-1 km helicity and CAPE.  As seen below, a distinct hook echo was present on the south side of the supercell, as well as a strong "couplet" on the storm-relative velocity image.

        

Posted At: October 15, 2006 @ 3:51 PM

Posted By: Reed Timmer

A tornado watch has been issued for Sunday afternoon and evening in the Pecos Valley of southwest Texas, as a powerful upper-level storm system rotates into the Southern Plains.  A strong low-level jet, sufficient moisture, and cold air aloft will contribute to the explosive development of supercells.  Given 0-1 km helicity values of 150+, tornadoes will also be possible with any isolated supercells.

           
As can be seen in the 21z RUC analysis below, the best 0-1 km helicity and CAPE is located over the central Pecos Valley, just south of the extreme southeast corner of NM.  However, it is likely this favorable area for tornadoes will extend over the remainder of the S Texas Plains this evening.  As can be seen in the surface wind barbs below in the CAPE map, a SSW to NNE surface boundary is also located across the western Pecos Valley.  If a storm can move along this boundary, the low-level vorticity could be locally enhanced.  We will keep you updated if any storms become tornadic in the next 4-6 hours.

        

Posted At: October 13, 2006 @ 7:52 AM

Posted By: Reed Timmer

An INCREDIBLE early season lake effect snowstorm struck areas downwind of Lake Erie on Thursday and Thursday night, with a monster snow band pummeling the Buffalo, NY area for several hours.  Officially, 14 inches of snow fell at Buffalo Niagara International Airport, with 2 feet falling in the suburbs.  220,000 people in the area are without power, and 80% of the roads are impassable!!  Check out the radar image below of the band from around midnight EDT.  You can see from the radar appearance that heavy rain was falling from the band over the warm lake, with snow falling over land (feathery nature of the radar echoes).  Thunder and lightning was common in this band.  INCREDIBLE!!!

Posted At: October 12, 2006 @ 4:51 PM

Posted By: Reed Timmer

Heavy lake effect snow today fell across western Michigan as unseasonably cold air swept across the warm 60 deg F waters.  As of 1 pm EDT, 1.4 inches of snow fell at the Grand Rapids NWS, with 3.5 inches reported in Kalamazoo just an hour to the south.  Both locations shattered snowfall records for the day, with the Grand Rapids snowfall the most since 1909.  60+ mph wind gusts were also reported along the lake shore.  At least a few more inches are likely over these areas through tonight, as heavy lake effect bands come ashore. 



Displayed below are some pictures my mom took from her house in Ada, MI, just east of Grand Rapids.  While light snow was falling at the time of the picture, very heavy snow was reported in the more intense bands.  Thunder and lightning can also occur with the intense lake effect snow squalls, since the clouds that produce these heavy snowfall rates are convective in nature.

Posted At: October 11, 2006 @ 1:03 PM

Posted By: Reed Timmer

The El Nino conditions are materializing in the Tropical Pacific as of mid-October, with the expected atmospheric component beginning to match that of a typical warm ENSO event (weaker than normal easterly Trade Winds in the Tropical Pacific).  Warm sea surface temperature anomalies have been present throughout the late summer and early fall, but the easterly Trade Winds have remained normal or even above normal until recently.  Realizing the coupled atmosphere-ocean El Nino developing, NOAA recently released a revised winter temperature/precipitation outlook  that matches typical El Nino teleconnections in the U.S., with warm temperature anomalies across the north-central U.S., and wet conditions along the southwest U.S.

  
As shown below, positive sea surface temperature anomalies of 2-3 deg C are developing in the eastern Pacific.  Sub-surface temperature anomalies of 4-5 deg C are also present in the eastern Pacific, so the SSTAs will likely increase further there.  Thus, an enhanced subtropical jet will likely be present for much of this winter and early spring, which could result in active severe weather patterns for the southern U.S.  The winter of 2001-02 was also a moderate El Nino event, and we saw a tornado in Texas on Dec 30 that year. 

Posted At: October 8, 2006 @ 11:14 AM

Posted By: Reed Timmer

Joe Bastardi from Accuweather said the following about this event:  "A WILD 10-DAY PERIOD WITH UNBELIEVABLE EARLY SEASON COLD AND SNOW OVER THE PLAINS AND INTO THE MIDWEST AND LAKES.  TREE SNAPPING SNOW AND WIND UPPER MISS VALLEY THROUGH WESTERN AND CENTRAL LAKES WITH PEAK GUSTS TO 70 MPH POSSIBLE". 

An unseasonably strong cold front will plow across the central and eastern U.S. during Wed-Fri of next week.  In terms of the cold air and low 500 mb heights, this event only occurs about once every 50 years this early in the season!!  Insanely strong winds and snow will be common across the northern U.S., and severe weather will likely accompany the cold front in the eastern U.S.  A blog from a tv meterologist in Grand Rapids, MI is comparing this event with the 19-20 Oct 1989 lake effect snow storm where 5-10' snow fell in western MI! The temperatures of the Great Lakes are still in the upper 50s, so when air this cold passes over the warm lake waters, heavy rain and snow is possible along the eastern shores of the lakes.  The snow will be wet and heavy, so downed trees and power outages will be possible if the heavy snow verifies.  We'll be monitoring this system closely, and may have to chase the severe weather and the lake effect snow!

Posted At: October 4, 2006 @ 4:58 PM

Posted By: Reed Timmer

Posted At: October 2, 2006 @ 10:39 PM

Posted By: Reed Timmer

The coast of Vietnam sustained major damage over the weekend from Typhoon Xangsane, which was packing 90 kt sustained winds at landfall.  Our friend James Reynolds was right in the middle of it all in Hoi An, which was in the left eyewall for over 2 hours.  The town of Danang, which was in the right eyewall, also sustained major damage with a substantial storm surge.  Displayed below are pictures from the road between Hoi An and Danang, which extends along the immediate coast line.  There is definite evidence of a major storm surge!

Posted At: October 1, 2006 @ 11:41 AM

Posted By: Reed Timmer

We finally heard from James Reynolds, after he sustained a near direct hit from strong typhoon Xangsane in Hoi An, Vietnam.  The typhoon was packing sustained winds of 90 kts at landfall, and James was in the left eyewall for hours.  Displayed below are some pictures he took during the peak of the storm, which made landfall duing the morning hours.