Wxstalker

2011 Spring Season Recap

2011-08-06T01:15:00.000-07:00

Chases: 10 (4/4, 4/15*, 4/27, 5/19, 5/20, 5/21**, 5/22, 5/23, 5/24*, 5/25*)
Successful Chases: 9 (4/3, 4/15, 4/27, 5/19, 5/21, 5/22, 5/23, 5/24, 5/25)
Busts: 1 (5/20)
Storms Intercepted: 13
Tornadoes: 7 [Strongest: EF4 (5/24)]
Largest Hail Intercepted: ~1.75in [(Golfball sized) (Does not include HailSTONE collection)]
Strongest Winds Encountered: ~60 mph
States Chased In: LA, AR, MS, OK, KS, AL
Miles Driven: 6,089

*denotes days where tornadoes were observed
**denotes multiple tornadoes observed

Recap:

4/4: Targeted Northwest Mississippi with Cooper in hopes of intercepting semi-discrete cells out ahead of the ongoing MCS, as well as bowing segments within the MCS. We succeeded in intercepting several semi-discrete cells that managed to produce sporadic quarter sized hail. Unfortunately, the section of the MCS that we traversed gusted out before reaching our location north of Tupelo, MS, therefore no severe winds were experienced on a historic day for wind damage reports.

4/15: Forecasted semi-discrete cells to form south of an ongoing MCS due to outflow boundary interactions in Central LA early on this day. This forecast verified, however class didn’t allow me to depart MLU until well after 10:00am. At this point, the initial discrete cell matured into a supercell and produced an EF3 tornado in Jackson, MS. I managed to salvage the chase by chasing all the way into far Eastern MS and extreme Western AL intercepting 3 different storms (1 originating from an outflow boundary, the other 2 from a “dry boundry”) bagging two wall clouds and a semi-rainwrapped cone tornado near Quitmann, MS.

4/27: Did not intend on chasing on this day, however ended up in the middle of the Apocalypse on the way home from Dauphin Island, AL. Cooper, Torres, Voight, Willis, Keys and I intercepted a strengthening storm near Crystal Springs, MS as it crossed I-55. This particular storm featured two “hooks” at the time of intercepting. We barely missed the first hook but managed to document and call in a rotating wall cloud associate with the second hook. The gradient behind the dry boundary in eastern LA was among the strongest that I’ve ever personally experienced - extremely strong gusty winds made driving a challenge.

5/19: Day one of Project HailSTONE was met with a marathon drive from MLU to Wellington, KS beginning at 2am. Operations commenced upon arrival in Wellington with a brief training before jumping right into the action. The team intercepted several storms the weakened rapidly before intercepting a storm that produced decent results near Jetmore, KS that evening. The day officially ended in Woodward, OK 24 hours after initially departing from MLU.

5/20: Day two of Project HailSTONE turned out to be a bust. However, this provided valuable time to have a proper training session as well as bonding time with members. Following training and practice, activities for the day included a heated game of rock curling, touring a wind farm, and climbing a mesa to watch a storm ~80 miles to our north at sunset.

5/21: Day three of Project HailSTONE was an epic day on many levels. The team intercepted two supercells that featured incredible structure and produced ~5 tornadoes total (4 were documented by Cooper and I before going into collection mode). To top this off, a successful data set was collected by the team.

5/22: Day four of Project HailSTONE was arguably the most difficult day mission-wise due to the HP nature of the storms. The strength as well as the destruction produced by the Joplin, MO storm made collection and communication extremely difficult on this day.

5/23: Day five of Project HailSTONE was by far the most successful day of the project. The team identified an Oklahoma record sized stone that was 6 inches in diameter.

5/24: The final day of Project HailSTONE was short lived due to the excessive forward speed of the storms as well as the high number of tornadoes. Operations were called off and the team chased the tornado outbreak in central OK. After nearly getting stuck on dirt and clay roads, Cooper and I rebounded and managed to punch into the hook of a tornado producing supercell near Chickasha, OK. We were able to follow and document the EF-4 for the duration of its lifetime.

5/25: Before ending our spring season, Cooper, Kelley and I chased the high risk in northeast Arkansas. We witnessed a brief tornado on our storm north of I-40 before chasing its persistent wallcloud into the flooded plains of northeastern Arkansas. Cut off by the historic Mississippi River flood, we trekked back toward I-40 in hopes of getting on the next storm. However, a very crowded I-40 prevented us from achieving this as the storm raced ahead of us into Tennessee producing a tornado around Memphis in its wake.

As tropical and fall severe weather seasons become more active, we will become active again. Full chase accounts of our spring chases will be coming soon.

HailSTONE Identifies Oklahoma Record Stone

2011-08-06T00:06:00.000-07:00

Project HailSTONE, the project in which me and Dylan participated in this past spring identified an Oklahoma state record hail stone (6 in. diameter) on 23 May 2011. Read more about this exciting announcement at http://www.hailstoneresearch.org/may2311news.html

March 5, 2011 Southern Louisiana Severe Wx

2011-03-12T13:37:00.000-08:00

This past Saturday, March 5, 2011, southern Louisiana was rocked with another round of severe weather, with the primary storm modes being wind and tornadoes. Unfortunately, this episode of severe weather proved to be both damaging and deadly, as a fairly short lived tornado produced EF2 damage in the town of Rayne, LA killing one person and injuring twelve others in its wake. This was one of nine tornadoes that were produced across Southern Louisiana last Saturday, with four occurring in WFO LCH's CWA and five occurring in WFO LIX's CWA (County Warning Area).

What caused this event?
Through the analysis of upper air soundings and maps, I was able to identify several important features that were responsible for the initiation of this severe weather event. In order for severe thunderstorms to occur, several conditions must be in place in conjunction with several atmospheric processes. A moist layer of sufficient depth must be present in the lower to mid troposphere (including the boundary layer), instability, and source of lift (e.g. forcing from a front, upper level shortwave). A fourth ingredient, wind shear, is crucial for the formation of supercell thunderstorms and tornadoes.

This event initiated when several subtle shortwaves downstream of a well defined vort max passed over SE Texas and SW Louisiana, providing the lift needed for thunderstorms to develop.

A series of subtle shortwaves are denoted by the red circle. A well defined vort max (red area) can be identified over west Texas. The "X" in this area denotes an area of maximum vorticity while the N to the north of this area denotes an area of minimum vorticity. With the area of interest being downstream of this vort max, positive vorticity was advected into the area with time thus enhancing vertical lift over SE Texas and SW LA

The 12Z sounding from WFO LCH profiled the atmosphere about an hour before the initiation of this event. Multiple features in this sounding support the potential of severe weather. The black boxes denote the depth of two significant dry layers in the atmosphere. The wind profiler shows backed surface winds and veering winds with height. Winds increase with height, thus indicating the presence of speed and directional wind shear. The red box in this area of the sounding shows slight backing of the winds at upper levels, thus indicating slight cold air advective tendancies. The "inferred temp advection" graph supports this observation, denoting temperatures decreasing at rates of 0.6 and 0.7 degrees Celsius per hour. The hodograph in the top right area of the picture supports the observations made from the wind profile. This tool shows how wind direction and speed change with height. 0-1 km shear (denoted by the black box) indicated that the atmosphere was conducive for rotating updrafts. Despite these features, a weak capping inversion in the lower levels was inhibiting convection at the time the atmosphere was profiled (SB CIN values of -46 and ML CIN values of -149). This cap quickly eroded in the hour following this sounding and allowed thunderstorms to develop.

The Event

The image above is a base reflectivity overview of the entire MCS. The red "L" just to the south of the Louisiana coast (Cameron Parish) denotes the location of the subsynoptic low that influenced storm motion. The black arrows show the differences in storm motion with respect to distance from and location around the low. Convection well ahead of the main thunderstorms featured a northerly component of motion whereas activity behind and north of the low featured a southerly component of motion (air rotates counterclockwise around low pressure systems in the northern hemisphere). The main convection associated with this system moved to the eastnortheast as the entire MCS propogated to the east.

Surface observations around the time of initiation (~13Z).

Jefferson Davis EF0's

This is a base reflectivity (BR) and storm relative velocity (SRV) image the supercell thunderstorm that produced two EF0 tornadoes in Jefferson Davis Parish. At the the screen shot was take, the second EF0 tornado was in progress. The base reflectivity product features an impressive signature that supports the strong velocity couplet that is featured in the SRV product. The BR image shows areas of higher reflectivity associated with heavier rainfall "spiraling" toward the area of lower pressure where the mesocyclone and tornado were located. The behavior of the rainbands is a direct result of the strong inbound/outbound velocities that are shown by the SRV product. The red arrow in the BR image denotes modified inflow air (modified by wetbulb cooling at the surface due to rainfall) being advected into the inflow notch to the northeast of the mesocyclone and tornado. This particular storm eventually gusted out as a rear inflow jet built into the area, leading to several more tornadoes, including the Rayne EF2.

Crowley & Rayne Tornadoes

Both the Crowley tornado (EF0) and the Rayne tornado (EF2) were the result of bookend vorticies, as a rear inflow jet built into the area. This inflow jet may have been the result of wet-bulb cooling occuring in the mid-levels of the thunderstorm that was located just to the west of the HP supercell that produced the Jefferson Davis Parish tornadoes.

In this series of photos, I utilized the base reflectivity (BR), storm relative velocity (SRV), echo top (ET), and normalized rotation (NROT). The echo top product shows cloud top heights. The NROT product is an algorithm that was developed by the makers of GR Analyst. This product features a range of -5 to +5. Anything above 1.0 is significant and values above 2.5 are extreme. A detailed explanation of this product can be found here: http://grlevelxstuff.com/forum/showthread.php?t=314.

The BR product in the photos above show streaks of lighter reflectivity in the trailing stratiform precipitation behind the tornado producing thunderstorm. This signature suggests the presence of a rear inflow jet. This occurs as strong winds change the direction of rain droplets from vertical to horizontal, thus preventing the radar beam from intercepting some these droplets and leading to lighter reflectivity returns. The series of photos also shows the evolution of the velocity couplet, with it being the strongest and tightest over the city of Rayne. Gate to gate velocity (inbound/outbound velocity combined) was 85 knots and NROT values were 1.53 at the time. Echo tops associated with this storm peaked ~41,000 feet.

All together, 683 homes were damage with 42 being completely destroyed and 48 receiving major damage in Rayne. Unfortunately, these two tornadoes injured a total of 15 people and killed one woman when a tree fell on the house she was in.

How does a bookend vortex form?

Bookend vorticies are the result of shear vorticity (a form of relative vorticity). The photo above illustrates this process very clearly. As strong winds move through an area, it creates areas of vorticity on both sides of the area of strongest wind. This is the same principal as dragging your hand in bathwater. The water that is not being pushed by your hand has a tendancy to rotate away from the area of forcing, thus creating vorticity on a small scale. Although the image above is a model of this principle at the 300 hPa level, this can occur at any level in the atmosphere.

Southeastern Louisiana Tornadoes
The tornadoes that were produced in southeastern Louisiana were also the result of a shear vorticity/bookend vortex situation. Of the five tornadoes in this region, four were EF0's and one was rated EF1.

These two cases from SE Louisiana explicitly show the same radar signatures that the Crowley and Rayne storms exhibited. Bookened vorticies and areas of rotation are depicted by the black circles in each image.

What lessons were learned?
In conclusion, March 5, 2011 is another classic example of the kinds or tornadoes that we are faced with in Southern Louisiana and throughout the southeastern US. Unlike many cases from the Great Plains, tornado producing storms in the south are often messy storm structure wise, making them much more difficult to detect and dangerous to chase.

South Lousiana Serial Derecho

2011-03-06T15:01:00.000-08:00

This past December 29, Southern Louisiana experienced a serial derecho. Little damage was done, with the only damage reports coming from the Intracoastal City area in the form of downed trees. An 80 mph wind gust was recorded from a private weather station in the Mouton Cove area and a 60 mph wind gust was recorded at the KATC-TV3 station in Lafayette, LA. Tornado warnings were issued by the NWS offices in Lake Charles and Slidell, due to the threat of brief tornadoes along the front of the MCS and associated with the bookend vorticy on the north side of the MCS.

The 0Z sounding from WFO LCH showcases several interesting features that led to the initiation of this event. While surface based CAPE values were only ~550 J/Kg and surface temperatures were in the lower 60's, several factors led to the destabilization of the atmosphere. First, the area's in the blue circle and red square show significant dry air layers. This is important, because these dry layers steepen lapse rates (temperature decrease with height) aloft, thus allowing the mid levels of the troposphere to destabilize. The significance of the second dry layer ~650mb is not known due to the failure of the carbon hygristor (measures atmospheric humidity) in the radiosonde at this level. The stratification of this particular layer (shown by the orange circle at 450mb) suggests the end of this dry layer. However, due to the absence of data at this point, this statement cannot be made with confidence. Finally, backing of the winds in the upper levels (as denoted by the green box in the wind profile) suggests cold air advection aloft. This is significant, because this increases lapse rates aloft, thus further destabilizing the atmosphere (a warm air parcel rises more rapidly with colder air surrounding it).

The radar images above shows the MCS bowing out around the Intracoastal City area. The rear inflow jet (RIJ) can clearly be seen in both base reflectivity and storm relative velocity products. The RIJ is the reason why an 80 mph wind gust was recorded around the Gator Cove area. The RIJ is also directly responsible for the bookend vortex (denoted by the blue circle) that formed on the north side of the MCS. It was this feature that prompted a tornado warning for parts of Vermillion, Iberia, and St. Martin Parishes. Although no tornado occured in this case, many tornadoes that occur with derechos occur in these bookend vorticies, therefore the warnings from the WFO LCH were justified.

2010 Chasing Recap

2011-01-09T18:30:00.000-08:00

Chases: 8 (1/20, 1/23, 3/27, 4/2, 4/24*, 5/1**, 5/19*, 12/31)
Successful Chases: 5 (3/27, 4/24, 5/1, 5/19, 12/31)
Busts: 3 [1/20 (class), 1/23, 4/2]
Storms Intercepted: 12
Tornadoes: 5 [Strongest: EF4 (4/24), Weakest: EF0 (5/1)]
Funnels:4
Wall Clouds:12
Largest Hail Encountered: Dime sized (.75 in)
Strongest Winds Encountered: ~80 mph
States Chased In: LA, AR, MS, TX, OK

*denotes days where tornadoes were observed
**denotes multiple tornadoes observed

*Note that the tornado on 5/19 was rainwrapped and was picked out of the rain due to violent left to right motion during post chase video analysis.

*Also, rain wrapped tornado was witnessed on 12/31, however funnel could not be seen, nor could violent left to right motion be made out in the rain. Power flashes were observed however.

Recap:

1/20: First tornado outbreak of the new decade. Clay, Cooper and I could not get out early due to an afternoon class. This caused us to miss the show, including the EF-3 tornado that impacted Waskom, TX.

1/23: Still reeling from the missed opportunity, Clay, Cooper and I chased a marginal slight risk across Southern Arkansas and busted badly due to a lack of instability. Thank you stratus clouds!

3/27: Targeted Central Arkansas while most other chasers targeted the OK/MO border due to a greater tornado risk. Enjoyed an LP supercell event across central Arkansas and intercepted multiple storms for the first time. I witnessed the hail shaft of one of the storms cross I-40 during rush hour just outside of LIT. I also experienced ~60 mph winds 4 miles north of Stuttgart associated with a bowing segment in the squall line that formed after the sun set.

4/2: Still feeling chase fever, I joined Wheeler, Cooper, and Ostarly on a slight risk chase over NE Texas. I initially targeted Mt. Pleasant, TX, however we hung out in SHV and accessed the situation due to lingering stratus that was surpressing daytime heating over the target area. Storms did initiate and went through the target area, but were only marginally severe at best. Again, morning crapvection and stratus won the battle that day….

4/24: This was a day of firsts. I finally intercepted my first tornado with Cooper in the Mississippi Delta. Unfortunately, it was a killer EF4. We also witnessed extensive tornado damage for the first time. In addition, I experienced the worst RFD to date associated with that storm and punched into the “bear’s cage” for the first time on this day.

5/1: Witnessed multiple tornadoes for the first time across Central Arkansas. All of them were brief however, leaving me feeling teased by Mother Nature at the end of the day…

5/19: Didn’t do the best job at forecasting on this day and played catch up for most of the afternoon. Cooper and I did witness a rainwrapped tornado around the Dover area as we were moving north to get in better position to intercept the storm. We also witnessed a brief funnel that got halfway to the ground as the storm was gusting out. This was not my favorite chase for a lot of reasons, but mainly due to the insane amount of traffic.

12/31: Chased in the Louisiana Delta region and across Central Mississippi with Cooper. We bagged two wall clouds on a single storm as it went through a cycle just west of Newellton, LA and witnessed a rain wrapped tornado move through the Richland/Pearl/Jackson, MS area. However, no violent left to right motion was noted from our location and we did not see the condensation funnel.

-JP

Another Successful Pre Holiday Chase

2011-01-09T18:19:00.000-08:00

I departed NIB around 8:30pm CDT on Thursday evening to travel to MLU to meet with Cooper for what would be a slight risk chase across the western parts of Dixie Alley. A new challenge for myself in forecasting this system was the fact that there were multiple target areas, including the NW Arkansas and the Ozark region of Missouri which is mostly bad chase area (with the exception of a few areas in Missouri). In addition, storm motion was going to be far faster than what is ideal to chase in these areas. Fast storm motion and poor road networks usually spell disaster. Taking all of this into account, we decided to play the southern scenario and initially target East Central Mississippi between Vicksburg and Jackson.

After a few hours of sleep, we awoke to semi discrete supercells racing across NW Arkansas producing several tornadoes in its wake. Being sorely out of position and having no desire to be playing catch-up with these fast moving storms, we decided to stick with our target area of East Central Mississippi. Cooper and I departed MLU around 9 am on Friday with an initial target of Vicksburg, MS. However, with storms already developing in the favorable thermodynamic environment that was present over SE Louisiana, I decided to target Jackson initially due to more road options.

We arrived at our target area around 11:30 CDT and began staging. The storms that formed over SE LA were tracking further east toward the jungles of West Central MS and were going into HP mode as expected. Meanwhile, a weak storm cluster formed just to the northeast of Lake Charles, LA. Based on the thermodynamic and dynamic environment that was present across all of South Louisiana, we decided to drive back toward Vicksburg and monitor the situation from there with viable road options to take us south and west.

In Vicksburg, Cooper and I noted the increasing temperature and moistness of the air. The SREF and RUC models were both indicating that a Theta E ridge (see http://www.theweatherprediction.com/habyhints/324/ for more info) was building north toward the I-20 corridor, with the main axis building in between Tallulah, LA and Vicksburg, MS. I noted that the storm cluster that formed NE of LCH was following the theta e ridge to the northeast, and it was only a matter of time before these storms were going to intensify and go severe. Therefore, Cooper and I decided that it would be best for us to reposition further west to cross the Mississippi River to have a change to intercept these storms before they merged into a squall line.

As we mobilized, the southernmost storm in the targeted broken line of storms went supercellular prompting a tornado warning from the NWS LCH, as this storm was in the extreme northeastern part of their CWA. Noting the track of these storms to the northeast and considerably slower storm motion (25-30 mph at this time), Cooper and I took Highway 65 south to attack a cell in the middle of the broken line the was beginning to show signs of forming a mesocyclone. As we began moving south, the storm that was targeted went supercellular and was warned on by the NWS in Jackson, MS. Around this time, we were inconvenienced by the loss of mobile internet. However, with the help of several nowcastors and visual knowledge, we were able to put ourselves in position for a good intercept 4 miles west of Newellton, LA along State Highway 4.

After sitting for about 20 minutes watching to storm, we were rewarded for our patience as the wall cloud associated with our storm appeared out of the rain. Very weak rotation was observed with this wall cloud. After calling it in to WFO JAN as well as capturing stills and photos of it, we decided to move north on Hwy 65 and parallel the wall cloud rather than sitting and waiting for the next storm. This decision was made in an attempt to 1) stick with that particular storm and 2) get back across the Mississippi River as soon as possible, as the severe threat was beginning to shift further east as the broken line of storms began to merge into a squall line.

On our way north, we ran into fellow chasers Conner McCrorey and David Reimer of Texas Storm Chasers and Scott Peake from OU, who were also on the same storm. As both teams continued north tracking the storm, we experienced a new wall cloud with this particular storm passing over the top of both of our vehicles. As it crossed the Highway, I noted weak vertical motion and little to no rotation associated with the wall cloud itself. The storm still retained supercell characteristics, as both teams were slammed with a very wet RFD containing ~60-65 mph winds. Due to the brief delay in the RFD reaching our location on the road after the wall cloud passed over us, I was able to infer that there was still broad rotation associated with the storm itself.

After punching through the newly developed squall line around Jackson, MS, Cooper and I targeted a discrete supercell with a confirmed tornado ahead of the main line that was translating NE toward the Jackson Metro area. With the lack of daylight left and poor terrain (lots of trees), I decided it was best to not punch the bears cage with the hope of getting a brief glimpse of the tornado. In addition, storm motion was much quicker (~45 mph) due to an increase in low level jet (850mb) wind speeds. Instead, we tracked a little further East to Highway 49, where we drove south into the town of Richland. There, we watched the rain wrapped tornado translate across the highway about 3 miles to our north noting power flashes and inflow winds well beneath the severe threshold.

Around this time, WFO JAN issued a Tornado Emergency for the city of Jackson, as this tornado was moving toward the city. After about a 5 minute wait, we decided to follow this storm toward Brandon, the next town east of Jackson on I-20. As we tracked East toward Brandon, we noted several power flashes associated with the tornado as were pushed around by winds in access of 55-60 mph in the backside of the storm. We also ran across tree limbs in the road around mile marker 50 on I-20, just a little damage associated with this EF-2 tornado.

Around this time, we noticed another cell to our southeast that was beginning to go supercellular. We managed to get ahead of this storm on I-20 before driving south on state highway 13 toward the town of Polkville. Despite the terrible terrain, we managed to find a small hill next to a clearing in the dense tree canopy to watch the storm approach our area. However, the storm gusted out before reaching our location and managed to recycle off to our Northeast. However, due to the lack of light, we decided to call it a chase.

Special thanks to Don Wheeler of LA Delta Community College and Brandon Thomas from the Alabama Storm Trackers for nowcasting assistance!

Chase Stats

Storms Intercepted: 4

Wall Clouds: 2

Highest winds: ~60 mph

Largest Hail: Dime sized (.75 in)

Miles Driven: 990

Our location relative to the rainwrapped tornado as it moved toward the Jackson area. Courtesy of Don Wheeler LDCC.

-JP

Spring Season Recap

2010-10-16T19:01:00.000-07:00

Due to school and other responsibilities, it has been a long time since I've last posted an entry. However, due to a brief lull in school activity, I was finally able to compile the stats from my springtime chases.

Chases: 7 (1/20, 1/23, 3/27, 4/2, 4/24*, 5/1**, 5/19*)
Successful Chases: 4 (3/27, 4/24, 5/1, 5/19)
Busts: 3 [1/20 (class), 1/23, 4/2]
Storms Intercepted: 8
Tornadoes: 5 [Strongest: EF4 (4/24), Weakest: EF0 (5/1)]
Funnels:4
Wall Clouds:10
Strongest Winds Encountered: ~80 mph
States Chased In: LA, AR, MS, TX, OK

*denotes days where tornadoes were observed
**denotes multiple tornadoes observed

As the overall pattern begins to change, I plan on being back out in the field later this fall for secondary severe weather season. Look for my stream on www.chasertv.com when that time comes.

-JP

Late Night Severe Weather

2010-05-16T15:27:00.000-07:00

Last night, a band of thunderstorms associated with a meso-low located in the NW Gulf of Mexico made its presence known along the coast of South Louisiana. This along with a conducive thermodynamic environment (temps ~73, dewpoints ~70, CAPE ~1800, decent lapse rates, and an LCL ~600m) allowed these thunderstorm's to flourish even with the absence of diurnal heating. One particular cell embedded in this band went supercellular around 1:35am prompting a tornado warning from the NWS office in Lake Charles. This continued a trend that was set earlier in the day when a discrete supercell apparently produced a tornado (not confirmed) in the Slidell CWA. This warning was allowed to expire, as the coupling never really got it's act together. However, tree and powerline damage was reported about two miles south of Kaplan along Highway 35.

Another Successful Chase

2010-05-04T18:27:00.000-07:00

I departed Monroe, LA with Cooper, Clay and Legendre at 9:00am for another high risk chase in Dixie Alley. On this day, we anticipated that there would be another substantial severe weather outbreak across eastern Arkansas for the second day in a row. Our reasoning was due to a strong, slow moving upper level through, models showing a secondary surface low developing, and a capping inversion in the morning sounding from LZK that would control convection and allow the atmosphere to clear and destabilize throughout the day. With all of this in mind, we decided to initially target Stuttgart, Arkansas.

On our way to Stuttgart, we core punched two strengthening thunderstorms that formed in the weakly capped environment of extreme southeast Arkansas. These cells eventually went severe and were warned on by the NWS in Little Rock. Torrential rainfall and brief gusty winds were encountered, but nothing severe during the time of core punching. Shortly thereafter, skies cleared and we began to notice extensive convection taking place and quickly subsiding due to the strong shear aloft and the cap that was present.

This would be the trend for much of the afternoon. After spending most of the afternoon in Stuttgart meeting Randy “The Outlaw” Hicks (Member of the Outlaw Chasers) and watching additional chasers converge on the town via spotternetwork, we decided to adjust our game plan and move west to the small town of Humnoke. There, we met John Sibely, Brett Adair and Brandon Thomas; chasers associated with Severe Studios and Chaser TV.

Finally, at 6:00pm, things began to pop around the Arkansas/Louisiana border. Six o’clock magic at its finest. After quickly forming a game plan, my team, and our new friends decided to form a convoy and charge south down State Highway 13 toward Pine Bluff, AR to intercept rapidly developing storms. We intercepted two brief torndaoes on I-530 right outside of Pine Bluff Arkanasas. Later on in the chase, we intercepted a third brief tornado as it crossed the road on our convoy. Finally, as night fell across Arkansas, we chased the storm that eventually dropped a tornado on the northside of Memphis capturing dramatic videos of lightning and a lightning illuminated wall cloud associated with the storm before giving up the chase around Marvell, AR.

In all, we observed 3 brief tornadoes, 5 wall clouds, and an additional 3 funnel clouds, thus making this an extremely successful chase on a day that was technically a “high risk bust”.

Bittersweet Day

2010-04-29T19:59:00.000-07:00

Departed Monroe, LA with Cooper at 9:30pm Friday to set up for what we anticipated was going to be a big day for supercells and tornadoes across northern Mississippi. We staged in Greenville, MS on Friday night and departed for our first high risk chase at 6am. At this particular time, convection was already occurring across northern LA into southeast AR but we decided to head east toward I-55 instead. At this point, storm initiation was occurring well the south of our location around the southeast LA/MS border and to our west along the I-20 corridor in LA. Taking this into consideration, we decided to drive south on I-55 toward Yazoo City where we staged and rested for a while.

After taking a look at the morning sounding from the NWS in Jackson, the latest RUC, and surface and upper air charts, we decided that it was best to reposition further north, therefore we began moving north on Hwy 49W toward Belzoni, a town with major road options in all directions. However, around 10:30AM, Cooper and I observed a pair of storms in Northeastern LA that we felt had potential to go severe. Therefore we decided to turn around and head south on 49W, before cutting across State Hwy 149 and 14 to get to US 61 in the town of Anguilla.

Around this time, the southernmost cell became supercellular and was warned on by the NWS in Jackson. We flew south on 61 in an attempt to get south of it, and managed to get to the town of Valley Park about 10 minutes before the tornado was forecasted to hit. Around this time, we experienced a complete failure of radar on the computer and I-Phone (GR Level 3 & Radarscope). After several intense minutes of contemplation, I decided to call several people for nowcasting. I was fortunate to get in touch with Christopher Barber, a fellow NELA Skywarn storm spotter. Using some exceptional nowcasting by him, as well as my own visual skill, Cooper and I managed to get about a mile south of the tornado’s path just as it approached the highway.

Around the same time we set up to observe the tornado, another chaser, Andy Pettis parked behind us and informed us that there was damage done in Eagle Bend, MS. Using the brief window of time we had before we were slammed by RFD, I managed to identify the tornado and captured several pictures of it crossing US-61. Afterward, I followed Eddie to the Eagle Bend community to assist with search and rescue efforts and to conduct damage surveys. This is how the rest of the day would be spent across northwest Mississippi.

Special thanks goes out to Christopher Barber for his excellent nowcasting while we were under the gun, Dylan Cooper for a good job navigating and nowcasting, and Don Wheeler for teaching me a lot of what I know about storm chasing. It took me roughly 13 months for me to catch my first tornado. I never thought it would be a historic EF-4 long track tornado on a high risk day in Mississippi. This tornado stayed on the ground for almost three hours and a total of 149.26 miles and was one of two EF-4 tornadoes on this day. There were total of 56 tornadoes across Dixie Alley on that day. Sadly, 12 lives were claimed by this powerful force of nature.

Long track supercell and tornado crossing US-61.

Going Mobile Today & Saturday

2010-04-22T23:13:00.000-07:00

A significant weather situation is shaping up for today and tomorrow across the region. I will be mobile in the field this afternoon and early Saturday morning through the evening. Track me on the spotter network map located at the bottom of the home page. Also, tune into the live chasecam next to the spotter network map. As things begin to initiate, I will begin streaming video to the internet. You can also access streaming through my qik site at http://qik.com/kf5cnt and spotter network at http://www.spotternetwork.org/google.php.

Possible Chase(s) This Weekend

2010-04-20T13:16:00.000-07:00

I am currently monitoring the progress of our next major weather maker. I will begin to assess and compare model runs tomorrow to begin making forecasts for a possible 2 day (Friday, Saturday) event across East Texas and Dixie Alley this weekend.

Here was the outlook discussion from the SPC this morning:

DAY 4-8 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
0953 AM CDT TUE APR 20 2010

VALID 231200Z - 281200Z

CORRECTED FOR DATE ERROR

...DISCUSSION...
A LARGE UPPER STORM SYSTEM WILL CONTINUE MOVING SLOWLY EWD
INTO/ACROSS THE CENTRAL U.S. DURING THE FIRST TWO DAYS OF THE
PERIOD...AFTER WHICH THE SYSTEM IS EXPECTED TO BEGIN
WEAKENING/SHIFTING MORE NEWD TOWARD THE MIDWEST.  MODELS BEGIN TO
DIVERGE FAIRLY SUBSTANTIALLY DAY 6 AND BEYOND...BUT AGREEMENT IS
SUFFICIENT DAYS 4-5 /FRI. AND SAT. APR. 23-24/ TO BOOST CONFIDENCE
WITH RESPECT TO THE EVOLUTION OF SEVERE POTENTIAL.

IT APPEARS ATTM THAT A WIDESPREAD AREA OF FAIRLY SUBSTANTIAL SEVERE
THREAT WILL EXIST DAY 4 /FRI THE 23RD/...WITH THE GREATEST THREAT
APPARENT ATTM FROM SERN KS/SWRN MO SSWWD INTO SERN TX.  HERE...A
MOIST/UNSTABLE PRE-FRONTAL AIRMASS IS EXPECTED...AND WITH FAVORABLE
SHEAR -- INCLUDING MID-LEVEL FLOW IN EXCESS OF 50 KT -- ATOP THE
FRONTAL ZONE...THE OVERALL ENVIRONMENT APPEARS FAVORABLE FOR AN
ACTIVE SEVERE WEATHER EVENT.

ENHANCED SEVERE POTENTIAL SHOULD SPREAD EWD INTO THE MS VALLEY
REGION DAY 5 /SAT. THE 24TH/...WITH A SIMILARLY FAVORABLE KINEMATIC
AND THERMODYNAMIC ENVIRONMENT LIKELY NEAR/AHEAD OF THE ADVANCING
FRONT.  BOTH DAYS...LARGE HAIL AND DAMAGING WINDS WILL BE
POSSIBLE...WHILE THE MOIST BOUNDARY LAYER AND FAVORABLY-STRONG SHEAR
ARE ALSO INDICATIVE OF TORNADO POTENTIAL.

April 2, 2010 Bust

2010-04-06T14:24:00.000-07:00

Departed Monroe, LA around 1:30pm with Wheeler and Ostarly, and met up with Cooper in SHV. After staging, we made our initial target area Longview, TX. On this day, we hoped to be in position to intercept severe thunderstorms before they went linear ahead of the cold front. However, stratus clouds plagued northeast Texas throughout the morning hours ahead of ongoing convection from the night before.

As we departed SHV, I observed a clearing in the low level clouds over our target area. As expected, temperatures increased rapidly and approached 80 degrees before a cluster of thunderstorms developed. These cells raced off to the northeast at 45mph making it impossible for us to get in position to intercept them. However, these cells never went severe and no reports were made by the plethora of chasers located along the I-30 corridor. This would turn out to be the only play of the day as stratus began to dominate the area once again effectively ending our chase as a BUST; the 2nd of the year for me (Jan 23 the other bust day).

The limiting factors on this particular day were the ongoing convection across North Central Texas, lingering stratus clouds that suppressed diurnal heating, strong meridional flow aloft, veering surface winds, the location of the main surface low (SE North Dakota), a weak secondary surface low (south central OK), and high LCL's (1700-1800m) further eastward into Louisiana. LCL height's of >1000m is considered ideal for tornadogenesis.

-JP

March 27, 2010 LP Supercell's

2010-03-30T10:51:00.000-07:00

A year ago to this day, I went on my first storm chase with Don Wheeler and Dr. Bon Mills in northeast Texas. While that day looked promising initially, it turned out to be a bust. A year later, March 27 once again shaped up to be a potentially good day for severe storms including isolated supercells across central Arkansas. This would give me an opportunity to see how much I’ve learned over the past year.

I departed Monroe, LA around 12:30 PM for my initial target spot in Pine Bluff, Arkansas. On this particular day, I anticipated that there would be isolated severe thunderstorms forming around central Arkansas later in the afternoon. These cells were elevated and of the low precipitation variety due to surface dewpoints only reaching the upper 40’s in central Arkansas. The primary severe threat for these cells would be hail due to the cold pocket of air aloft that helped the atmosphere to destabilize. This threat would eventually shift to damaging winds as these cells congealed into a squall line as the evening progressed.

After staging in Pine Bluff, I decided to shift my target area northward toward Little Rock, as convection was ongoing at this time in northwest Arkansas along and north of the I-40 corridor. As I arrived in Little Rock, these cells began to go severe. After assessing the situation, I decided to move west on I-40 toward these storms.

As I moved west, I targeted several developing cells south of I-40 with potential to go severe moving northeast toward Conway County at 40 mph. I positioned myself just outside of the town of Menifee to intercept the southernmost of 2 LP supercells. These cells merged just to the north of my location and became prolific hail producers. I intercepted the southern edge of the storm and experienced pea sized hail, rain and several positive CG lightning strikes.

I then decided to charge east on I-40 as I targeted another LP supercell that formed southwest of my location in Garland County. This cell also moved northeast at 40 mph. I managed to outrun the core of the storm before pulling over on the Interstate to document it crossing the road in the town of Mayflower. I was treated with a nice sunset in the process.

Once the sun set, I decided to drive east into the delta area to get ahead of these storms as they began to go linear. I managed to do so before driving south on Hwy 63. I intercepted the squall line about 4 miles outside of Stuttgart, AR just as it began to bow out. I experienced severe straight line winds in excess of 60+ mph. However, I did not witness any damage around my intercept location. Once the line passed through, I enjoyed some of the anvil lightning before heading back to Monroe.

-JP

December 24, 2009 SW Louisiana Tornado Outbreak

2010-03-20T15:35:00.000-07:00

I departed New Iberia, LA around 4:30 AM for my initial target spot at Iowa, LA targeting the leading edge of a rapidly developing squall line that was located just to the west of the Texas/Louisiana border. I anticipated discrete low topped HP supercells with the potential to produce tornadoes along the I-10 corridor as the line moved east.

After a short time accessing the developing situation in Iowa, I decided to take Hwy 165 NE to Kinder where I got on Hwy 190 to go back east. At 7 AM, things began to take shape with three HP supercells developing ahead of the main squall line; one to the northeast of Eunice and two south of I-10 between the towns of Welsh and Crowley. Being out of position for the cell northeast of Eunice, I targeted the cell south of Crowley.

Around this time, I went through multiple data gaps, which caused me to adjust my strategy and move north toward Ville Platte in order to reposition myself about three miles northeast of Ville Platte to allow the storm to come to me rather than going south after it. At approximately 8:22 AM the NWS (LCH) issued a tornado warning right on top of my location.

A few minutes later, the heavy precipitation associated with the core of the cell decreased; and, I spotted the rotating wall cloud associated with the storm. I quickly chased the wall cloud northeast and watched as it became rain wrapped once again. Shortly after, I experienced strong RFD winds about nine miles Southwest of Bunkie.

I then traveled south on Hwy 71 dissecting the squall line before moving east again on Hwy 190 to get ahead of the it for another chance at intercepting any discrete cells; but, mother nature failed to produce any. My chase ended shortly after noon as I intercepted the squall line in the parking lot of a gas station in Hammond, LA.

In all, there were 12 confirmed tornadoes across southwest Louisiana, including three EF2’s, thus making this event the largest tornado outbreak since May 15, 2008. There were numerous reports of damage across the region and only four injuries. Sadly, there was one fatality in Scott, LA due to a tree falling onto a house. Special thanks to Don Wheeler (LA Delta CC) for his excellent nowcasting during my periods of data gaps and to Matt Clay (NWS SCEP) for handling my reports. This helped make my first planned chase on my own a success.

My location relative to the area of interest on radar at the time of the wall cloud sighting. Photo courtesy of Don Wheeler (LDCC).

-JP