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FCST: April 29 – KS/OK/TX/MO/IA

TUESDAY EVENING UPDATE: I am not liking the look of the EML in southern KS Thursday afternoon and into the evening hours, albeit if a supercell goes along the dryline it has extreme potential to be violent.  I am becoming a little more focused on an area a little closer to home based on this evenings NAM-WRF and SREF…..would like to see a couple more model runs before I bite on it….but I am thinking my chase on Thursday will not be in south central Kansas….at least based on the data I am looking at tonight…look for an update tomorrow on the blog.

OLD DISCUSSION (MONDAY EVENING)
INITIAL TARGET LOCATION: Blackwell, OK

DISCUSSION:
A surface low over north central North Dakota with a cold front stretching back to the Rio Grande Valley will interact with a deep surface low forecasted to be in central Kansas by 0Z/30 and be the setup for severe thunderstorms in the central plains.  A warm front will extend from the northern area of low pressure through southern MN back into the Ohio Valley.  A dryline will also be associated with this setup in north central Oklahoma and extend back into central TX.  Here is a look at the forecasted surface map at 0Z/30.

A 300mb 110 to 120 knot jet is forecasted to be rounding the base of the trough at 0Z/30.  Embedded within this jet is an 80 knot jet streak nosing into west central OK and edging into south central KS just west of the I-35 corridor.  This system, without a doubt, has plenty of shear to work with, but will it have all of the other ingredients for a severe weather setup?

The GFS and NAM-WRF both show a negatively tilted trough ejecting out into the plains and into northern TX at 0Z/30.  Overall bulk shear from the surface to 500mb is well over 60kts. The 850mb and 500mb crossovers are  favorable for supercells, no matter how short lived they are! 

700mb temps do not look to be an issue as far as EML goes.  Any forcing at all should be able to erode any cap by mid to late afternoon, especially as the dryline mixes to the east.

700mb UVV’s are appreciable along the I-35 corridor from Wichita, KS to Oklahoma City, OK

A significant 850mb jet of 60 to 70kts running parallel to the surface features will make the storm motions horrendous and nearly unable to chase safely!  Storm motions are forecasted to be from the southwest at well over 45 kts, especially along the northern edge of the cold front where it has already overtaken the dryline.  Further south things may remain more discrete for a little longer period of time due to low level shear being better in the southern play.  I still think one will need to set up in their preferred target area and let the storms come racing to you!!

850mb dewpoints are appreciable with a very apparent dry slot nosing into southwestern and south central Kansas at 0Z/30.

Surface temperatures are forecasted to be in the mid to upper 70’s over the target area.  SELY surface winds will be slightly backed at 0Z/30 which may enhance the tornado threat across southern KS and northern OK, at least early on in the evolution of the system.

Moisture return into the target areas is a bit questionable at this time, but feel low to mid 60 dewpoints can be realized during the afternoon on Thursday.  I do see a nice dryline bulge in SW/SC KS at 0Z/30 which may become a factor as models continue to show consistency in the moisture return.  The surface moisture will be the key to determine if this dryline will become a factor in this severe weather setup.

CAPE values are modest in the 1000 to 1500 J/KG range on both model runs, especially along and just west of the I-35 corridor from Wichita, KS to Oklahoma City, OK

The CINH and EML, may indeed be a factor, but I still believe with the upper air dynamics and forcing from the arrival of the dryline/cold front will erode any cap by mid to late afternoon on Thursday.

EHI is maximized over southern KS and northern/central Oklahoma at 0Z/30.  This is basically along and west of the I-35 corridor from Wichita, KS to Oklahoma City, OK.  Overall helicity values are maximized in northern and central Oklahoma.

The NAM-WRF is showing the cold front breaking out precip from southern South Dakota to the Red River in Texas by 0Z/30. 

Here is a quick look at the SKEW-T and Hodo for Ponca City, OK at 0Z/30:

I anticipate discrete cells firing ahead of the dryline in southern KS, northern and central Oklahoma by mid to late afternoon before they are overtaken by the advancing cold front.  I look for the predominant storm mode to be linear with embedded supercells, especially farther north in Kansas, with the possibility of discrete supercells further south, most likely a tail end charlie play.

For this forecast, I have discounted the ECMWF, which has a slower solution, albeit a more favored one, for a blend of the NAM-WRF and GFS.  The NAM-WRF and GFS have come into better agreement the last few model runs, whereas the ECMWF is slower by 24 hours or so!  I will be watching this setup as we move toward Thursday but it has all of the ingredients, except for moisture right now, to be a decent severe setup in the central plains.

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Late April tornado outbreak!

Hey y’all, Marcus Diaz here. Its been a long, yet exciting day for both me and Chris Rice here in the Texas panhandle. He caught 5 tornadoes, and I got 6 today in the area east of Amarillo. We decided from the morning that we’d play the dryline bulge setting up in the central TX panhandle. We were almost tempted to race north towards some tornadic cells in the northern TX panhandle that were about to cross into some really great CAPE values, but we held out ground. The CAPE where we were stationed originally was sitting at 2000 SBCAPE, with great backing winds coliding into the dryline. Storms were popping up along that dryline, but we finally got our small cell that developed about 60 miles to the east of the dryline. The storm went absolutely insane with all the ripe CAPE and great surface winds. This storm produced 2 tornadoes in between Goodnight and Groom, TX in rural Armstrong County. That storm went into some iffy terrain, so we jumped back to a new cell right on its heels. This was the monster of the day. The storm had a solid 65 mph inflow wind. We pursued the storm east on I-40 and quickly saw a needle tornado rope on the outside edge of the wall cloud. Unfortunately the tornado lifted by the time we stopped. We ended up about 2 miles north of Alanreed, TX, where the storm dropped an addition 4, possibly 5 tornadoes!!

Here’s my pictures of the 4 tornadoes I took still from:

Twin funnels almost to the ground!

First tornado of the day.

Tornado #2 touched down shortly after, and was on the ground for several minutes.


Chris Rice in front of me watching this roping funnel. We aren’t too sure if this funnel ever touched down, so unless I get confirmation we’re not calling it a tornado.

Tornado #5 roping out. This tornado had a full condensation funnel prior to me getting this shot.

Tornado #6 all the way down.

Video still of tornado #7

and finally, video still of tornado #8

I’m going to have to go through the footage to see just how many tornadoes we got near Alanreed, but this was defiantely a great day for ANYONE out there chasing. A more detailed report will come soon. For now, Chris Rice is resting in Oklahoma, and is going to be in Kansas tomorrow taking advantage of another great setup. Steve Polley will also be out playing the triple point in NW MO, SE NE, SW IA area. Watch the streams tomorrow at www.stormchaselive.com!!

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FCST: April 23 NW MO and NE KS

Friday morning update: INITIAL TARGET AREA: I have adjusted my target area a bit west based on the latest data.  I am  looking at a line from Hiawatha, KS to Seward, NE.  I will adjust this afternoon after looking at MesoAnalysis data.

Thursday Evening Update:  Quick look at the 0Z NAM-WRF as the GFS is still initializing and the 0Z time frame is not available as I type this blog entry….the SREF was also used as a guide….models paint a rather ominous picture for Northern MO for Friday afternoon and evening.  Lapse rates are approaching 8 to 9C with the potential for some very large hail….The only thing that may be the saving grace for the tor potential is the helicity values in the lower 1-3km of the atmoshphere…if these values change the tornado potential will increase dramatically….will need to watch the surface charts very close tomorrow as well as visible satellite….the ability of overnight convection to clear, sunshine to break out and destabilize the atmoshpere and the position of the warm front will be important factors…remnant outflow boundaries should also be considered from overnight convection ….Dewpoints are forecasted to be in the mid 60’s and CAPE values in the 2500 J/KG in NW MO….surface winds are backed which is a plus and overall bulk shear is 60kts Sfc-500mb, coupled with an increasing LLJ of 40kts….as well as the triple point being very close by….hodos look appreciable….challenging forecast that is going to depend on how it all looks tomorrow morning in real time….right now I am liking the NW MO area from St. Joseph to Bethany, MO for a chase target….with initiation in the 21Z time frame and things really ramping up toward 0Z/24……this will be a nowcasting event with mesoanalysis data being scrutinzed heavily as we head into the afternoon hours…..

OLD DISCUSSION:
The storm system in the desert southwest will be ejecting out into the central plains late tonight and into Friday.  This storm system will bring the potential of wide spread severe weather, and potentially significant, throughout the central CONUS. 

I have not had a chance to look at the model progs in depth and have only skimmed them.  ATTM it appears the greatest threat for severe weather including the potential for significant tornadoes will be along the warm front draped from SE NE back through northern MO/southern IA into IL and near the triple point in SE NE, NE KS and NW MO.  Here is a look at the forecasted surface map for 7 p.m. Friday evening:

A very warm and moist air mass is forecasted to be in place along and south of this front.  Afternoon heating will destabilize the atmosphere and poise the area for Supercell thunderstorms.  One must take into account the overnight convection and residual cloud cover, but the dynamics of the system are quite impressive.  Here is a look at the 500mb analysisn and Dp’s from the GFS and NAM-WRF for 0Z/24:

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ME and SCL Chaser Marcus Diaz bags tornado near Amarillo April 20

http://www.stormchaselive.com and MesoExtreme Storm Chaser Marcus Diaz, along with Storms Chaser Wesley Luginbyhl and Brady Kendrick, bagged a cone tornado near Amarillo, TX at approximately 7:03 p.m. CDT. 

Here is a quick look at the radar image exhibiting the classic hook echo and meso markers SW of Amarillo (AMA):

GRLevel 3 Image Courtesy of Storm Chaser Trevor Black
StormLab 4.0 SRV Image Courtesy of Forecaster/Storm Chaser Scott Metsker
Marcus will have some pics up later tonight.  In a brief phone interview a few moments ago, Marcus said he was very excited about bagging the unexpected tornado.  ME and SCL StormChaser Steve Polley was nowcasting for Marcus from Cameron, MO.  Excellent job fellas!!!! 
Brief Environment Discussion:
The storm originated in an enivronment with dewpoints in the upper 40’s to lower 50’s NW of AMA.  The storm propagated to the SSE into mid 50’s to near 60 F dewpoints.  Surface temps were in the upper 60’s to near 70 in the western panhandle region and the mid 50’s to near 60 in the eastern panhandle region.  This baroclinic zone (aka battle zone between air masses) along with marginal shear, decent moisture and an increasing nocturnal LLJ at 850mb of 25 to 30 kts were the factors that played into the evolution of this tornadic supercell.  In addition, the storm moved to the SSE into more moist air, CAPE values were approaching 2250 J/kg and SRH was approaching 300m2/s2. 
Data for discussion obtained from the RUC per F5 data and SPC MesoAnalysis Page.

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FCST: April 19 CO,WY,NE,KS

Target Location:

Goodland, KS – Initiation 6 p.m. to 8 p.m. MDT (GFS/NAM-WRF Blend) 

Forecast Discussion:

A slight risk and some upslope potential exists for E. CO, E. WY, W. NE and NW KS during the Monday afternoon and evening time frame.  The main risk would be margianlly severe hail and gusty thunderstorm winds.    Here is a current look at the surface features in the aforementioned target area:

The one fly in the ointment will be the residual cloud cover in the area which will affect overall instability. Upper level RH’s are forecasted to be over 70%. Decent CAPE is a lacking, but nonetheless is in the 500 to 1000 J/kg.

   

A weak short wave disturbance is visible at the 500mb level in NE CO at 0Z/20 and ejecting out into the plains.  With a developing surface low and associated trough in western NE and eastern CO. 

Surface temperatures in the mid to upper 70’s and Dp’s in the upper 40’s to low 50’s.  The 925mb and 850mb Dp’s are appreciable so the depth and quality of moisture return is not an issue with this setup when one takes into account the higer terrain.
 
A 50 to 60kt upper level jet streak is feeding into eastern WY, NE CO and NW KS along with a weak (20-30 kt LLJ) visible at 850mb at 0Z/20 .  The overall bulk shear is also borderline at  30-40kts.  The winds are also veered to unidirectional throughout the column.   I do not expect any robust, rotating updrafts with this setup, with no tornado potential at all!

 NAM-WRF has precip breaking out in NW KS with the potential for some strong thunderstorms before daytime heating wanes.

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steve polley storm chaser