Chase Case #15

[Paul Austin]

21z Update

21Z Observations:


Surface Observations:
Eastern CONUS
Northern Plains
Central Plains
Southern Plains
Upper Midwest
Mississippi Valley

Visible Satellite Imagery:
National
Northern Plains
Central Plains
Mid-Mississippi Valley

Infrared Satellite Imagery:
National

Radar Imagery:
Northern Plains
Central Plains
Southern Plains
Upper Mississippi Valley
Middle Mississippi Valley
Lower Mississippi Valley

Vertical Wind Profiler Imagery:
500m-3000m AGL
3000m-9000m MSL

Per Request:
21z National Synoptic Analysis

Mesoscale Discussions and Weather Watches:

MD 9 Graphic

MESOSCALE DISCUSSION 9[FONT=&quot]
[/FONT]NWS STORM PREDICTION CENTER NORMAN OK[FONT=&quot]
[/FONT]0342 PM CDT[FONT=&quot]
[/FONT]AREAS AFFECTED...SERN OK...NERN/N CNTRL TX...SWRN AR ANS NWRN LA[FONT=&quot]
[/FONT]CONCERNING...TORNADO WATCH...[FONT=&quot]

[/FONT]VALID 2042Z - 2245Z[FONT=&quot]
[/FONT]WIDELY SCATTERED STORMS EXPECTED TO DEVELOP ALONG/N OF WARM FRONT[FONT=&quot]
[/FONT]ACROSS PARTS OF THE ARKLATEX REGION LATER THIS AFTERNOON. TIMING OF[FONT=&quot]
[/FONT]INITIATION REMAINS UNCERTAIN. ONCE STORMS DEVELOP...SUPERCELLS WILL[FONT=&quot]
[/FONT]BE LIKELY.[FONT=&quot]

[/FONT]WARM FRONT FROM NRN LA WNWWD THROUGH NERN TX CONTINUES TO LIFT[FONT=&quot]
[/FONT]SLOWLY NWD. ATMOSPHERE HAS BECOME VERY UNSTABLE IN VICINITY OF THIS[FONT=&quot]
[/FONT]BOUNDARY WITH MLCAPES NOW FROM 2500 TO 3000 J/KG. HOWEVER... SPECIAL[FONT=&quot]
[/FONT]18Z SOUNDINGS FROM FORT WORTH AND SHREVEPORT SHOWED A CAPPING[FONT=&quot]
[/FONT]INVERSION...AND CUMULUS CLOUDS ALONG THE BOUNDARY STILL APPEAR[FONT=&quot]
[/FONT]SOMEWHAT SUPPRESSED ON CURRENT SATELLITE IMAGERY. STORM INITIATION[FONT=&quot]
[/FONT]HAS BEEN INHIBITED SO FAR BY PRESENCE OF CAP...WEAK LOW LEVEL[FONT=&quot]
[/FONT]FLOW/CONVERGENCE ALONG THE WARM FRONT AND LARGE SCALE SUBSIDENCE[FONT=&quot]
[/FONT]ASSOCIATED WITH UPPER RIDGE. LOW LEVEL JET WILL BEGIN TO INCREASE[FONT=&quot]
[/FONT]LATER THIS AFTERNOON/EVENING...ESPECIALLY OVER WRN HALF OF WW AS[FONT=&quot]
[/FONT]RIDGE AXIS SHIFTS EWD...AND THIS MAY ENHANCE LIFT ALONG/N OF THE[FONT=&quot]
[/FONT]BOUNDARY. THUS INITIATION IS STILL POSSIBLE...BUT PROBABLY MORE[FONT=&quot]
[/FONT]LIKELY LATER THIS AFTERNOON/EARLY EVENING.[FONT=&quot]

[/FONT]
URGENT - IMMEDIATE BROADCAST REQUESTED[FONT=&quot]
[/FONT]TORNADO WATCH NUMBER 4
NWS STORM PREDICTION CENTER NORMAN OK [FONT=&quot]
[/FONT]400 PM CDT[FONT=&quot]
[/FONT]THE NWS STORM PREDICTION CENTER HAS ISSUED A[FONT=&quot]
[/FONT]TORNADO WATCH FOR PORTIONS OF [FONT=&quot]

[/FONT]SOUTHWEST OKLAHOMA[FONT=&quot]
[/FONT]NORTHWEST TEXAS[FONT=&quot]

[/FONT]EFFECTIVE THIS AFTERNOON AND EVENING FROM 400 PM UNTIL[FONT=&quot]
[/FONT]900 PM CDT.[FONT=&quot]

[/FONT]TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS[FONT=&quot]
[/FONT]TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.[FONT=&quot]

[/FONT]THE TORNADO WATCH AREA IS ALONG AND 115 STATUTE MILES EAST AND[FONT=&quot]
[/FONT]WEST OF A LINE FROM 40 MILES NORTH NORTHWEST OF ALTUS OKLAHOMA TO[FONT=&quot]
[/FONT]95 MILES SOUTHWEST OF WICHITA FALLS TEXAS.[FONT=&quot]

[/FONT]REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR[FONT=&quot]
[/FONT]TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA.[FONT=&quot]
[/FONT]PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING[FONT=&quot]
[/FONT]WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE[FONT=&quot]
[/FONT]WARNINGS.[FONT=&quot]

[/FONT]OTHER WATCH INFORMATION...CONTINUE...WW 2...WW 3...[FONT=&quot]

[/FONT]DISCUSSION...LINE OF TCU AND A SMALL CB HAS DEVELOPED ALONG THE DRY[FONT=&quot]
[/FONT]LINE JUST EAST OF LBB. GIVEN THE VERY UNSTABLE AIR MASS /MLCAPES TO[FONT=&quot]
[/FONT]3000 J/KG /...ALONG WITH SUFFICIENT DEEP LAYER SHEAR...ACTIVITY WILL[FONT=&quot]
[/FONT]LIKELY CONTINUE TO INCREASE AND EVOLVE INTO SUPERCELLS. VERY LARGE[FONT=&quot]
[/FONT]HAIL AND ISOLATED TORNADOES CAN BE EXPECTED AS ACTIVITY SHIFTS EWD[FONT=&quot]
[/FONT]INTO THE MID EVENING.[FONT=&quot]

[/FONT]AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL[FONT=&quot]
[/FONT]SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE WIND[FONT=&quot]
[/FONT]GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.[FONT=&quot]
[/FONT]MEAN STORM MOTION VECTOR 27020.[FONT=&quot]

[/FONT]

Chase Positioning Map

 

[Michael O'Keeffe]

Storm exploding to my SW (in Guthrie, TX). Will make the intercept!

 

[Jason Branz]

Interesting...continue south or wait for initiation up here in Memphis area? Well...let's head down 287 to CDS, then south and watch to see what the first storm does. The temp-dewpoint spreads are a little high down there for my liking, but a general NE movement of that cell will bring it into lower spreads. So we're departing Memphis TX and targeting Paducah TX for now. Roads out here east of 83 are sparse...hopefully we can get a fix on the movement of this cell before long.

EDIT: Oops...missed the storm vector on the red box text. With that motion I'll keep heading south to intercept that cell, waving to DPS along the way.

 

[Andrea Griffa]

A storm has just developed not far from Scott Bluff,Ne: so far it's pretty weak; let's see how it evolves.

 

[Paul Austin]

Urgent Notice

At 2117 spotters report a tornado 3 miles east of Tilford, SD.

 

[Bob Hartig]

Reading the MDs for Texas, looking at the surface obs in my area, and resisting the urge to get on my hands and knees and pound the dirt. I'm not familiar with what it takes to chase upslope scenarios, but I sure don't like the moisture where I'm at. I do like the towers going up all around me, but they're high-based. I was hoping better dewpoints would move in, but it looks like they're just getting scoured. Guess I'll just travel with these towers and see what happens. I don't have any real expectations right now, but I'm not ready to throw in the towel quite yet.

<Sigh> Have fun down there, all you southern chasers. You made a better call than I did.

 

[Dann Cianca]

Moving down to Minneola, Kansas. Should be there by 23Z ... seeing a cu field below the cirrus which looks to be thinning out.

 

[Charles Kuster]

Based on the 21Z data, the only move I will make is to go slightly south to the intersection of highway 283 and 412 (6 miles south of Laverne, OK) in order to improve my road options.

 

[Tarmo Tanilsoo]

Right now staying put at Wakeeney and watching the skies. Looks like the skies might clear in a few hours over "here" and I am seeing some development over NE Colorado. So I am hoping that eventually something would also approach this area as well.

 

[David Wolfson]

Vis satellite leads me a little south to Turkey, TX, before 22Z.

 

[Wes Carter]

On to Crowell, TX and South on Highway 6 and hopefully intercept the storm Michael O'Keefe and Paul Townsend are on. It looks promising right now. How's the Verizon service here? I have a feeling I need to keep my eyes open for other development that might be better suited for me where I'm at. But for now, I'm going for this one.

 

[Dennis Dennison]

Heading southeast towards Wichita Falls,Tx

 

[Matt Gingery]

I am jumping on HWY 281 North in Nebraska near Kearney, and heading to Mitchell SD. I should be there by 23z and I plan on traversing I-90 and chasing whatever is clever along and north and south of I-90 from Mitchell to Kadoka through sunset, and maybe into the night. Hopefully I can catch something as I travel north on 281. . .

 

[Bob Gould]

Based on latest data, heading west on US 70 from Ardmore Ok, will check radar as I roll through Waurika towards Randlett OK.

 

[Josh Richardson]

Im out here in CO for god knows what reason.....after arriving in Salina this morning I should have just flew SW to at least the OK/KS border or further instead of waiting and waiting in Hays most of the day and then having no where to go but west. Oh well, hopefully this is a 2 day chase because this one of hell of a long drive back home after a bust.