MAY 27, 1997

MARSHALL, TEXAS CHASE
Tim Marshall only

10:02 262.5 FLOWER MOUND- Sixth consecutive chase day. Overcast skies, north winds. Upper low still northwest of us. The front/outflow boundary has passed the Dallas area this morning. The boundary is oriented nearly east-west from Dallas to Shreveport and then drops southward to near San Antonio. SPC has issued a moderate risk for east Texas. There are very high instabilities there with mid-and upper- 70 dewpoints. It's an iffy situation today due to weak surface and upper winds, but I like the convergence along the boundary especially at or near the apex of the boundary -where surface convergence is greatest at 10am. I figure to head out I-20 and play the boundary. Any storm that fires west should move towards me. Target town is Longview. Both yesterday and the day before, the key was staying about 200 miles south of the surface low -instead of playing the surface low -it doesn't matter where the convergence max will be as the upper level disturbance will ignite the volatile atmosphere -the storm will make its own convergence.

10:52 308 Southeast of Dallas- I am still in northwest winds. Very hazy, Very humid. A line of towers can be seen to my southeast. Encountered windshift line at I-20 and 635.

12:55 449 MARSHALL- Stopped in Marshall, set up and watched The Weather Channel. They showed two small echoes just south of me. It's very hazy.

1:07 449 MARSHALL - Thunderstorm developing south of here. South wind.

(Severe Thunderstorm Warning- 12:49pm - Storm produced dime size hail in Carthage, Texas at 12:33pm and is intensifying, moving east at 15 mph.

(1:16pm- T-BOX issued from Dallas to Shreveport)

-new convection late is more important than early convection. -remain 100 miles east-southeast of the low.

1:30 449 Other storms are developing to my west and southwest now. They are moving SE. One storm is near Athens and another is south of Waco. I can't see anything here in the trees, low visibility's, heavy rain and frequent lightning. Storms SW of me will have better storm relative helicity, so I'll head back towards Dallas and drop south.

2:00 481 I-20 W. is closed due to traffic accident. There is at least a two to three mile back up and no frontage roads! Some cars tried to cross the median, but its fully of water and they are stuck good.

3:00 481 Interstate reopens, heading westbound.

4:30 590 DALLAS, TX- I am hearing about a tornadic storm which moved down I-35 and struck Jarrell, Texas. I-35 SW is reportedly closed at Salado. Sure missed the show here. Decided to go home.

5:30 639 FLOWER MOUND - 377miles 7.6 hours. TRW

Summary: Storms propagated southwestward along the northeast-southwest boundary for some reason. I remain perplexed by why such tornadic storms formed along this boundary -yet where I was -at the convergence center at 10am - nothing really severe happened..