Alert archive / Texas / Mesoscale Discussions in 2009

Mesoscale Discussion 656

May 1, 20095 counties in Oklahoma; 19 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 1, 2009, 2:48 PM CDT for 5 counties in Oklahoma; 19 counties in Texas. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued: May 1, 2009, 2:48 PM CDT (19:48 UTC)
Expired: May 1, 2009, 4:15 PM CDT
In force: 87 min
Issued by: the Storm Prediction Center

All 24 counties

Carter County, OK, Cotton County, OK, Jefferson County, OK, Love County, OK, Murray County, OK, Archer County, TX, Baylor County, TX, Clay County, TX, Cooke County, TX, Fisher County, TX, Haskell County, TX, Jack County, TX, Jones County, TX, Knox County, TX, Montague County, TX, Palo Pinto County, TX, Shackelford County, TX, Stephens County, TX, Stonewall County, TX, Taylor County, TX, Throckmorton County, TX, Wichita County, TX, Wise County, TX, Young County, TX

The radar

The Dyess AFB radar (KDYX), 104 km from the middle of the area, began a volume at 19:52 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Tornado Watch 222May 1, 3:10 PM CDT

The nearest sounding before it

Fort Worth, TX (KFWD), launched 12:00Z, 7.8 hours before the alert went out and 161 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1780 J/kg
Mixed-layer CIN: -96 J/kg
Mixed-layer LCL: 552 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 13 m²/s²
0-3 km storm-relative helicity: 55 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 2.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 30, 7:54 PM CDT	Severe Thunderstorm Watch	SPC	Beckham, Blaine, Caddo, Canadian, Cleveland, Custer and 15 more	5 hr
Apr 30, 11:41 PM CDT	Mesoscale Discussion	SPC	Beckham, Blaine, Caddo, Canadian, Cleveland, Custer and 15 more	64 min
May 1, 12:45 AM CDT	Severe Thunderstorm Watch	SPC	Adair, Canadian, Cherokee, Cleveland, Craig, Creek and 29 more	6 hr
May 1, 3:00 AM CDT	Mesoscale Discussion	SPC	Adair, Cherokee, Craig, Creek, Delaware, Garfield and 16 more	2 hr
May 1, 6:08 AM CDT	Mesoscale Discussion	SPC	Adair, Alfalfa, Cherokee, Craig, Creek, Delaware and 18 more	67 min
May 1, 7:26 AM CDT	Severe Thunderstorm Watch	SPC	Adair, Cherokee, Cleveland, Creek, Garfield, Grant and 27 more	7 hr
May 1, 10:32 AM CDT	Mesoscale Discussion	SPC	Adair, Cherokee, Mayes, Noble, Osage, Pawnee and 5 more	58 min
May 1, 1:22 PM CDT	Mesoscale Discussion	SPC	Adair, Cherokee, Cleveland, Creek, Garfield, Grant and 20 more	53 min
May 1, 3:09 PM CDT	Tornado Watch	SPC	Atoka, Bryan, Carter, Cleveland, Coal, Comanche and 16 more	7 hr

Nearby

Mesoscale Discussions in Texas, 2009 Mesoscale Discussions in Oklahoma, 2009 Every mesoscale discussion in 2009

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.