Alert archive / Texas / Mesoscale Discussions in 2005

Mesoscale Discussion 409

March 27, 200521 parishes in Louisiana; 32 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Mar 27, 2005, 12:52 AM CST for 21 parishes in Louisiana; 32 counties in Texas. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued: Mar 27, 2005, 12:52 AM CST (06:52 UTC)
Expired: Mar 27, 2005, 2:45 AM CST
In force: 113 min
Issued by: the Storm Prediction Center

All 53 counties

Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, De Soto Parish, LA, Evangeline Parish, LA, Grant Parish, LA, Iberia Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Natchitoches Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Saint Landry Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Winn Parish, LA, Angelina County, TX, Aransas County, TX, Austin County, TX, Brazoria County, TX, Calhoun County, TX, Chambers County, TX, Fort Bend County, TX, Galveston County, TX, Goliad County, TX, Hardin County, TX, Harris County, TX, Jackson County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Matagorda County, TX, Montgomery County, TX, Nacogdoches County, TX, Newton County, TX, Orange County, TX, Polk County, TX, Refugio County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Trinity County, TX, Tyler County, TX, Victoria County, TX, Walker County, TX, Waller County, TX, Wharton County, TX

The radar

The Houston radar (KHGX), 36 km from the middle of the area, began a volume at 06:52 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.

Severe Thunderstorm Watch 95Mar 27, 1:35 AM CST

The nearest sounding before it

Shreveport, LA (KSHV), launched 00:00Z, 6.9 hours before the alert went out and 322 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 664 m above ground
0-6 km bulk shear: 79 kt
0-1 km storm-relative helicity: 207 m²/s²
0-3 km storm-relative helicity: 394 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.4

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
Mar 26, 9:18 PM CST	Mesoscale Discussion	SPC	East Carroll, Franklin, Morehouse, Richland, West Carroll	57 min
Mar 27, 1:14 AM CST	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, Livingston, Orleans, Saint Bernard and 7 more	91 min
Mar 27, 1:35 AM CST	Severe Thunderstorm Watch	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 9 more	6 hr
Mar 27, 3:27 AM CST	Mesoscale Discussion	SPC	Washington	33 min
Mar 27, 3:48 AM CST	Mesoscale Discussion	SPC	Acadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 8 more	87 min
Mar 27, 6:24 AM CST	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 10 more	2 hr

Nearby

Mesoscale Discussions in Texas, 2005 Mesoscale Discussions in Louisiana, 2005 Every mesoscale discussion in 2005

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.