Alert archive / Alabama / Mesoscale Discussions in 2009

Mesoscale Discussion 287

March 27, 20094 states

The Storm Prediction Center issued this mesoscale discussion at Mar 27, 2009, 2:23 AM CDT for 4 states. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued
Mar 27, 2009, 2:23 AM CDT (07:23 UTC)
Expired
Mar 27, 2009, 3:30 AM CDT
In force
67 min
Issued by
the Storm Prediction Center
All 30 counties

Baldwin County, AL, Choctaw County, AL, Clarke County, AL, Conecuh County, AL, Covington County, AL, Escambia County, AL, Mobile County, AL, Monroe County, AL, Washington County, AL, Escambia County, FL, Okaloosa County, FL, Santa Rosa County, FL, Assumption Parish, LA, Jefferson Parish, LA, Lafourche Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Terrebonne Parish, LA, Forrest County, MS, George County, MS, Greene County, MS, Harrison County, MS, Jackson County, MS, Lamar County, MS, Perry County, MS, Stone County, MS, Wayne County, MS

The radar

The Mobile radar (KMOB), 118 km from the middle of the area, began a volume at 07:27 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.

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 7.4 hours before the alert went out and 48 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-pSkew-T log-p diagram, Slidell Radar S, LA at 00:00Z on 2009-03-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1797 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Slidell Radar S, LA at 00:00Z on 2009-03-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 203 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
1797 J/kg
Mixed-layer CIN
-18 J/kg
Mixed-layer LCL
559 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
203 m²/s²
0-3 km storm-relative helicity
245 m²/s²
Significant tornado parameter
3.0
Supercell composite
10.8

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.

IssuedProductOfficeCountiesLasted
Mar 26, 11:53 PM CDTMesoscale DiscussionSPCBaldwin, Mobile97 min
Mar 27, 12:48 AM CDTTornado WatchSPCBaldwin, Choctaw, Clarke, Conecuh, Covington, Escambia and 3 more7 hr
Mar 27, 4:37 AM CDTMesoscale DiscussionSPCCoffee, Conecuh, Covington, Escambia, Geneva, Houston53 min
Mar 27, 5:02 AM CDTTornado WatchSPCCoffee, Dale, Geneva, Henry, Houston5 hr
Mar 27, 6:35 AM CDTMesoscale DiscussionSPCCoffee, Covington, Dale, Geneva, Henry, Houston55 min
Mar 27, 9:51 AM CDTMesoscale DiscussionSPCFranklin, Gadsden, Gulf, Jefferson, Leon, Liberty and 3 more24 min
Mar 27, 10:05 AM CDTTornado WatchSPCDixie, Franklin, Jefferson, Lafayette, Leon, Madison and 2 more3 hr
Mar 27, 12:11 PM CDTMesoscale DiscussionSPCAlachua, Baker, Bradford, Clay, Columbia, Dixie and 12 more64 min
Mar 26, 9:13 PM CDTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Caldwell and 16 more92 min
Mar 27, 12:33 PM CDTMesoscale DiscussionSPCBossier, Caddo57 min
Mar 27, 2:34 PM CDTMesoscale DiscussionSPCAllen, Avoyelles, Beauregard, Evangeline, Rapides, Saint Landry and 1 more56 min
Mar 27, 2:54 PM CDTTornado WatchSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, East Baton Rouge and 14 more6 hr
Mar 27, 4:16 PM CDTTornado WatchSPCCaldwell, Catahoula, Concordia, Franklin, Grant, LaSalle and 1 more4 hr
Mar 27, 4:49 PM CDTTornado WatchSPCCameron3 hr
Mar 27, 5:53 PM CDTMesoscale DiscussionSPCBienville, Bossier, Claiborne, East Carroll, Jackson, Lincoln and 7 more97 min
Mar 27, 6:18 PM CDTMesoscale DiscussionSPCLivingston, Saint Helena, Saint Tammany, Tangipahoa, Washington57 min
Mar 27, 6:35 PM CDTTornado WatchSPCBienville, Bossier, Caddo, Claiborne, De Soto, East Carroll and 13 more7 hr

Nearby

Mesoscale Discussions in Alabama, 2009Mesoscale Discussions in Louisiana, 2009Mesoscale Discussions in Mississippi, 2009Every 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.