Alert archive / Alabama / Mesoscale Discussions in 2017

Mesoscale Discussion 436

April 4, 201714 counties in Alabama; 6 counties in Florida; 4 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 4, 2017, 11:54 PM CDT for 14 counties in Alabama; 6 counties in Florida; 4 counties in Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 4, 2017, 11:54 PM CDT (04:54 UTC)
Expired
Apr 5, 2017, 2:00 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 24 counties

Baldwin County, AL, Butler County, AL, Clarke County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Escambia County, AL, Geneva County, AL, Houston County, AL, Mobile County, AL, Monroe County, AL, Washington County, AL, Escambia County, FL, Holmes County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL, Washington County, FL, George County, MS, Greene County, MS, Jackson County, MS, Perry County, MS

The radar

The Mobile radar (KMOB), 73 km from the middle of the area, began a volume at 04:55 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, 4.9 hours before the alert went out and 221 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 2017-04-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2017-04-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 128 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1664 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
128 m²/s²
0-3 km storm-relative helicity
152 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 5, 1:37 AM CDTSevere Thunderstorm WatchSPCAutauga, Barbour, Bibb, Blount, Bullock, Butler and 42 more6 hr
Apr 5, 3:41 AM CDTMesoscale DiscussionSPCAutauga, Barbour, Bibb, Bullock, Butler, Chambers and 38 more2 hr
Apr 5, 6:15 AM CDTMesoscale DiscussionSPCAutauga, Barbour, Bibb, Bullock, Butler, Calhoun and 35 more90 min
Apr 5, 6:54 AM CDTTornado WatchSPCAutauga, Baldwin, Barbour, Bibb, Bullock, Butler and 44 more8 hr
Apr 5, 9:43 AM CDTMesoscale DiscussionSPCBarbour, Chambers, Lee, Macon, Russell, Tallapoosa2 hr
Apr 5, 11:54 AM CDTTornado Watch PDSSPCDale, Geneva, Henry, Houston10 hr
Apr 5, 1:02 PM CDTMesoscale DiscussionSPCBlount, Cullman, DeKalb, Jackson, Jefferson, Lauderdale and 8 more2 hr
Apr 5, 1:50 PM CDTTornado WatchSPCAutauga, Barbour, Bibb, Blount, Bullock, Calhoun and 36 more8 hr
Apr 5, 2:12 PM CDTMesoscale DiscussionSPCBarbour, Bullock, Dale, Henry, Houston, Lee and 2 more93 min
Apr 5, 3:29 PM CDTMesoscale DiscussionSPCBaldwin, Clarke, Conecuh, Escambia, Marengo, Mobile and 3 more3 hr
Apr 5, 3:51 PM CDTMesoscale DiscussionSPCBlount, Calhoun, Chambers, Cherokee, Chilton, Clay and 19 more84 min
Apr 5, 6:57 PM CDTMesoscale DiscussionSPCAutauga, Blount, Bullock, Calhoun, Chambers, Cherokee and 20 more48 min
Apr 5, 10:38 AM CDTMesoscale DiscussionSPCLeon97 min

Nearby

Mesoscale Discussions in Alabama, 2017Mesoscale Discussions in Florida, 2017Mesoscale Discussions in Mississippi, 2017Every mesoscale discussion in 2017

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.