Alert archive / Alabama / Mesoscale Discussions in 2017

Mesoscale Discussion 416

April 3, 20174 states

The Storm Prediction Center issued this mesoscale discussion at Apr 3, 2017, 6:43 AM CDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 3, 2017, 6:43 AM CDT (11:43 UTC)
Expired
Apr 3, 2017, 8:45 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 32 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, Henry County, AL, Houston County, AL, Mobile County, AL, Monroe County, AL, Washington County, AL, Bay County, FL, Calhoun County, FL, Escambia County, FL, Holmes County, FL, Jackson County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL, Washington County, FL, Plaquemines Parish, LA, Saint Bernard Parish, LA, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Stone County, MS

The radar

The Mobile radar (KMOB), 75 km from the middle of the area, began a volume at 11:44 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, 11.7 hours before the alert went out and 178 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 2017-04-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2436 joules per kilogram.LCLEL10008507005003002001001 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 2017-04-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 298 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
2436 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
480 m above ground
0-6 km bulk shear
57 kt
0-1 km storm-relative helicity
298 m²/s²
0-3 km storm-relative helicity
333 m²/s²
Significant tornado parameter
4.6
Supercell composite
19.5

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 3, 1:48 AM CDTTornado WatchSPCBaldwin, Choctaw, Clarke, Mobile, Washington10 hr
Apr 3, 1:51 AM CDTMesoscale DiscussionSPCBibb, Blount, Calhoun, Cherokee, Clay, Cleburne and 6 more114 min
Apr 3, 3:59 AM CDTMesoscale DiscussionSPCAutauga, Baldwin, Bibb, Butler, Chilton, Choctaw and 17 more2 hr
Apr 3, 4:25 AM CDTSevere Thunderstorm WatchSPCAutauga, Barbour, Bibb, Bullock, Chambers, Chilton and 14 more7 hr
Apr 3, 7:06 AM CDTTornado WatchSPCButler, Coffee, Conecuh, Covington, Crenshaw, Dale and 6 more6 hr
Apr 3, 7:45 AM CDTMesoscale DiscussionSPCBarbour, Bullock, Chambers, Coosa, Elmore, Lee and 6 more90 min
Apr 3, 9:25 AM CDTMesoscale DiscussionSPCBarbour, Dale, Geneva, Henry, Houston, Lee and 1 more65 min
Apr 3, 12:32 PM CDTTornado WatchSPCCalhoun, Dixie, Franklin, Gadsden, Gulf, Jefferson and 6 more6 hr
Apr 3, 2:21 PM CDTMesoscale DiscussionSPCBay, Calhoun, Franklin, Gadsden, Gulf, Jefferson and 5 more54 min
Apr 3, 5:57 PM CDTMesoscale DiscussionSPCBaker, Bradford, Clay, Columbia, Dixie, Duval and 17 more93 min
Apr 2, 8:07 PM CDTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 8 more83 min
Apr 2, 8:24 PM CDTTornado WatchSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 10 more6 hr
Apr 2, 9:09 PM CDTMesoscale DiscussionSPCCatahoula, Concordia, East Baton Rouge, East Feliciana, Livingston, Madison and 8 more2 hr
Apr 2, 11:37 PM CDTMesoscale DiscussionSPCAcadia, Ascension, Assumption, Avoyelles, East Baton Rouge, East Feliciana and 18 more83 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.