Alert archive / Georgia / Mesoscale Discussions in 2017

Mesoscale Discussion 441

April 5, 2017Leon County, Florida; 58 counties in Georgia; Allendale County, Hampton County, South Carolina

The Storm Prediction Center issued this mesoscale discussion at Apr 5, 2017, 11:38 AM EDT for Leon County, Florida; 58 counties in Georgia; Allendale County, Hampton County, South Carolina. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued
Apr 5, 2017, 11:38 AM EDT (15:38 UTC)
Expired
Apr 5, 2017, 1:15 PM EDT
In force
97 min
Issued by
the Storm Prediction Center
Chance of a watch
95%
All 61 counties

Leon County, FL, Appling County, GA, Atkinson County, GA, Bacon County, GA, Baker County, GA, Ben Hill County, GA, Berrien County, GA, Bleckley County, GA, Brooks County, GA, Bulloch County, GA, Burke County, GA, Calhoun County, GA, Candler County, GA, Coffee County, GA, Colquitt County, GA, Cook County, GA, Crisp County, GA, Decatur County, GA, Dodge County, GA, Dooly County, GA, Dougherty County, GA, Early County, GA, Effingham County, GA, Emanuel County, GA, Evans County, GA, Glascock County, GA, Grady County, GA, Houston County, GA, Irwin County, GA, Jeff Davis County, GA, Jefferson County, GA, Jenkins County, GA, Johnson County, GA, Lanier County, GA, Laurens County, GA, Lee County, GA, Long County, GA, Lowndes County, GA, McDuffie County, GA, Miller County, GA, Mitchell County, GA, Montgomery County, GA, Pierce County, GA, Pulaski County, GA, Screven County, GA, Tattnall County, GA, Telfair County, GA, Thomas County, GA, Tift County, GA, Toombs County, GA, Treutlen County, GA, Turner County, GA, Twiggs County, GA, Washington County, GA, Wayne County, GA, Wheeler County, GA, Wilcox County, GA, Wilkinson County, GA, Worth County, GA, Allendale County, SC, Hampton County, SC

The radar

The Robins AFB radar (KJGX), 98 km from the middle of the area, began a volume at 15:37 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

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 3.6 hours before the alert went out and 185 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, Tallahassee Rgnl, FL at 12:00Z on 2017-04-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1335 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, Tallahassee Rgnl, FL at 12:00Z on 2017-04-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 151 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
1335 J/kg
Mixed-layer CIN
-57 J/kg
Mixed-layer LCL
643 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
151 m²/s²
0-3 km storm-relative helicity
152 m²/s²
Significant tornado parameter
0.9
Supercell composite
8.2

Open this sounding in Storm Lab

The text

As transmitted.

085 
ACUS11 KWNS 051539
SWOMCD
SPC MCD 051538 
SCZ000-GAZ000-FLZ000-051715-

Mesoscale Discussion 0441
NWS Storm Prediction Center Norman OK
1038 AM CDT Wed Apr 05 2017

Areas affected...FL Panhandle...GA...Southwest SC

Concerning...Severe potential...Watch likely 

Valid 051538Z - 051715Z

Probability of Watch Issuance...95 percent

SUMMARY...Tornado Watch will be issued by 17z to address increasing
severe threat from the eastern FL Panhandle into SC.

DISCUSSION...Boundary-layer cu field is beginning to deepen from the
eastern FL Panhandle into southeast GA as surface temperatures rise
to near 80F.  Latest high-res Vis imagery depicts
clustering/towering CU along a corridor from near MAI to near VDI. 
Substantial breaks in cloud cover suggest additional heating can be
expected and thunderstorms will likely evolve over the next few
hours.  Given the strength of the wind fields and rising instability
there is increasing concern for discrete supercell formation by
early afternoon.  Environmental parameters appear favorable for a
few strong tornadoes across this region, in addition to large hail
and damaging winds.  Tornado watch will be issued for parts of this
area by 17z.

..Darrow/Hart.. 04/05/2017

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...CHS...CAE...JAX...FFC...TAE...

LAT...LON   31318496 33498250 32908093 31498180 30278426 31318496

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 5, 12:54 AM EDTMesoscale DiscussionSPCEscambia, Holmes, Okaloosa, Santa Rosa, Walton, Washington2 hr
Apr 5, 2:37 AM EDTSevere Thunderstorm WatchSPCHolmes, Jackson6 hr
Apr 5, 4:41 AM EDTMesoscale DiscussionSPCHolmes, Jackson2 hr
Apr 5, 7:54 AM EDTTornado WatchSPCBay, Calhoun, Escambia, Gulf, Holmes, Jackson and 4 more8 hr
Apr 5, 12:54 PM EDTTornado Watch PDSSPCBay, Calhoun, Gadsden, Gulf, Holmes, Jackson and 3 more10 hr
Apr 5, 3:12 PM EDTMesoscale DiscussionSPCBay, Calhoun, Gadsden, Jackson, Washington93 min
Apr 5, 4:29 PM EDTMesoscale DiscussionSPCEscambia, Santa Rosa3 hr
Apr 5, 7:15 AM EDTMesoscale DiscussionSPCCalhoun, Carroll, Chattahoochee, Clay, Clayton, Cobb and 26 more90 min
Apr 5, 10:25 AM EDTMesoscale DiscussionSPCBaldwin, Banks, Barrow, Bartow, Burke, Butts and 45 more95 min
Apr 5, 10:43 AM EDTMesoscale DiscussionSPCBaldwin, Ben Hill, Bibb, Bleckley, Bulloch, Burke and 69 more2 hr
Apr 5, 2:02 PM EDTMesoscale DiscussionSPCDade, Walker2 hr
Apr 5, 2:50 PM EDTTornado WatchSPCBartow, Carroll, Catoosa, Chattooga, Cherokee, Clayton and 26 more8 hr
Apr 5, 4:51 PM EDTMesoscale DiscussionSPCBartow, Carroll, Catoosa, Chattooga, Dade, Douglas and 10 more84 min
Apr 5, 6:29 PM EDTMesoscale DiscussionSPCAppling, Atkinson, Bacon, Berrien, Brantley, Brooks and 22 more61 min
Apr 5, 7:57 PM EDTMesoscale DiscussionSPCBarrow, Bartow, Butts, Carroll, Catoosa, Chattahoochee and 46 more48 min
Apr 5, 2:02 PM EDTMesoscale DiscussionSPCDarlington, Dillon, Florence, Lee, Marion, Williamsburg58 min
Apr 5, 2:45 PM EDTTornado WatchSPCDarlington, Dillon, Florence, Georgetown, Horry, Marion and 2 more5 hr
Apr 5, 4:23 PM EDTMesoscale DiscussionSPCBerkeley, Darlington, Dillon, Florence, Georgetown, Horry and 2 more97 min

Nearby

Mesoscale Discussions in Georgia, 2017Mesoscale Discussions in South Carolina, 2017Mesoscale Discussions in Florida, 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.