Alert archive / Georgia / Mesoscale Discussions in 2017

Mesoscale Discussion 13

January 2, 201716 counties in Alabama; 11 counties in Florida; 37 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Jan 2, 2017, 5:36 PM CST for 16 counties in Alabama; 11 counties in Florida; 37 counties in Georgia. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued
Jan 2, 2017, 5:36 PM CST (23:36 UTC)
Expired
Jan 2, 2017, 7:30 PM CST
In force
114 min
Issued by
the Storm Prediction Center
All 64 counties

Barbour County, AL, Bullock County, AL, Butler County, AL, Coffee County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Escambia County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Lee County, AL, Macon County, AL, Montgomery County, AL, Pike County, AL, Russell County, AL, Bay County, FL, Calhoun County, FL, Escambia County, FL, Gadsden County, FL, Holmes County, FL, Jackson County, FL, Liberty County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL, Washington County, FL, Baker County, GA, Ben Hill County, GA, Bleckley County, GA, Calhoun County, GA, Chattahoochee County, GA, Clay County, GA, Colquitt County, GA, Crisp County, GA, Decatur County, GA, Dodge County, GA, Dooly County, GA, Dougherty County, GA, Early County, GA, Grady County, GA, Harris County, GA, Houston County, GA, Irwin County, GA, Lee County, GA, Macon County, GA, Marion County, GA, Miller County, GA, Mitchell County, GA, Muscogee County, GA, Pulaski County, GA, Quitman County, GA, Randolph County, GA, Schley County, GA, Seminole County, GA, Stewart County, GA, Sumter County, GA, Taylor County, GA, Terrell County, GA, Tift County, GA, Turner County, GA, Webster County, GA, Wilcox County, GA, Worth County, GA

The radar

The Ft Rucker radar (KEOX), 41 km from the middle of the area, began a volume at 23:40 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, 11.6 hours before the alert went out and 149 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 2017-01-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 235 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Tallahassee Rgnl, FL at 12:00Z on 2017-01-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 143 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
235 J/kg
Mixed-layer CIN
-25 J/kg
Mixed-layer LCL
683 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
143 m²/s²
0-3 km storm-relative helicity
192 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.9

Open this sounding in Storm Lab

The text

As transmitted.

322 
ACUS11 KWNS 022336
SWOMCD
SPC MCD 022336 
GAZ000-FLZ000-ALZ000-030130-

Mesoscale Discussion 0013
NWS Storm Prediction Center Norman OK
0536 PM CST Mon Jan 02 2017

Areas affected...MS Delta...southern AL and GA...FL Panhandle

Concerning...Tornado Watch 3...4...

Valid 022336Z - 030130Z

The severe weather threat for Tornado Watch 3, 4 continues.

SUMMARY...The threat for damaging wind and isolated tornadoes
continues across the watch areas.

DISCUSSION...Surface analysis shows a warm front from southeastern
AL across southern GA, with 65-70 dewpoints to the south and
relatively stable and dry air to the north. Meanwhile, a cold front
continues to surge eastward from central AL southwestward into
southeast LA, accompanied by a line of thunderstorms with gusty
winds.

The main tornado threat area remains along the warm front, where
cells intersecting the front have shown persistent areas of
rotation. VWPs from southeast AL show large looping low-level
hodographs with 0-1 km SRH on the order of 250 m2/s2. This, along
with ample moisture, should continue to support a risk of a
transient tornado as cells interact with the warm front. However,
increasing rain and storms from the west will likely disrupt storm
mode later this evening, with the main forcing for ascent with the
upper trough also lifting away from the area.

..Jewell.. 01/02/2017

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

ATTN...WFO...FFC...TAE...BMX...MOB...

LAT...LON   29738547 30118588 30298658 30238727 30178770 30288775
            30688747 31608686 32518625 32858537 32658447 32458327
            32008294 31558325 31038387 29738547

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 2, 7:08 AM CSTMesoscale DiscussionSPCBibb, Choctaw, Greene, Hale, Marengo, Perry and 3 more97 min
Jan 2, 10:17 AM CSTMesoscale DiscussionSPCBaldwin, Clarke, Mobile, Washington118 min
Jan 2, 11:22 AM CSTTornado WatchSPCBaldwin, Butler, Choctaw, Clarke, Conecuh, Covington and 8 more9 hr
Jan 2, 12:59 PM CSTMesoscale DiscussionSPCAutauga, Barbour, Bullock, Butler, Chambers, Chilton and 17 more2 hr
Jan 2, 2:03 PM CSTMesoscale DiscussionSPCBaldwin, Butler, Choctaw, Clarke, Coffee, Conecuh and 10 more117 min
Jan 2, 3:46 PM CSTTornado WatchSPCBarbour, Bullock, Coffee, Dale, Geneva, Henry and 3 more8 hr

Nearby

Mesoscale Discussions in Georgia, 2017Mesoscale Discussions in Alabama, 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.