Alert archive / Alabama / Mesoscale Discussions in 2016

Mesoscale Discussion 39

January 21, 20164 states

The Storm Prediction Center issued this mesoscale discussion at Jan 21, 2016, 8:38 PM CST for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jan 21, 2016, 8:38 PM CST (02:38 UTC)
Expired
Jan 21, 2016, 10:45 PM CST
In force
2 hr
Issued by
the Storm Prediction Center
All 24 counties

Baldwin County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Escambia County, AL, Geneva 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, Jefferson Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Perry County, MS, Stone County, MS

The radar

The Mobile radar (KMOB), 27 km from the middle of the area, began a volume at 02:38 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 nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 2.6 hours before the alert went out and 169 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 2016-01-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 390 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 2016-01-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 305 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
390 J/kg
Mixed-layer CIN
-43 J/kg
Mixed-layer LCL
738 m above ground
0-6 km bulk shear
70 kt
0-1 km storm-relative helicity
305 m²/s²
0-3 km storm-relative helicity
332 m²/s²
Significant tornado parameter
0.8
Supercell composite
4.5

Open this sounding in Storm Lab

The text

As transmitted.

862 
ACUS11 KWNS 220239
SWOMCD
SPC MCD 220238 
FLZ000-ALZ000-MSZ000-LAZ000-220445-

MESOSCALE DISCUSSION 0039
NWS STORM PREDICTION CENTER NORMAN OK
0838 PM CST THU JAN 21 2016

AREAS AFFECTED...PORTIONS OF SOUTHEASTERN LA...SOUTHEASTERN MS...SRN
AL..AND THE WRN FL PANHANDLE

CONCERNING...TORNADO WATCH 7...

VALID 220238Z - 220445Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 7 CONTINUES.

SUMMARY...THE THREAT FOR TORNADOES AND A FEW DAMAGING WIND GUSTS
WILL CONTINUE TO SHIFT EAST ACROSS WW 7 THIS EVENING...WITH THE
THREAT LIKELY MAXIMIZED ACROSS SOUTHEASTERN PORTIONS OF THE WATCH
OVERNIGHT.

DISCUSSION...AS THE MID/UPPER-LEVEL CYCLONE CONTINUES TO MATURE THIS
EVENING NEAR THE SABINE VALLEY...THE LOW-LEVEL MASS RESPONSE TO THE
EAST FEATURES INCREASING SLY FLOW AND MODEST NWD TRANSPORT OF RICHER
MOISTURE ONSHORE THE CNTRL GULF COAST. ADDITIONALLY...LOCAL VWP DATA
SUGGEST THIS RESPONSE IS SUPPORTING 0-1 KM SRH UPWARDS OF 300 M2/S2.
WHILE BUOYANCY DECREASES SOMEWHAT WITH EASTERN EXTENT /THUS REDUCING
THE HAIL THREAT SOME THIS EVENING/...STRENGTHENING FLOW AND A MODEST
INCREASE IN LOW-LEVEL MOISTURE WILL CONTINUE TO FAVOR UPDRAFT
ROTATION IN CELLS MOVING ONSHORE...AS WELL AS WITHIN THE LINE
APPROACHING FROM THE WEST. THE THREAT MAY BE PARTICULARLY MAXIMIZED
OVER THE NEXT FEW HOURS ACROSS SRN AL AND THE WRN FL
PANHANDLE...WHERE STRONG 850-700 MB FLOW WILL OVERLAP A MAXIMUM IN
LOW/MID-LEVEL BUOYANCY.

..PICCA.. 01/22/2016

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...TAE...MOB...JAN...LIX...

LAT...LON   31338902 31698716 31588600 31358582 30348579 29048920
            29068956 29519024 31338902

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 21, 6:53 PM CSTTornado WatchSPCAutauga, Baldwin, Butler, Choctaw, Clarke, Coffee and 21 more10 hr
Jan 21, 11:33 PM CSTMesoscale DiscussionSPCConecuh, Escambia57 min
Jan 22, 1:56 AM CSTMesoscale DiscussionSPCCoffee, Dale, Geneva, Henry, Houston2 hr
Jan 22, 4:51 AM CSTMesoscale DiscussionSPCFranklin, Gadsden, Jefferson, Leon, Liberty, Madison and 2 more84 min
Jan 22, 7:37 AM CSTMesoscale DiscussionSPCBroward, Charlotte, Citrus, Collier, DeSoto, Hardee and 13 more2 hr
Jan 22, 8:49 AM CSTSevere Thunderstorm WatchSPCBrevard, Charlotte, Citrus, DeSoto, Flagler, Hardee and 21 more5 hr
Jan 22, 12:16 PM CSTMesoscale DiscussionSPCBrevard, Charlotte, DeSoto, Hardee, Highlands, Hillsborough and 13 more119 min
Jan 21, 6:05 PM CSTMesoscale DiscussionSPCMorehouse6 hr
Jan 22, 3:58 AM CSTMesoscale DiscussionSPCAttala, Benton, Bolivar, Calhoun, Carroll, Chickasaw and 25 more5 hr

Nearby

Mesoscale Discussions in Alabama, 2016Mesoscale Discussions in Mississippi, 2016Mesoscale Discussions in Florida, 2016Every mesoscale discussion in 2016

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.