Alert archive / Oklahoma / Mesoscale Discussions in 2015

Mesoscale Discussion 367

April 18, 201516 counties in Oklahoma; 6 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 18, 2015, 7:46 PM CDT for 16 counties in Oklahoma; 6 counties in Texas. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued: Apr 18, 2015, 7:46 PM CDT (00:46 UTC)
Expired: Apr 18, 2015, 9:15 PM CDT
In force: 89 min
Issued by: the Storm Prediction Center

All 22 counties

Beckham County, OK, Blaine County, OK, Comanche County, OK, Custer County, OK, Dewey County, OK, Ellis County, OK, Greer County, OK, Harmon County, OK, Jackson County, OK, Kiowa County, OK, Major County, OK, Roger Mills County, OK, Tillman County, OK, Washita County, OK, Woods County, OK, Woodward County, OK, Childress County, TX, Cottle County, TX, Foard County, TX, Hardeman County, TX, Wichita County, TX, Wilbarger County, TX

The radar

The Altus AFB radar (KFDR), 106 km from the middle of the area, began a volume at 00:49 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

Norman, OK (KOUN), launched 00:00Z, 0.8 hours before the alert went out and 166 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 927 J/kg
Mixed-layer CIN: -11 J/kg
Mixed-layer LCL: 1566 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 56 m²/s²
0-3 km storm-relative helicity: 72 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 2.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

948 
ACUS11 KWNS 190047
SWOMCD
SPC MCD 190046 
OKZ000-TXZ000-190215-

MESOSCALE DISCUSSION 0367
NWS STORM PREDICTION CENTER NORMAN OK
0746 PM CDT SAT APR 18 2015

AREAS AFFECTED...PORTIONS OF WRN/NRN OK...WRN NORTH TX...FAR ERN TX
PANHANDLE

CONCERNING...TORNADO WATCH 73...

VALID 190046Z - 190215Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 73 CONTINUES.

SUMMARY...THE RISK FOR SVR TSTMS CONTINUES ACROSS TORNADO WATCH 73.

DISCUSSION...WITH INCREASED CONVECTIVE COVERAGE ACROSS PORTIONS OF
WRN OK INVOF AND N OF I-40 -- INCLUDING NUMEROUS CELL
MERGERS/BOUNDARY INTERACTIONS -- THE OVERALL TORNADO POTENTIAL WILL
CONTINUE TO LESSEN ESPECIALLY WITH THE ONSET OF NOCTURNAL COOLING.
REGARDLESS...THE 00Z OUN RAOB SAMPLED H7-H5 LAPSE RATES AROUND 7.5
C/KM SUPPORTING MODERATE POTENTIAL INSTABILITY AND AROUND 30 KT OF
EFFECTIVE BULK SHEAR. AREAS WHERE CONVECTIVE OVERTURNING HAS NOT
BEEN SUBSTANTIAL MAY BE SUBJECT TO SOME SVR RISK BEYOND THE
SCHEDULED 02Z EXPIRATION TIME OF THE WW. INCREASING LARGE-SCALE
DCVA/ASCENT FROM THE W WILL CONTINUE TO MAINTAIN SUCH POTENTIAL --
MAINLY WITH SVR HAIL -- INTO THE NIGHT. IT IS POSSIBLE THAT PORTIONS
OF SEVERE THUNDERSTORM WATCH 77 COULD BE EXTENDED WWD TO ADDRESS
THIS POTENTIAL ACROSS PARTS OF WRN OK AND WRN N TX.

..COHEN.. 04/19/2015

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

ATTN...WFO...OUN...LUB...AMA...

LAT...LON   35010019 36639970 36839858 36539818 36219840 35169843
            33769849 33699978 34100033 35010019

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 18, 8:02 PM CDT	Mesoscale Discussion	SPC	Carter, Cleveland, Coal, Creek, Garvin, Hughes and 13 more	88 min
Apr 19, 12:43 PM CDT	Mesoscale Discussion	SPC	Adair, Alfalfa, Atoka, Blaine, Bryan, Caddo and 51 more	2 hr
Apr 19, 1:42 PM CDT	Severe Thunderstorm Watch	SPC	Adair, Cherokee, Choctaw, Cleveland, Craig, Creek and 32 more	6 hr
Apr 19, 2:31 PM CDT	Severe Thunderstorm Watch	SPC	McCurtain	7 hr
Apr 18, 8:24 PM CDT	Mesoscale Discussion	SPC	Anderson, Bastrop, Bell, Blanco, Brazos, Burleson and 25 more	96 min
Apr 19, 1:52 PM CDT	Mesoscale Discussion	SPC	Angelina, Austin, Bowie, Brazoria, Brazos, Burleson and 44 more	53 min
Apr 19, 4:45 PM CDT	Mesoscale Discussion	SPC	Angelina, Austin, Bastrop, Brazos, Burleson, Caldwell and 35 more	2 hr
Apr 19, 5:46 PM CDT	Tornado Watch	SPC	Angelina, Nacogdoches, Panola, Sabine, San Augustine, Shelby	6 hr
Apr 19, 6:56 PM CDT	Mesoscale Discussion	SPC	Austin, Chambers, Colorado, Fort Bend, Galveston, Harris and 5 more	64 min

Nearby

Mesoscale Discussions in Oklahoma, 2015 Mesoscale Discussions in Texas, 2015 Every mesoscale discussion in 2015

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.