Alert archive / Arkansas / Tornado Watches in 2015

Tornado Watch 548

November 17, 20158 counties in Arkansas; 8 counties in Mississippi; Shelby County, Tipton County, Tennessee

The Storm Prediction Center issued this tornado watch at Nov 17, 2015, 3:15 PM CST for 8 counties in Arkansas; 8 counties in Mississippi; Shelby County, Tipton County, Tennessee. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Nov 17, 2015, 3:15 PM CST (21:15 UTC)
Expired
Nov 17, 2015, 7:13 PM CST
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
0.5 in
Strongest gust expected
60 kt

Counties Craighead County, AR, Crittenden County, AR, Cross County, AR, Lee County, AR, Mississippi County, AR, Phillips County, AR, Poinsett County, AR, St. Francis County, AR, Coahoma County, MS, DeSoto County, MS, Panola County, MS, Quitman County, MS, Tallahatchie County, MS, Tate County, MS, Tunica County, MS, Yalobusha County, MS, Shelby County, TN, Tipton County, TN

The radar

The Memphis radar (KNQA), 108 km from the middle of the area, began a volume at 21:15 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
10%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

2 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Nov 17, 4:53 PM CSTSevere Thunderstorm WarningMEGLee, Phillips37 min
Nov 17, 5:02 PM CSTTornado WarningMEGPhillips23 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Little Rock, AR (KBYH), launched 12:00Z, 9.3 hours before the alert went out and 67 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, Little Rock, AR at 12:00Z on 2015-11-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 344 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, Little Rock, AR at 12:00Z on 2015-11-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 403 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
344 J/kg
Mixed-layer CIN
-23 J/kg
Mixed-layer LCL
618 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
403 m²/s²
0-3 km storm-relative helicity
550 m²/s²
Significant tornado parameter
0.9
Supercell composite
8.5

Open this sounding in Storm Lab

The text

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

855 
WWUS20 KWNS 172110
SEL8  
SPC WW 172110
ARZ000-MSZ000-TNZ000-180300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 548
NWS STORM PREDICTION CENTER NORMAN OK
310 PM CST TUE NOV 17 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  NORTHEAST ARKANSAS
  NORTHWEST MISSISSIPPI
  EXTREME SOUTHWEST TENNESSEE

* EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 310 PM UNTIL
  900 PM CST.

* PRIMARY THREATS INCLUDE...
  A COUPLE TORNADOES POSSIBLE
  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

SUMMARY...A SQUALL LINE PRESENT OVER CENTRAL ARKANSAS THIS AFTERNOON
WILL PROGRESS EAST ACROSS THE WATCH AREA LATE THIS AFTERNOON AND
THIS EVENING.  WHILE DAMAGING STRAIGHT-LINE WINDS WILL BE THE
PRIMARY HAZARD...A COUPLE OF TORNADOES ARE ALSO POSSIBLE.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 50 STATUTE
MILES EAST AND WEST OF A LINE FROM 85 MILES SOUTH SOUTHWEST OF
MEMPHIS TENNESSEE TO 45 MILES NORTH NORTHWEST OF MEMPHIS
TENNESSEE.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 545...WW 546...WW 547...

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
400. MEAN STORM MOTION VECTOR 21045.


...MEAD

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Nov 17, 4:35 AM CSTMesoscale DiscussionSPCBenton, Crawford, Franklin, Howard, Johnson, Logan and 9 more115 min
Nov 17, 4:48 AM CSTTornado WatchSPCHoward, Little River, Miller, Sevier4 hr
Nov 17, 6:27 AM CSTSevere Thunderstorm WatchSPCBaxter, Benton, Boone, Carroll, Clark, Conway and 21 more6 hr
Nov 17, 8:24 AM CSTMesoscale DiscussionSPCColumbia, Lafayette66 min
Nov 17, 8:55 AM CSTTornado WatchSPCColumbia, Hempstead, Howard, Lafayette, Little River, Miller and 3 more7 hr
Nov 17, 9:59 AM CSTMesoscale DiscussionSPCArkansas, Ashley, Baxter, Boone, Bradley, Calhoun and 58 more2 hr
Nov 17, 11:07 AM CSTTornado WatchSPCArkansas, Bradley, Calhoun, Clark, Cleburne, Cleveland and 21 more6 hr
Nov 17, 12:19 PM CSTMesoscale DiscussionSPCAshley, Chicot116 min
Nov 17, 12:36 PM CSTTornado WatchSPCAshley, Chicot7 hr
Nov 17, 1:35 PM CSTMesoscale DiscussionSPCArkansas, Cleburne, Cleveland, Craighead, Crittenden, Cross and 25 more115 min
Nov 17, 3:19 PM CSTMesoscale DiscussionSPCClay, Fulton, Greene, Izard, Lawrence, Randolph and 1 more116 min
Nov 17, 5:36 PM CSTMesoscale DiscussionSPCCrittenden, Cross, Lee, Monroe, Phillips, Poinsett and 1 more84 min

Nearby

Tornado Watches in Arkansas, 2015Tornado Watches in Mississippi, 2015Tornado Watches in Tennessee, 2015Every tornado watch 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.