Mesoscale Discussion 963

Issued

Jun 17, 2016, 1:30 PM CDT (18:30 UTC)

Expired

Jun 17, 2016, 3:30 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Chance of a watch

40%

The Western Arkansas radar (KSRX), 114 km from the middle of the area, began a volume at 18:32 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.

691 
ACUS11 KWNS 171831
SWOMCD
SPC MCD 171830 
MSZ000-ARZ000-LAZ000-TXZ000-OKZ000-172030-

MESOSCALE DISCUSSION 0963
NWS STORM PREDICTION CENTER NORMAN OK
0130 PM CDT FRI JUN 17 2016

AREAS AFFECTED...SWRN HALF OF AR / ERN OK / NERN LA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 171830Z - 172030Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...ISOLATED TO SCATTERED THUNDERSTORMS ARE FORECAST TO
DEVELOP LATER  THIS AFTERNOON.  A THREAT FOR ISOLATED DAMAGING WINDS
AND SEVERE HAIL WILL PROBABLY ACCOMPANY THE STRONGER STORMS.  THE
PROBABILITY FOR A SEVERE THUNDERSTORM WATCH APPEARS GREATEST OVER
SERN AR AND ADJACENT PORTIONS OF SRN AR AND NERN LA /50
PERCENT/...WHILE A LOWER PROBABILITY SEEMINGLY EXISTS FARTHER W INTO
ERN OK /20 PERCENT/.

DISCUSSION...VISIBLE SATELLITE IMAGERY SHOWS CU FIELD DEVELOPING
OVER SERN AR EXTENDING WNWWD INTO THE OUACHITA MTNS IN SWRN AR AND
SERN OK.  THIS AREA IS LOCATED ALONG AND TO THE S OF A PRE-FRONTAL
WIND SHIFT LOCATED FROM NRN MS WWD INTO CNTRL AR AND ARCING NWWD
INTO THE BOSTON MTNS.  A MCV OVER N-CNTRL AR WILL LIKELY CONTINUE TO
DRIFT SWD INTO CNTRL AR THROUGH THE LATE AFTERNOON.

SURFACE OBSERVATIONS SHOW TEMPS HAVE WARM INTO THE LOWER 90S DEG F
WITH DEWPOINTS IN THE LOWER-MID 70S.  MODIFYING THE 12Z LZK RAOB FOR
18Z SURFACE CONDITIONS S OF THE PRE-FRONTAL WIND SHIFT...YIELDS
AROUND 3200 J/KG MLCAPE.  GENERALLY WEAK SHEAR WILL LIMIT STORM
ORGANIZATION TO A MULTICELLULAR PULSE-LIKE MODE...YET THE VERY
UNSTABLE AIRMASS WILL PROMOTE VIGOROUS SHORT-LIVED UPDRAFT PULSES. 
LIKEWISE...CONSIDERABLE WATER-LOADING IS FORECAST GIVEN LOWEST
100-MB MEAN MIXING RATIOS AROUND 16-17 G/KG AND PW IN EXCESS OF 1.5
INCHES.  THE 12Z LZK RAOB ALSO EXHIBITED A RELATIVELY DRY LAYER
/H85-H7/ WHICH MAY YIELD SOME EVAPORATIVE POTENTIAL.

NEEDLESS TO SAY...ISOLATED TO SCATTERED STORMS ARE FORECAST TO
DEVELOP AND FOCUS ALONG THE PRE-FRONTAL BOUNDARY AND NEAR STRONGER
TERRAIN-INDUCED CIRCULATIONS OVER THE SWRN AR/ERN OK VICINITY. 
STRONG TO SEVERE MULTICELLS CAPABLE OF AN ISOLATED WIND-DAMAGE AND
SEVERE-HAIL THREAT WILL PROBABLY ACCOMPANY THE STRONGER CORES.

..SMITH/GUYER.. 06/17/2016

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

ATTN...WFO...MEG...JAN...LZK...SHV...TSA...

LAT...LON   33729484 35629532 36159448 35799380 35009293 34389073
            31949119 33729484

Mesoscale Discussions in Arkansas, 2016Mesoscale Discussions in Louisiana, 2016Mesoscale Discussions in Oklahoma, 2016Every mesoscale discussion in 2016

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.