Severe Storm Outlook Narrative (AC)
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
ACUS11 KWNS 301810
SWOMCD
SPC MCD 301809
MSZ000-LAZ000-ARZ000-302045-

MESOSCALE DISCUSSION 1245
NWS STORM PREDICTION CENTER NORMAN OK
0109 PM CDT TUE JUN 30 2015

AREAS AFFECTED...PORTIONS OF NRN/ERN LA...CNTRL/SRN/WRN MS...FAR SRN
AR

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 301809Z - 302045Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...THE AREA IS BEING MONITORED FOR AN INCREASING RISK OF
SEVERE THUNDERSTORMS AND POSSIBLE WW ISSUANCE.

DISCUSSION...AN OUTFLOW BOUNDARY FROM EARLIER CONVECTION ARCS FROM
FAR SERN AR TO S-CNTRL MS...INTERSECTING A DIFFUSE FRONTAL ZONE
DRAPED W/E NEAR THE LA/AR BORDER. THE EFFECTIVE TRIPLE POINT IS VERY
NEAR WEST CARROLL PARISH LA...WHERE ENHANCED MESOSCALE CONVERGENCE
IS FOSTERING TOWERING CUMULUS. OTHER CUMULUS BUILD-UPS ARE EVIDENT
NEAR THE FRONTAL ZONE AND ALONG THE OUTFLOW BOUNDARY. THE AIR MASS
IS BECOMING STRONGLY UNSTABLE IN THE NON-CONVECTIVELY-PERTURBED AIR
S OF THE FRONTAL ZONE...WITH DIABATIC SFC HEATING AMIDST DEWPOINTS
IN THE LOWER/MIDDLE 70S SUPPORTING 2500-3500 J/KG OF MLCAPE.
THUNDERSTORMS WILL LIKELY BLOSSOM ACROSS THE REGION IN THE NEXT FEW
HOURS -- INITIATING NEAR THE FRONT AND OUTFLOW BOUNDARY -- AND
BECOME INTENSE OWING TO THE STRONG BUOYANCY. SHV AND JAN VWPS
SUGGEST THAT THE STRONGER VERTICAL SHEAR IS DISPLACED E OF THE
STRONGEST BUOYANCY. HOWEVER...THE STRONG BUOYANCY WILL STILL SUPPORT
INTENSE UPDRAFT MASS FLUXES...WITH CORRESPONDING RISKS FOR DMGG WIND
GUSTS AND SVR HAIL. THE DMGG-WIND RISK WOULD LOCALLY INCREASE WHERE
COLD POOLS AMALGAMATE YIELDING UPSCALE CONVECTIVE GROWTH. THIS
ACTIVITY MAY SPREAD E INTO THE MODIFYING COLD POOL IN MS...WHERE
DEEP SHEAR WILL BE SLIGHTLY ENHANCED -- PERHAPS FACILITATING MORE
ORGANIZED/FORWARD-PROPAGATING CONVECTIVE CLUSTERS.

..COHEN/HART.. 06/30/2015

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

ATTN...WFO...JAN...LIX...LCH...SHV...

LAT...LON   31959004 31319026 31129118 31289289 32149389 33039367
            33119214 32949090 31959004




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.