Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 251831
SWOMCD
SPC MCD 251830
MOZ000-ARZ000-OKZ000-252030-

MESOSCALE DISCUSSION 0139
NWS STORM PREDICTION CENTER NORMAN OK
0130 PM CDT WED MAR 25 2015

AREAS AFFECTED...PORTIONS OF SRN MO AND NRN AR

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 251830Z - 252030Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...THE RISK FOR SEVERE THUNDERSTORMS WITH LARGE
HAIL...DAMAGING WINDS...AND POSSIBLY ONE OR TWO TORNADOES WILL
INCREASE DURING THE NEXT FEW HOURS. A WW WILL LIKELY BE REQUIRED.

DISCUSSION...RECENT SFC OBSERVATIONS INDICATE THE NWD RETURN OF
MODESTLY RICH LOW-LEVEL MOISTURE...WITH SFC DEWPOINTS IN THE MIDDLE
50S EXTENDING AS FAR N AS PARTS OF N-CNTRL AND NW AR. SIMILAR
MOISTURE WILL CONTINUE TO ADVANCE NWD ACROSS THE OZARKS AND VICINITY
INTO THE EVENING HOURS...AHEAD OF A TIGHTENING BAROCLINIC ZONE TO
THE NW/N. THIS BAROCLINIC ZONE...AND RELATED SFC FRONT...WILL
ADVANCE SEWD/SWD ACROSS THE DISCUSSION AREA INTO THE EVENING HOURS.
IN THE MEANTIME...ONGOING CINH -- EVIDENT IN BILLOWS AND STANDING
WAVE CLOUD FORMATIONS PER VIS IMAGERY -- WILL CONTINUE TO ERODE WITH
INSOLATION-SUPPORTED DIABATIC SFC HEATING. FURTHERMORE...LARGE-SCALE
ASCENT ATTENDANT TO AN UPSTREAM SHORTWAVE TROUGH CROSSING WRN OK AND
WRN N TX WILL AFFECT THE REGION BY LATE AFTERNOON...WHILE
DIFFERENTIAL HEATING ON THE SRN FRINGES OF ELEVATED CONVECTION
ACROSS SWRN MO LOCALLY ENHANCES BAROCLINICITY.

AS A RESULT OF THESE FACTORS...SFC-BASED CONVECTION WILL LIKELY
DEVELOP ACROSS THE REGION IN THE 20Z-22Z TIME FRAME -- MAINLY ACROSS
PARTS OF SRN MO -- AND SPREAD EWD/ESEWD. STORMS DEVELOPING FARTHER W
ACROSS OK WILL MOVE INTO AND ACROSS AR LATE THIS AFTERNOON INTO THE
EVENING.

WITH H7-H5 LAPSE RATES AROUND 8.0-8.5 C/KM ABOVE THE AFOREMENTIONED
MOISTURE...MLCAPE AROUND 1000-2500 J/KG WILL EXIST S OF THE SFC
FRONT. GIVEN 45-60 KT OF EFFECTIVE BULK SHEAR...WITH VECTORS
ORIENTED WITH A SUBSTANTIAL FRONT/BOUNDARY-PARALLEL
COMPONENT...INTENSE CONVECTION WILL LIKELY EVOLVE INTO BOWING/LEWP
SEGMENTS WITH LARGE HAIL AND DAMAGING WINDS. SOME TORNADO POTENTIAL
CANNOT BE RULED OUT...ESPECIALLY IF ANY SUPERCELLS ARE SUSTAINED
PROVIDED BACKED SFC FLOW ENHANCING LOW-LEVEL SRH. HOWEVER...OVERALL
CONFIDENCE IN A PROLONGED TORNADO RISK MAY BE MITIGATED BY
/1/ POTENTIALLY UNFAVORABLE CONVECTIVE MODE.../2/ LACK OF MORE
ROBUST BOUNDARY-LAYER MOISTURE RETURN...AND /3/ UNDERCUTTING NATURE
OF THE CONVECTIVELY AUGMENTED SYNOPTIC FRONT.

A MESOSCALE DISCUSSION FOR AREAS W OF THIS REGION IS FORTHCOMING
SHORTLY.

..COHEN/BUNTING.. 03/25/2015

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

ATTN...WFO...LZK...SGF...TSA...

LAT...LON   36939464 37259337 36989170 35609153 35139282 35369427
            35949452 36939464



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