Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 281812
SWOMCD
SPC MCD 281812
ILZ000-IAZ000-MOZ000-KSZ000-NEZ000-282045-

MESOSCALE DISCUSSION 1629
NWS STORM PREDICTION CENTER NORMAN OK
0112 PM CDT THU AUG 28 2014

AREAS AFFECTED...PORTIONS OF SRN IA...WRN IL...NRN MO...NERN
KS...FAR SERN NEB

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 281812Z - 282045Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...THE AREA IS BEING MONITORED FOR MARGINAL SVR-TSTM
POTENTIAL THROUGH THE AFTERNOON. WHILE CONVECTIVE TRENDS WILL
CONTINUE TO BE MONITORED...WW ISSUANCE IS CURRENTLY UNLIKELY.

DISCUSSION...SFC MESOANALYSIS INDICATES A STATIONARY BOUNDARY
BISECTING IA FROM NW TO SE THAT EXTENDS FARTHER SE TO THE LOWER OHIO
VALLEY. BROAD...MODEST ISENTROPIC ASCENT IS MAINTAINING
CLOUDS...SHOWERS...AND THUNDERSTORMS ON EITHER SIDE OF THIS
BOUNDARY. THIS HAS GIVEN RISE TO A WAVY DIFFERENTIAL HEATING
BOUNDARY ANALYZED ACROSS NRN MO INTO NERN KS. SFC WIND FIELDS
SUGGEST THAT CONVERGENCE ALONG EITHER OF THESE BOUNDARIES IS WEAK.
HOWEVER...DIURNALLY DEEPENING PBL CIRCULATIONS COUPLED WITH
STRENGTHENING BAROCLINICITY INVOF THE DIFFERENTIAL HEATING BOUNDARY
WILL LIKELY FOSTER AN INCREASE IN CONVECTIVE COVERAGE AND INTENSITY
DURING THE NEXT FEW HOURS...AS LOW-LEVEL WAA PERSISTS -- ESPECIALLY
NEAR/ON THE COOLER SIDE OF THE DIFFERENTIAL HEATING BOUNDARY.

STRONG HEATING OF RICH BOUNDARY-LAYER MOISTURE CONTINUES ON THE WARM
SIDE OF THIS BOUNDARY...SUPPORTING 1000-2000 J/KG OF MLCAPE.
HOWEVER...VWP DATA SUGGEST THAT ANY SUBSTANTIVE DEEP-LAYER SHEAR
CAPABLE OF SUPPORTING MORE ORGANIZED/SUSTAINED STORMS EXISTS ON THE
COLD SIDE OF THIS BOUNDARY WHERE INSTABILITY IS MORE MARGINAL.
NEVERTHELESS...THE OVERLAP OF BUOYANCY/VERTICAL SHEAR MAY BE
SUFFICIENT ACROSS THE MCD AREA TO SUPPORT A FEW MULTICELL CLUSTERS
WITH LOCALLY DMGG WIND GUSTS AND PERHAPS MARGINALLY SVR HAIL. A
BRIEF/TRANSIENT SUPERCELL OR TWO MAY ALSO OCCUR WHERE SFC WINDS ARE
MORE BACKED BENEATH 25-30-KT MID-LEVEL WSWLYS SAMPLED BY THE DMX/DVN
VWPS N OF THE DIFFERENTIAL HEATING BOUNDARY. SUCH ACTIVITY COULD
PRODUCE A WEAK TORNADO. HOWEVER...WITHOUT GREATER COVERAGE OF
FAVORABLE JUXTAPOSITION OF STRONGER BUOYANCY/SHEAR FOR SVR
THUNDERSTORMS...THE OVERALL SVR POTENTIAL SHOULD REMAIN LIMITED.

..COHEN/MEAD.. 08/28/2014

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

ATTN...WFO...LSX...DVN...DMX...EAX...OAX...TOP...

LAT...LON   41679144 41599047 40569061 39989141 39579266 39029586
            39219631 40069564 41109370 41679144



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