MESO: Mesoscale Discussion 1797

ACUS11 KWNS 292035
SWOMCD
SPC MCD 292034
MTZ000-IDZ000-292130-

MESOSCALE DISCUSSION 1797
NWS STORM PREDICTION CENTER NORMAN OK
0334 PM CDT THU AUG 29 2013

AREAS AFFECTED...ID PANHANDLE...NWRN MT

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 292034Z - 292130Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...THE POTENTIAL FOR A FEW STRONG-SVR WIND GUSTS WILL
INCREASE THIS AFTERNOON AS TSTMS DEVELOP ACROSS THE ID PANHANDLE
INTO NWRN MT. A WW IS NOT EXPECTED ATTM...BUT CONVECTIVE TRENDS WILL
CONTINUE TO BE MONITORED.

DISCUSSION...A BAND OF ASCENT ACCOMPANYING A SHORTWAVE UPPER TROUGH
MOVING THROUGH CNTRL ORE/WA IS AIDING IN THE DEVELOPMENT OF A BROKEN
LINE OF SHOWER/TSTMS NEAR THE ID/WA BORDER. SFC TEMPERATURES HAVE
HEATED INTO THE 70S AND 80S E OF THIS AREA...AMIDST DEWPOINTS IN THE
50S...RESULTING IN MLCAPE VALUES GENERALLY RANGING BETWEEN 500-1000
J/KG. MEANWHILE...20Z SUBJECTIVE SFC ANALYSIS SHOWS A DEVELOPING
COLD FRONT ACROSS ERN WA...WHICH IS FORECAST TO ACCELERATE EWD THIS
AFTERNOON IN TANDEM WITH THE EJECTING SHORTWAVE.

INCREASING LOW-LEVEL CONVERGENCE ALONG THE FRONT SHOULD FOCUS
CONVECTIVE DEVELOPMENT INTO A BROKEN LINE THROUGH THE NEXT 2-3 HRS.
STEEP LOW-LEVEL LAPSE RATES AND EFFECTIVE SHEAR VALUES OF 30-40 KTS
WILL SUPPORT LINE SEGMENTS CAPABLE OF PRODUCING STRONG-SVR WIND
GUSTS. BRIEF/TRANSIENT SUPERCELL STRUCTURES WILL ALSO BE POSSIBLE
WITH ANY STORM THAT CAN REMAIN DISCRETE...AND COULD POSE A THREAT
FOR SMALL TO MARGINALLY SVR HAIL. GIVEN MARGINAL INSTABILITY...THE
POTENTIAL FOR A WIDESPREAD SVR THREAT MAY BE LIMITED...WHICH
PRECLUDES THE NEED FOR A WW ATTM. HOWEVER...CONVECTIVE TRENDS
CONTINUE TO BE MONITORED.

..ROGERS/THOMPSON.. 08/29/2013

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

ATTN...WFO...TFX...MSO...OTX...

LAT...LON 45791605 47181683 48981677 48991275 49031099 47201129
46361218 45701472 45791605

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