Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 022322
SWOMCD
SPC MCD 022322
IAZ000-MOZ000-KSZ000-NEZ000-030015-

MESOSCALE DISCUSSION 1591
NWS STORM PREDICTION CENTER NORMAN OK
0622 PM CDT SUN AUG 02 2015

AREAS AFFECTED...SOUTHERN IOWA AND NORTHERN MISSOURI

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 022322Z - 030015Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...THUNDERSTORMS ARE DEVELOPING ALONG A COLD FRONT WITHIN A
VERY UNSTABLE ATMOSPHERE. LARGE HAIL AND DAMAGING WINDS WILL BE
POSSIBLE WITH THE STRONGEST THUNDERSTORMS. HOWEVER...THIS THREAT IS
EXPECTED TO DIMINISH AFTER THE NEXT 2-3 HOURS. AS SUCH...A WATCH IS
NOT ANTICIPATED AT THIS TIME...BUT WILL CONTINUE TO BE ASSESSED.

DISCUSSION...THUNDERSTORMS ARE DEVELOPING/STRENGTHENING...ALONG A
SLOWLY SOUTHWARD-MOVING COLD FRONT. AHEAD OF THE COLD
FRONT...SURFACE TEMPERATURES HAVE WARMED INTO THE UPPER-80S TO
LOW-90S F WITH DEW POINT TEMPERATURES IN THE LOW-T0-MID 70S F.
THIS...COUPLED WITH STEEP MID-LEVEL LAPSE RATES HAVE COMBINED TO
YIELD MUCAPE VALUES ABOVE 4000 J/KG. ADDITIONALLY...THIS AREA IS ON
THE SOUTHERN EDGE OF THE STRONGER MID-LEVEL FLOW RESULTING IN
DEEP-LAYER SHEAR VALUES ON THE ORDER OF 35 KTS. THE COMBINATION OF
CAPE AND DEEP-LAYER SHEAR IN THE PRESENCE OF CONVERGENCE ALONG THE
SURFACE-COLD FRONT WILL SUPPORT CONTINUED THUNDERSTORM DEVELOPMENT
IN THE NEAR TERM...WITH LARGE HAIL/DAMAGING WINDS POSSIBLE WITH THE
STRONGEST THUNDERSTORM CORES.

HOWEVER...CONVERGENCE ALONG THE COLD FRONT IS EXPECTED TO WEAKEN
WITH TIME...AND THE LOSS OF DAY-TIME HEATING AND LOWER SURFACE DEW
POINT TEMPERATURES TO THE SOUTH /ACROSS MISSOURI/ WILL CONTRIBUTE TO
A WEAKENING OF THE OVERALL INSTABILITY. AS SUCH...IT APPEARS THERE
MAY ONLY BE A BRIEF WINDOW OF OPPORTUNITY FOR THUNDERSTORMS TO HAVE
A SUSTAINED LARGE HAIL/DAMAGING WIND THREAT. A WATCH IS NOT
ANTICIPATED AT THIS TIME...ALTHOUGH TRENDS WILL CONTINUE TO BE
ASSESSED.

..MARSH/CORFIDI.. 08/02/2015

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

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

LAT...LON   41169762 41509674 41799335 41619202 40909148 40129165
            39879332 39889541 40339703 40629771 41169762




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