Severe Storm Outlook Narrative (AC)
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939
ACUS11 KWNS 171920
SWOMCD
SPC MCD 171920
WIZ000-MIZ000-IAZ000-MNZ000-172115-

MESOSCALE DISCUSSION 0687
NWS STORM PREDICTION CENTER NORMAN OK
0220 PM CDT SUN MAY 17 2015

AREAS AFFECTED...WI

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 171920Z - 172115Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...SHOWERS AND OCCASIONAL TSTMS ARE EXPECTED TO CONTINUE
ACROSS THE REGION. SOME ISOLATED GUSTY WINDS AND HAIL ARE POSSIBLE
BUT THE MARGINAL NATURE OF THE TREAT IS EXPECTED TO PRECLUDE THE
NEED FOR A WW.

DISCUSSION...REGIONAL RADAR IMAGERY HAS SHOWN A GENERAL INCREASE IN
CONVECTIVE ACTIVITY ACROSS MUCH OF WI. MUCH OF THIS ACTIVITY LACKS
LIGHTNING WITH THE WARM LAYER ALOFT AND WEAK LAPSE RATES SAMPLED BY
THE 18Z DVN SOUNDING LIKELY LIMITING INSTABILITY AND KEEPING EL
TEMPS TOO WARM. OVERALL KINEMATIC ENVIRONMENT IS SUPPORTIVE OF A
SEVERE WEATHER THREAT WITH 18Z DVN SOUNDING REPORTING OVER 40 KT OF
EFFECTIVE BULK SHEAR AND 0-1 KM SRH OVER 100 M2/S2. RECENT VAD DATA
FROM ARX AND GRB ALSO REPORT SIMILAR SRH VALUES. HOWEVER...DESPITE
DECENT LOW-LEVEL MOISTURE /DEWPOINTS IN THE MID 60S/...INSTABILITY
IS EXPECTED TO REMAIN WEAK AS A RESULT OF PREVIOUSLY MENTIONED POOR
LAPSE RATES. SURFACE-BASED INSTABILITY IS EXPECTED TO REMAIN BELOW
1000 J PER KG. GIVEN THE STRENGTH OF THE WIND FIELDS SOME SEVERE IS
POSSIBLE BUT THE LACK OF THERMODYNAMIC SUPPORT WILL LIKELY KEEP ANY
SEVERE THREAT ISOLATED. TRENDS ACROSS THE REGION WILL BE MONITORED
BUT A WW IS CURRENTLY CONSIDERED UNLIKELY.

..MOSIER/THOMPSON.. 05/17/2015

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

ATTN...WFO...MQT...GRB...MKX...DLH...ARX...MPX...

LAT...LON   46029213 46259144 46228919 45528836 43958795 43058843
            42969084 43739156 44129179 45069260 46029213




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