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Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 180029
SWOMCD
SPC MCD 180028
SDZ000-NEZ000-NDZ000-MTZ000-WYZ000-180200-

MESOSCALE DISCUSSION 0673
NWS STORM PREDICTION CENTER NORMAN OK
0728 PM CDT FRI MAY 17 2013

AREAS AFFECTED...NE WYOMING..SE MONTANA...WRN AND CENTRAL SOUTH
DAKOTA

CONCERNING...SEVERE THUNDERSTORM WATCH 167...

VALID 180028Z - 180200Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 167
CONTINUES.

SUMMARY...TSTMS ARE EXPECTED TO PERSIST FOR THE NEXT FEW HOURS
ACROSS PORTIONS OF WRN SOUTH DAKOTA AND ERN WYOMING...WITH LARGE
HAIL AND ISOLATED DAMAGING WINDS THE PRIMARY CONCERNS.
ADDITIONALLY...A NEW WW MAY BE REQUIRED DOWNSTREAM OF WW167 ACROSS
PORTIONS OF CENTRAL SOUTH DAKOTA WITHIN THE HOUR.

DISCUSSION...AT 00 UTC...A CLUSTER OF TSTMS WAS ONGOING ACROSS
PORTIONS OF SWRN SOUTH DAKOTA AND NWRN NEBRASKA. THESE TSTMS WERE
MOVING ENE AND LOCATED IN AN ENVIRONMENT CHARACTERIZED BY DEEP-LAYER
SHEAR AOA 35 KTS AND MLCAPE VALUES AROUND 1000 J/KG. THIS
ENVIRONMENT SHOULD PERSIST THROUGH THE NEXT FEW HOURS AND SUPPORT AN
ONGOING SVR THREAT. FARTHER E...THE ENVIRONMENT APPEARS TO BE
CONDUCIVE FOR THE MAINTENANCE OF THE ONGOING TSTMS AS THEY MOVE ENE
OUT OF WW167. FURTHERMORE...RECENT RADAR TRENDS SUGGEST THE
POSSIBILITY OF A DEVELOPING MCV ACROSS BENNETT AND JACKSON COUNTIES
IN SOUTH DAKOTA WHICH SHOULD HELP MAINTAIN TSTM INTENSITY...AT LEAST
IN THE SHORT TERM. THIS WOULD SUGGEST THE NEED FOR A NEW WW
DOWNSTREAM OF WW167. THE PRIMARY CONCERN WITH ANY NEW WATCH WOULD
CONTINUE TO BE LARGE HAIL AND ISOLATED DAMAGING WIND GUSTS.

TO THE NW...ACROSS NE WYOMING AND WEST-CENTRAL SOUTH DAKOTA...TSTMS
ARE EXPECTED TO PERSIST FOR THE NEXT FEW HOURS. ALTHOUGH THE
ENVIRONMENT IS NOT AS FAVORABLE HERE AS TO THE SOUTHEAST...IT SHOULD
REMAIN CONDUCIVE FOR THE CONTINUATION OF AN ISOLATED SVR
THREAT...WITH LARGE HAIL AND ISOLATE DAMAGING WIND GUSTS THE PRIMARY
CONCERNS.

..MARSH/GUYER.. 05/18/2013

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

ATTN...WFO...FSD...ABR...BIS...LBF...UNR...CYS...BYZ...

LAT...LON   45000595 46120383 44990139 43869906 43029897 42720141
            43060305 43830530 45000595

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